1
|
Duan Z, Li X, Li S, Zhou H, Hu L, Xia H, Xie L, Xie F. Nosocomial surveillance of multidrug-resistant Acinetobacter baumannii: a genomic epidemiological study. Microbiol Spectr 2024; 12:e0220723. [PMID: 38197661 PMCID: PMC10846281 DOI: 10.1128/spectrum.02207-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 12/14/2023] [Indexed: 01/11/2024] Open
Abstract
Acinetobacter baumannii is a major opportunistic pathogen causing hospital-acquired infections, and it is imperative to comprehend its evolutionary and epidemiological dynamics in hospitals to prevent and control nosocomial transmission. Here, we present a comprehensive genomic epidemiological study involving the genomic sequencing and antibiotic resistance profiling of 634 A. baumannii strains isolated from seven intensive care units (ICUs) of a Chinese general hospital over 2 consecutive years. Our study reveals that ST2 is highly dominant (90.54%) in the ICUs, with 98.90% of the ST2 exhibiting multidrug resistant or extensively drug resistant. Phylogenetic analyses of newly sequenced genomes and public data suggest that nosocomial isolates originated outside the hospital but evolved inside. The major lineages appear to be stable, with 9 of the 28 identified nosocomial epidemic clones infecting over 60% of the affected patients. However, outbreaks of two highly evolved clones have been observed in different hospitals, suggesting significant inter-hospital transmission chains. By coupling patient medical records and genomic divergence of the ST2, we found that cross-ward patient transfer played a crucial role in pathogen's nosocomial transmission. Additionally, we identified 831 potential adaptive evolutionary loci and 44 associated genes by grouping and comparing the genomes of clones with different prevalence. Overall, our study provides a comprehensive and contemporary survey on the epidemiology and genomic evolution of A. baumannii in a large Chinese general hospital. These findings shed light on the nosocomial evolution and transmission of A. baumannii and offers valuable information for transmission prevention and antibiotic therapy.IMPORTANCEThis study delved into the genomic evolution and transmission of nosocomial Acinetobacter baumannii on a large scale, spanning both an extended time period and the largest sample size to date. Through molecular epidemiological investigations based on genomics, we can directly trace the origin of the pathogen, detecting and monitoring outbreaks of infectious diseases in a timely manner, and ensuring public health safety. In addition, this study also collects a large amount of genomic and antibiotic resistance detection data, which is helpful for phenotype prediction based on genomic sequencing. It enables patients to receive personalized antibiotic treatment quickly, helps doctors select antibiotics more accurately, and contributes to reducing the use of antibiotics and lowering the risk of antibiotic resistance development.
Collapse
Affiliation(s)
- Zhimei Duan
- College of Pulmonary and Critical Care Medicine, Chinese PLA General Hospital, Beijing, China
| | - Xuming Li
- Department of Scientific Affairs, Hugobiotech Co., Ltd., Beijing, China
| | - Song Li
- Department of Scientific Affairs, Hugobiotech Co., Ltd., Beijing, China
| | - Hui Zhou
- Department of Scientific Affairs, Hugobiotech Co., Ltd., Beijing, China
| | - Long Hu
- Department of Scientific Affairs, Hugobiotech Co., Ltd., Beijing, China
| | - Han Xia
- Department of Scientific Affairs, Hugobiotech Co., Ltd., Beijing, China
| | - Lixin Xie
- College of Pulmonary and Critical Care Medicine, Chinese PLA General Hospital, Beijing, China
| | - Fei Xie
- College of Pulmonary and Critical Care Medicine, Chinese PLA General Hospital, Beijing, China
| |
Collapse
|
2
|
Ilyas M, Purkait D, Atmakuri K. Genomic islands and their role in fitness traits of two key sepsis-causing bacterial pathogens. Brief Funct Genomics 2024; 23:55-68. [PMID: 36528816 DOI: 10.1093/bfgp/elac051] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/03/2022] [Accepted: 11/11/2022] [Indexed: 01/21/2024] Open
Abstract
To survive and establish a niche for themselves, bacteria constantly evolve. Toward that, they not only insert point mutations and promote illegitimate recombinations within their genomes but also insert pieces of 'foreign' deoxyribonucleic acid, which are commonly referred to as 'genomic islands' (GEIs). The GEIs come in several forms, structures and types, often providing a fitness advantage to the harboring bacterium. In pathogenic bacteria, some GEIs may enhance virulence, thus altering disease burden, morbidity and mortality. Hence, delineating (i) the GEIs framework, (ii) their encoded functions, (iii) the triggers that help them move, (iv) the mechanisms they exploit to move among bacteria and (v) identification of their natural reservoirs will aid in superior tackling of several bacterial diseases, including sepsis. Given the vast array of comparative genomics data, in this short review, we provide an overview of the GEIs, their types and the compositions therein, especially highlighting GEIs harbored by two important pathogens, viz. Acinetobacter baumannii and Klebsiella pneumoniae, which prominently trigger sepsis in low- and middle-income countries. Our efforts help shed some light on the challenges these pathogens pose when equipped with GEIs. We hope that this review will provoke intense research into understanding GEIs, the cues that drive their mobility across bacteria and the ways and means to prevent their transfer, especially across pathogenic bacteria.
Collapse
Affiliation(s)
- Mohd Ilyas
- Bacterial Pathogenesis Lab, Infection and Immunity Group, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana 121001, India
| | - Dyuti Purkait
- Bacterial Pathogenesis Lab, Infection and Immunity Group, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana 121001, India
| | - Krishnamohan Atmakuri
- Bacterial Pathogenesis Lab, Infection and Immunity Group, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana 121001, India
| |
Collapse
|
3
|
Ambrose SJ, Hall RM. Variation in the plasmid backbone and dif module content of R3-T33 Acinetobacter plasmids. Plasmid 2024; 129-130:102722. [PMID: 38631562 DOI: 10.1016/j.plasmid.2024.102722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 04/08/2024] [Accepted: 04/13/2024] [Indexed: 04/19/2024]
Abstract
The predominant type of plasmids found in Acinetobacter species encode a Rep_3 initiation protein and many of these carry their accessory genes in dif modules. Here, available sequences of the 14 members of the group of Rep_3 plasmids typed as R3-T33, using a threshold of 95% identity in the repA gene, were compiled and compared. These plasmids were from various Acinetobacter species. The pdif sites were identified allowing the backbone and dif modules to be defined. As for other Rep_3 plasmids carrying dif modules, orfX encoding a protein of unknown function was found downstream of repA followed by a pdif site in the orientation XerC binding site-spacer-XerD binding site. Most backbones (n = 12) also included mobA and mobC genes but the two plasmids with the most diverged repA and orfX genes had different backbone contents. Although the gene content of the plasmid backbone was largely conserved, extensive recombinational exchange was detected and only two small groups carried identical or nearly identical backbones. Individual plasmids were associated with 1 to 13 dif modules. Many different dif modules were identified, including ones containing antibiotic or chromate resistance genes and several toxin/antitoxin gene pairs. In some cases, modules carrying the same genes were significantly diverged. Generally, the orientation of the pdif sites alternated such that C modules (XerC binding sites internal) alternated with D modules (XerD binding sites internal). However, fusions of two dif modules via mutational inactivation or loss of a pdif site were also detected.
Collapse
Affiliation(s)
- Stephanie J Ambrose
- School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia.
| | - Ruth M Hall
- School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia
| |
Collapse
|
4
|
Patel KD, Gulick AM. Structural and functional insights into δ-poly-L-ornithine polymer biosynthesis from Acinetobacter baumannii. Commun Biol 2023; 6:982. [PMID: 37752201 PMCID: PMC10522769 DOI: 10.1038/s42003-023-05362-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 09/15/2023] [Indexed: 09/28/2023] Open
Abstract
Cationic homo-polyamino acid (CHPA) peptides containing isopeptide bonds of diamino acids have been identified from Actinomycetes strains. However, none has been reported from other bacteria. Here, we report a δ-poly-L-ornithine synthetase from Acinetobacter baumannii, which we name PosA. Surprisingly, structural analysis of the adenylation domain and biochemical assay shows L-ornithine as the substrate for PosA. The product from the enzymatic reaction was purified and identified as poly-L-ornithine composed of 7-12 amino acid units. Chemical labeling of the polymer confirmed the isopeptide linkage of δ-poly-L-ornithine. We examine the biological activity of chemically synthesized 12-mer δ-poly-L-ornithine, illustrating that the polymer may act as an anti-fungal agent. Structures of the isolated adenylation domain from PosA are presented with several diamino acids and biochemical assays identify important substrate binding residues. Structurally-guided genome-mining led to the identification of homologs with different substrate binding residues that could activate additional substrates. A homolog from Bdellovibrionales sp. shows modest activity with L-arginine but not with any diamino acids observed to be substrates for previously examined CHPA synthetases. Our study indicates the possibility that additional CHPAs may be produced by various microbes, supporting the further exploration of uncharacterized natural products.
Collapse
Affiliation(s)
- Ketan D Patel
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, SUNY, Buffalo, NY, 14203, USA
| | - Andrew M Gulick
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, SUNY, Buffalo, NY, 14203, USA.
| |
Collapse
|
5
|
Ambrose SJ, Hamidian M, Hall RM. The extensively antibiotic resistant ST111 Acinetobacter baumannii isolate RBH2 carries an extensive mobile element complement of plasmids, transposons and insertion sequences. Plasmid 2023; 128:102707. [PMID: 37678515 DOI: 10.1016/j.plasmid.2023.102707] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 08/31/2023] [Accepted: 09/04/2023] [Indexed: 09/09/2023]
Abstract
The complete genome of RBH2, a sporadic, carbapenem resistant ST111 Acinetobacter baumannii isolate from Brisbane, Australia was determined and analysed. RBH2 is extensively resistant and the chromosome includes two transposons carrying antibiotic resistance genes, AbaR4 (oxa23 in Tn2006) and Tn7::Tn2006 (dfrA1, sat2, aadA1, oxa23). The chromosome also includes two copies of Tn6175, a transposon carrying putative copper resistance genes, and 1-17 copies of six different insertion sequences. RBH2 has six plasmids ranging in size from 6 kb - 141 kb, four carrying antibiotic resistance genes. Plasmids pRBH2-1 (aadB) and pRBH2-2 (aphA6 in TnaphA6) were found to be essentially identical to known plasmids pRAY*-v1 and pS21-1, respectively. The largest plasmids, pRBH2-5 (oxa23 in AbaR4) and pRBH2-6 (oxa23 in AbaR4::ISAba11 and sul2, tet(B), strA and strB in Tn6172) have known transfer-proficient relatives. pRBH2-5, an RP-T1 (RepAci6) plasmid, also carries a different putative copper resistance transposon related to Tn6177 found in pS21-2. The backbone of pRBH2-5 is related to those of previously described RepAci6 plasmids pAb-G7-2 and pA85-3 but has some distinctive features. Three different RepAci6 backbone types were distinguished, Type 1 (pAb-G7-2), Type 2 (pA85-3) and Type 3 (pRBH2-5 and pS21-2). pRBH2-6 is closely related to pAB3 and their backbones differ by only 5 SNPs. Plasmids pRBH2-3 and pRBH2-4 do not carry antibiotic resistance genes. pRBH2-3 does not include an identifiable rep gene and is a novel plasmid type. pRBH2-4 is of the R3-T3 type and includes segments of the larger pABTJ2 that heads this group. Other ST111 genomes carry different plasmids.
Collapse
Affiliation(s)
- Stephanie J Ambrose
- School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia.
| | - Mehrad Hamidian
- School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia; Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Ruth M Hall
- School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia
| |
Collapse
|
6
|
Ghafoori SM, Abdollahpour S, Shirmast P, Forwood JK. Crystallographic structure determination and analysis of a potential short-chain dehydrogenase/reductase (SDR) from multi-drug resistant Acinetobacter baumannii. PLoS One 2023; 18:e0289992. [PMID: 37616198 PMCID: PMC10449147 DOI: 10.1371/journal.pone.0289992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 07/30/2023] [Indexed: 08/26/2023] Open
Abstract
Bacterial antibiotic resistance remains an ever-increasing worldwide problem, requiring new approaches and enzyme targets. Acinetobacter baumannii is recognised as one of the most significant antibiotic-resistant bacteria, capable of carrying up to 45 different resistance genes, and new drug discovery targets for this organism is an urgent priority. Short-chain dehydrogenase/reductase enzymes are a large protein family with >60,000 members involved in numerous biosynthesis pathways. Here, we determined the structure of an SDR protein from A. baumannii and assessed the putative co-factor comparisons with previously co-crystalised enzymes and cofactors. This study provides a basis for future studies to examine these potential co-factors in vitro.
Collapse
Affiliation(s)
- Seyed Mohammad Ghafoori
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga, Wagga, NSW, Australia
| | - Soha Abdollahpour
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga, Wagga, NSW, Australia
| | - Paniz Shirmast
- Menzies Health Institute Queensland and School of Medical Sciences, Griffith University, Gold Coast, QLD, Australia
| | - Jade K. Forwood
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga, Wagga, NSW, Australia
| |
Collapse
|
7
|
Cain AK, Hamidian M. Portrait of a killer: Uncovering resistance mechanisms and global spread of Acinetobacter baumannii. PLoS Pathog 2023; 19:e1011520. [PMID: 37561719 PMCID: PMC10414682 DOI: 10.1371/journal.ppat.1011520] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023] Open
Abstract
Antibiotic resistance is a growing global concern in the field of medicine as it renders bacterial infections difficult to treat and often more severe. Acinetobacter baumannii is a gram-negative bacterial pathogen causing a wide range of infections, including pneumonia, sepsis, urinary tract infections, and wound infections. A. baumannii has emerged as a significant healthcare-associated pathogen due to its high level of antibiotic resistance. The global spread of antibiotic-resistant strains of A. baumannii has resulted in limited treatment options, leading to increased morbidity and mortality rates, especially in vulnerable populations such as the elderly and immunocompromised individuals, as well as longer hospital stays and higher healthcare costs. Further complicating the situation, multi- and pan-drug-resistant strains of A. baumannii are becoming increasingly common, and these deadly strains are resistant to all or almost all available antibiotics. A. baumannii employs various clever strategies to develop antibiotic resistance, including horizontal transfer of resistance genes, overexpression of inherent efflux pumps that remove drugs from the cell, intrinsic mutations, combined with natural selection under antibiotic selective pressure leading to emergence of successful resistance clones. The typical multidrug resistance phenotype of A. baumannii is, therefore, an orchestrated collimation of all these mechanisms combined with the worldwide spread of "global clones," rendering infections caused by this pathogen challenging to control and treat. To address the escalating problem of antibiotic resistance in A. baumannii, there is a need for increased surveillance, strict infection control measures, and the development of new treatment strategies, requiring a concerted effort by healthcare professionals, researchers, and policymakers.
Collapse
Affiliation(s)
- Amy K. Cain
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW, Australia
| | - Mehrad Hamidian
- Australian Institute of Microbiology and Infection, University of Technology Sydney, Ultimo, NSW, Australia
| |
Collapse
|
8
|
Hussain MA, Mohamed MS, Altayb HN, Mohamed AO, Ashour A, Osman W, Sherif AE, Ghazawi KF, Miski SF, Ibrahim SRM, Mohamed GA, Sindi IA, Alshamrani AA, Elgaml A. Comparative Genomic Analysis of Multi-Drug Resistant Pseudomonas aeruginosa Sequence Type 235 Isolated from Sudan. Microorganisms 2023; 11:1432. [PMID: 37374934 DOI: 10.3390/microorganisms11061432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/20/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
Pseudomonas aeruginosa (P. aeruginosa) is known to be associated with resistance to practically all known antibiotics. This is a cross-sectional, descriptive, laboratory-based analytical study in which 200 P. aeruginosa clinical isolates were involved. The DNA of the most resistant isolate was extracted and its whole genome was sequenced, assembled, annotated, and announced, strain typing was ascribed, and it was subjected to comparative genomic analysis with two susceptible strains. The rate of resistance was 77.89%, 25.13%, 21.61%, 18.09%, 5.53%, and 4.52% for piperacillin, gentamicin, ciprofloxacin, ceftazidime, meropenem, and polymyxin B, respectively. Eighteen percent (36) of the tested isolates exhibited a MDR phenotype. The most MDR strain belonged to epidemic sequence type 235. Comparative genomic analysis of the MDR strain (GenBank: MVDK00000000) with two susceptible strains revealed that the core genes were shared by the three genomes but there were accessory genes that were strain-specific, and this MDR genome had a low CG% (64.6%) content. A prophage sequence and one plasmid were detected in the MDR genome, but amazingly, it contained no resistant genes for drugs with antipseudomonal activity and there was no resistant island. In addition, 67 resistant genes were detected, 19 of them were found only in the MDR genome and 48 genes were efflux pumps, and a novel deleterious point mutation (D87G) was detected in the gyrA gene. The novel deleterious mutation in the gyrA gene (D87G) is a known position behind quinolone resistance. Our findings emphasize the importance of adoption of infection control strategies to prevent dissemination of MDR isolates.
Collapse
Affiliation(s)
- Mohamed A Hussain
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, International University of Africa, Khartoum P.O. Box 2469, Sudan
| | - Malik Suliman Mohamed
- Department of Pharmaceutics, College of Pharmacy, Jouf University, Sakaka 72388, Saudi Arabia
- Department of Pharmaceutics, Faculty of Pharmacy, University of Khartoum, Khartoum 11111, Sudan
| | - Hisham N Altayb
- Department of Biochemistry, Faculty of Sciences, King Abdulaziz University, Jeddah 23589, Saudi Arabia
| | - Ahmed Osman Mohamed
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, International University of Africa, Khartoum P.O. Box 2469, Sudan
| | - Ahmed Ashour
- Department of Pharmacognosy, Faculty of Pharmacy, Prince Sattam Bin Abdulaziz University, Alkharj 11942, Saudi Arabia
- Department of Pharmacognosy, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
| | - Wadah Osman
- Department of Pharmacognosy, Faculty of Pharmacy, Prince Sattam Bin Abdulaziz University, Alkharj 11942, Saudi Arabia
- Department of Pharmacognosy, Faculty of Pharmacy, University of Khartoum, Khartoum 11115, Sudan
| | - Asmaa E Sherif
- Department of Pharmacognosy, Faculty of Pharmacy, Prince Sattam Bin Abdulaziz University, Alkharj 11942, Saudi Arabia
- Department of Pharmacognosy, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
| | - Kholoud F Ghazawi
- Clinical Pharmacy Department, College of Pharmacy, Umm Al-Qura University, Makkah 24382, Saudi Arabia
| | - Samar F Miski
- Department of Pharmacology and Toxicology, College of Pharmacy, Taibah University, Al-Madinah Al-Munawwarah 30078, Saudi Arabia
| | - Sabrin R M Ibrahim
- Department of Chemistry, Preparatory Year Program, Batterjee Medical College, Jeddah 21442, Saudi Arabia
- Department of Pharmacognosy, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt
| | - Gamal A Mohamed
- Department of Natural Products and Alternative Medicine, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Ikhlas A Sindi
- Department of Biology, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Ahmad A Alshamrani
- Pharmaceutical Care Department, Ministry of National Guard-Health Affairs, Jeddah 22384, Saudi Arabia
| | - Abdelaziz Elgaml
- Microbiology and Immunology Department, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
- Microbiology and Immunology Department, Faculty of Pharmacy, Horus University, New Damietta 34511, Egypt
| |
Collapse
|
9
|
Pokhrel A, Li L, Short FL, Paulsen IT. A suite of modular, all-synthetic suicide vectors for allelic exchange mutagenesis in multidrug resistant Acinetobacter strains. BMC Microbiol 2023; 23:137. [PMID: 37202723 DOI: 10.1186/s12866-023-02844-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 03/31/2023] [Indexed: 05/20/2023] Open
Abstract
BACKGROUND Acinetobacter baumannii is an opportunistic human pathogen that causes a variety of infections in immunosuppressed individuals and patients in intensive care units. The success of this pathogen in nosocomial settings can be directly attributed to its persistent nature and its ability to rapidly acquire multidrug resistance. It is now considered to be one of the top priority pathogens for development of novel therapeutic approaches. Several high-throughput techniques have been utilised to identify the genetic determinants contributing to the success of A. baumannii as a global pathogen. However, targeted gene-function studies remain challenging due to the lack of appropriate genetic tools. RESULTS Here, we have constructed a series of all-synthetic allelic exchange vectors - pALFI1, pALFI2 and pALFI3 - with suitable selection markers for targeted genetic studies in highly drug resistant A. baumannii isolates. The vectors follow the Standard European Vector Architecture (SEVA) framework for easy replacement of components. This method allows for rapid plasmid construction with the mutant allele, efficient conjugational transfer using a diaminopimelic acid-dependent Escherichia coli donor strain, efficient positive selection using the suitable selection markers and finally, sucrose-dependent counter-selection to obtain double-crossovers. CONCLUSIONS We have used this method to create scar-less deletion mutants in three different strains of A. baumannii, which resulted in up to 75% deletion frequency of the targeted gene. We believe this method can be effectively used to perform genetic manipulation studies in multidrug resistant Gram-negative bacterial strains.
Collapse
Affiliation(s)
- Alaska Pokhrel
- School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Liping Li
- School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW, 2109, Australia
| | - Francesca L Short
- School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia.
- Department of Microbiology, Monash University, 19 Innovation Walk, Clayton, VIC, 3800, Australia.
| | - Ian T Paulsen
- School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia.
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW, 2109, Australia.
| |
Collapse
|
10
|
Prity FT, Tobin LA, Maharajan R, Paulsen IT, Cain AK, Hamidian M. The evolutionary tale of eight novel plasmids in a colistin-resistant environmental Acinetobacter baumannii isolate. Microb Genom 2023; 9. [PMID: 37171842 DOI: 10.1099/mgen.0.001010] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023] Open
Abstract
Acinetobacter baumannii is an important opportunistic pathogen known for its high levels of resistance to many antibiotics, particularly those considered last resorts such as colistin and carbapenems. Plasmids of this organism are increasingly associated with the spread of clinically important antibiotic resistance genes. Although A. baumannii is a ubiquitous organism, to date, most of the focus has been on studying strains recovered from clinical samples ignoring those isolated in the environment (soil, water, food, etc.). Here, we analysed the genetic structures of eight novel plasmids carried by an environmental colistin-resistant A. baumannii (strain E-072658) recovered in a recycled fibre pulp in a paper mill in Finland. It was shown that E-072658 carries a new variant of the mcr-4 colistin resistance gene (mcr-4.7) in a novel Tn3-family transposon (called Tn6926) carried by a novel plasmid p8E072658. E-072658 is also resistant to sulphonamide compounds; consistent with this, the sul2 sulphonamide resistance gene was found in a pdif module. E-072658 also carries six additional plasmids with no antibiotic resistance genes, but they contained several pdif modules shared with plasmids carried by clinical strains. Detailed analysis of the genetic structure of all eight plasmids carried by E-072658 showed a complex evolutionary history revealing genetic exchange events within the genus Acinetobacter beyond the clinical or environmental origin of the strains. This work provides evidence that environmental strains might act as a source for some of the clinically significant antibiotic resistance genes.
Collapse
Affiliation(s)
- Farzana T Prity
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Liam A Tobin
- Australian Institute for Microbiology & Infection, University of Technology Sydney, Ultimo, NSW, 2007, Australia
| | - Ram Maharajan
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Ian T Paulsen
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Amy K Cain
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Mehrad Hamidian
- Australian Institute for Microbiology & Infection, University of Technology Sydney, Ultimo, NSW, 2007, Australia
| |
Collapse
|
11
|
Peters DL, Davis CM, Harris G, Zhou H, Rather PN, Hrapovic S, Lam E, Dennis JJ, Chen W. Characterization of Virulent T4-Like Acinetobacter baumannii Bacteriophages DLP1 and DLP2. Viruses 2023; 15:v15030739. [PMID: 36992448 PMCID: PMC10051250 DOI: 10.3390/v15030739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 03/07/2023] [Accepted: 03/09/2023] [Indexed: 03/16/2023] Open
Abstract
The world is currently facing a global health crisis due to the rapid increase in antimicrobial-resistant bacterial infections. One of the most concerning pathogens is Acinetobacter baumannii, which is listed as a Priority 1 pathogen by the World Health Organization. This Gram-negative bacterium has many intrinsic antibiotic resistance mechanisms and the ability to quickly acquire new resistance determinants from its environment. A limited number of effective antibiotics against this pathogen complicates the treatment of A. baumannii infections. A potential treatment option that is rapidly gaining interest is “phage therapy”, or the clinical application of bacteriophages to selectively kill bacteria. The myoviruses DLP1 and DLP2 (vB_AbaM-DLP_1 and vB_AbaM-DLP_2, respectively) were isolated from sewage samples using a capsule minus variant of A. baumannii strain AB5075. Host range analysis of these phages against 107 A. baumannii strains shows a limited host range, infecting 15 and 21 for phages DLP1 and DLP2, respectively. Phage DLP1 has a large burst size of 239 PFU/cell, a latency period of 20 min, and virulence index of 0.93. In contrast, DLP2 has a smaller burst size of 24 PFU/cell, a latency period of 20 min, and virulence index of 0.86. Both phages show potential for use as therapeutics to combat A. baumannii infections.
Collapse
Affiliation(s)
- Danielle L. Peters
- Human Health Therapeutics (HHT) Research Center, National Research Council Canada, Ottawa, ON K1A 0R6, Canada
- Correspondence:
| | - Carly M. Davis
- Human Health Therapeutics (HHT) Research Center, National Research Council Canada, Ottawa, ON K1A 0R6, Canada
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Greg Harris
- Human Health Therapeutics (HHT) Research Center, National Research Council Canada, Ottawa, ON K1A 0R6, Canada
| | - Hongyan Zhou
- Human Health Therapeutics (HHT) Research Center, National Research Council Canada, Ottawa, ON K1A 0R6, Canada
| | - Philip N. Rather
- Department of Microbiology and Immunology, Emory University, Atlanta, GA 30322, USA
- Research Service, Atlanta VA Medical Center, Decatur, GA 30033, USA
| | - Sabahudin Hrapovic
- Aquatic and Crop Resource Development (ACRD) Research Center, National Research Council Canada, Montreal, QC H4P 2R2, Canada
| | - Edmond Lam
- Aquatic and Crop Resource Development (ACRD) Research Center, National Research Council Canada, Montreal, QC H4P 2R2, Canada
| | - Jonathan J. Dennis
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Wangxue Chen
- Human Health Therapeutics (HHT) Research Center, National Research Council Canada, Ottawa, ON K1A 0R6, Canada
- Department of Biology, Brock University, St. Catharines, ON L2S 3A1, Canada
| |
Collapse
|
12
|
Traglia GM, Pasteran F, Escalante J, Nishimura B, Tuttobene MR, Subils T, Nuñez MR, Rivollier MG, Corso A, Tolmasky ME, Ramirez MS. Genomic Comparative Analysis of Two Multi-Drug Resistance (MDR) Acinetobacter baumannii Clinical Strains Assigned to International Clonal Lineage II Recovered Pre- and Post-COVID-19 Pandemic. BIOLOGY 2023; 12:358. [PMID: 36979049 PMCID: PMC10045941 DOI: 10.3390/biology12030358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 02/09/2023] [Accepted: 02/23/2023] [Indexed: 02/26/2023]
Abstract
BACKGROUND After the emergence of COVID-19, numerous cases of A. baumannii/SARS-CoV-2 co-infection were reported. Whether the co-infecting A. baumannii strains have distinctive characteristics remains unknown. METHODS AND RESULTS A. baumannii AMA_NO was isolated in 2021 from a patient with COVID-19. AMA166 was isolated from a mini-BAL used on a patient with pneumonia in 2016. Both genomes were similar, but they possessed 337 (AMA_NO) and 93 (AMA166) unique genes that were associated with biofilm formation, flagellar assembly, antibiotic resistance, secretion systems, and other functions. The antibiotic resistance genes were found within mobile genetic elements. While both strains harbored the carbapenemase-coding gene blaOXA-23, only the strain AMA_NO carried blaNDM-1. Representative functions coded for by virulence genes are the synthesis of the outer core of lipooligosaccharide (OCL5), biosynthesis and export of the capsular polysaccharide (KL2 cluster), high-efficiency iron uptake systems (acinetobactin and baumannoferrin), adherence, and quorum sensing. A comparative phylogenetic analysis including 239 additional sequence type (ST) 2 representative genomes showed high similarity to A. baumannii ABBL141. Since the degree of similarity that was observed between A. baumannii AMA_NO and AMA166 is higher than that found among other ST2 strains, we propose that they derive from a unique background based on core-genome phylogeny and comparative genome analysis. CONCLUSIONS Acquisition or shedding of specific genes could increase the ability of A. baumannii to infect patients with COVID-19.
Collapse
Affiliation(s)
- German Matias Traglia
- Departamento de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la Republica, Montevideo 11200, Uruguay
| | - Fernando Pasteran
- National Regional Reference Laboratory for Antimicrobial Resistance (NRL), Servicio Antimicrobianos, Instituto Nacional de Enfermedades Infecciosas, ANLIS Dr. Carlos G. Malbrán, Buenos Aires 1282, Argentina
| | - Jenny Escalante
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA
| | - Brent Nishimura
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA
| | - Marisel R. Tuttobene
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Rosario 2000, Argentina
| | - Tomás Subils
- Instituto de Procesos Biotecnológicos y Químicos de Rosario (IPROBYQ, CONICET-UNR), Rosario 2000, Argentina
| | - Maria Rosa Nuñez
- Laboratorio de Microbiología, Hospital Provincial Neuquén Dr. Castro Rendón, Neuquén 8300, Argentina
| | | | - Alejandra Corso
- National Regional Reference Laboratory for Antimicrobial Resistance (NRL), Servicio Antimicrobianos, Instituto Nacional de Enfermedades Infecciosas, ANLIS Dr. Carlos G. Malbrán, Buenos Aires 1282, Argentina
| | - Marcelo E. Tolmasky
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA
| | - Maria Soledad Ramirez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA
| |
Collapse
|
13
|
Patel KD, Ahmed SF, MacDonald MR, Gulick AM. Structural Studies of Modular Nonribosomal Peptide Synthetases. Methods Mol Biol 2023; 2670:17-46. [PMID: 37184698 DOI: 10.1007/978-1-0716-3214-7_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The non-ribosomal peptide synthetases (NRPSs) are a family of modular enzymes involved in the production of peptide natural products. Not restricted by the constraints of ribosomal peptide and protein production, the NRPSs are able to incorporate unusual amino acids and other suitable building blocks into the final product. The NRPSs operate with an assembly line strategy in which peptide intermediates are covalently tethered to a peptidyl carrier protein and transported to different catalytic domains for the multiple steps in the biosynthesis. Often the carrier and catalytic domains are joined into a single large multidomain protein. This chapter serves to introduce the NRPS enzymes, using the nocardicin NRPS system as an example that highlights many common features to NRPS biochemistry. We then describe recent advances in the structural biology of NRPSs focusing on large multidomain structures that have been determined.
Collapse
Affiliation(s)
- Ketan D Patel
- Department of Structural Biology, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Syed Fardin Ahmed
- Department of Structural Biology, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Monica R MacDonald
- Department of Structural Biology, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Andrew M Gulick
- Department of Structural Biology, University at Buffalo, SUNY, Buffalo, NY, USA.
- Department of Structural Biology, Jacobs School of Medicine & Biomedical Sciences, Buffalo, NY, USA.
| |
Collapse
|
14
|
Rahimzadeh G, Rezai MS, Farshidi F. Genotypic Patterns of Multidrug-Resistant Acinetobacter baumannii: A Systematic Review. Adv Biomed Res 2023; 12:56. [PMID: 37200758 PMCID: PMC10186031 DOI: 10.4103/abr.abr_434_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/30/2023] [Accepted: 02/01/2023] [Indexed: 05/20/2023] Open
Abstract
Acinetobacter baumannii (A. baumannii) is one of the most common bacteria in nosocomial infections. Inappropriate usage of antibiotics has led to expanding emergence resistance to A. baumannii as a multidrug-resistant (MDR) strain. Empirical antibiotic therapy is necessary to evaluate the resistant gene pattern of MDR A. baumannii. For this purpose, the present study evaluated the resistance genes pattern of MDR A. baumannii collected from hospitalized patients using a genotypic diagnostic technique. To find evidence related to the study objectives, databases were searched such as Google Scholar, Web of Science, Science Direct, PubMed, and Scopus from 2000 to 2022, with specified keywords in the title and text of the articles. Articles were included based on inclusion and exclusion criteria. The mentioned database displayed 284 articles. After screening, 65 eligible articles were included. The results showed that various b-lactamases genes, aminoglycoside-modifying enzymes (AMEs) genes, and pump-expressing genes are resistance gene patterns in MDR A. baumannii isolates. MDR A. baumannii has significantly become resistant to b-lactams, carbapenems, and aminoglycosides.
Collapse
Affiliation(s)
- Golnar Rahimzadeh
- Pediatric Infectious Diseases Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mohammad S. Rezai
- Pediatric Infectious Diseases Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran
- Address for correspondence: Prof. Mohammad S. Rezai, Pediatric Infectious Diseases Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari - 4815838477, Iran. E-mail:
| | - Fereshteh Farshidi
- Pediatric Infectious Diseases Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran
| |
Collapse
|
15
|
Russo TA, Umland TC, Deng X, El Mazouni F, Kokkonda S, Olson R, Carlino-MacDonald U, Beanan J, Alvarado CL, Tomchick DR, Hutson A, Chen H, Posner B, Rathod PK, Charman SA, Phillips MA. Repurposed dihydroorotate dehydrogenase inhibitors with efficacy against drug-resistant Acinetobacter baumannii. Proc Natl Acad Sci U S A 2022; 119:e2213116119. [PMID: 36512492 PMCID: PMC9907071 DOI: 10.1073/pnas.2213116119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 11/08/2022] [Indexed: 12/15/2022] Open
Abstract
New antimicrobials are needed for the treatment of extensively drug-resistant Acinetobacter baumannii. The de novo pyrimidine biosynthetic enzyme dihydroorotate dehydrogenase (DHODH) is a validated drug target for malaria and human autoimmune diseases. We provide genetic evidence that A. baumannii DHODH (AbDHODH) is essential for bacterial survival in rodent infection models. We chemically validate the target by repurposing a unique library of ~450 triazolopyrimidine/imidazopyrimidine analogs developed for our malaria DHODH program to identify 21 compounds with submicromolar activity on AbDHODH. The most potent (DSM186, DHODH IC50 28 nM) had a minimal inhibitory concentration of ≤1 µg/ml against geographically diverse A. baumannii strains, including meropenem-resistant isolates. A structurally related analog (DSM161) with a long in vivo half-life conferred significant protection in the neutropenic mouse thigh infection model. Encouragingly, the development of resistance to these compounds was not identified in vitro or in vivo. Lastly, the X-ray structure of AbDHODH bound to DSM186 was solved to 1.4 Å resolution. These data support the potential of AbDHODH as a drug target for the development of antimicrobials for the treatment of A. baumannii and potentially other high-risk bacterial infections.
Collapse
Affiliation(s)
- Thomas A. Russo
- Department of Medicine, Veterans Administration Western New York Healthcare System, Buffalo, NY14215
- The Department of Medicine, University at Buffalo-State University of New York, Buffalo, NY14203
- Department of Microbiology and Immunology, University at Buffalo-State University of New York, Buffalo, NY14203
- The Witebsky Center for Microbial Pathogenesis, University at Buffalo-State University of New York, Buffalo, NY14203
| | - Timothy C. Umland
- Department of Structural Biology, University at Buffalo State University of New York, Buffalo, NY14203
- Hauptman Woodward Medical Research Institute, Buffalo, NY14203
| | - Xiaoyi Deng
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, TX75390
| | - Farah El Mazouni
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, TX75390
| | - Sreekanth Kokkonda
- Department of Chemistry, University of Washington, Seattle, WA98195
- Department of Global Health, University of Washington, Seattle, WA98195
| | - Ruth Olson
- Department of Medicine, Veterans Administration Western New York Healthcare System, Buffalo, NY14215
- The Department of Medicine, University at Buffalo-State University of New York, Buffalo, NY14203
| | - Ulrike Carlino-MacDonald
- Department of Medicine, Veterans Administration Western New York Healthcare System, Buffalo, NY14215
- The Department of Medicine, University at Buffalo-State University of New York, Buffalo, NY14203
| | - Janet Beanan
- Department of Medicine, Veterans Administration Western New York Healthcare System, Buffalo, NY14215
- The Department of Medicine, University at Buffalo-State University of New York, Buffalo, NY14203
| | - Cassandra L. Alvarado
- Department of Medicine, Veterans Administration Western New York Healthcare System, Buffalo, NY14215
- The Department of Medicine, University at Buffalo-State University of New York, Buffalo, NY14203
| | - Diana R. Tomchick
- Department of Biophysics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX75390
| | - Alan Hutson
- Department of Biostatistics and Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, NY14203
| | - Hong Chen
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, TX75390
| | - Bruce Posner
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, TX75390
| | - Pradipsinh K. Rathod
- Department of Chemistry, University of Washington, Seattle, WA98195
- Department of Global Health, University of Washington, Seattle, WA98195
| | - Susan A. Charman
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC3052Australia
| | - Margaret A. Phillips
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, TX75390
| |
Collapse
|
16
|
Gordillo Altamirano FL, Kostoulias X, Subedi D, Korneev D, Peleg AY, Barr JJ. Phage-antibiotic combination is a superior treatment against Acinetobacter baumannii in a preclinical study. EBioMedicine 2022; 80:104045. [PMID: 35537278 PMCID: PMC9097682 DOI: 10.1016/j.ebiom.2022.104045] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 03/30/2022] [Accepted: 04/22/2022] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Clinical phage therapy is often delivered alongside antibiotics. However, the phenomenon of phage-antibiotic synergy has been mostly studied in vitro. Here, we assessed the in vivo bactericidal effect of a phage-antibiotic combination on Acinetobacter baumannii AB900 using phage øFG02, which binds to capsular polysaccharides and leads to antimicrobial resensitisation in vitro. METHODS We performed a two-stage preclinical study using a murine model of severe A. baumannii AB900 bacteraemia. In the first stage, with an endpoint of 11 h, mice (n = 4 per group) were treated with either PBS, ceftazidime, phage øFG02, or the combination of phage and ceftazidime. The second stage involved only the latter two groups (n = 5 per group), with a prolonged endpoint of 16 h. The primary outcome was the average bacterial burden from four body sites (blood, liver, kidney, and spleen). Bacterial colonies from phage-treated mice were retrieved and screened for phage-resistance. FINDINGS In the first stage, the bacterial burden (CFU/g of tissue) of the combination group (median: 4.55 × 105; interquartile range [IQR]: 2.79 × 105-2.81 × 106) was significantly lower than the PBS (median: 2.42 × 109; IQR: 1.97 × 109-3.48 × 109) and ceftazidime groups (median: 3.86 × 108; IQR: 2.15 × 108-6.35 × 108), but not the phage-only group (median: 1.28 × 107; IQR: 4.71 × 106-7.13 × 107). In the second stage, the combination treatment (median: 1.72 × 106; IQR: 5.11 × 105-4.00 × 106) outperformed the phage-only treatment (median: 7.46 × 107; IQR: 1.43 × 107-1.57 × 108). Phage-resistance emerged in 96% of animals receiving phages, and all the tested isolates (n = 11) had loss-of-function mutations in genes involved in capsule biosynthesis and increased sensitivity to ceftazidime. INTERPRETATION øFG02 reliably drives the in vivo evolution of A. baumannii AB900 towards a capsule-deficient, phage-resistant phenotype that is resensitised to ceftazidime. This mechanism highlights the clinical potential of using phage therapy to target A. baumannii and restore antibiotic activity. FUNDING National Health and Medical Research Council (Australia).
Collapse
Affiliation(s)
- Fernando L Gordillo Altamirano
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia; Centre to Impact AMR, Monash University, Clayton, Victoria, Australia; Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Xenia Kostoulias
- Centre to Impact AMR, Monash University, Clayton, Victoria, Australia; Infection Program, Department of Microbiology Monash University, Monash Biomedicine Discovery Institute, Clayton, Victoria, Australia
| | - Dinesh Subedi
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia; Centre to Impact AMR, Monash University, Clayton, Victoria, Australia
| | - Denis Korneev
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia; Faculty of Science, School of BioSciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Anton Y Peleg
- Centre to Impact AMR, Monash University, Clayton, Victoria, Australia; Infection Program, Department of Microbiology Monash University, Monash Biomedicine Discovery Institute, Clayton, Victoria, Australia; Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria, Australia.
| | - Jeremy J Barr
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia; Centre to Impact AMR, Monash University, Clayton, Victoria, Australia.
| |
Collapse
|
17
|
Ding Z, Li Z, Zhao Y, Hao J, Li T, Liu Y, Zeng Z, Liu J. Phenotypic and Genotypic Characteristics of a Tigecycline-Resistant Acinetobacter pittii Isolate Carrying bla NDM-1 and the Novel bla OXA Allelic Variant bla OXA-1045. Front Microbiol 2022; 13:868152. [PMID: 35602052 PMCID: PMC9116503 DOI: 10.3389/fmicb.2022.868152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 03/30/2022] [Indexed: 11/13/2022] Open
Abstract
A tigecycline-resistant Acinetobacter pittii clinical strain from pleural fluid carrying a blaNDM–1 gene and a novel blaOXA gene, blaOXA–1045, was isolated and characterized. The AP2044 strain acquired two copies of the blaNDM–1 gene and six antibiotic resistance genes (ARGs) from other pathogens. According to the whole-genome investigation, the GC ratios of ARGs (50–60%) were greater than those of the chromosomal backbone (39.46%), indicating that ARGs were horizontally transferred. OXA-1045 belonged to the OXA-213 subfamily and the amino acid sequence of OXA-1045 showed 89% similarity to the amino acid sequences of OXA-213. Then, blaOXA–1045 and blaOXA–213 were cloned and the minimum inhibitory concentrations (MICs) of β-lactams in the transformants were determined using the broth microdilution method. OXA-1045 was able to confer a reduced susceptibility to piperacillin and piperacillin-tazobactam compared to OXA-213. AP2044 strain exhibited low pathogenicity in Galleria mellonella infection models. The observation of condensed biofilm using the crystal violet staining method and scanning electron microscopy (SEM) suggested that the AP2044 strain was a weak biofilm producer. Quantitative reverse transcription-PCR (qRT-PCR) was used to detect the expression of resistance-nodulation-cell division (RND) efflux pump-related genes. The transcription level of adeB and adeJ genes increased significantly and was correlated with tigecycline resistance. Therefore, our genomic and phenotypic investigations revealed that the AP2044 strain had significant genome plasticity and natural transformation potential, and the emergence of antibiotic resistance in these unusual bacteria should be a concern for future investigations.
Collapse
Affiliation(s)
- Zixuan Ding
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Zhaoyinqian Li
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Yuanqing Zhao
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Jingchen Hao
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Tingting Li
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Yao Liu
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Zhangrui Zeng
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Jinbo Liu
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| |
Collapse
|
18
|
Genetic Resistance Determinants in Clinical Acinetobacter pittii Genomes. Antibiotics (Basel) 2022; 11:antibiotics11050676. [PMID: 35625320 PMCID: PMC9137642 DOI: 10.3390/antibiotics11050676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/10/2022] [Accepted: 05/16/2022] [Indexed: 12/14/2022] Open
Abstract
Antimicrobial-resistant pathogenic bacteria are an increasing problem in public health, especially in the healthcare environment, where nosocomial infection microorganisms find their niche. Among these bacteria, the genus Acinetobacter which belongs to the ESKAPE pathogenic group harbors different multi-drug resistant (MDR) species that cause human nosocomial infections. Although A. baumannii has always attracted more interest, the close-related species A. pittii is the object of more study due to the increase in its isolation and MDR strains. In this work, we present the genomic analysis of five clinically isolated A. pittii strains from a Spanish hospital, with special attention to their genetic resistance determinants and plasmid structures. All the strains harbored different genes related to β-lactam resistance, as well as different MDR efflux pumps. We also found and described, for the first time in this species, point mutations that seem linked with colistin resistance, which highlights the relevance of this comparative analysis among the pathogenic species isolates.
Collapse
|
19
|
The StkSR Two-Component System Influences Colistin Resistance in Acinetobacter baumannii. Microorganisms 2022; 10:microorganisms10050985. [PMID: 35630428 PMCID: PMC9146086 DOI: 10.3390/microorganisms10050985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/13/2022] [Accepted: 04/22/2022] [Indexed: 01/27/2023] Open
Abstract
Acinetobacter baumannii is an opportunistic human pathogen responsible for numerous severe nosocomial infections. Genome analysis on the A. baumannii clinical isolate 04117201 revealed the presence of 13 two-component signal transduction systems (TCS). Of these, we examined the putative TCS named here as StkSR. The stkR response regulator was deleted via homologous recombination and its progeny, ΔstkR, was phenotypically characterized. Antibiogram analyses of ΔstkR cells revealed a two-fold increase in resistance to the clinically relevant polymyxins, colistin and polymyxin B, compared to wildtype. PAGE-separation of silver stained purified lipooligosaccharide isolated from ΔstkR and wildtype cells ruled out the complete loss of lipooligosaccharide as the mechanism of colistin resistance identified for ΔstkR. Hydrophobicity analysis identified a phenotypical change of the bacterial cells when exposed to colistin. Transcriptional profiling revealed a significant up-regulation of the pmrCAB operon in ΔstkR compared to the parent, associating these two TCS and colistin resistance. These results reveal that there are multiple levels of regulation affecting colistin resistance; the suggested ‘cross-talk’ between the StkSR and PmrAB two-component systems highlights the complexity of these systems.
Collapse
|
20
|
A Variant Carbapenem Inactivation Method (CIM) for Acinetobacter baumannii Group with Shortened Time-to-Result: rCIM-A. Pathogens 2022; 11:pathogens11040482. [PMID: 35456157 PMCID: PMC9024794 DOI: 10.3390/pathogens11040482] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/10/2022] [Accepted: 04/13/2022] [Indexed: 02/01/2023] Open
Abstract
Carbapenem-resistant Acinetobacter baumannii group organisms (CRAB) are challenging because the choice between targeted, new antibiotic drug options and hygiene measures should be guided by a timely identification of resistance mechanisms. In CRAB, acquired class-D carbapenemases (CHDLs) are active against meropenem and imipenem. If PCR methods are not the first choice, phenotypic methods have to be implemented. While promising, the carbapenemase inactivation method (CIM) using meropenem-hydrolysis is, however, hampered by poor performance or overly long time-to-result. We developed a rapid CIM (rCIM-A) with good performance using ertapenem, imipenem, and meropenem disks, 2-h permeabilization and incubation with the test strain in trypticase soy broth, and a read-out of residual carbapenem activity after 6 h, and optionally after 16–18 h. Using clinical isolates and type-strains of Acinetobacter (n = 67) not harboring carbapenemases (n = 28) or harboring acquired carbapenemases (n = 39), the sensitivity of detection was 97.4% with the imipenem disk after 6 h at a specificity of 92.9%. If the inhibition zone around the ertapenem disk at 6 h was 6 or ≤26 mm at 16–18 h, or ≤25.5 mm for meropenem, the specificity was 100%. Because of the high negative predictive value, the rCIM-A seems particularly appropriate in areas of lower CRAB-frequency.
Collapse
|
21
|
Gülbüz M, Saral Sariyer A. Combined in silico approach and whole genome sequencing: Acinetobacter baumannii ST218 isolate harboring ADC-73 β-lactamase which has a similar C-loop with ADC-56 and ADC-68 β-lactamase. J Mol Graph Model 2022; 114:108195. [DOI: 10.1016/j.jmgm.2022.108195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 04/07/2022] [Accepted: 04/11/2022] [Indexed: 11/28/2022]
|
22
|
Dong JF, Feng CJ, Wang P, Li RQ, Zou QH. Comparative genomics analysis of Acinetobacter baumannii multi-drug resistant and drug sensitive strains in China. Microb Pathog 2022; 165:105492. [DOI: 10.1016/j.micpath.2022.105492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/28/2022] [Accepted: 03/15/2022] [Indexed: 10/18/2022]
|
23
|
Le C, Pimentel C, Pasteran F, Tuttobene MR, Subils T, Escalante J, Nishimura B, Arriaga S, Carranza A, Mezcord V, Vila AJ, Corso A, Actis LA, Tolmasky ME, Bonomo RA, Ramírez MS. Human Serum Proteins and Susceptibility of Acinetobacter baumannii to Cefiderocol: Role of Iron Transport. Biomedicines 2022; 10:biomedicines10030600. [PMID: 35327400 PMCID: PMC8945497 DOI: 10.3390/biomedicines10030600] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 02/25/2022] [Accepted: 03/01/2022] [Indexed: 01/10/2023] Open
Abstract
Cefiderocol, a recently introduced antibiotic, has a chemical structure that includes a cephalosporin that targets cell wall synthesis and a chlorocatechol siderophore moiety that facilitates cell penetration by active iron transporters. Analysis of the effect that human serum, human serum albumin, and human pleural fluid had on growing Acinetobacter baumannii showed that genes related to iron uptake were down-regulated. At the same time, β-lactamase genes were expressed at higher levels. The minimum inhibitory concentrations of this antimicrobial in A. baumannii cells growing in the presence of human serum, human serum albumin, or human pleural fluid were higher than those measured when these fluids were absent from the culture medium. These results correlate with increased expression levels of β-lactamase genes and the down-regulation of iron uptake-related genes in cultures containing human serum, human serum albumin, or human pleural fluid. These modifications in gene expression could explain the less-than-ideal clinical response observed in patients with pulmonary or bloodstream A. baumannii infections. The exposure of the infecting cells to the host’s fluids could cause reduced cefiderocol transport capabilities and increased resistance to β-lactams. The regulation of genes that could impact the A. baumannii susceptibility to cefiderocol, or other antibacterials, is an understudied phenomenon that merits further investigation.
Collapse
Affiliation(s)
- Casin Le
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (C.L.); (C.P.); (J.E.); (B.N.); (S.A.); (A.C.); (V.M.); (M.E.T.)
| | - Camila Pimentel
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (C.L.); (C.P.); (J.E.); (B.N.); (S.A.); (A.C.); (V.M.); (M.E.T.)
| | - Fernando Pasteran
- National/Regional Reference Laboratory for Antimicrobial Resistance (NRL), Servicio Antimicrobianos, Instituto Nacional de Enfermedades Infecciosas, ANLIS Dr. Carlos G. Malbrán, Buenos Aires C1282, Argentina; (F.P.); (A.C.)
| | - Marisel R. Tuttobene
- Área Biología Molecular, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario S2000, Argentina;
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Rosario S2000, Argentina;
| | - Tomás Subils
- Instituto de Procesos Biotecnológicos y Químicos de Rosario (IPROBYQ, CONICET-UNR), Rosario S2002, Argentina;
| | - Jenny Escalante
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (C.L.); (C.P.); (J.E.); (B.N.); (S.A.); (A.C.); (V.M.); (M.E.T.)
| | - Brent Nishimura
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (C.L.); (C.P.); (J.E.); (B.N.); (S.A.); (A.C.); (V.M.); (M.E.T.)
| | - Susana Arriaga
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (C.L.); (C.P.); (J.E.); (B.N.); (S.A.); (A.C.); (V.M.); (M.E.T.)
| | - Aimee Carranza
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (C.L.); (C.P.); (J.E.); (B.N.); (S.A.); (A.C.); (V.M.); (M.E.T.)
| | - Vyanka Mezcord
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (C.L.); (C.P.); (J.E.); (B.N.); (S.A.); (A.C.); (V.M.); (M.E.T.)
| | - Alejandro J. Vila
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Rosario S2000, Argentina;
- Área Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario S2000, Argentina
| | - Alejandra Corso
- National/Regional Reference Laboratory for Antimicrobial Resistance (NRL), Servicio Antimicrobianos, Instituto Nacional de Enfermedades Infecciosas, ANLIS Dr. Carlos G. Malbrán, Buenos Aires C1282, Argentina; (F.P.); (A.C.)
| | - Luis A. Actis
- Department of Microbiology, Miami University, Oxford, OH 45056, USA;
| | - Marcelo E. Tolmasky
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (C.L.); (C.P.); (J.E.); (B.N.); (S.A.); (A.C.); (V.M.); (M.E.T.)
| | - Robert A. Bonomo
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
- Research Service and GRECC, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH 44106, USA
- Correspondence: (R.A.B.); (M.S.R.); Tel.: +1-216-791-3800 (R.A.B.); Tel.: +1-657-278-4562 (M.S.R.)
| | - Maria Soledad Ramírez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (C.L.); (C.P.); (J.E.); (B.N.); (S.A.); (A.C.); (V.M.); (M.E.T.)
- Correspondence: (R.A.B.); (M.S.R.); Tel.: +1-216-791-3800 (R.A.B.); Tel.: +1-657-278-4562 (M.S.R.)
| |
Collapse
|
24
|
Genetic Diversity of Antimicrobial Resistance and Key Virulence Features in Two Extensively Drug-Resistant Acinetobacter baumannii Isolates. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19052870. [PMID: 35270562 PMCID: PMC8910769 DOI: 10.3390/ijerph19052870] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/25/2022] [Accepted: 02/27/2022] [Indexed: 01/27/2023]
Abstract
In recent decades, Acinetobacter baumannii emerged as a major infective menace in healthcare settings due to scarce therapeutic options to treat infections. Therefore, undertaking genome comparison analyses of multi-resistant A. baumannii strains could aid the identification of key bacterial determinants to develop innovative anti-virulence approaches. Following genome sequencing, we performed a molecular characterization of key genes and genomic comparison of two A. baumannii strains, #36 and #150, with selected reference genomes. Despite a different antibiotic resistance gene content, the analyzed strains showed a very similar antibiogram profile. Interestingly, the lack of some important virulence determinants (i.e., bap, ata and omp33–36) did not abrogate their adhesive abilities to abiotic and biotic surfaces, as reported before; indeed, strains retained these capacities, although to a different extent, suggesting the presence of distinct vicarious genes. Conversely, secretion systems, lipopolysaccharide (LPS), capsule and iron acquisition systems were highly similar to A. baumannii reference strains. Overall, our analyses increased our knowledge on A. baumannii genomic content and organization as well as the genomic events occurring in nosocomial isolates to better fit into changing healthcare environments.
Collapse
|
25
|
Hamidian M, Maharjan RP, Farrugia DN, Delgado NN, Dinh H, Short FL, Kostoulias X, Peleg AY, Paulsen IT, Cain AK. Genomic and phenotypic analyses of diverse non-clinical Acinetobacter baumannii strains reveals strain-specific virulence and resistance capacity. Microb Genom 2022; 8. [PMID: 35166651 PMCID: PMC8942024 DOI: 10.1099/mgen.0.000765] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Acinetobacter baumannii is a critically important pathogen known for its widespread antibiotic resistance and ability to persist in hospital-associated environments. Whilst the majority of A. baumannii infections are hospital-acquired, infections from outside the hospital have been reported with high mortality. Despite this, little is known about the natural environmental reservoir(s) of A. baumannii and the virulence potential underlying non-clinical strains. Here, we report the complete genome sequences of six diverse strains isolated from environments such as river, soil, and industrial sites around the world. Phylogenetic analyses showed that four of these strains were unrelated to representative nosocomial strains and do not share a monophyletic origin, whereas two had sequence types belonging to the global clone lineages GC1 and GC2. Further, the majority of these strains harboured genes linked to virulence and stress protection in nosocomial strains. These genotypic properties correlated well with in vitro virulence phenotypic assays testing resistance to abiotic stresses, serum survival, and capsule formation. Virulence potential was confirmed in vivo, with most environmental strains able to effectively kill Galleria mellonella greater wax moth larvae. Using phenomic arrays and antibiotic resistance profiling, environmental and nosocomial strains were shown to have similar substrate utilisation patterns although environmental strains were distinctly more sensitive to antibiotics. Taken together, these features of environmental A. baumannii strains suggest the existence of a strain-specific distinct gene pools for niche specific adaptation. Furthermore, environmental strains appear to be equally virulent as contemporary nosocomial strains but remain largely antibiotic sensitive.
Collapse
Affiliation(s)
- Mohammad Hamidian
- The iThree institute, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Ram P Maharjan
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Daniel N Farrugia
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Natasha N Delgado
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Hue Dinh
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Francesca L Short
- Infection & Immunity Program Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, VIC 3800, Australia
| | - Xenia Kostoulias
- Infection & Immunity Program Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, VIC 3800, Australia
| | - Anton Y Peleg
- Infection & Immunity Program Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, VIC 3800, Australia.,Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, VIC, 3004, Australia
| | - Ian T Paulsen
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Amy K Cain
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| |
Collapse
|
26
|
Selim S, Faried OA, Almuhayawi MS, Mohammed OA, Saleh FM, Warrad M. Dynamic Gene Clusters Mediating Carbapenem-Resistant Acinetobacter baumannii Clinical Isolates. Antibiotics (Basel) 2022; 11:antibiotics11020168. [PMID: 35203771 PMCID: PMC8868416 DOI: 10.3390/antibiotics11020168] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 01/24/2022] [Accepted: 01/26/2022] [Indexed: 02/04/2023] Open
Abstract
Acinetobacter baumanni (A. baumannii), a nonfermenting Gram-negative bacterium, has recently been associated with a broad range of nosocomial infections. To gain more meaningful insight into the problem of nosocomial illnesses caused by the multidrug-resistant (MDR) A. baumannii, as well as the factors that increase the risk of catching these infections, this investigation included a total of 86 clinical A. baumannii infections. Repetitive extragenic palindromic (REP)-PCR was used to investigate imipenem-resistant A. baumannii isolates for dynamic gene clusters causing carbapenem resistance. Four distinct A. baumannii lineages were found in the REP-PCR-DNA fingerprints of all isolates, with 95% of the samples coming from two dominant lineages. Imipenem, amikacin, and ciprofloxacin were less effective against genotype (A) isolates because of enhanced antibiotic tolerance. Lastly, to gain more insight into the mode of action of imipenem, we explored the binding affinity of imipenem toward different Acinetobacter baumannii OXA beta-lactamase class enzymes.
Collapse
Affiliation(s)
- Samy Selim
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka 72341, Saudi Arabia
- Correspondence:
| | - Osama Ahmed Faried
- Medical Microbiology and Immunology Department, Faculty of Medicine, Beni-Suef University, Beni-Suef 62513, Egypt;
| | - Mohamed S. Almuhayawi
- Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
| | - Osama A. Mohammed
- Department of Clinical Pharmacology, Faculty of Medicine, Ain Shams University, Cairo 11566, Egypt;
- Department of Clinical Pharmacology, Faculty of Medicine, Bisha University, Bisha 61922, Saudi Arabia
| | - Fayez M. Saleh
- Department of Medical Microbiology, Faculty of Medicine, University of Tabuk, Tabuk 71491, Saudi Arabia;
| | - Mona Warrad
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences at Al-Quriat, Jouf University, Al-Quriat 77454, Saudi Arabia;
| |
Collapse
|
27
|
Breine A, Van Gysel M, Elsocht M, Whiteway C, Philippe C, Quinet T, Valcek A, Wouters J, Ballet S, Van der Henst C. Antimicrobial Activity of a Repurposed Harmine-Derived Compound on Carbapenem-Resistant Acinetobacter baumannii Clinical Isolates. Front Cell Infect Microbiol 2022; 11:789672. [PMID: 35141168 PMCID: PMC8819726 DOI: 10.3389/fcimb.2021.789672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 12/15/2021] [Indexed: 11/18/2022] Open
Abstract
Objectives The spread of antibiotic resistant bacteria is an important threat for human health. Acinetobacter baumannii bacteria impose such a major issue, as multidrug- to pandrug-resistant strains have been isolated, rendering some infections untreatable. In this context, carbapenem-resistant A. baumannii bacteria were ranked as top priority by both WHO and CDC. In addition, A. baumannii bacteria survive in harsh environments, being capable of resisting to disinfectants and to persist prolonged periods of desiccation. Due to the high degree of variability found in A. baumannii isolates, the search for new antibacterials is very challenging because of the requirement of drug target conservation amongst the different strains. Here, we screened a chemical library to identify compounds active against several reference strains and carbapenem-resistant A. baumannii bacteria. Methods A repurposing drug screen was undertaken to identify A. baumannii growth inhibitors. One hit was further characterized by determining the IC50 and testing the activity on 43 modern clinical A. baumannii isolates, amongst which 40 are carbapenem-resistant. Results The repurposing screen led to the identification of a harmine-derived compound, called HDC1, which proves to have bactericidal activity on the multidrug-resistant AB5075-VUB reference strain with an IC50 of 48.23 µM. In addition, HDC1 impairs growth of 43 clinical A. baumannii isolates. Conclusions We identified a compound with inhibitory activity on all tested strains, including carbapenem-resistant clinical A. baumannii isolates.
Collapse
Affiliation(s)
- Anke Breine
- Microbial Resistance and Drug Discovery, Vlaams Instituut voor Biotechnologie-Vrije Universiteit Brussel (VIB-VUB) Center for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB), Flanders Institute for Biotechnology, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Mégane Van Gysel
- Namur Medicine and Drug Innovation Center (NAMEDIC), University of Namur (UNamur), Namur, Belgium
| | - Mathias Elsocht
- Research Group of Organic Chemistry, Departments of Chemistry and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Clémence Whiteway
- Microbial Resistance and Drug Discovery, Vlaams Instituut voor Biotechnologie-Vrije Universiteit Brussel (VIB-VUB) Center for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB), Flanders Institute for Biotechnology, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Chantal Philippe
- Research Unit in the Biology of Microorganisms (URBM), NARILIS, University of Namur (UNamur), Namur, Belgium
| | - Théo Quinet
- Laboratory of Evolutionary Genetics and Ecology, URBE, University of Namur (UNamur), Namur, Belgium
- Molecular Biology and Evolution, Universite´ Libre de Bruxelles (ULB), Brussels, Belgium
| | - Adam Valcek
- Microbial Resistance and Drug Discovery, Vlaams Instituut voor Biotechnologie-Vrije Universiteit Brussel (VIB-VUB) Center for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB), Flanders Institute for Biotechnology, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Johan Wouters
- Namur Medicine and Drug Innovation Center (NAMEDIC), University of Namur (UNamur), Namur, Belgium
| | - Steven Ballet
- Research Group of Organic Chemistry, Departments of Chemistry and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Charles Van der Henst
- Microbial Resistance and Drug Discovery, Vlaams Instituut voor Biotechnologie-Vrije Universiteit Brussel (VIB-VUB) Center for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB), Flanders Institute for Biotechnology, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- *Correspondence: Charles Van der Henst,
| |
Collapse
|
28
|
Naing SY, Hordijk J, Duim B, Broens EM, van der Graaf-van Bloois L, Rossen JW, Robben JH, Leendertse M, Wagenaar JA, Zomer AL. Genomic Investigation of Two Acinetobacter baumannii Outbreaks in a Veterinary Intensive Care Unit in The Netherlands. Pathogens 2022; 11:pathogens11020123. [PMID: 35215067 PMCID: PMC8875366 DOI: 10.3390/pathogens11020123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/17/2022] [Accepted: 01/19/2022] [Indexed: 01/27/2023] Open
Abstract
Acinetobacter baumannii is a nosocomial pathogen that frequently causes healthcare-acquired infections. The global spread of multidrug-resistant (MDR) strains with its ability to survive in the environment for extended periods imposes a pressing public health threat. Two MDR A. baumannii outbreaks occurred in 2012 and 2014 in a companion animal intensive care unit (caICU) in the Netherlands. Whole-genome sequencing (WGS) was performed on dog clinical isolates (n = 6), environmental isolates (n = 5), and human reference strains (n = 3) to investigate if the isolates of the two outbreaks were related. All clinical isolates shared identical resistance phenotypes displaying multidrug resistance. Multi-locus Sequence Typing (MLST) revealed that all clinical isolates belonged to sequence type ST2. The core genome MLST (cgMLST) results confirmed that the isolates of the two outbreaks were not related. Comparative genome analysis showed that the outbreak isolates contained different gene contents, including mobile genetic elements associated with antimicrobial resistance genes (ARGs). The time-measured phylogenetic reconstruction revealed that the outbreak isolates diverged approximately 30 years before 2014. Our study shows the importance of WGS analyses combined with molecular clock investigations to reduce transmission of MDR A. baumannii infections in companion animal clinics.
Collapse
Affiliation(s)
- Soe Yu Naing
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands; (S.Y.N.); (J.H.); (B.D.); (E.M.B.); (L.v.d.G.-v.B.); (M.L.); (J.A.W.)
| | - Joost Hordijk
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands; (S.Y.N.); (J.H.); (B.D.); (E.M.B.); (L.v.d.G.-v.B.); (M.L.); (J.A.W.)
| | - Birgitta Duim
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands; (S.Y.N.); (J.H.); (B.D.); (E.M.B.); (L.v.d.G.-v.B.); (M.L.); (J.A.W.)
| | - Els M. Broens
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands; (S.Y.N.); (J.H.); (B.D.); (E.M.B.); (L.v.d.G.-v.B.); (M.L.); (J.A.W.)
| | - Linda van der Graaf-van Bloois
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands; (S.Y.N.); (J.H.); (B.D.); (E.M.B.); (L.v.d.G.-v.B.); (M.L.); (J.A.W.)
| | - John W. Rossen
- Department of Medical Microbiology, University Medical Center, University of Groningen, 9700 AB Groningen, The Netherlands;
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Joris H. Robben
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands;
| | - Masja Leendertse
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands; (S.Y.N.); (J.H.); (B.D.); (E.M.B.); (L.v.d.G.-v.B.); (M.L.); (J.A.W.)
| | - Jaap A. Wagenaar
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands; (S.Y.N.); (J.H.); (B.D.); (E.M.B.); (L.v.d.G.-v.B.); (M.L.); (J.A.W.)
| | - Aldert L. Zomer
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, The Netherlands; (S.Y.N.); (J.H.); (B.D.); (E.M.B.); (L.v.d.G.-v.B.); (M.L.); (J.A.W.)
- Correspondence:
| |
Collapse
|
29
|
Zhou K, Liang J, Dong X, Zhang P, Feng C, Shi W, Gao M, Li Q, Zhang X, Lu J, Lin X, Li K, Zhang H, Zhu M, Bao Q. Identification and Characterization of a Novel Chromosomal Aminoglycoside 2'- N-Acetyltransferase, AAC(2')-If, From an Isolate of a Novel Providencia Species, Providencia wenzhouensis R33. Front Microbiol 2021; 12:711037. [PMID: 34867838 PMCID: PMC8640171 DOI: 10.3389/fmicb.2021.711037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 10/08/2021] [Indexed: 11/15/2022] Open
Abstract
Multidrug-resistant bacteria from different sources have been steadily emerging, and an increasing number of resistance mechanisms are being uncovered. In this work, we characterized a novel resistance gene named aac(2′)-If from an isolate of a novel Providencia species, Providencia wenzhouensis R33 (CCTCC AB 2021339). Susceptibility testing and enzyme kinetic parameter analysis were conducted to determine the function of the aminoglycoside 2′-N-acetyltransferase. Whole-genome sequencing and comparative genomic analysis were performed to elucidate the molecular characteristics of the genome and the genetic context of the resistance gene-related sequences. Among the functionally characterized resistance genes, AAC(2′)-If shares the highest amino acid sequence identity of 70.79% with AAC(2′)-Ia. AAC(2′)-If confers resistance to several aminoglycoside antibiotics, showing the highest resistance activity against ribostamycin and neomycin. The recombinant strain harboring aac(2′)-If (pUCP20-aac(2′)-If/DH5α) showed 256- and 128-fold increases in the minimum inhibitory concentration (MIC) levels to ribostamycin and neomycin, respectively, compared with those of the control strains (DH5α and pUCP20/DH5α). The results of the kinetic analysis of AAC(2′)-If were consistent with the MIC results of the cloned aac(2′)-If with the highest catalytic efficiency for ribostamycin (kcat/Km ratio = [3.72 ± 0.52] × 104 M–1⋅s–1). Whole-genome sequencing demonstrated that the aac(2′)-If gene was located on the chromosome with a relatively unique genetic environment. Identification of a novel aminoglycoside resistance gene in a strain of a novel Providencia species will help us find ways to elucidate the complexity of resistance mechanisms in the microbial population.
Collapse
Affiliation(s)
- Kexin Zhou
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China.,Key Laboratory of Medical Genetics of Zhejiang Province, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Biomedical Informatics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Jialei Liang
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China.,Key Laboratory of Medical Genetics of Zhejiang Province, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Biomedical Informatics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Xu Dong
- Key Laboratory of Medical Genetics of Zhejiang Province, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Biomedical Informatics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Peiyao Zhang
- Key Laboratory of Medical Genetics of Zhejiang Province, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Biomedical Informatics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Chunlin Feng
- Key Laboratory of Medical Genetics of Zhejiang Province, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Biomedical Informatics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Weina Shi
- Key Laboratory of Medical Genetics of Zhejiang Province, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Biomedical Informatics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Mengdi Gao
- Key Laboratory of Medical Genetics of Zhejiang Province, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Biomedical Informatics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Qiaoling Li
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China.,Key Laboratory of Medical Genetics of Zhejiang Province, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Biomedical Informatics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Xueya Zhang
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China.,Key Laboratory of Medical Genetics of Zhejiang Province, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Biomedical Informatics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Junwan Lu
- Key Laboratory of Medical Genetics of Zhejiang Province, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Biomedical Informatics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Xi Lin
- Key Laboratory of Medical Genetics of Zhejiang Province, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Biomedical Informatics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Kewei Li
- Key Laboratory of Medical Genetics of Zhejiang Province, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Biomedical Informatics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Hailin Zhang
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China.,Institute of Biomedical Informatics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Mei Zhu
- Department of Clinical Laboratory, Zhejiang Hospital, Hangzhou, China
| | - Qiyu Bao
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China.,Key Laboratory of Medical Genetics of Zhejiang Province, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China.,Institute of Biomedical Informatics, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| |
Collapse
|
30
|
Yang JL, Yang CJ, Chuang YC, Sheng WH, Chen YC, Chang SC. Association of capsular polysaccharide locus 2 with prognosis of Acinetobacter baumannii bacteraemia. Emerg Microbes Infect 2021; 11:83-90. [PMID: 34825848 PMCID: PMC8725928 DOI: 10.1080/22221751.2021.2011624] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Acinetobacter baumannii causes healthcare-associated infections worldwide. Capsular polysaccharide (CPS) is shown an important virulence factor of A. baumannii both in vitro and in vivo. Capsule locus 2 (KL2) for CPS is the most common KL type and is associated with carbapenem resistance. It is unclear whether KL2 is related to the clinical outcome of invasive A. baumannii infection. Here we had followed patients with A. baumannii bacteraemia prospectively between 2009 and 2014. One-third of the unduplicated blood isolates were randomly selected each year for microbiological and clinical studies. The KL2 gene cluster was identified using polymerase chain reaction. A total of 148 patients were enrolled randomly. Eighteen isolates (12.2%) carried KL2, and 130 isolates (87.8%) didn’t. Compared with non-KL2 isolates, KL2 isolates had significantly higher resistance to imipenem, sulbactam, and tigecycline. Compared with the non-KL group, in the KL2 group, the hospital stay before development of bacteraemia was longer (P < 0.001), a higher percentage had pneumonia (P = 0.004), and the white blood cell count was lower (P = 0.03). Infection with KL2 A. baumannii predicted mortality (adjusted hazard ratio [aHR], 2.03; 95% confidence interval [CI], 1.09–3.78; P = 0.03), independently of the Pitt bacteraemia score (aHR, 1.34; 95% CI, 1.23–1.46; P < 0.001) and leucopenia (aHR, 2.16; 95% CI, 1.30–3.57; P = 0.003). Thrombocytopenia contributed to the effect of KL2 on mortality in bacteraemia (Sobel test P = 0.01). Large-scale studies are warranted to confirm these findings and the underlying mechanisms deserve further investigation.
Collapse
Affiliation(s)
- Jia-Ling Yang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Chia-Jui Yang
- Department of Internal Medicine, Far Eastern Memorial Hospital, New Taipei City, Taiwan.,School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yu-Chung Chuang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Wang-Huei Sheng
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Yee-Chun Chen
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Shan-Chwen Chang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| |
Collapse
|
31
|
The Molecular Basis of Acinetobacter baumannii Cadmium Toxicity and Resistance. Appl Environ Microbiol 2021; 87:e0171821. [PMID: 34495707 DOI: 10.1128/aem.01718-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Acinetobacter species are ubiquitous Gram-negative bacteria that can be found in water, in soil, and as commensals of the human skin. The successful inhabitation of Acinetobacter species in diverse environments is primarily attributable to the expression of an arsenal of stress resistance determinants, which includes an extensive repertoire of metal ion efflux systems. Metal ion homeostasis in the hospital pathogen Acinetobacter baumannii contributes to pathogenesis; however, insights into its metal ion transporters for environmental persistence are lacking. Here, we studied the impact of cadmium stress on A. baumannii. Our functional genomics and independent mutant analyses revealed a primary role for CzcE, a member of the cation diffusion facilitator (CDF) superfamily, in resisting cadmium stress. We also show that the CzcCBA heavy metal efflux system contributes to cadmium efflux. Collectively, these systems provide A. baumannii with a comprehensive cadmium translocation pathway from the cytoplasm to the periplasm and subsequently the extracellular space. Furthermore, analysis of the A. baumannii metallome under cadmium stress showed zinc depletion, as well as copper enrichment, both of which are likely to influence cellular fitness. Overall, this work provides new knowledge on the role of a broad arsenal of membrane transporters in A. baumannii metal ion homeostasis. IMPORTANCE Cadmium toxicity is a widespread problem, yet the interaction of this heavy metal with biological systems is poorly understood. Some microbes have evolved traits to proactively counteract cadmium toxicity, including Acinetobacter baumannii, which is notorious for persisting in harsh environments. Here, we show that A. baumannii utilizes a dedicated cadmium efflux protein in concert with a system that is primarily attuned to zinc efflux to efficiently overcome cadmium stress. The molecular characterization of A. baumannii under cadmium stress revealed how active cadmium efflux plays a key role in preventing the dysregulation of bacterial metal ion homeostasis, which appeared to be a primary means by which cadmium exerts toxicity upon the bacterium.
Collapse
|
32
|
Insights into the Resistome and Phylogenomics of a ST195 Multidrug-Resistant Acinetobacter baumannii Clinical Isolate from the Czech Republic. Life (Basel) 2021; 11:life11101079. [PMID: 34685451 PMCID: PMC8537504 DOI: 10.3390/life11101079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 10/01/2021] [Accepted: 10/06/2021] [Indexed: 11/17/2022] Open
Abstract
Increasing antimicrobial resistance in nosocomial pathogens, such as Acinetobacter baumannii, is becoming a serious threat to public health. It is necessary to detect β-lactamase-producing microorganisms in clinical settings to be able to control the spread of carbapenem resistance. This study was conducted to evaluate the presence of β-lactamases in a selected clinical isolate of A. baumannii of ST2P/ST195Ox and to characterize possible enzymes, as well as its β-lactam resistome, using PCR and whole-genome sequencing analysis. PCR and sequencing confirmed that the isolate harbored five bla gene alleles, namely, blaADC-73, blaTEM-1, blaOXA-23, blaOXA-58 and blaOXA-66, as well as aminoglycosides, macrolides, sulfonamides and tetracyclines resistance determinants, which were either chromosomally and/or plasmid located. Furthermore, a gene order comparison using MAUVE alignment showed multiple changes compared with the clinical isolate of Malaysian A. baumannii AC30 genome and 76 regions with high homology. This study suggests that resistance to β-lactams in this A. baumannii isolate is mainly due to an overproduction of β-lactamases in combination with other resistance mechanism (efflux pump system).
Collapse
|
33
|
Massier S, Robin B, Mégroz M, Wright A, Harper M, Hayes B, Cosette P, Broutin I, Boyce JD, Dé E, Hardouin J. Phosphorylation of Extracellular Proteins in Acinetobacter baumannii in Sessile Mode of Growth. Front Microbiol 2021; 12:738780. [PMID: 34659171 PMCID: PMC8517400 DOI: 10.3389/fmicb.2021.738780] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 08/30/2021] [Indexed: 11/21/2022] Open
Abstract
Acinetobacter baumannii is a problematic nosocomial pathogen owing to its increasing resistance to antibiotics and its great ability to survive in the hospital environment, which is linked to its capacity to form biofilms. Structural and functional investigations of post-translational modifications, such as phosphorylations, may lead to identification of candidates for therapeutic targets against this pathogen. Here, we present the first S/T/Y phosphosecretome of two A. baumannii strains, the reference strain ATCC 17978 and the virulent multi-drug resistant strain AB0057, cultured in two modes of growth (planktonic and biofilm) using TiO2 chromatography followed by high resolution mass spectrometry. In ATCC 17978, we detected a total of 137 (97 phosphoproteins) and 52 (33 phosphoproteins) phosphosites in biofilm and planktonic modes of growth, respectively. Similarly, in AB0057, 155 (119 phosphoproteins) and 102 (74 phosphoproteins) phosphosites in biofilm and planktonic modes of growth were identified, respectively. Both strains in the biofilm mode of growth showed a higher number of phosphosites and phosphoproteins compared to planktonic growth. Several phosphorylated sites are localized in key regions of proteins involved in either drug resistance (β-lactamases), adhesion to host tissues (pilins), or protein secretion (Hcp). Site-directed mutagenesis of the Hcp protein, essential for type VI secretion system-mediated interbacterial competition, showed that four of the modified residues are essential for type VI secretion system activity.
Collapse
Affiliation(s)
- Sébastien Massier
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
- PISSARO Proteomic Facility, IRIB, Mont-Saint-Aignan, France
| | - Brandon Robin
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
| | - Marianne Mégroz
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Amy Wright
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Marina Harper
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Brooke Hayes
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Pascal Cosette
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
- PISSARO Proteomic Facility, IRIB, Mont-Saint-Aignan, France
| | | | - John D. Boyce
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Emmanuelle Dé
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
| | - Julie Hardouin
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
- PISSARO Proteomic Facility, IRIB, Mont-Saint-Aignan, France
| |
Collapse
|
34
|
Colistin and Carbapenem-Resistant Acinetobacter baumannii Aci46 in Thailand: Genome Analysis and Antibiotic Resistance Profiling. Antibiotics (Basel) 2021; 10:antibiotics10091054. [PMID: 34572636 PMCID: PMC8468411 DOI: 10.3390/antibiotics10091054] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/26/2021] [Accepted: 08/27/2021] [Indexed: 12/12/2022] Open
Abstract
Resistance to the last-line antibiotics against invasive Gram-negative bacterial infection is a rising concern in public health. Multidrug resistant (MDR) Acinetobacter baumannii Aci46 can resist colistin and carbapenems with a minimum inhibitory concentration of 512 µg/mL as determined by microdilution method and shows no zone of inhibition by disk diffusion method. These phenotypic characteristics prompted us to further investigate the genotypic characteristics of Aci46. Next generation sequencing was applied in this study to obtain whole genome data. We determined that Aci46 belongs to Pasture ST2 and is phylogenetically clustered with international clone (IC) II as the predominant strain in Thailand. Interestingly, Aci46 is identical to Oxford ST1962 that previously has never been isolated in Thailand. Two plasmids were identified (pAci46a and pAci46b), neither of which harbors any antibiotic resistance genes but pAci46a carries a conjugational system (type 4 secretion system or T4SS). Comparative genomics with other polymyxin and carbapenem-resistant A. baumannii strains (AC30 and R14) identified shared features such as CzcCBA, encoding a cobalt/zinc/cadmium efflux RND transporter, as well as a drug transporter with a possible role in colistin and/or carbapenem resistance in A. baumannii. Single nucleotide polymorphism (SNP) analyses against MDR ACICU strain showed three novel mutations i.e., Glu229Asp, Pro200Leu, and Ala138Thr, in the polymyxin resistance component, PmrB. Overall, this study focused on Aci46 whole genome data analysis, its correlation with antibiotic resistance phenotypes, and the presence of potential virulence associated factors.
Collapse
|
35
|
Ma P, Phillips-Jones MK. Membrane Sensor Histidine Kinases: Insights from Structural, Ligand and Inhibitor Studies of Full-Length Proteins and Signalling Domains for Antibiotic Discovery. Molecules 2021; 26:molecules26165110. [PMID: 34443697 PMCID: PMC8399564 DOI: 10.3390/molecules26165110] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/02/2021] [Accepted: 08/19/2021] [Indexed: 12/19/2022] Open
Abstract
There is an urgent need to find new antibacterial agents to combat bacterial infections, including agents that inhibit novel, hitherto unexploited targets in bacterial cells. Amongst novel targets are two-component signal transduction systems (TCSs) which are the main mechanism by which bacteria sense and respond to environmental changes. TCSs typically comprise a membrane-embedded sensory protein (the sensor histidine kinase, SHK) and a partner response regulator protein. Amongst promising targets within SHKs are those involved in environmental signal detection (useful for targeting specific SHKs) and the common themes of signal transmission across the membrane and propagation to catalytic domains (for targeting multiple SHKs). However, the nature of environmental signals for the vast majority of SHKs is still lacking, and there is a paucity of structural information based on full-length membrane-bound SHKs with and without ligand. Reasons for this lack of knowledge lie in the technical challenges associated with investigations of these relatively hydrophobic membrane proteins and the inherent flexibility of these multidomain proteins that reduces the chances of successful crystallisation for structural determination by X-ray crystallography. However, in recent years there has been an explosion of information published on (a) methodology for producing active forms of full-length detergent-, liposome- and nanodisc-solubilised membrane SHKs and their use in structural studies and identification of signalling ligands and inhibitors; and (b) mechanisms of signal sensing and transduction across the membrane obtained using sensory and transmembrane domains in isolation, which reveal some commonalities as well as unique features. Here we review the most recent advances in these areas and highlight those of potential use in future strategies for antibiotic discovery. This Review is part of a Special Issue entitled “Interactions of Bacterial Molecules with Their Ligands and Other Chemical Agents” edited by Mary K. Phillips-Jones.
Collapse
Affiliation(s)
- Pikyee Ma
- Laboratory of Biomolecular Research, Paul Scherrer Institute, CH-5232 Villigen, Switzerland;
| | - Mary K. Phillips-Jones
- National Centre for Macromolecular Hydrodynamics, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK
- Correspondence:
| |
Collapse
|
36
|
Douraghi M, Aris P, To J, Myers GSA, Hamidian M. Two carbapenem-resistant ST1:ST231:KL1:OCL1 Acinetobacter baumannii strains recovered in Tehran, Iran, carry AbaR31 in the chromosome and AbaR4 and Tn aphA6 in a RepAci6 plasmid. JAC Antimicrob Resist 2021; 3:dlab112. [PMID: 34377981 PMCID: PMC8346695 DOI: 10.1093/jacamr/dlab112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 07/06/2021] [Indexed: 11/14/2022] Open
Abstract
Objectives To analyse the context of genes conferring antibiotic resistance in two carbapenem-resistant Acinetobacter baumannii isolates recovered in Tehran, Iran. Methods The antibiotic resistance phenotype for 28 antibiotics was determined using disc diffusion. The whole genome sequences of ABH008 and ABS200 were determined using the Illumina HiSeq X Ten platform. Resistance genes were identified using ResFinder and multilocus sequence types were determined using the Oxford and Institut Pasteur schemes. Results Isolates ABH008 and ABS200, recovered in 2012 and 2013, respectively, in two different Tehran hospitals, belong to the common global clone 1 lineage, ST1IP and ST231OX. They are resistant to sulfamethoxazole, tetracycline, gentamicin, amikacin, third-generation cephalosporins and carbapenems. Despite being isolated in different hospitals, phylogenetic analysis indicated they are closely related. Consistent with this, both isolates carry catA1, sul1, aacC1 and aadA1 in a novel variant of the AbaR3-type resistance island, named AbaR31. Both isolates are resistant to amikacin and carbapenems owing to aphA6 and oxa23, respectively. The oxa23 gene is located in the AbaR4 resistance island, and aphA6 in TnaphA6, and both mobile elements are in an ∼90 kbp plasmid encoding the putative RepAci6 replication initiation protein. Resistance to third-generation cephalosporins is due to the acquisition by homologous recombination of a 5 kb DNA segment that contains ISAba1-ampC from a ST623 strain. Conclusions The resistance gene complements of ABH008 and ABS200 were found in AbaR31 and a plasmid that encodes RepAci6. The close genetic relationship of ABH008 and ABS200, despite each being recovered from different hospitals, indicates transmission between the two hospitals.
Collapse
Affiliation(s)
- Masoumeh Douraghi
- Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Parisa Aris
- Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Joyce To
- The iThree institute, University of Technology Sydney, Ultimo, NSW, Australia
| | - Garry S A Myers
- The iThree institute, University of Technology Sydney, Ultimo, NSW, Australia
| | - Mohammad Hamidian
- The iThree institute, University of Technology Sydney, Ultimo, NSW, Australia
| |
Collapse
|
37
|
Interplay between meropenem and human serum albumin on expression of carbapenem resistance genes and natural competence in Acinetobacter baumannii. Antimicrob Agents Chemother 2021; 65:e0101921. [PMID: 34280015 DOI: 10.1128/aac.01019-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii A118, a mostly susceptible strain and AB5075, carbapenem-resistant, were cultured in Lysogeny broth (LB) or LB with different supplements: 3.5% human serum albumin (HSA), human serum (HS), meropenem, or meropenem plus 3.5% HSA. Natural transformation levels were enhanced in A. baumannii A118 and AB5075 cultured in medium supplemented with 3.5% HSA. Addition of meropenem plus 3.5% HSA caused synergistic enhancement of natural transformation in A. baumannii A118. Medium containing 3.5% HSA or meropenem enhanced the expression levels of the competence and type IV pilus associated genes. The combination meropenem plus 3.5% HSA produced a synergistic enhancement in the expression levels of many of these genes. The addition of HS, which has a high content of HSA, was also an inducer of these genes. Cultures grown in medium supplemented with HS or 3.5% HSA also affected resistance genes, which were expressed at higher or lower levels depending on the modification required to enhance resistance. The inducing or repressing activity of these modulators also occurred in three more carbapenem-resistant strains tested. An exception was the A. baumannii AMA16 blaNDM-1 gene, which was repressed in the presence of 3.5% HSA. In conclusion, HSA produces an enhancement of natural transformation and a modification in expression levels of competence genes and antibiotic resistance. Furthermore, when HSA is combined with carbapenems, which may increase the stress response, the expression of genes involved in natural competence is increased in A. baumannii. This process may favor the acquisition of foreign DNA and accelerate evolution. Importance Acinetobacter baumannii causes a variety of nosocomial- and community-infections that are usually resistant to multiple antimicrobial agents. As new strains acquire more resistance genes, these infections become more difficult to treat and mortality can reach up to 39%. The high genomic plasticity exhibited by A. baumannii must be the consequence of numerous mechanisms that include acquiring foreign DNA and recombination. Here, we describe the ability of A. baumannii to induce competence genes when exposed to environments that resemble those found in the human body during untreated infection or after administration of carbapenems. In this latter scenario expression of genes related to resistance also modify their expression levels such that resistance is increased. The contributions of this article are two-fold. Firstly, when A. baumannii is exposed to products present during infection, it responds, augmenting the ability to capture DNA and accelerate evolution. Secondly, in those conditions, the bacterium also modifies the expression of resistance genes to increase its resistance levels. In summary, recognition of substances that are naturally (e.g., HSA) or artificially (treatment with carbapenems) induces A. baumannii to enhance expression of resistance determinants and genes regulating competence.
Collapse
|
38
|
Lower Respiratory Tract Pathogens and Their Antimicrobial Susceptibility Pattern: A 5-Year Study. Antibiotics (Basel) 2021; 10:antibiotics10070851. [PMID: 34356772 PMCID: PMC8300710 DOI: 10.3390/antibiotics10070851] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/30/2021] [Accepted: 07/09/2021] [Indexed: 12/11/2022] Open
Abstract
Lower respiratory tract infections (LRTIs) are the most common infections in humans. It is estimated that 2.74 million deaths worldwide occur each year due to LRTIs. The aim of the study was to determine the frequency and antibiotic susceptibility pattern of microorganisms isolated from respiratory samples of patients with LRTIs. Between January 2015 and December 2019, a total of 7038 sputum and bronchoaspirate samples from suspected LRTI patients were collected. Among them, 2753 samples (39.1%) showed significant microbial growth on culture media. The LRTI rate was higher in patients with male gender (67.1%) and with age between 40–59 years (48.6%). The microorganism identification and antibiotic susceptibility testing were performed with Vitek 2. Out of 4278 isolates species, 3102 (72.5%) were Gram-negative bacteria, 1048 (24.5%) were Gram-positive bacteria, and 128 (3.0%) were Candida spp. Major microorganisms isolated were Acinetobacter baumannii (18.6%), Staphylococcus aureus (15.2%), Pseudomonas aeruginosa (14.2%), and Klebsiella pneumoniae (10.9%). In antimicrobial susceptibility testing, Staphylococcus aureus isolates were mostly resistant to Penicillin G (84.1%) and Oxacillin (48.1%), whereas they demonstrated maximum sensitivity to Tigecycline (100%) and Linezolid (99.5%). Among Gram-negative isolates, Acinetobacter baumannii showed maximum sensitivity to Colistin but was resistant to other antibiotics (95–99%). Klebsiella pneumoniae isolates were mostly resistant to Cefotaxime (72.7%) and sensitive to Gentamicin (54.3%), and Pseudomonas aeruginosa was resistant to Ciprofloxacin (40.3%) and sensitive to Amikacin (85.9%). Gram-negative bacteria represented the species most commonly isolated. A high rate of antimicrobial resistance was observed in this study. In conclusion, the correct identification of causative microorganisms and their susceptibility patterns to antibiotics is crucial for choosing targeted and effective antibiotic therapy in LRTIs, and to prevent the emergence of multidrug-resistant bacteria.
Collapse
|
39
|
Pimentel C, Le C, Tuttobene MR, Subils T, Papp-Wallace KM, Bonomo RA, Tolmasky ME, Ramirez MS. Interaction of Acinetobacter baumannii with Human Serum Albumin: Does the Host Determine the Outcome? Antibiotics (Basel) 2021; 10:antibiotics10070833. [PMID: 34356754 PMCID: PMC8300715 DOI: 10.3390/antibiotics10070833] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/06/2021] [Accepted: 07/06/2021] [Indexed: 01/16/2023] Open
Abstract
Acinetobacter baumannii has become a serious threat to human health due to its extreme antibiotic resistance, environmental persistence, and capacity to survive within the host. Two A. baumannii strains, A118 and AB5075, commonly used as model systems, and three carbapenem-resistant strains, which are becoming ever more dangerous due to the multiple drugs they can resist, were exposed to 3.5% human serum albumin (HSA) and human serum (HS) to evaluate their response with respect to antimicrobial resistance, biofilm formation, and quorum sensing, all features responsible for increasing survival and persistence in the environment and human body. Expression levels of antibiotic resistance genes were modified differently when examined in different strains. The cmlA gene was upregulated or downregulated in conditions of exposure to 3.5% HSA or HS depending on the strain. Expression levels of pbp1 and pbp3 tended to be increased by the presence of HSA and HS, but the effect was not seen in all strains. A. baumannii A118 growing in the presence of HS did not experience increased expression of these genes. Aminoglycoside-modifying enzymes were also expressed at higher or lower levels in the presence of HSA or HS. Still, the response was not uniform; in some cases, expression was enhanced, and in other cases, it was tapered. While A. baumannii AB5075 became more susceptible to rifampicin in the presence of 3.5% HSA or HS, strain A118 did not show any changes. Expression of arr2, a gene involved in resistance to rifampicin present in A. baumannii AMA16, was expressed at higher levels when HS was present in the culture medium. HSA and HS reduced biofilm formation and production of N-Acyl Homoserine Lactone, a compound intimately associated with quorum sensing. In conclusion, HSA, the main component of HS, stimulates a variety of adaptative responses in infecting A. baumannii strains.
Collapse
Affiliation(s)
- Camila Pimentel
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831-3599, USA; (C.P.); (C.L.); (M.E.T.)
| | - Casin Le
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831-3599, USA; (C.P.); (C.L.); (M.E.T.)
| | - Marisel R. Tuttobene
- Área Biología Molecular, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario 2000, Argentina;
| | - Tomas Subils
- Instituto de Procesos Biotecnológicos y Químicos de Rosario (IPROBYQ, CONICET-UNR), Rosario S2002LRK, Argentina;
| | - Krisztina M. Papp-Wallace
- Research Service and GRECC, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA; (K.M.P.-W.); (R.A.B.)
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH 44106, USA
| | - Robert A. Bonomo
- Research Service and GRECC, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA; (K.M.P.-W.); (R.A.B.)
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH 44106, USA
| | - Marcelo E. Tolmasky
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831-3599, USA; (C.P.); (C.L.); (M.E.T.)
| | - Maria Soledad Ramirez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831-3599, USA; (C.P.); (C.L.); (M.E.T.)
- Correspondence: ; Tel.: +1-657-278-4562
| |
Collapse
|
40
|
Antimicrobial Resistance Determinants in Genomes and Plasmids from Acinetobacter baumannii Clinical Isolates. Antibiotics (Basel) 2021; 10:antibiotics10070753. [PMID: 34206348 PMCID: PMC8300758 DOI: 10.3390/antibiotics10070753] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 06/13/2021] [Indexed: 12/30/2022] Open
Abstract
Acinetobacter baumannii is a Gram-negative coccoid rod species, clinically relevant as a human pathogen, included in the ESKAPE group. Carbapenem-resistant A. baumannii (CRAB) are considered by the World Health Organization (WHO) as a critical priority pathogen for the research and development of new antibiotics. Some of the most relevant features of this pathogen are its intrinsic multidrug resistance and its ability to acquire rapid and effective new resistant determinants against last-resort clinical antibiotics, mostly from other ESKAPE species. The presence of plasmids and mobile genetic elements in their genomes contributes to the acquisition of new antimicrobial resistance determinants. However, although A. baumannii has arisen as an important human pathogen, information about these elements is still not well understood. Current genomic analysis availability has increased our ability to understand the microevolution of bacterial pathogens, including point mutations, genetic dissemination, genomic stability, and pan- and core-genome compositions. In this work, we deeply studied the genomes of four clinical strains from our hospital, and the reference strain ATCC®19606TM, which have shown a remarkable ability to survive and maintain their effective capacity when subjected to long-term stress conditions. With that, our aim was presenting a detailed analysis of their genomes, including antibiotic resistance determinants and plasmid composition.
Collapse
|
41
|
Abstract
Acinetobacter spp. have become of increased clinical importance as studies have shown the antimicrobial resistant potential of these species. Efflux pumps can lead to reduced susceptibility to a variety of antibiotics and are present in large number across Acinetobacter spp. There are six families of efflux pumps that have been shown to be of clinical relevance: the major facilitator superfamily (MFS), small multidrug resistance (SMR) family, ATP-binding cassette (ABC) family, multidrug and toxic compound extrusion (MATE) family, proteobacterial antimicrobial compound efflux (PACE) family, and the resistance-nodulation-division (RND) family. Much work has been done for understanding and characterizing the roles these efflux pumps play in relation to antimicrobial resistance and the physiology of these bacteria. RND efflux pumps, with their expansive substrate profiles, are a major component of Acinetobacter spp. antimicrobial resistance. New discoveries over the last decade have shed light on the complex regulation of these efflux pumps, leading to greater understanding and the potential of slowing the reduced susceptibility seen in these bacterial species.
Collapse
|
42
|
Discrimination of hospital isolates of Acinetobacter baumannii using repeated sequences and whole genome alignment differential analysis. J Appl Genet 2021; 62:511-521. [PMID: 34105103 PMCID: PMC8357709 DOI: 10.1007/s13353-021-00640-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 03/08/2021] [Accepted: 05/19/2021] [Indexed: 11/13/2022]
Abstract
An optimized method for bacterial strain differentiation, based on combination of Repeated Sequences and Whole Genome Alignment Differential Analysis (RS&WGADA), is presented in this report. In this analysis, 51 Acinetobacter baumannii multidrug-resistance strains from one hospital environment and patients from 14 hospital wards were classified on the basis of polymorphisms of repeated sequences located in CRISPR region, variation in the gene encoding the EmrA-homologue of E. coli, and antibiotic resistance patterns, in combination with three newly identified polymorphic regions in the genomes of A. baumannii clinical isolates. Differential analysis of two similarity matrices between different genotypes and resistance patterns allowed to distinguish three significant correlations (p < 0.05) between 172 bp DNA insertion combined with resistance to chloramphenicol and gentamycin. Interestingly, 45 and 55 bp DNA insertions within the CRISPR region were identified, and combined during analyses with resistance/susceptibility to trimethoprim/sulfamethoxazole. Moreover, 184 or 1374 bp DNA length polymorphisms in the genomic region located upstream of the GTP cyclohydrolase I gene, associated mainly with imipenem susceptibility, was identified. In addition, considerable nucleotide polymorphism of the gene encoding the gamma/tau subunit of DNA polymerase III, an enzyme crucial for bacterial DNA replication, was discovered. The differentiation analysis performed using the above described approach allowed us to monitor the distribution of A. baumannii isolates in different wards of the hospital in the time frame of several years, indicating that the optimized method may be useful in hospital epidemiological studies, particularly in identification of the source of primary infections.
Collapse
|
43
|
Pan-Resistome Insights into the Multidrug Resistance of Acinetobacter baumannii. Antibiotics (Basel) 2021; 10:antibiotics10050596. [PMID: 34069870 PMCID: PMC8157372 DOI: 10.3390/antibiotics10050596] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/18/2021] [Accepted: 04/22/2021] [Indexed: 02/02/2023] Open
Abstract
Acinetobacter baumannii is an important Gram-negative opportunistic pathogen that is responsible for many nosocomial infections. This etiologic agent has acquired, over the years, multiple mechanisms of resistance to a wide range of antimicrobials and the ability to survive in different environments. In this context, our study aims to elucidate the resistome from the A. baumannii strains based on phylogenetic, phylogenomic, and comparative genomics analyses. In silico analysis of the complete genomes of A. baumannii strains was carried out to identify genes involved in the resistance mechanisms and the phylogenetic relationships and grouping of the strains based on the sequence type. The presence of genomic islands containing most of the resistance gene repertoire indicated high genomic plasticity, which probably enabled the acquisition of resistance genes and the formation of a robust resistome. A. baumannii displayed an open pan-genome and revealed a still constant genetic permutation among their strains. Furthermore, the resistance genes suggest a specific profile within the species throughout its evolutionary history. Moreover, the current study performed screening and characterization of the main genes present in the resistome, which can be used in applied research to develop new therapeutic methods to control this important bacterial pathogen.
Collapse
|
44
|
Borelli TC, Lovate GL, Scaranello AFT, Ribeiro LF, Zaramela L, Pereira-dos-Santos FM, Silva-Rocha R, Guazzaroni ME. Combining Functional Genomics and Whole-Genome Sequencing to Detect Antibiotic Resistance Genes in Bacterial Strains Co-Occurring Simultaneously in a Brazilian Hospital. Antibiotics (Basel) 2021; 10:antibiotics10040419. [PMID: 33920372 PMCID: PMC8070361 DOI: 10.3390/antibiotics10040419] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/01/2021] [Accepted: 04/06/2021] [Indexed: 01/01/2023] Open
Abstract
(1) Background: The rise of multi-antibiotic resistant bacteria represents an emergent threat to human health. Here, we investigate antibiotic resistance mechanisms in bacteria of several species isolated from an intensive care unit in Brazil. (2) Methods: We used whole-genome analysis to identify antibiotic resistance genes (ARGs) and plasmids in 34 strains of Gram-negative and Gram-positive bacteria, providing the first genomic description of Morganella morganii and Ralstonia mannitolilytica clinical isolates from South America. (3) Results: We identified a high abundance of beta-lactamase genes in resistant organisms, including seven extended-spectrum beta-lactamases (OXA-1, OXA-10, CTX-M-1, KPC, TEM, HYDRO, BLP) shared between organisms from different species. Additionally, we identified several ARG-carrying plasmids indicating the potential for a fast transmission of resistance mechanism between bacterial strains. Furthermore, we uncovered two pairs of (near) identical plasmids exhibiting multi-drug resistance. Finally, since many highly resistant strains carry several different ARGs, we used functional genomics to investigate which of them were indeed functional. In this sense, for three bacterial strains (Escherichia coli, Klebsiella pneumoniae, and M. morganii), we identified six beta-lactamase genes out of 15 predicted in silico as those mainly responsible for the resistance mechanisms observed, corroborating the existence of redundant resistance mechanisms in these organisms. (4) Conclusions: Systematic studies similar to the one presented here should help to prevent outbreaks of novel multidrug-resistant bacteria in healthcare facilities.
Collapse
Affiliation(s)
- Tiago Cabral Borelli
- Department of Biology, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14049-901, Brazil; (T.C.B.); (G.L.L.); (A.F.T.S.); (L.F.R.)
| | - Gabriel Lencioni Lovate
- Department of Biology, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14049-901, Brazil; (T.C.B.); (G.L.L.); (A.F.T.S.); (L.F.R.)
| | - Ana Flavia Tonelli Scaranello
- Department of Biology, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14049-901, Brazil; (T.C.B.); (G.L.L.); (A.F.T.S.); (L.F.R.)
| | - Lucas Ferreira Ribeiro
- Department of Biology, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14049-901, Brazil; (T.C.B.); (G.L.L.); (A.F.T.S.); (L.F.R.)
| | - Livia Zaramela
- Department of Pediatrics, University of California San Diego, San Diego, CA 92161, USA;
| | - Felipe Marcelo Pereira-dos-Santos
- Department of Cell and Molecular Biology, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14049-900, Brazil; (F.M.P.-d.-S.); (R.S.-R.)
| | - Rafael Silva-Rocha
- Department of Cell and Molecular Biology, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14049-900, Brazil; (F.M.P.-d.-S.); (R.S.-R.)
| | - María-Eugenia Guazzaroni
- Department of Biology, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14049-901, Brazil; (T.C.B.); (G.L.L.); (A.F.T.S.); (L.F.R.)
- Correspondence:
| |
Collapse
|
45
|
Colistin Dependence in Extensively Drug-Resistant Acinetobacter baumannii Strain Is Associated with IS Ajo2 and IS Aba13 Insertions and Multiple Cellular Responses. Int J Mol Sci 2021; 22:ijms22020576. [PMID: 33430070 PMCID: PMC7827689 DOI: 10.3390/ijms22020576] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 02/06/2023] Open
Abstract
The nosocomial opportunistic Gram-negative bacterial pathogen Acinetobacter baumannii is resistant to multiple antimicrobial agents and an emerging global health problem. The polymyxin antibiotic colistin, targeting the negatively charged lipid A component of the lipopolysaccharide on the bacterial cell surface, is often considered as the last-resort treatment, but resistance to colistin is unfortunately increasing worldwide. Notably, colistin-susceptible A. baumannii can also develop a colistin dependence after exposure to this drug in vitro. Colistin dependence might represent a stepping stone to resistance also in vivo. However, the mechanisms are far from clear. To address this issue, we combined proteogenomics, high-resolution microscopy, and lipid profiling to characterize and compare A. baumannii colistin-susceptible clinical isolate (Ab-S) of to its colistin-dependent subpopulation (Ab-D) obtained after subsequent passages in moderate colistin concentrations. Incidentally, in the colistin-dependent subpopulation the lpxA gene was disrupted by insertion of ISAjo2, the lipid A biosynthesis terminated, and Ab-D cells displayed a lipooligosaccharide (LOS)-deficient phenotype. Moreover, both mlaD and pldA genes were perturbed by insertions of ISAjo2 and ISAba13, and LOS-deficient bacteria displayed a capsule with decreased thickness as well as other surface imperfections. The major changes in relative protein abundance levels were detected in type 6 secretion system (T6SS) components, the resistance-nodulation-division (RND)-type efflux pumps, and in proteins involved in maintenance of outer membrane asymmetry. These findings suggest that colistin dependence in A. baumannii involves an ensemble of mechanisms seen in resistance development and accompanied by complex cellular events related to insertional sequences (ISs)-triggered LOS-deficiency. To our knowledge, this is the first study demonstrating the involvement of ISAjo2 and ISAba13 IS elements in the modulation of the lipid A biosynthesis and associated development of dependence on colistin.
Collapse
|
46
|
Deems A, Du Prey M, Dowd SE, McLaughlin RW. Characterization of the Biodiesel Degrading Acinetobacter oleivorans Strain PT8 Isolated from the Fecal Material of a Painted Turtle (Chrysemys picta). Curr Microbiol 2021; 78:522-527. [PMID: 33392672 DOI: 10.1007/s00284-020-02320-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 12/07/2020] [Indexed: 11/26/2022]
Abstract
Acinetobacter species are gram-negative, non-fermenting bacteria with coccobacilli morphology. The bacteria are found ubiquitously and have the ability to occupy niches which include environmental sites, animals, and humans. The original purpose of this study was to determine if painted turtles (Chrysemys picta) living in the wild in Western Wisconsin were colonized with carbapenem-resistant bacteria. Fecal samples from ten turtles were examined for carbapenem-resistant bacteria. None of the isolates were found to be carbapenem resistant by antimicrobial susceptibility testing. However, all the isolates were resistant to other β-lactams and chloramphenicol classes of antimicrobials. One isolate, Acinetobacter oleivorans strain PT8, was selected for additional characterization, including whole-genome sequencing (WGS). Strain PT8 is capable of degrading biodiesel, forming biofilms, and has a putative type 6 gene cluster. Finally, the taxonomic position of the available whole-genome sequences of 25 A. oleivorans genomes from purified isolates was determined.
Collapse
Affiliation(s)
- Amanda Deems
- General Studies, Gateway Technical College, 3520-30th Avenue, Kenosha, WI, 53144, USA
| | - Michael Du Prey
- General Studies, Gateway Technical College, 3520-30th Avenue, Kenosha, WI, 53144, USA
| | - Scot E Dowd
- MR DNA (Molecular Research LP), Shallowater, TX, USA
| | | |
Collapse
|
47
|
Ayibieke A, Kobayashi A, Suzuki M, Sato W, Mahazu S, Prah I, Mizoguchi M, Moriya K, Hayashi T, Suzuki T, Iwanaga S, Ablordey A, Saito R. Prevalence and Characterization of Carbapenem-Hydrolyzing Class D β-Lactamase-Producing Acinetobacter Isolates From Ghana. Front Microbiol 2020; 11:587398. [PMID: 33281784 PMCID: PMC7691484 DOI: 10.3389/fmicb.2020.587398] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 10/15/2020] [Indexed: 12/14/2022] Open
Abstract
Multidrug resistance, especially carbapenem resistance in Acinetobacter bacteria is a global healthcare concern. However, available data on the phenotypic and genotypic characteristics of Acinetobacter isolates from West Africa, including Ghana is scanty. Our aim was to investigate the antibiotic resistance profile and genotypic characteristics of Acinetobacter isolates from Ghana and to characterize carbapenemase producers using whole-genome sequencing (WGS). A total of 36 Acinetobacter isolates collected at three hospitals in Ghana between 2016 and 2017 were analyzed. MICs were determined by commercial antibiotic plates. Acinetobacter baumannii MLST was determined using the Pasteur scheme. WGS of OXA-carbapenemase producers was performed using short- and long-read sequencing strategies. The resistance rate was highest for trimethoprim/sulfamethoxazole (n = 22; 61%). Six (16.7%) and eight (22.2%) isolates were resistant to ceftazidime and colistin, respectively. Two (5.6%) isolates were resistant and one (2.8%) isolate had intermediate sensitivity to three carbapenems. Fifteen STs were identified in 24 A. baumannii isolates including six new STs (ST1467 ∼ ST1472). ST78 was the predominant (n = 6) followed by ST1469 (n = 3). Four carbapenemase-producing A. baumannii isolates also were identified. Isogenic ST103 isolates Ab-B004d-c and Ab-D10a-a harbored blaOXA–23 within Tn2007 on identical plasmids, pAb-B004d-c_3, and pAb-D10a-a_3. ST1472 isolate Ab-C102 and ST107 isolate Ab-C63 carried blaOXA–58 and blaOXA–420, a rare blaOXA–58 variant, respectively, within novel genetic contexts. Our results show that A. baumannii isolates of diverse and unique genotypes, including OXA-carbapenemase producers, are circulating in Ghana highlighting the need for a wider surveillance of antimicrobial resistance.
Collapse
Affiliation(s)
- Alafate Ayibieke
- Department of Molecular Microbiology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Ayumi Kobayashi
- Department of Molecular Microbiology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Masato Suzuki
- Antimicrobial Resistance Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Wakana Sato
- Department of Molecular Microbiology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Samiratu Mahazu
- Department of Molecular Microbiology, Tokyo Medical and Dental University, Tokyo, Japan.,Department of Environmental Parasitology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Isaac Prah
- Department of Molecular Microbiology, Tokyo Medical and Dental University, Tokyo, Japan.,Department of Molecular Virology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Miyuki Mizoguchi
- Department of Infection Control and Prevention, The University of Tokyo Hospital, Tokyo, Japan
| | - Kyoji Moriya
- Department of Infection Control and Prevention, The University of Tokyo Hospital, Tokyo, Japan
| | - Takaya Hayashi
- Department of Molecular Virology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Toshihiko Suzuki
- Department of Bacterial Pathogenesis, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shiroh Iwanaga
- Department of Environmental Parasitology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Anthony Ablordey
- Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Ryoichi Saito
- Department of Molecular Microbiology, Tokyo Medical and Dental University, Tokyo, Japan
| |
Collapse
|
48
|
Sheldon JR, Skaar EP. Acinetobacter baumannii can use multiple siderophores for iron acquisition, but only acinetobactin is required for virulence. PLoS Pathog 2020; 16:e1008995. [PMID: 33075115 PMCID: PMC7595644 DOI: 10.1371/journal.ppat.1008995] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 10/29/2020] [Accepted: 09/18/2020] [Indexed: 12/22/2022] Open
Abstract
Acinetobacter baumannii is an emerging pathogen that poses a global health threat due to a lack of therapeutic options for treating drug-resistant strains. In addition to acquiring resistance to last-resort antibiotics, the success of A. baumannii is partially due to its ability to effectively compete with the host for essential metals. Iron is fundamental in shaping host-pathogen interactions, where the host restricts availability of this nutrient in an effort to curtail bacterial proliferation. To circumvent restriction, pathogens possess numerous mechanisms to obtain iron, including through the use of iron-scavenging siderophores. A. baumannii elaborates up to ten distinct siderophores, encoded from three different loci: acinetobactin and pre-acinetobactin (collectively, acinetobactin), baumannoferrins A and B, and fimsbactins A-F. The expression of multiple siderophores is common amongst bacterial pathogens and often linked to virulence, yet the collective contribution of these siderophores to A. baumannii survival and pathogenesis has not been investigated. Here we begin dissecting functional redundancy in the siderophore-based iron acquisition pathways of A. baumannii. Excess iron inhibits overall siderophore production by the bacterium, and the siderophore-associated loci are uniformly upregulated during iron restriction in vitro and in vivo. Further, disrupting all of the siderophore biosynthetic pathways is necessary to drastically reduce total siderophore production by A. baumannii, together suggesting a high degree of functional redundancy between the metabolites. By contrast, inactivation of acinetobactin biosynthesis alone impairs growth on human serum, transferrin, and lactoferrin, and severely attenuates survival of A. baumannii in a murine bacteremia model. These results suggest that whilst A. baumannii synthesizes multiple iron chelators, acinetobactin is critical to supporting growth of the pathogen on host iron sources. Given the acinetobactin locus is highly conserved and required for virulence of A. baumannii, designing therapeutics targeting the biosynthesis and/or transport of this siderophore may represent an effective means of combating this pathogen.
Collapse
Affiliation(s)
- Jessica R. Sheldon
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Eric P. Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- * E-mail:
| |
Collapse
|
49
|
Laird TS, Flores N, Leveau JHJ. Bacterial catabolism of indole-3-acetic acid. Appl Microbiol Biotechnol 2020; 104:9535-9550. [PMID: 33037916 DOI: 10.1007/s00253-020-10938-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/21/2020] [Accepted: 09/27/2020] [Indexed: 12/18/2022]
Abstract
Indole-3-acetic acid (IAA) is a molecule with the chemical formula C10H9NO2, with a demonstrated presence in various environments and organisms, and with a biological function in several of these organisms, most notably in plants where it acts as a growth hormone. The existence of microorganisms with the ability to catabolize or assimilate IAA has long been recognized. To date, two sets of gene clusters underlying this property in bacteria have been identified and characterized: one (iac) is responsible for the aerobic degradation of IAA into catechol, and another (iaa) for the anaerobic conversion of IAA to 2-aminobenzoyl-CoA. Here, we summarize the literature on the products, reactions, and pathways that these gene clusters encode. We explore two hypotheses about the benefit that iac/iaa gene clusters confer upon their bacterial hosts: (1) exploitation of IAA as a source of carbon, nitrogen, and energy; and (2) interference with IAA-dependent processes and functions in other organisms, including plants. The evidence for both hypotheses will be reviewed for iac/iaa-carrying model strains of Pseudomonas putida, Enterobacter soli, Acinetobacter baumannii, Paraburkholderia phytofirmans, Caballeronia glathei, Aromatoleum evansii, and Aromatoleum aromaticum, more specifically in the context of access to IAA in the environments from which these bacteria were originally isolated, which include not only plants, but also soils and sediment, as well as patients in hospital environments. We end the mini-review with an outlook for iac/iaa-inspired research that addresses current gaps in knowledge, biotechnological applications of iac/iaa-encoded enzymology, and the use of IAA-destroying bacteria to treat pathologies related to IAA excess in plants and humans. KEY POINTS: • The iac/iaa gene clusters encode bacterial catabolism of the plant growth hormone IAA. • Plants are not the only environment where IAA or IAA-degrading bacteria can be found. • The iac/iaa genes allow growth at the expense of IAA; other benefits remain unknown.
Collapse
Affiliation(s)
- Tyler S Laird
- Department of Plant Pathology, University of California Davis, Davis, CA, 95616, USA
| | - Neptali Flores
- Department of Plant Pathology, University of California Davis, Davis, CA, 95616, USA
| | - Johan H J Leveau
- Department of Plant Pathology, University of California Davis, Davis, CA, 95616, USA.
| |
Collapse
|
50
|
A Diverse Panel of Clinical Acinetobacter baumannii for Research and Development. Antimicrob Agents Chemother 2020; 64:AAC.00840-20. [PMID: 32718956 DOI: 10.1128/aac.00840-20] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/18/2020] [Indexed: 12/20/2022] Open
Abstract
Over the past two decades, Acinetobacter baumannii has emerged as a leading cause of nosocomial infections worldwide. Of particular concern are panresistant strains, leading the World Health Organization (WHO) to designate carbapenem-resistant A. baumannii as a priority 1 (critical) pathogen for research and development of new antibiotics. A key component in supporting this effort is accessibility to diverse and clinically relevant strains for testing. Here, we describe a panel of 100 diverse A. baumannii strains for use in this endeavor. Whole-genome sequencing was performed on 3,505 A. baumannii isolates housed at the Multidrug-Resistant Organism Repository and Surveillance Network. Isolates were cultured from clinical samples at health care facilities around the world between 2001 and 2017. Core-genome multilocus sequence typing and high-resolution single nucleotide polymorphism (SNP)-based phylogenetic analyses were used to select a final panel of 100 strains that captured the genetic diversity of the collection. Comprehensive antibiotic susceptibility testing was also performed on all 100 isolates using 14 clinically relevant antibiotics. The final 100-strain diversity panel contained representative strains from 70 different traditional Pasteur scheme multilocus sequence types, including major epidemic clones. This diversity was also reflected in antibiotic susceptibility and antimicrobial resistance (AMR) gene content, with phenotypes ranging from pansensitive to panresistant, and over 100 distinct AMR gene alleles identified from 32 gene families. This panel provides the most diverse and comprehensive set of A. baumannii strains for use in developing solutions for combating antibiotic resistance. The panel and all available metadata, including genome sequences, will be available to industry and academic institutions and federal and other laboratories free of charge.
Collapse
|