1
|
Yin C, Alam MZ, Fallon JT, Huang W. Advances in Development of Novel Therapeutic Strategies against Multi-Drug Resistant Pseudomonas aeruginosa. Antibiotics (Basel) 2024; 13:119. [PMID: 38391505 PMCID: PMC10885988 DOI: 10.3390/antibiotics13020119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/19/2024] [Accepted: 01/23/2024] [Indexed: 02/24/2024] Open
Abstract
Pseudomonas aeruginosa (P. aeruginosa) with multi-drug resistance (MDR) is a major cause of serious healthcare-associated infections, leading to high morbidity and mortality. This opportunistic pathogen is responsible for various infectious diseases, such as those seen in cystic fibrosis, ventilator-associated pneumonia, urinary tract infection, otitis externa, and burn and wound injuries. Due to its relatively large genome, P. aeruginosa has great diversity and can use various molecular mechanisms for antimicrobial resistance. For example, outer membrane permeability can contribute to antimicrobial resistance and is determined by lipopolysaccharide (LPS) and porin proteins. Recent findings on the regulatory interaction between peptidoglycan and LPS synthesis provide additional clues against pathogenic P. aeruginosa. This review focuses on recent advances in antimicrobial agents and inhibitors targeting LPS and porin proteins. In addition, we explore current and emerging treatment strategies for MDR P. aeruginosa, including phages, vaccines, nanoparticles, and their combinatorial therapies. Novel strategies and their corresponding therapeutic agents are urgently needed for combating MDR pathogens.
Collapse
Affiliation(s)
- Changhong Yin
- Department of Pathology and Laboratory Medicine, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | - Md Zahidul Alam
- Department of Pathology and Laboratory Medicine, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | - John T Fallon
- Department of Pathology and Laboratory Medicine, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | - Weihua Huang
- Department of Pathology and Laboratory Medicine, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| |
Collapse
|
2
|
Erdmann MB, Gardner PP, Lamont IL. The PitA protein contributes to colistin susceptibility in Pseudomonas aeruginosa. PLoS One 2023; 18:e0292818. [PMID: 37824582 PMCID: PMC10569645 DOI: 10.1371/journal.pone.0292818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 09/28/2023] [Indexed: 10/14/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes a wide range of problematic infections in individuals with predisposing conditions. Infections can be treated with colistin but some isolates are resistant to this antibiotic. To better understand the genetic basis of resistance, we experimentally evolved 19 independent resistant mutants from the susceptible laboratory strain PAO1. Whole genome sequencing identified mutations in multiple genes including phoQ and pmrB that have previously been associated with resistance, pitA that encodes a phosphate transporter, and carB and eno that encode enzymes of metabolism. Individual mutations were engineered into the genome of strain PAO1. Mutations in pitA, pmrB and phoQ increased the minimum inhibitory concentration (MIC) for colistin 8-fold, making the bacteria resistant. Engineered pitA/phoQ and pitA/pmrB double mutants had higher MICs than single mutants, demonstrating additive effects on colistin susceptibility. Single carB and eno mutations did not increase the MIC suggesting that their effect is dependent on the presence of other mutations. Many of the resistant mutants had increased susceptibility to β-lactams and lower growth rates than the parental strain demonstrating that colistin resistance can impose a fitness cost. Two hundred and fourteen P. aeruginosa isolates from a range of sources were tested and 18 (7.8%) were colistin resistant. Sequence variants in genes identified by experimental evolution were present in the 18 resistant isolates and may contribute to resistance. Overall our results identify pitA mutations as novel contributors to colistin resistance and demonstrate that resistance can reduce fitness of the bacteria.
Collapse
Affiliation(s)
| | - Paul P. Gardner
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Iain L. Lamont
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| |
Collapse
|
3
|
Liang Y, Li J, Xu Y, He Y, Jiang B, Wu C, Shan B, Shi H, Song G. Genomic variations in polymyxin-resistant Pseudomonas aeruginosa clinical isolates and their effects on polymyxin resistance. Braz J Microbiol 2023; 54:655-664. [PMID: 36930447 PMCID: PMC10234930 DOI: 10.1007/s42770-023-00933-3] [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: 10/30/2022] [Accepted: 02/13/2023] [Indexed: 03/18/2023] Open
Abstract
Infection with P. aeruginosa, one of the most relevant opportunistic pathogens in hospital-acquired infections, can lead to high mortality due to its low antibiotic susceptibility to limited choices of antibiotics. Polymyxin as last-resort antibiotics is used in the treatment of systemic infections caused by multidrug-resistant P. aeruginosa strains, so studying the emergence of polymyxin-resistant was a must. The present study was designed to define genomic differences between paired polymyxin-susceptible and polymyxin-resistant P. aeruginosa strains and established polymyxin resistance mechanisms, and common chromosomal mutations that may confer polymyxin resistance were characterized. A total of 116 CRPA clinical isolates from patients were collected from three tertiary care hospitals in China during 2017-2021. Our study found that polymyxin B resistance represented 3.45% of the isolated carbapenem-resistant P. aeruginosa (CRPA). No polymyxin-resistant isolates were positive for mcr (1-8 and 10) gene and efflux mechanisms. Key genetic variations identified in polymyxin-resistant isolates involved missense mutations in parR, parS, pmrB, pmrA, and phoP. The waaL and PA5005 substitutions related to LPS synthesis were detected in the highest levels of resistant strain (R1). The missense mutations H398R in ParS (4/4), Y345H in PmrB (4/4), and L71R in PmrA (3/4) were the predominant. Results of the PCR further confirmed that mutation of pmrA, pmrB, and phoP individually or simultaneously did affect the expression level of resistant populations and can directly increase the expression of arnBCADTEF operon to contribute to polymyxin resistance. In addition, we reported 3 novel mutations in PA1945 (2129872_A < G, 2130270_A < C, 2130272_T < G) that may confer polymyxin resistance in P. aeruginosa. Our findings enriched the spectrum of chromosomal mutations, highlighted the complexity at the molecular level, and multifaceted interplay mechanisms underlying polymyxin resistance in P. aeruginosa.
Collapse
Affiliation(s)
- Yuan Liang
- Department of Clinical Laboratory, First Affiliated Hospital of Kunming Medical University, Kunming, 650032, China
- Yunnan Key Laboratory of Laboratory Medicine, Kunming, 650032, China
- Yunnan Province Clinical Research Center for Laboratory Medicine, Kunming, 650032, China
| | - Jie Li
- Department of Clinical Laboratory, First Affiliated Hospital of Kunming Medical University, Kunming, 650032, China
- Yunnan Key Laboratory of Laboratory Medicine, Kunming, 650032, China
- Yunnan Province Clinical Research Center for Laboratory Medicine, Kunming, 650032, China
| | - Yunmin Xu
- Department of Clinical Laboratory, First Affiliated Hospital of Kunming Medical University, Kunming, 650032, China
- Yunnan Key Laboratory of Laboratory Medicine, Kunming, 650032, China
- Yunnan Province Clinical Research Center for Laboratory Medicine, Kunming, 650032, China
| | - Yuan He
- Department of Clinical Laboratory, First Affiliated Hospital of Kunming Medical University, Kunming, 650032, China
- Yunnan Key Laboratory of Laboratory Medicine, Kunming, 650032, China
- Yunnan Province Clinical Research Center for Laboratory Medicine, Kunming, 650032, China
| | - Bo Jiang
- Department of Clinical Laboratory, First Affiliated Hospital of Kunming Medical University, Kunming, 650032, China
- Yunnan Key Laboratory of Laboratory Medicine, Kunming, 650032, China
- Yunnan Province Clinical Research Center for Laboratory Medicine, Kunming, 650032, China
| | - Chunyan Wu
- Department of Clinical Laboratory, First Affiliated Hospital of Kunming Medical University, Kunming, 650032, China
- Yunnan Key Laboratory of Laboratory Medicine, Kunming, 650032, China
- Yunnan Province Clinical Research Center for Laboratory Medicine, Kunming, 650032, China
| | - Bin Shan
- Department of Clinical Laboratory, First Affiliated Hospital of Kunming Medical University, Kunming, 650032, China
- Yunnan Key Laboratory of Laboratory Medicine, Kunming, 650032, China
- Yunnan Province Clinical Research Center for Laboratory Medicine, Kunming, 650032, China
| | - Hongqiong Shi
- Department of Clinical Laboratory, First Affiliated Hospital of Kunming Medical University, Kunming, 650032, China.
- Yunnan Key Laboratory of Laboratory Medicine, Kunming, 650032, China.
- Yunnan Province Clinical Research Center for Laboratory Medicine, Kunming, 650032, China.
| | - Guibo Song
- Department of Clinical Laboratory, First Affiliated Hospital of Kunming Medical University, Kunming, 650032, China.
- Yunnan Key Laboratory of Laboratory Medicine, Kunming, 650032, China.
- Yunnan Province Clinical Research Center for Laboratory Medicine, Kunming, 650032, China.
| |
Collapse
|
4
|
Collalto D, Fortuna A, Visca P, Imperi F, Rampioni G, Leoni L. Synergistic Activity of Colistin in Combination with Clofoctol against Colistin Resistant Gram-Negative Pathogens. Microbiol Spectr 2023; 11:e0427522. [PMID: 36802038 PMCID: PMC10100712 DOI: 10.1128/spectrum.04275-22] [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: 11/08/2022] [Accepted: 01/31/2023] [Indexed: 02/23/2023] Open
Abstract
Colistin is a bactericidal antibiotic identified decades ago which is active against a number of Gram-negative pathogens. After early elimination from clinical use due to toxicity issues, colistin has been reintroduced as a last-resort treatment for antibiotic-resistant Gram-negative infections lacking other therapeutic options. Inevitably, colistin resistance has emerged among clinical isolates, making the development of colistin adjuvants extremely beneficial. Clofoctol is a synthetic antibiotic active against Gram-positive bacteria, with low toxicity and high tropism for the airways. Interestingly, clofoctol has been found to have multiple biological activities and has been proposed for the treatment of several obstructive lung diseases, including asthma, lung cancer, and SARS-CoV-2 infection. In this study, the activity of clofoctol as a colistin adjuvant was investigated in Gram-negative lung pathogens that are critical for the high prevalence of multidrug-resistant isolates, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. Clofoctol potentiated the bactericidal effect of colistin in all tested strains and reduced colistin MICs below the susceptibility breakpoint in nearly all colistin-resistant strains. Overall, this observation supports the development of inhaled clofoctol-colistin formulations for the treatment of difficult-to-treat airway infections caused by Gram-negative pathogens. IMPORTANCE Colistin is used as a last-resort antibiotic against extensively drug-resistant Gram-negative pathogens. However, colistin resistance is on the rise. Clofoctol is an antibiotic used against Gram-positive bacteria, with low toxicity and high penetration and storage in the airways. Here, a strong synergistic activity of the colistin-clofoctol combination against colistin-resistant Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii isolates is reported, supporting the development of clofoctol-colistin formulations for the therapy of difficult-to-treat airways infections caused by these Gram-negative pathogens.
Collapse
Affiliation(s)
| | | | - Paolo Visca
- Department of Science, University Roma Tre, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Francesco Imperi
- Department of Science, University Roma Tre, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Giordano Rampioni
- Department of Science, University Roma Tre, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Livia Leoni
- Department of Science, University Roma Tre, Rome, Italy
| |
Collapse
|
5
|
Regulatory Landscape of the Pseudomonas aeruginosa Phosphoethanolamine Transferase Gene eptA in the Context of Colistin Resistance. Antibiotics (Basel) 2023; 12:antibiotics12020200. [PMID: 36830112 PMCID: PMC9952513 DOI: 10.3390/antibiotics12020200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/14/2023] [Accepted: 01/16/2023] [Indexed: 01/21/2023] Open
Abstract
Pseudomonas aeruginosa has the genetic potential to acquire colistin resistance through the modification of lipopolysaccharide by the addition of 4-amino-4-deoxy-L-arabinose (L-Ara4N) or phosphoethanolamine (PEtN), mediated by the arn operon or the eptA gene, respectively. However, in vitro evolution experiments and genetic analysis of clinical isolates indicate that lipopolysaccharide modification with L-Ara4N is invariably preferred over PEtN addition as the colistin resistance mechanism in this bacterium. Since little is known about eptA regulation in P. aeruginosa, we generated luminescent derivatives of the reference strain P. aeruginosa PAO1 to monitor arn and eptA promoter activity. We performed transposon mutagenesis assays to compare the likelihood of acquiring mutations leading to arn or eptA induction and to identify eptA regulators. The analysis revealed that eptA was slightly induced under certain stress conditions, such as arginine or biotin depletion and accumulation of the signal molecule diadenosine tetraphosphate, but the induction did not confer colistin resistance. Moreover, we demonstrated that spontaneous mutations leading to colistin resistance invariably triggered arn rather than eptA expression, and that eptA was not induced in resistant mutants upon colistin exposure. Overall, these results suggest that the contribution of eptA to colistin resistance in P. aeruginosa may be limited by regulatory restraints.
Collapse
|
6
|
Singkham-In U, Phuengmaung P, Makjaroen J, Saisorn W, Bhunyakarnjanarat T, Chatsuwan T, Chirathaworn C, Chancharoenthana W, Leelahavanichkul A. Chlorhexidine Promotes Psl Expression in Pseudomonas aeruginosa That Enhances Cell Aggregation with Preserved Pathogenicity Demonstrates an Adaptation against Antiseptic. Int J Mol Sci 2022; 23:ijms23158308. [PMID: 35955437 PMCID: PMC9368580 DOI: 10.3390/ijms23158308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/20/2022] [Accepted: 07/25/2022] [Indexed: 11/16/2022] Open
Abstract
Because Pseudomonas aeruginosa is frequently in contact with Chlorhexidine (a regular antiseptic), bacterial adaptations are possible. In comparison with the parent strain, the Chlorhexidine-adapted strain formed smaller colonies with metabolic downregulation (proteomic analysis) with the cross-resistance against colistin (an antibiotic for several antibiotic-resistant bacteria), partly through the modification of L-Ara4N in the lipopolysaccharide at the outer membrane. Chlorhexidine-adapted strain formed dense liquid–solid interface biofilms with enhanced cell aggregation partly due to the Chlorhexidine-induced overexpression of psl (exopolysaccharide-encoded gene) through the LadS/GacSA pathway (c-di-GMP-independence) in 12 h biofilms and maintained the aggregation with SiaD-mediated c-di-GMP dependence in 24 h biofilms as evaluated by polymerase chain reaction (PCR). The addition of Ca2+ in the Chlorhexidine-adapted strain facilitated several Psl-associated genes, indicating an impact of Ca2+ in Psl production. The activation by Chlorhexidine-treated sessile bacteria demonstrated a lower expression of IL-6 and IL-8 on fibroblasts and macrophages than the activation by the parent strain, indicating the less inflammatory reactions from Chlorhexidine-exposed bacteria. However, the 14-day severity of the wounds in mouse caused by Chlorhexidine-treated bacteria versus the parent strain was similar, as indicated by wound diameters and bacterial burdens. In conclusion, Chlorhexidine induced psl over-expression and colistin cross-resistance that might be clinically important.
Collapse
Affiliation(s)
- Uthaibhorn Singkham-In
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, 1873 Rama 4 Road, Pathumwan, Bangkok 10330, Thailand; (U.S.-I.); (P.P.); (C.C.)
| | - Pornpimol Phuengmaung
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, 1873 Rama 4 Road, Pathumwan, Bangkok 10330, Thailand; (U.S.-I.); (P.P.); (C.C.)
| | - Jiradej Makjaroen
- Center of Excellence in Systems Biology, Faculty of Medicine, Chulalongkorn University, 1873 Rama 4 Road, Pathumwan, Bangkok 10330, Thailand;
| | - Wilasinee Saisorn
- Translational Research in Inflammation and Immunology Research Unit (TRIRU), Department of Microbiology, Faculty of Medicine, Chulalongkorn University, 1873 Rama 4 Road, Pathumwan, Bangkok 10330, Thailand; (W.S.); (T.B.)
| | - Thansita Bhunyakarnjanarat
- Translational Research in Inflammation and Immunology Research Unit (TRIRU), Department of Microbiology, Faculty of Medicine, Chulalongkorn University, 1873 Rama 4 Road, Pathumwan, Bangkok 10330, Thailand; (W.S.); (T.B.)
| | - Tanittha Chatsuwan
- Antimicrobial Resistance and Stewardship Research Unit, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, 1873 Rama 4 Road, Pathumwan, Bangkok 10330, Thailand;
| | - Chintana Chirathaworn
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, 1873 Rama 4 Road, Pathumwan, Bangkok 10330, Thailand; (U.S.-I.); (P.P.); (C.C.)
| | - Wiwat Chancharoenthana
- Tropical Nephrology Research Unit, Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
- Correspondence: (W.C.); (A.L.); Tel.: +66-2-306-9130 (W.C.); +66-2-256-4251 (A.L.); Fax: +66-2-354-9150 (W.C.); +66-2-252-6920 (A.L.)
| | - Asada Leelahavanichkul
- Translational Research in Inflammation and Immunology Research Unit (TRIRU), Department of Microbiology, Faculty of Medicine, Chulalongkorn University, 1873 Rama 4 Road, Pathumwan, Bangkok 10330, Thailand; (W.S.); (T.B.)
- Correspondence: (W.C.); (A.L.); Tel.: +66-2-306-9130 (W.C.); +66-2-256-4251 (A.L.); Fax: +66-2-354-9150 (W.C.); +66-2-252-6920 (A.L.)
| |
Collapse
|
7
|
Laborda P, Hernando-Amado S, Martínez JL, Sanz-García F. Antibiotic Resistance in Pseudomonas. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:117-143. [DOI: 10.1007/978-3-031-08491-1_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
8
|
Cervoni M, Lo Sciuto A, Bianchini C, Mancone C, Imperi F. Exogenous and Endogenous Phosphoethanolamine Transferases Differently Affect Colistin Resistance and Fitness in Pseudomonas aeruginosa. Front Microbiol 2021; 12:778968. [PMID: 34777328 PMCID: PMC8578941 DOI: 10.3389/fmicb.2021.778968] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 10/07/2021] [Indexed: 12/15/2022] Open
Abstract
Colistin represents a last-line treatment option for infections caused by multidrug resistant Gram-negative pathogens, including Pseudomonas aeruginosa. Colistin resistance generally involves the modification of the lipid A moiety of lipopolysaccharide (LPS) with positively charged molecules, namely phosphoethanolamine (PEtN) or 4-amino-4-deoxy-L-arabinose (Ara4N), that reduce colistin affinity for its target. Several lines of evidence highlighted lipid A aminoarabinosylation as the primary colistin resistance mechanism in P. aeruginosa, while the contribution of phosphoethanolamination remains elusive. PEtN modification can be due to either endogenous (chromosomally encoded) PEtN transferase(s) (e.g., EptA in P. aeruginosa) or plasmid borne MCR enzymes, commonly found in enterobacteria. By individually cloning eptA and mcr-1 into a plasmid for inducible gene expression, we demonstrated that MCR-1 and EptA have comparable PEtN transferase activity in P. aeruginosa and confer colistin resistance levels similar to those provided by lipid A aminoarabinosylation. Notably, EptA, but not MCR-1, negatively affects P. aeruginosa growth and, to a lesser extent, cell envelope integrity when expressed at high levels. Mutagenesis experiments revealed that PEtN transferase activity does not account for the noxious effects of EptA overexpression, that instead requires a C-terminal tail unique to P. aeruginosa EptA, whose function remains unknown. Overall, this study shows that both endogenous and exogenous PEtN transferases can promote colistin resistance in P. aeruginosa, and that PEtN and MCR-1 mediated resistance has no impact on growth and cell envelope homeostasis, suggesting that there may be no fitness barriers to the spread of mcr-1 in P. aeruginosa.
Collapse
Affiliation(s)
| | | | | | - Carmine Mancone
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Francesco Imperi
- Department of Science, Roma Tre University, Rome, Italy.,IRCCS Fondazione Santa Lucia, Rome, Italy
| |
Collapse
|
9
|
Ghirga F, Stefanelli R, Cavinato L, Lo Sciuto A, Corradi S, Quaglio D, Calcaterra A, Casciaro B, Loffredo MR, Cappiello F, Morelli P, Antonelli A, Rossolini GM, Mangoni M, Mancone C, Botta B, Mori M, Ascenzioni F, Imperi F. A novel colistin adjuvant identified by virtual screening for ArnT inhibitors. J Antimicrob Chemother 2021; 75:2564-2572. [PMID: 32514531 PMCID: PMC7443731 DOI: 10.1093/jac/dkaa200] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 03/31/2020] [Accepted: 04/21/2020] [Indexed: 12/20/2022] Open
Abstract
Background Colistin is a last-resort treatment option for many MDR Gram-negative bacteria. The covalent addition of l-aminoarabinose to the lipid A moiety of LPS is the main colistin resistance mechanism in the human pathogen Pseudomonas aeruginosa. Objectives Identification (by in silico screening of a chemical library) of potential inhibitors of ArnT, which catalyses the last committed step of lipid A aminoarabinosylation, and their validation in vitro as colistin adjuvants. Methods The available ArnT crystal structure was used for a docking-based virtual screening of an in-house library of natural products. The resulting putative ArnT inhibitors were tested in growth inhibition assays using a reference colistin-resistant P. aeruginosa strain. The most promising compound was further characterized for its range of activity, specificity and cytotoxicity. Additionally, the effect of the compound on lipid A aminoarabinosylation was verified by MS analyses of lipid A. Results A putative ArnT inhibitor (BBN149) was discovered by molecular docking and demonstrated to specifically potentiate colistin activity in colistin-resistant P. aeruginosa isolates, without relevant effect on colistin-susceptible strains. BBN149 also showed adjuvant activity against colistin-resistant Klebsiella pneumoniae and low toxicity to bronchial epithelial cells. Lipid A aminoarabinosylation was reduced in BBN149-treated cells, although only partially. Conclusions This study demonstrates that in silico screening targeting ArnT can successfully identify inhibitors of colistin resistance and provides a promising lead compound for the development of colistin adjuvants for the treatment of MDR bacterial infections.
Collapse
Affiliation(s)
- Francesca Ghirga
- Center for Life Nano Science@Sapienza, Italian Institute of Technology, Rome, Italy
| | - Roberta Stefanelli
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Rome, Italy.,Department of Sciences, 'Department of Excellence 2018 - 2022', Roma Tre University, Rome, Italy
| | - Luca Cavinato
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Rome, Italy
| | - Alessandra Lo Sciuto
- Department of Sciences, 'Department of Excellence 2018 - 2022', Roma Tre University, Rome, Italy
| | - Silvia Corradi
- Center for Life Nano Science@Sapienza, Italian Institute of Technology, Rome, Italy.,Department of Chemistry and Technology of Drugs, 'Department of Excellence 2018 - 2022', Sapienza University of Rome, Rome, Italy
| | - Deborah Quaglio
- Department of Chemistry and Technology of Drugs, 'Department of Excellence 2018 - 2022', Sapienza University of Rome, Rome, Italy
| | - Andrea Calcaterra
- Department of Chemistry and Technology of Drugs, 'Department of Excellence 2018 - 2022', Sapienza University of Rome, Rome, Italy
| | - Bruno Casciaro
- Center for Life Nano Science@Sapienza, Italian Institute of Technology, Rome, Italy
| | - Maria Rosa Loffredo
- Department of Biochemical Sciences, Sapienza University of Rome, Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Rome, Italy
| | - Floriana Cappiello
- Department of Biochemical Sciences, Sapienza University of Rome, Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Rome, Italy
| | - Patrizia Morelli
- Microbiology Laboratory, Giannina Gaslini Institute, Genoa, Italy
| | - Alberto Antonelli
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.,Clinical Microbiology and Virology Unit, Florence Careggi University Hospital, Florence, Italy
| | - Gian Maria Rossolini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.,Clinical Microbiology and Virology Unit, Florence Careggi University Hospital, Florence, Italy
| | - Marialuisa Mangoni
- Department of Biochemical Sciences, Sapienza University of Rome, Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Rome, Italy
| | - Carmine Mancone
- Department of Molecular Medicine, 'Department of Excellence 2018 - 2022', Sapienza University of Rome, Rome, Italy
| | - Bruno Botta
- Department of Chemistry and Technology of Drugs, 'Department of Excellence 2018 - 2022', Sapienza University of Rome, Rome, Italy
| | - Mattia Mori
- Department of Biotechnology, Chemistry and Pharmacy, 'Department of Excellence 2018 - 2022', University of Siena, Siena, Italy
| | - Fiorentina Ascenzioni
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Rome, Italy
| | - Francesco Imperi
- Department of Sciences, 'Department of Excellence 2018 - 2022', Roma Tre University, Rome, Italy
| |
Collapse
|
10
|
Langendonk RF, Neill DR, Fothergill JL. The Building Blocks of Antimicrobial Resistance in Pseudomonas aeruginosa: Implications for Current Resistance-Breaking Therapies. Front Cell Infect Microbiol 2021; 11:665759. [PMID: 33937104 PMCID: PMC8085337 DOI: 10.3389/fcimb.2021.665759] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 03/29/2021] [Indexed: 12/12/2022] Open
Abstract
P. aeruginosa is classified as a priority one pathogen by the World Health Organisation, and new drugs are urgently needed, due to the emergence of multidrug-resistant (MDR) strains. Antimicrobial-resistant nosocomial pathogens such as P. aeruginosa pose unwavering and increasing threats. Antimicrobial stewardship has been a challenge during the COVID-19 pandemic, with a majority of those hospitalized with SARS-CoV2 infection given antibiotics as a safeguard against secondary bacterial infection. This increased usage, along with increased handling of sanitizers and disinfectants globally, may further accelerate the development and spread of cross-resistance to antibiotics. In addition, P. aeruginosa is the primary causative agent of morbidity and mortality in people with the life-shortening genetic disease cystic fibrosis (CF). Prolonged periods of selective pressure, associated with extended antibiotic treatment and the actions of host immune effectors, results in widespread adaptive and acquired resistance in P. aeruginosa found colonizing the lungs of people with CF. This review discusses the arsenal of resistance mechanisms utilized by P. aeruginosa, how these operate under high-stress environments such as the CF lung and how their interconnectedness can result in resistance to multiple antibiotic classes. Intrinsic, adaptive and acquired resistance mechanisms will be described, with a focus on how each layer of resistance can serve as a building block, contributing to multi-tiered resistance to antimicrobial activity. Recent progress in the development of anti-resistance adjuvant therapies, targeting one or more of these building blocks, should lead to novel strategies for combatting multidrug resistant P. aeruginosa. Anti-resistance adjuvant therapy holds great promise, not least because resistance against such therapeutics is predicted to be rare. The non-bactericidal nature of anti-resistance adjuvants reduce the selective pressures that drive resistance. Anti-resistance adjuvant therapy may also be advantageous in facilitating efficacious use of traditional antimicrobials, through enhanced penetration of the antibiotic into the bacterial cell. Promising anti-resistance adjuvant therapeutics and targets will be described, and key remaining challenges highlighted. As antimicrobial stewardship becomes more challenging in an era of emerging and re-emerging infectious diseases and global conflict, innovation in antibiotic adjuvant therapy can play an important role in extending the shelf-life of our existing antimicrobial therapeutic agents.
Collapse
Affiliation(s)
- R. Frèdi Langendonk
- Institute of Infection, Veterinary and Ecological Science, University of Liverpool, Liverpool, United Kingdom
| | | | | |
Collapse
|
11
|
Morpholinium-based ionic liquids show antimicrobial activity against clinical isolates of Pseudomonas aeruginosa. Res Microbiol 2021; 172:103817. [PMID: 33741516 DOI: 10.1016/j.resmic.2021.103817] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 03/02/2021] [Accepted: 03/04/2021] [Indexed: 11/22/2022]
Abstract
Pseudomonas aeruginosa is a multi-drug resistant (MDR) pathogen. It is classified by WHO as one of the most life-threatening pathogens causing nosocomial infections. Some of its clinical isolates and their subpopulations show high persistence to many antibiotics that are recommended by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Thus, there is a need for non-traditional classes of antibiotics to fight the increasing threat of MDR P. aeruginosa. Ionic liquids (IL) are one such promising class of novel antibiotics. We selected four strains of P. aeruginosa and studied the growth inhibition and other effects of 12 different ILs. We used the well-characterized P. aeruginosa PAO1 (ATCC 15692) as model strain and compared it to three other isolates from chronic lung infection (LES B58), skin burn infection (UCBPP-PA14) and keratitis infection (39016), respectively. The ILs consisted of either 4,4-didecylmorpholinium [Dec2Mor]+ or 4-decyl-4-ethylmorpholinium [DecEtMor]+ cations combined with different anions. We found that the ILs with 4,4-didecylmorpholinium [Dec2Mor]+ cations most effectively inhibited bacterial growth as well as reduced strain fitness and virulence factor production. Our results indicate that these ILs could be used to treat P. aeruginosa infections.
Collapse
|
12
|
Zhang Z, Ortega D, Rush A, Blankenship LR, Cheng ZJ, Moore RE, Tran MLN, Sandoval LG, Aboulhosn K, Watanabe S, Cortez KS, Perlman DH, Semmelhack MF, Miller Conrad LC. Antibiotic Adjuvant Activity Revealed in a Photoaffinity Approach to Determine the Molecular Target of Antipyocyanin Compounds. ACS Infect Dis 2021; 7:535-543. [PMID: 33587590 DOI: 10.1021/acsinfecdis.0c00160] [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: 11/30/2022]
Abstract
Infections with Pseudomonas aeruginosa are a looming threat to public health. New treatment strategies are needed to combat this pathogen, for example, by blocking the production of virulence factors like pyocyanin. A photoaffinity analogue of an antipyocyanin compound was developed to interrogate the inhibitor's molecular mechanism of action. While we sought to develop antivirulence inhibitors, the proteomics results suggested that the compounds had antibiotic adjuvant activity. Unexpectedly, we found that these compounds amplify the bactericidal activity of colistin, a well-characterized antibiotic, suggesting they may represent a first-in-class antibiotic adjuvant therapy. Analogues have the potential not only to widen the therapeutic index of cationic antimicrobial peptides like colistin, but also to be effective against colistin-resistant strains, strengthening our arsenal to combat P. aeruginosa infections.
Collapse
Affiliation(s)
- Zinan Zhang
- Department of Chemistry, Princeton University, Washington Road, Princeton, New Jersey 08544, United States
| | - Dominic Ortega
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Anthony Rush
- Department of Bioengineering, Stanford University, 443 Via Ortega, Stanford, California 94305, United States
| | - Lauren R. Blankenship
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Zi Jun Cheng
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Rebecca E. Moore
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Minh L. N. Tran
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Lucero G. Sandoval
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Kareem Aboulhosn
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Seiichiro Watanabe
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - Kendra S. Cortez
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| | - David H. Perlman
- Princeton Proteomics and Mass Spectrometry Center, Princeton University, Washington Road, Princeton, New Jersey 08544, United States
| | - Martin F. Semmelhack
- Department of Chemistry, Princeton University, Washington Road, Princeton, New Jersey 08544, United States
| | - Laura C. Miller Conrad
- Department of Chemistry, San José State University, 1 Washington Square, San Jose, California 95192, United States
| |
Collapse
|
13
|
Buré C, Le Sénéchal C, Macias L, Tokarski C, Vilain S, Brodbelt JS. Characterization of Isomers of Lipid A from Pseudomonas aeruginosa PAO1 by Liquid Chromatography with Tandem Mass Spectrometry with Higher-Energy Collisional Dissociation and Ultraviolet Photodissociation. Anal Chem 2021; 93:4255-4262. [PMID: 33625828 PMCID: PMC8377747 DOI: 10.1021/acs.analchem.0c05069] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lipopolysaccharides (LPS) constitute the outermost layer of Gram-negative bacteria and consequently play an important role in bacterial infections. In order to address public health issues posed by Gram-negative bacteria, it is necessary to elucidate the structure of the molecular actors at the forefront of infections. LPS virulence and toxicity are partially modulated by lipid A, a hydrophobic saccharolipid that anchors LPS to the bacterial outer membrane. Understanding the lipid A structure is inherently intertwined with understanding its role as an endotoxin. Accordingly, several successful strategies incorporating tandem mass spectrometry have been applied toward the structural analysis of lipid A. Herein, a shotgun HCD strategy was applied toward the characterization of the lipid A profile of Pseudomonas aeruginosa PAO1. This analysis was enhanced by the development of an LC-MS/MS approach to eliminate isomeric signals in the MS/MS spectra that confounded characterization. Importantly, combining reverse phase chromatography with HCD and ultraviolet photodissociation analyses of the lipid A profile revealed the presence of previously unreported lipid A acyl chain positional isomers. Altogether, these strategies provide the most in-depth structural and molecular characterization of PAO1 lipid A to date.
Collapse
Affiliation(s)
- Corinne Buré
- Institute of Chemistry & Biology of Membranes & Nanoobjects, UMR 5248, CNRS, University of Bordeaux, Bordeaux INP, Bordeaux, Pessac F-33076, France
- Department of Chemistry, University of Texas, Austin, Texas 78712, United States
| | - Caroline Le Sénéchal
- Institute of Chemistry & Biology of Membranes & Nanoobjects, UMR 5248, CNRS, University of Bordeaux, Bordeaux INP, Bordeaux, Pessac F-33076, France
| | - Luis Macias
- Department of Chemistry, University of Texas, Austin, Texas 78712, United States
| | - Caroline Tokarski
- Institute of Chemistry & Biology of Membranes & Nanoobjects, UMR 5248, CNRS, University of Bordeaux, Bordeaux INP, Bordeaux, Pessac F-33076, France
| | - Sébastien Vilain
- Institute of Chemistry & Biology of Membranes & Nanoobjects, UMR 5248, CNRS, University of Bordeaux, Bordeaux INP, Bordeaux, Pessac F-33076, France
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas, Austin, Texas 78712, United States
| |
Collapse
|
14
|
Quaglio D, Mangoni ML, Stefanelli R, Corradi S, Casciaro B, Vergine V, Lucantoni F, Cavinato L, Cammarone S, Loffredo MR, Cappiello F, Calcaterra A, Erazo S, Ghirga F, Mori M, Imperi F, Ascenzioni F, Botta B. ent-Beyerane Diterpenes as a Key Platform for the Development of ArnT-Mediated Colistin Resistance Inhibitors. J Org Chem 2020; 85:10891-10901. [PMID: 32806095 PMCID: PMC8009527 DOI: 10.1021/acs.joc.0c01459] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Colistin is a last-resort antibiotic for the treatment of multidrug resistant Gram-negative bacterial infections. Recently, a natural ent-beyerene diterpene was identified as a promising inhibitor of the enzyme responsible for colistin resistance mediated by lipid A aminoarabinosylation in Gram-negative bacteria, namely, ArnT (undecaprenyl phosphate-alpha-4-amino-4-deoxy-l-arabinose arabinosyl transferase). Here, semisynthetic analogues of hit were designed, synthetized, and tested against colistin-resistant Pseudomonas aeruginosa strains including clinical isolates to exploit the versatility of the diterpene scaffold. Microbiological assays coupled with molecular modeling indicated that for a more efficient colistin adjuvant activity, likely resulting from inhibition of the ArnT activity by the selected compounds and therefore from their interaction with the catalytic site of ArnT, an ent-beyerane scaffold is required along with an oxalate-like group at C-18/C-19 or a sugar residue at C-19 to resemble L-Ara4N. The ent-beyerane skeleton is identified for the first time as a privileged scaffold for further cost-effective development of valuable colistin resistance inhibitors.
Collapse
Affiliation(s)
- Deborah Quaglio
- Department of Chemistry and Technology of Drugs, "Department of Excellence 2018-2022", Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Maria Luisa Mangoni
- Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Roberta Stefanelli
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Via dei Sardi 70, 00185 Rome, Italy.,Department of Science, Roma Tre University, Viale Guglielmo Marconi 446, 00146 Rome, Italy
| | - Silvia Corradi
- Department of Chemistry and Technology of Drugs, "Department of Excellence 2018-2022", Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.,Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Viale Regina Elena, 291, 00161 Rome, Italy
| | - Bruno Casciaro
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Viale Regina Elena, 291, 00161 Rome, Italy
| | - Valeria Vergine
- Department of Chemistry and Technology of Drugs, "Department of Excellence 2018-2022", Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Federica Lucantoni
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Via dei Sardi 70, 00185 Rome, Italy
| | - Luca Cavinato
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Via dei Sardi 70, 00185 Rome, Italy
| | - Silvia Cammarone
- Department of Chemistry and Technology of Drugs, "Department of Excellence 2018-2022", Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Maria Rosa Loffredo
- Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Floriana Cappiello
- Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Andrea Calcaterra
- Department of Chemistry and Technology of Drugs, "Department of Excellence 2018-2022", Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Silvia Erazo
- Department of Pharmacological and Toxicological Chemistry, Faculty of Chemical and Pharmaceutical Sciences, University of Chile, 1058 Santiago, Chile
| | - Francesca Ghirga
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Viale Regina Elena, 291, 00161 Rome, Italy
| | - Mattia Mori
- Department of Biotechnology, Chemistry and Pharmacy, "Department of Excellence 2018-2022", University of Siena, via Aldo Moro 2, 53100 Siena, Italy
| | - Francesco Imperi
- Department of Science, Roma Tre University, Viale Guglielmo Marconi 446, 00146 Rome, Italy
| | - Fiorentina Ascenzioni
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Via dei Sardi 70, 00185 Rome, Italy
| | - Bruno Botta
- Department of Chemistry and Technology of Drugs, "Department of Excellence 2018-2022", Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| |
Collapse
|
15
|
Hypermutator Pseudomonas aeruginosa Exploits Multiple Genetic Pathways To Develop Multidrug Resistance during Long-Term Infections in the Airways of Cystic Fibrosis Patients. Antimicrob Agents Chemother 2020; 64:AAC.02142-19. [PMID: 32071060 DOI: 10.1128/aac.02142-19] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 12/20/2019] [Indexed: 12/30/2022] Open
Abstract
Pseudomonas aeruginosa exploits intrinsic and acquired resistance mechanisms to resist almost every antibiotic used in chemotherapy. Antimicrobial resistance in P. aeruginosa isolates recovered from cystic fibrosis (CF) patients is further enhanced by the occurrence of hypermutator strains, a hallmark of chronic infections in CF patients. However, the within-patient genetic diversity of P. aeruginosa populations related to antibiotic resistance remains unexplored. Here, we show the evolution of the mutational resistome profile of a P. aeruginosa hypermutator lineage by performing longitudinal and transversal analyses of isolates collected from a CF patient throughout 20 years of chronic infection. Our results show the accumulation of thousands of mutations, with an overall evolutionary history characterized by purifying selection. However, mutations in antibiotic resistance genes appear to have been positively selected, driven by antibiotic treatment. Antibiotic resistance increased as infection progressed toward the establishment of a population constituted by genotypically diversified coexisting sublineages, all of which converged to multidrug resistance. These sublineages emerged by parallel evolution through distinct evolutionary pathways, which affected genes of the same functional categories. Interestingly, ampC and ftsI, encoding the β-lactamase and penicillin-binding protein 3, respectively, were found to be among the most frequently mutated genes. In fact, both genes were targeted by multiple independent mutational events, which led to a wide diversity of coexisting alleles underlying β-lactam resistance. Our findings indicate that hypermutators, apart from boosting antibiotic resistance evolution by simultaneously targeting several genes, favor the emergence of adaptive innovative alleles by clustering beneficial/compensatory mutations in the same gene, hence expanding P. aeruginosa strategies for persistence.
Collapse
|
16
|
Lo Sciuto A, Cervoni M, Stefanelli R, Mancone C, Imperi F. Effect of lipid A aminoarabinosylation on Pseudomonas aeruginosa colistin resistance and fitness. Int J Antimicrob Agents 2020; 55:105957. [PMID: 32278012 DOI: 10.1016/j.ijantimicag.2020.105957] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 03/10/2020] [Accepted: 03/20/2020] [Indexed: 01/06/2023]
Abstract
Colistin represents the last-line treatment option against many multidrug-resistant Gram-negative pathogens. Several lines of evidence indicate that aminoarabinosylation of the lipid A moiety of lipopolysaccharide (LPS) is an essential step for the development of colistin resistance in Pseudomonas aeruginosa. However, whether it is sufficient to confer resistance in this bacterium remains unclear. The aim of this work was to investigate the specific contribution of lipid A aminoarabinosylation to colistin resistance in P. aeruginosa and evaluate the effect of this resistance mechanism on bacterial fitness. Recombinant strains constitutively expressing the enzymes for lipid A aminoarabinosylation were generated in a small collection of reference and clinical isolates and verified by quantitative reverse transcription polymerase chain reaction (qRT-PCR), lipid A extraction and mass spectrometry. The effect of aminoarabinosylated lipid A on colistin resistance was found to be strain- and culture condition-dependent. Higher levels of resistance were generally obtained in the presence of divalent cations, which appear to be important for aminoarabinosylation-mediated colistin resistance. High colistin resistance was also observed for most strains in human serum and in artificial sputum medium, which should partly mimic growth conditions during infection. The results of growth, biofilm, cell envelope integrity and Galleria mellonella infection assays indicate that lipid A aminoarabinosylation does not cause relevant fitness costs in P. aeruginosa.
Collapse
Affiliation(s)
| | | | - Roberta Stefanelli
- Department of Science, Roma Tre University, Rome, Italy; Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Rome, Italy
| | - Carmine Mancone
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | | |
Collapse
|
17
|
The Role of Pseudomonas aeruginosa Lipopolysaccharide in Bacterial Pathogenesis and Physiology. Pathogens 2019; 9:pathogens9010006. [PMID: 31861540 PMCID: PMC7168646 DOI: 10.3390/pathogens9010006] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/15/2019] [Accepted: 12/17/2019] [Indexed: 12/13/2022] Open
Abstract
The major constituent of the outer membrane of Gram-negative bacteria is lipopolysaccharide (LPS), which is comprised of lipid A, core oligosaccharide, and O antigen, which is a long polysaccharide chain extending into the extracellular environment. Due to the localization of LPS, it is a key molecule on the bacterial cell wall that is recognized by the host to deploy an immune defence in order to neutralize invading pathogens. However, LPS also promotes bacterial survival in a host environment by protecting the bacteria from these threats. This review explores the relationship between the different LPS glycoforms of the opportunistic pathogen Pseudomonas aeruginosa and the ability of this organism to cause persistent infections, especially in the genetic disease cystic fibrosis. We also discuss the role of LPS in facilitating biofilm formation, antibiotic resistance, and how LPS may be targeted by new antimicrobial therapies.
Collapse
|
18
|
Tierney AR, Rather PN. Roles of two-component regulatory systems in antibiotic resistance. Future Microbiol 2019; 14:533-552. [PMID: 31066586 DOI: 10.2217/fmb-2019-0002] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Two-component regulatory systems (TCSs) are a major mechanism by which bacteria sense and respond to changes in their environment. TCSs typically consist of two proteins that bring about major regulation of the cell genome through coordinated action mediated by phosphorylation. Environmental conditions that activate TCSs are numerous and diverse and include exposure to antibiotics as well as conditions inside a host. The resulting regulatory action often involves activation of antibiotic defenses and changes to cell physiology that increase antibiotic resistance. Examples of resistance mechanisms enacted by TCSs contained in this review span those found in both Gram-negative and Gram-positive species and include cell surface modifications, changes in cell permeability, increased biofilm formation, and upregulation of antibiotic-degrading enzymes.
Collapse
Affiliation(s)
- Aimee Rp Tierney
- Department of Microbiology & Immunology, Emory University School of Medicine, Atlanta, GA, 30322 USA
| | - Philip N Rather
- Department of Microbiology & Immunology, Emory University School of Medicine, Atlanta, GA, 30322 USA.,Research Service, Department of Veterans' Affairs, Atlanta VA Health Care System, Decatur, GA, 30033 USA
| |
Collapse
|