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Cavallo I, Oliva A, Pages R, Sivori F, Truglio M, Fabrizio G, Pasqua M, Pimpinelli F, Di Domenico EG. Acinetobacter baumannii in the critically ill: complex infections get complicated. Front Microbiol 2023; 14:1196774. [PMID: 37425994 PMCID: PMC10325864 DOI: 10.3389/fmicb.2023.1196774] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 06/05/2023] [Indexed: 07/11/2023] Open
Abstract
Acinetobacter baumannii is increasingly associated with various epidemics, representing a serious concern due to the broad level of antimicrobial resistance and clinical manifestations. During the last decades, A. baumannii has emerged as a major pathogen in vulnerable and critically ill patients. Bacteremia, pneumonia, urinary tract, and skin and soft tissue infections are the most common presentations of A. baumannii, with attributable mortality rates approaching 35%. Carbapenems have been considered the first choice to treat A. baumannii infections. However, due to the widespread prevalence of carbapenem-resistant A. baumannii (CRAB), colistin represents the main therapeutic option, while the role of the new siderophore cephalosporin cefiderocol still needs to be ascertained. Furthermore, high clinical failure rates have been reported for colistin monotherapy when used to treat CRAB infections. Thus, the most effective antibiotic combination remains disputed. In addition to its ability to develop antibiotic resistance, A. baumannii is also known to form biofilm on medical devices, including central venous catheters or endotracheal tubes. Thus, the worrisome spread of biofilm-producing strains in multidrug-resistant populations of A. baumannii poses a significant treatment challenge. This review provides an updated account of antimicrobial resistance patterns and biofilm-mediated tolerance in A. baumannii infections with a special focus on fragile and critically ill patients.
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Affiliation(s)
- Ilaria Cavallo
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Alessandra Oliva
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Rebecca Pages
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Francesca Sivori
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Mauro Truglio
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Giorgia Fabrizio
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Martina Pasqua
- Department of Biology and Biotechnology "C. Darwin" Sapienza University of Rome, Rome, Italy
| | - Fulvia Pimpinelli
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Enea Gino Di Domenico
- Department of Biology and Biotechnology "C. Darwin" Sapienza University of Rome, Rome, Italy
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2
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Castanheira M, Mendes RE, Gales AC. Global Epidemiology and Mechanisms of Resistance of Acinetobacter baumannii-calcoaceticus Complex. Clin Infect Dis 2023; 76:S166-S178. [PMID: 37125466 PMCID: PMC10150277 DOI: 10.1093/cid/ciad109] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Acinetobacter baumannii-calcoaceticus complex is the most commonly identified species in the genus Acinetobacter and it accounts for a large percentage of nosocomial infections, including bacteremia, pneumonia, and infections of the skin and urinary tract. A few key clones of A. baumannii-calcoaceticus are currently responsible for the dissemination of these organisms worldwide. Unfortunately, multidrug resistance is a common trait among these clones due to their unrivalled adaptive nature. A. baumannii-calcoaceticus isolates can accumulate resistance traits by a plethora of mechanisms, including horizontal gene transfer, natural transformation, acquisition of mutations, and mobilization of genetic elements that modulate expression of intrinsic and acquired genes.
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Affiliation(s)
| | | | - Ana C Gales
- Division of Infectious Diseases, Department of Internal Medicine, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
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3
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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.
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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
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4
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Noel HR, Petrey JR, Palmer LD. Mobile genetic elements in Acinetobacter antibiotic-resistance acquisition and dissemination. Ann N Y Acad Sci 2022; 1518:166-182. [PMID: 36316792 PMCID: PMC9771954 DOI: 10.1111/nyas.14918] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Pathogenic Acinetobacter species, most notably Acinetobacter baumannii, are a significant cause of healthcare-associated infections worldwide. Acinetobacter infections are of particular concern to global health due to the high rates of multidrug resistance and extensive drug resistance. Widespread genome sequencing and analysis has determined that bacterial antibiotic resistance is often acquired and disseminated through the movement of mobile genetic elements, including insertion sequences (IS), transposons, integrons, and conjugative plasmids. In Acinetobacter specifically, resistance to carbapenems and cephalosporins is highly correlated with IS, as many ISAba elements encode strong outwardly facing promoters that are required for sufficient expression of β-lactamases to confer clinical resistance. Here, we review the role of mobile genetic elements in antibiotic resistance in Acinetobacter species through the framework of the mechanism of resistance acquisition and with a focus on experimentally validated mechanisms.
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Affiliation(s)
- Hannah R. Noel
- Department of Microbiology and Immunology University of Illinois Chicago Chicago Illinois USA
| | - Jessica R. Petrey
- Department of Microbiology and Immunology University of Illinois Chicago Chicago Illinois USA
| | - Lauren D. Palmer
- Department of Microbiology and Immunology University of Illinois Chicago Chicago Illinois USA
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5
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Kaderabkova N, Bharathwaj M, Furniss RCD, Gonzalez D, Palmer T, Mavridou DAI. The biogenesis of β-lactamase enzymes. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35943884 DOI: 10.1099/mic.0.001217] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The discovery of penicillin by Alexander Fleming marked a new era for modern medicine, allowing not only the treatment of infectious diseases, but also the safe performance of life-saving interventions, like surgery and chemotherapy. Unfortunately, resistance against penicillin, as well as more complex β-lactam antibiotics, has rapidly emerged since the introduction of these drugs in the clinic, and is largely driven by a single type of extra-cytoplasmic proteins, hydrolytic enzymes called β-lactamases. While the structures, biochemistry and epidemiology of these resistance determinants have been extensively characterized, their biogenesis, a complex process including multiple steps and involving several fundamental biochemical pathways, is rarely discussed. In this review, we provide a comprehensive overview of the journey of β-lactamases, from the moment they exit the ribosomal channel until they reach their final cellular destination as folded and active enzymes.
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Affiliation(s)
- Nikol Kaderabkova
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
| | - Manasa Bharathwaj
- Centre to Impact AMR, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - R Christopher D Furniss
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Diego Gonzalez
- Laboratoire de Microbiologie, Institut de Biologie, Université de Neuchâtel, Neuchâtel, 2000, Switzerland
| | - Tracy Palmer
- Microbes in Health and Disease, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Despoina A I Mavridou
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA.,John Ring LaMontagne Center for Infectious Diseases, The University of Texas at Austin, Austin, Texas, USA
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Abstract
Class C β-lactamases or cephalosporinases can be classified into two functional groups (1, 1e) with considerable molecular variability (≤20% sequence identity). These enzymes are mostly encoded by chromosomal and inducible genes and are widespread among bacteria, including Proteobacteria in particular. Molecular identification is based principally on three catalytic motifs (64SXSK, 150YXN, 315KTG), but more than 70 conserved amino-acid residues (≥90%) have been identified, many close to these catalytic motifs. Nevertheless, the identification of a tiny, phylogenetically distant cluster (including enzymes from the genera Legionella, Bradyrhizobium, and Parachlamydia) has raised questions about the possible existence of a C2 subclass of β-lactamases, previously identified as serine hydrolases. In a context of the clinical emergence of extended-spectrum AmpC β-lactamases (ESACs), the genetic modifications observed in vivo and in vitro (point mutations, insertions, or deletions) during the evolution of these enzymes have mostly involved the Ω- and H-10/R2-loops, which vary considerably between genera, and, in some cases, the conserved triplet 150YXN. Furthermore, the conserved deletion of several amino-acid residues in opportunistic pathogenic species of Acinetobacter, such as A. baumannii, A. calcoaceticus, A. pittii and A. nosocomialis (deletion of residues 304-306), and in Hafnia alvei and H. paralvei (deletion of residues 289-290), provides support for the notion of natural ESACs. The emergence of higher levels of resistance to β-lactams, including carbapenems, and to inhibitors such as avibactam is a reality, as the enzymes responsible are subject to complex regulation encompassing several other genes (ampR, ampD, ampG, etc.). Combinations of resistance mechanisms may therefore be at work, including overproduction or change in permeability, with the loss of porins and/or activation of efflux systems.
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Sanz-García F, Gil-Gil T, Laborda P, Ochoa-Sánchez LE, Martínez JL, Hernando-Amado S. Coming from the Wild: Multidrug Resistant Opportunistic Pathogens Presenting a Primary, Not Human-Linked, Environmental Habitat. Int J Mol Sci 2021; 22:8080. [PMID: 34360847 PMCID: PMC8347278 DOI: 10.3390/ijms22158080] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/22/2021] [Accepted: 07/24/2021] [Indexed: 12/24/2022] Open
Abstract
The use and misuse of antibiotics have made antibiotic-resistant bacteria widespread nowadays, constituting one of the most relevant challenges for human health at present. Among these bacteria, opportunistic pathogens with an environmental, non-clinical, primary habitat stand as an increasing matter of concern at hospitals. These organisms usually present low susceptibility to antibiotics currently used for therapy. They are also proficient in acquiring increased resistance levels, a situation that limits the therapeutic options for treating the infections they cause. In this article, we analyse the most predominant opportunistic pathogens with an environmental origin, focusing on the mechanisms of antibiotic resistance they present. Further, we discuss the functions, beyond antibiotic resistance, that these determinants may have in the natural ecosystems that these bacteria usually colonize. Given the capacity of these organisms for colonizing different habitats, from clinical settings to natural environments, and for infecting different hosts, from plants to humans, deciphering their population structure, their mechanisms of resistance and the role that these mechanisms may play in natural ecosystems is of relevance for understanding the dissemination of antibiotic resistance under a One-Health point of view.
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Affiliation(s)
| | | | | | | | - José L. Martínez
- Centro Nacional de Biotecnología, CSIC, 28049 Madrid, Spain; (F.S.-G.); (T.G.-G.); (P.L.); (L.E.O.-S.); (S.H.-A.)
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8
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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.
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Essential gene analysis in Acinetobacter baumannii by high-density transposon mutagenesis and CRISPR interference. J Bacteriol 2021; 203:e0056520. [PMID: 33782056 DOI: 10.1128/jb.00565-20] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Acinetobacter baumannii is a poorly understood bacterium capable of life-threatening infections in hospitals. Few antibiotics remain effective against this highly resistant pathogen. Developing rationally-designed antimicrobials that can target A. baumannii requires improved knowledge of the proteins that carry out essential processes allowing growth of the organism. Unfortunately, studying essential genes has been challenging using traditional techniques, which usually require time-consuming recombination-based genetic manipulations. Here, we performed saturating mutagenesis with dual transposon systems to identify essential genes in A. baumannii and we developed a CRISPR-interference (CRISPRi) system for facile analysis of these genes. We show that the CRISPRi system enables efficient transcriptional silencing in A. baumannii Using these tools, we confirmed the essentiality of the novel cell division protein AdvA and discovered a previously uncharacterized AraC-family transcription factor (ACX60_RS03245) that is necessary for growth. In addition, we show that capsule biosynthesis is a conditionally essential process, with mutations in late-acting steps causing toxicity in strain ATCC 17978 that can be bypassed by blocking early-acting steps or activating the BfmRS stress response. These results open new avenues for analysis of essential pathways in A. baumannii ImportanceNew approaches are urgently needed to control A. baumannii, one of the most drug resistant pathogens known. To facilitate the development of novel targets that allow inhibition of the pathogen, we performed a large-scale identification of genes whose products the bacterium needs for growth. We also developed a CRISPR-based gene knockdown tool that operates efficiently in A. baumannii, allowing rapid analysis of these essential genes. We used these methods to define multiple processes vital to the bacterium, including a previously uncharacterized gene-regulatory factor and export of a protective polymeric capsule. These tools will enhance our ability to investigate processes critical for the essential biology of this challenging hospital-acquired pathogen.
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Tietgen M, Leukert L, Sommer J, Kramer JS, Brunst S, Wittig I, Proschak E, Göttig S. Characterization of the novel OXA-213-like β-lactamase OXA-822 from Acinetobacter calcoaceticus. J Antimicrob Chemother 2021; 76:626-634. [PMID: 33201995 DOI: 10.1093/jac/dkaa488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 10/29/2020] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES This study analysed the novel carbapenem-hydrolysing class D β-lactamase OXA-822 identified in the clinical Acinetobacter calcoaceticus isolate AC_2117. METHODS WGS was employed for identification of β-lactamases. Micro-broth dilution was used for evaluation of antibiotic susceptibility of AC_2117 and transformants containing blaOXA-822. After heterologous purification of OXA-822, OXA-359 and OXA-213, enzyme kinetics were determined using spectrometry. The effect of OXA-822 upon meropenem treatment was analysed in the Galleria mellonella in vivo infection model. RESULTS OXA-822 is a member of the intrinsic OXA-213-like family found in A. calcoaceticus and Acinetobacter pittii. Amino acid sequence similarity to the nearest related OXA-359 was 97%. Production of OXA-822, OXA-359 and OXA-213 in Acinetobacter baumannii ATCC® 19606T resulted in elevated MICs for carbapenems (up to 16-fold). Penicillinase activity of the purified OXA-822 revealed high KM values, in the millimolar range, combined with high turnover numbers. OXA-822 showed the highest affinity to carbapenems, but affinity to imipenem was ∼10-fold lower compared with other carbapenems. Molecular modelling revealed that imipenem does not interact with a negatively charged side chain of OXA-822, as doripenem does, leading to the lower affinity. Presence of OXA-822 decreased survival of infected Galleria mellonella larvae after treatment with meropenem. Only 52.7% ± 7.7% of the larvae survived after 24 h compared with 90.9% ± 3.7% survival in the control group. CONCLUSIONS The novel OXA-822 from a clinical A. calcoaceticus isolate displayed penicillinase and carbapenemase activity in vitro, elevated MICs in different species and decreased carbapenem susceptibility in A. baumannii in vivo.
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Affiliation(s)
- Manuela Tietgen
- Institute for Medical Microbiology and Infection Control, Hospital of the Goethe University, Frankfurt am Main, Germany.,Faculty of Biological Sciences of the Goethe University, Frankfurt am Main, Germany.,University Center of Competence for Infection Control of the State of Hesse, Frankfurt am Main, Germany
| | - Laura Leukert
- Institute for Medical Microbiology and Infection Control, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Julian Sommer
- Institute for Medical Microbiology and Infection Control, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Jan S Kramer
- Institute of Pharmaceutical Chemistry, Goethe University, Frankfurt am Main, Germany
| | - Steffen Brunst
- Institute of Pharmaceutical Chemistry, Goethe University, Frankfurt am Main, Germany
| | - Ilka Wittig
- Functional Proteomics, Faculty of Medicine, Goethe University, Frankfurt am Main, Germany
| | - Ewgenij Proschak
- Institute of Pharmaceutical Chemistry, Goethe University, Frankfurt am Main, Germany
| | - Stephan Göttig
- Institute for Medical Microbiology and Infection Control, Hospital of the Goethe University, Frankfurt am Main, Germany
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The Role of Uniform Meropenem Usage in Acinetobacter baumannii Clone Replacement. Antibiotics (Basel) 2021; 10:antibiotics10020127. [PMID: 33572723 PMCID: PMC7911629 DOI: 10.3390/antibiotics10020127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 01/19/2021] [Accepted: 01/26/2021] [Indexed: 01/01/2023] Open
Abstract
The dominant carbapenem resistant Acinetobacter baumannii harboring blaOXA-23-like carbapenemase was replaced by blaOXA-40-like carriers in a Hungarian tertiary-care center with high meropenem but relatively low imipenem use. We hypothesized that alterations in antibiotic consumption may have contributed to this switch. Our workgroup previous study examined the relation between resistance spiral and the antibiotic consumption, and the results suggest that the antibiotic usage provoked the increasing resistance in case of A. baumannii. We aimed at measuring the activity of imipenem and meropenem to compare the selection pressure exerted by the different carbapenems in time-kill assays. Strain replacement was confirmed by whole genome sequencing, core-genome multilocus sequence typing (cgMLST), and resistome analysis. Based on results of the time-kill assays, we found a significant difference between two different sequence-types (STs) in case of meropenem, but not in case of imipenem susceptibility. The newly emerged ST636 and ST492 had increased resistance level against meropenem compared to the previously dominant ST2 and ST49. On the other hand, the imipenem and colistin resistance profiles were similar. These results suggest, that the uniform meropenem usage may have contributed to A. baumannii strain replacement in our setting.
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12
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Arredondo A, Blanc V, Mor C, Nart J, León R. Resistance to β-lactams and distribution of β-lactam resistance genes in subgingival microbiota from Spanish patients with periodontitis. Clin Oral Investig 2020; 24:4639-4648. [PMID: 32495224 DOI: 10.1007/s00784-020-03333-1] [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: 01/20/2020] [Accepted: 05/08/2020] [Indexed: 12/11/2022]
Abstract
OBJECTIVES The aim of this study was to analyze the distribution of β-lactamase genes and the multidrug resistance profiles in β-lactam-resistant subgingival bacteria from patients with periodontitis. MATERIALS AND METHODS Subgingival samples were obtained from 130 Spanish patients with generalized periodontitis stage III or IV. Samples were grown on agar plates with amoxicillin or cefotaxime and incubated in anaerobic and microaerophilic conditions. Isolates were identified to the species level by the sequencing of their 16S rRNA gene. A screening for the following β-lactamase genes was performed by the polymerase chain reaction (PCR) technique: blaTEM, blaSHV, blaCTX-M, blaCfxA, blaCepA, blaCblA, and blaampC. Additionally, multidrug resistance to tetracycline, chloramphenicol, streptomycin, erythromycin, and kanamycin was assessed, growing the isolates on agar plates with breakpoint concentrations of each antimicrobial. RESULTS β-lactam-resistant isolates were found in 83% of the patients. Seven hundred and thirty-seven isolates from 35 different genera were obtained, with Prevotella and Streptococcus being the most identified genera. blaCfxA was the gene most detected, being observed in 24.8% of the isolates, followed by blaTEM (12.9%). Most of the isolates (81.3%) were multidrug-resistant. CONCLUSIONS This study shows that β-lactam resistance is widespread among Spanish patients with periodontitis. Furthermore, it suggests that the subgingival commensal microbiota might be a reservoir of multidrug resistance and β-lactamase genes. CLINICAL RELEVANCE Most of the samples yielded β-lactam-resistant isolates, and 4 different groups of bla genes were detected among the isolates. Most of the isolates were also multidrug-resistant. The results show that, although β-lactams may still be effective, their future might be hindered by the presence of β-lactam-resistant bacteria and the presence of transferable bla genes.
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Affiliation(s)
- Alexandre Arredondo
- Department of Microbiology, Dentaid Research Center, Cerdanyola del Vallès, Spain.,Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Vanessa Blanc
- Department of Microbiology, Dentaid Research Center, Cerdanyola del Vallès, Spain
| | - Carolina Mor
- Department of Periodontology, Universitat Internacional de Catalunya, Barcelona, Spain
| | - José Nart
- Department of Periodontology, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Rubén León
- Department of Microbiology, Dentaid Research Center, Cerdanyola del Vallès, Spain.
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13
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Böhm ME, Razavi M, Flach CF, Larsson DGJ. A Novel, Integron-Regulated, Class C β-Lactamase. Antibiotics (Basel) 2020; 9:antibiotics9030123. [PMID: 32183280 PMCID: PMC7148499 DOI: 10.3390/antibiotics9030123] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 12/26/2022] Open
Abstract
AmpC-type β-lactamases severely impair treatment of many bacterial infections, due to their broad spectrum (they hydrolyze virtually all β-lactams, except fourth-generation cephalosporins and carbapenems) and the increasing incidence of plasmid-mediated versions. The original chromosomal AmpCs are often tightly regulated, and their expression is induced in response to exposure to β-lactams. Regulation of mobile ampC expression is in many cases less controlled, giving rise to constitutively resistant strains with increased potential for development or acquisition of additional resistances. We present here the identification of two integron-encoded ampC genes, blaIDC-1 and blaIDC-2 (integron-derived cephalosporinase), with less than 85% amino acid sequence identity to any previously annotated AmpC. While their resistance pattern identifies them as class C β-lactamases, their low isoelectric point (pI) values make differentiation from other β-lactamases by isoelectric focusing impossible. To the best of our knowledge, this is the first evidence of an ampC gene cassette within a class 1 integron, providing a mobile context with profound potential for transfer and spread into clinics. It also allows bacteria to adapt expression levels, and thus reduce fitness costs, e.g., by cassette-reshuffling. Analyses of public metagenomes, including sewage metagenomes, show that the discovered ampCs are primarily found in Asian countries.
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Affiliation(s)
- Maria-Elisabeth Böhm
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden; (M.-E.B.); (M.R.); (C.-F.F.)
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Mohammad Razavi
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden; (M.-E.B.); (M.R.); (C.-F.F.)
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Carl-Fredrik Flach
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden; (M.-E.B.); (M.R.); (C.-F.F.)
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - D. G. Joakim Larsson
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden; (M.-E.B.); (M.R.); (C.-F.F.)
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
- Correspondence:
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14
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Abstract
β-Lactam antibiotics have been widely used as therapeutic agents for the past 70 years, resulting in emergence of an abundance of β-lactam-inactivating β-lactamases. Although penicillinases in Staphylococcus aureus challenged the initial uses of penicillin, β-lactamases are most important in Gram-negative bacteria, particularly in enteric and nonfermentative pathogens, where collectively they confer resistance to all β-lactam-containing antibiotics. Critical β-lactamases are those enzymes whose genes are encoded on mobile elements that are transferable among species. Major β-lactamase families include plasmid-mediated extended-spectrum β-lactamases (ESBLs), AmpC cephalosporinases, and carbapenemases now appearing globally, with geographic preferences for specific variants. CTX-M enzymes include the most common ESBLs that are prevalent in all areas of the world. In contrast, KPC serine carbapenemases are present more frequently in the Americas, the Mediterranean countries, and China, whereas NDM metallo-β-lactamases are more prevalent in the Indian subcontinent and Eastern Europe. As selective pressure from β-lactam use continues, multiple β-lactamases per organism are increasingly common, including pathogens carrying three different carbapenemase genes. These organisms may be spread throughout health care facilities as well as in the community, warranting close attention to increased infection control measures and stewardship of the β-lactam-containing drugs in an effort to control selection of even more deleterious pathogens.
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Ingti B, Upadhyay S, Hazarika M, Khyriem AB, Paul D, Bhattacharya P, Joshi SR, Bora D, Dhar D, Bhattacharjee A. Distribution of carbapenem resistant Acinetobacter baumannii with bla ADC-30 and induction of ADC-30 in response to beta-lactam antibiotics. Res Microbiol 2020; 171:128-133. [PMID: 31988011 DOI: 10.1016/j.resmic.2020.01.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 11/09/2019] [Accepted: 01/14/2020] [Indexed: 10/25/2022]
Abstract
A wide range of intrinsic Acinetobacter-derived cephalosporinases (ADC) along with other carbapenemases has now been detected in Acinetobacter baumannii leaving clinicians with few treatment options. The present study reports the spread of ADC-30 co-producing KPC-2 along with other β-lactamases among carbapenem resistant A. baumannii strains obtained from ICU patients in two Indian hospitals. Primer extension analysis revealed higher transcript level of the ADC gene when induced with cefoxitin at 8 μg/ml (170 fold), ceftriaxone at 8 μg/ml (136 fold), ceftazidime at 4 μg/ml (65 fold), cefepime at 8 μg/ml (77 fold) and aztreonam at 8 μg/ml (21 fold) when compared with the basal level without antibiotic pressure. Slight increase in expression of blaADC-30 when induced with imipenem and meropenem at 0.25 μg/ml (3 and 6 fold) was observed and may help in conferring resistance to carbapenem. MLST analysis revealed the circulation of A. baumannii sequence types ST188, ST386, ST583 and ST390 in these hospitals.
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Affiliation(s)
- Birson Ingti
- Department of Microbiology, Assam University, Silchar, 788011, India; Department of Microbiology, Royal Global University, Guwahati, 781035, India
| | - Supriya Upadhyay
- Department of Biotechnology & Bioinformatics, North Eastern Hill University, Shillong, 793022, Meghalaya, India
| | | | - Annie Bakorlin Khyriem
- Department of Microbiology, North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences, Shillong, Meghalaya, India
| | - Deepjyoti Paul
- Department of Microbiology, Assam University, Silchar, 788011, India
| | - Prithwis Bhattacharya
- Department of Anesthesiology, North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences, Shillong, Meghalaya, India
| | - S R Joshi
- Department of Biotechnology & Bioinformatics, North Eastern Hill University, Shillong, 793022, Meghalaya, India.
| | - Debajyoti Bora
- Department of Statistics, Dibrugarh University, Dibrugarh, India
| | - Debadatta Dhar
- Department of Microbiology, Silchar Medical College and Hospital, Silchar, India
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Mlynarcik P, Bardon J, Htoutou Sedlakova M, Prochazkova P, Kolar M. Identification of novel OXA-134-like β-lactamases in Acinetobacter lwoffii and Acinetobacter schindleri isolated from chicken litter. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2019; 163:141-146. [DOI: 10.5507/bp.2018.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 06/22/2018] [Indexed: 11/23/2022] Open
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Tietgen M, Kramer JS, Brunst S, Djahanschiri B, Wohra S, Higgins PG, Weidensdorfer M, Riedel-Christ S, Pos KM, Gonzaga A, Steglich M, Nübel U, Ebersberger I, Proschak E, Göttig S. Identification of the novel class D β-lactamase OXA-679 involved in carbapenem resistance in Acinetobacter calcoaceticus. J Antimicrob Chemother 2019; 74:1494-1502. [PMID: 30844059 DOI: 10.1093/jac/dkz080] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 01/30/2019] [Accepted: 02/01/2019] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVES The aim of this study was to characterize the Acinetobacter calcoaceticus clinical isolate AC_2117 with the novel carbapenem-hydrolysing class D β-lactamase (CHDL) OXA-679. METHODS Identification of the species and β-lactamases was verified by genome sequencing (PacBio) and phylogenetic analyses. Antibiotic susceptibility of AC_2117 and transformants harbouring cloned blaOXA-679 was evaluated using antibiotic gradient strips and microbroth dilution. OXA-679 was purified heterologously and kinetic parameters were determined using spectrometry or isothermal titration calorimetry. The impact of OXA-679 production during imipenem therapy was evaluated in the Galleria mellonella infection model. RESULTS Sequencing of the complete genome of the clinical A. calcoaceticus isolate AC_2117 identified a novel CHDL, termed OXA-679. This enzyme shared sequence similarity of 71% to each of the families OXA-143 and OXA-24/40. Phylogenetic analyses revealed that OXA-679 represents a member of a new OXA family. Cloning and expression of blaOXA-679 as well as measurement of kinetic parameters revealed the effective hydrolysis of carbapenems which resulted in reduced susceptibility to carbapenems in Escherichia coli and A. calcoaceticus, and high-level carbapenem resistance in Acinetobacter baumannii. Infection of larvae of G. mellonella with a sublethal dose of blaOXA-679-expressing A. baumannii could not be cured by high-dose imipenem therapy, indicating carbapenem resistance in vivo. CONCLUSIONS We identified blaOXA-679 in a clinical A. calcoaceticus isolate that represents a member of the new OXA-679 family and that conferred high-level carbapenem resistance in vitro and in vivo.
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Affiliation(s)
- Manuela Tietgen
- Institute of Medical Microbiology and Infection Control, Hospital of the Goethe University, Frankfurt am Main, Germany.,Faculty of Biological Sciences of the Goethe University, Frankfurt am Main, Germany
| | - Jan S Kramer
- Institute of Pharmaceutical Chemistry, Goethe University, Frankfurt am Main, Germany
| | - Steffen Brunst
- Institute of Pharmaceutical Chemistry, Goethe University, Frankfurt am Main, Germany
| | - Bardya Djahanschiri
- Applied Bioinformatics Group, Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt am Main, Germany
| | - Sonali Wohra
- Institute of Medical Microbiology and Infection Control, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Paul G Higgins
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Cologne, Germany.,German Center for Infection Research (DZIF), partner site Bonn-Cologne, Germany
| | - Marko Weidensdorfer
- Institute of Medical Microbiology and Infection Control, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Sara Riedel-Christ
- Institute of Medical Microbiology and Infection Control, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Klaas M Pos
- Institute of Biochemistry, Goethe University, Frankfurt am Main, Germany
| | - Aitor Gonzaga
- Leibniz Institute DSMZ - Deutsche Sammlung von Mikroorganismen und Zellkulturen, Braunschweig, Germany
| | - Matthias Steglich
- Leibniz Institute DSMZ - Deutsche Sammlung von Mikroorganismen und Zellkulturen, Braunschweig, Germany.,German Center for Infection Research (DZIF), partner site Hannover-Braunschweig, Germany
| | - Ulrich Nübel
- Leibniz Institute DSMZ - Deutsche Sammlung von Mikroorganismen und Zellkulturen, Braunschweig, Germany.,German Center for Infection Research (DZIF), partner site Hannover-Braunschweig, Germany
| | - Ingo Ebersberger
- Applied Bioinformatics Group, Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt am Main, Germany.,Senckenberg Biodiversity and Climate Research Centre Frankfurt (BIK-F), Frankfurt am Main, Germany
| | - Ewgenij Proschak
- Institute of Pharmaceutical Chemistry, Goethe University, Frankfurt am Main, Germany
| | - Stephan Göttig
- Institute of Medical Microbiology and Infection Control, Hospital of the Goethe University, Frankfurt am Main, Germany
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Mendes RE, Jones RN, Woosley LN, Cattoir V, Castanheira M. Application of Next-Generation Sequencing for Characterization of Surveillance and Clinical Trial Isolates: Analysis of the Distribution of β-lactamase Resistance Genes and Lineage Background in the United States. Open Forum Infect Dis 2019; 6:S69-S78. [PMID: 30895217 PMCID: PMC6419912 DOI: 10.1093/ofid/ofz004] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Background Sequencing technologies and techniques have seen remarkable transformation and innovation that have significantly affected sequencing capability. Data analyses have replaced sequencing as the main challenge. This paper provides an overview on applying next-generation sequencing (NGS) and analysis and discusses the benefits and challenges. In addition, this document shows results from using NGS and bioinformatics tools to screen for β-lactamase genes and assess the epidemiological structure of Escherichia coli– and Klebsiella pneumoniae–causing bloodstream (BSIs) and urinary tract (UTIs) infections in patients hospitalized in the United States during the SENTRY Antimicrobial Surveillance Program for 2016. Methods A total of 3525 isolates (2751 E. coli and 774 K. pneumoniae) causing BSIs (n = 892) and UTIs (n = 2633) in hospitalized patients in the United States were included. Isolates were tested for susceptibility by broth microdilution, and those that met a minimum inhibitory concentration (MIC)–based screening criteria had their genomes sequenced and analyzed. Results A total of 11.6% and 16.1% of E. coli–causing UTIs and BSIs, respectively, met the MIC-based criteria, whereas 11.0% and 13.7% of K. pneumoniae isolates causing UTIs and BSIs, respectively, met the criteria. Among E. coli, blaCTX-M variants (87.6% overall) prevailed (60.5% of CTX-M group 1 and 26.9% of group 9). A total of 60.3% of K. pneumoniae isolates carried blaCTX-M variants (52.7% and 7.6% of groups 1 and 9, respectively). Two E. coli (0.6%) and 13 K. pneumoniae (12.9%) isolates harbored blaKPC. Among KPC-producing K. pneumoniae (2 from BSIs and 11 from UTIs), 84.6% (11/13) were ST258 (CC258). Seventeen and 38 unique clonal complexes (CCs) were noted in E. coli that caused BSIs and UTIs, respectively, and CC131 (or ST131) was the most common CC among BSI (53.6%) and UTI (58.2%) isolates. Twenty-three and 26 CCs were noted among K. pneumoniae–causing BSIs and UTIs, respectively. CC258 (28.3%) prevailed in UTI pathogens, whereas CC307 (15.0%) was the most common CC among BSI isolates. Conclusions This study provides a benchmark for the distribution of β-lactamase genes and the population structure information for the most common Enterobacteriaceae species responsible for BSIs and UTIs in US medical centers during the 2016 SENTRY Program.
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Affiliation(s)
| | | | | | - Vincent Cattoir
- University Hospital of Rennes, Department of Clinical Microbiology, Rennes, France.,National Reference Center for Antimicrobial Resistance, Rennes, France.,University of Rennes 1, Unit Inserm U1230, Rennes, France
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de Azevedo FKSF, Dutra V, Nakazato L, Mello CM, Pepato MA, de Sousa ATHI, Takahara DT, Hahn RC, Souto FJD. Molecular epidemiology of multidrug-resistant Acinetobacter baumannii infection in two hospitals in Central Brazil: the role of ST730 and ST162 in clinical outcomes. J Med Microbiol 2018; 68:31-40. [PMID: 30516469 DOI: 10.1099/jmm.0.000853] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
PURPOSE Acinetobacter baumannii is a major cause of multidrug-resistant nosocomial infections. The characteristics of A. baumannii at two hospitals in a city in Central Brazil are described by analysing the phenotypes and molecular profiles of isolates recovered from 87 patients. METHODOLOGY The isolates were identified and their antimicrobial susceptibility was evaluated using the the Bact/Alert 3D and Vitek2 methods. Patients' clinical data were obtained from medical files. Genes associated with resistance to carbapenems were analysed by multilocus sequence typing, clinical and bacteriological variables were analysed by descriptive statistics, and logistic models were generated to adjust the associations. RESULTS Sixty-four (73.5 %) out of 87 A. baumannii isolates analysed were from patients in intensive care. The mortality rate was 43.7 %. Eighty (91.9 %) isolates were resistant to imipenem and 86 were susceptible to colistin (98.8 %). The blaOXA-23 gene (78.2 %) and its upstream insertion ISAba1 (55.2 %) were predominant, followed by blaOXA-24 (55.2 %) and blaOXA-143 (28.7 %). The blaOXA-23 gene and ISAba1 were independently associated with resistance to imipenem (P<0.05). There were 13 different sequence types (STs) among the 35 isolates. ST1 (nine; 25.7 %), ST162 (eight; 22.8 %) and ST730 (six; 17.1 %) were the most common, and four new STs were identified. The isolates were grouped into five clonal complexes (CC1, CC15, CC79, CC108 and CC162) plus a singleton using eburst. CONCLUSION Respiratory infection, age >60 years and use of noradrenaline were factors associated with fatality. ST730 (CC79) was associated with higher mortality (P<0.05) and ST162 (CC162) was associated with increased survival probability (P<0.05).
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Affiliation(s)
| | - Valéria Dutra
- 2Laboratory of Veterinary Microbiology and Molecular Biology, College of Veterinary Medicine, Federal University of Mato Grosso, Mato Grosso, Brazil
| | - Luciano Nakazato
- 2Laboratory of Veterinary Microbiology and Molecular Biology, College of Veterinary Medicine, Federal University of Mato Grosso, Mato Grosso, Brazil
| | - Camila Martines Mello
- 1College of Medicine, Júlio Muller Hospital University, Federal University of Mato Grosso, Mato Grosso State, Brazil
| | - Marco Andrey Pepato
- 1College of Medicine, Júlio Muller Hospital University, Federal University of Mato Grosso, Mato Grosso State, Brazil
| | | | - Doracilde Terume Takahara
- 1College of Medicine, Júlio Muller Hospital University, Federal University of Mato Grosso, Mato Grosso State, Brazil
| | - Rosane Christine Hahn
- 1College of Medicine, Júlio Muller Hospital University, Federal University of Mato Grosso, Mato Grosso State, Brazil
| | - Francisco José Dutra Souto
- 1College of Medicine, Júlio Muller Hospital University, Federal University of Mato Grosso, Mato Grosso State, Brazil
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Abstract
β-Lactamases, the major resistance determinant for β-lactam antibiotics in Gram-negative bacteria, are ancient enzymes whose origins can be traced back millions of years ago. These well-studied enzymes, currently numbering almost 2,800 unique proteins, initially emerged from environmental sources, most likely to protect a producing bacterium from attack by naturally occurring β-lactams. Their ancestors were presumably penicillin-binding proteins that share sequence homology with β-lactamases possessing an active-site serine. Metallo-β-lactamases also exist, with one or two catalytically functional zinc ions. Although penicillinases in Gram-positive bacteria were reported shortly after penicillin was introduced clinically, transmissible β-lactamases that could hydrolyze recently approved cephalosporins, monobactams, and carbapenems later became important in Gram-negative pathogens. Nomenclature is based on one of two major systems. Originally, functional classifications were used, based on substrate and inhibitor profiles. A later scheme classifies β-lactamases according to amino acid sequences, resulting in class A, B, C, and D enzymes. A more recent nomenclature combines the molecular and biochemical classifications into 17 functional groups that describe most β-lactamases. Some of the most problematic enzymes in the clinical community include extended-spectrum β-lactamases (ESBLs) and the serine and metallo-carbapenemases, all of which are at least partially addressed with new β-lactamase inhibitor combinations. New enzyme variants continue to be described, partly because of the ease of obtaining sequence data from whole-genome sequencing studies. Often, these new enzymes are devoid of any phenotypic descriptions, making it more difficult for clinicians and antibiotic researchers to address new challenges that may be posed by unusual β-lactamases.
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Affiliation(s)
- Karen Bush
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA
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21
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Domingues S, Rosário N, Ben Cheikh H, Da Silva GJ. ISAba1 and Tn6168 acquisition by natural transformation leads to third-generation cephalosporins resistance in Acinetobacter baumannii. INFECTION GENETICS AND EVOLUTION 2018; 63:13-16. [PMID: 29758354 DOI: 10.1016/j.meegid.2018.05.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 05/09/2018] [Accepted: 05/10/2018] [Indexed: 11/15/2022]
Abstract
Acinetobacter baumannii has intrinsic beta-lactamase genes, namely ampC and blaOXA-51-like, which are only strongly expressed when the ISAba1 insertion sequence is upstream the 5' end of the genes. A second ampC gene has also been identified in some clinical A. baumannii strains. The increased expression of these genes leads to resistance to beta-lactams, including third-generation cephalosporins and/or carbapenems. The aim of this work was to assess the involvement of natural transformation in the transfer of chromosomal ampC-associated mobile elements, and related changes in the resistance profile of recipient cells. Natural transformation assays with the naturally competent A. baumannii A118 clinical isolate as recipient cell and the multidrug resistant A. baumannii Ab51 clinical isolate as the source of donor DNA produced transformants. All tested transformants showed integration of the ISAba1 close to the ampC gene. In two transformants, the ISAba1 was acquired by transposition and inserted between the usual folE and the ampC genes. The remaining transformants acquired the ISAba1 adjacent to a second ampC gene, as part of Tn6168, likely by homologous recombination. Our study demonstrates that natural transformation can contribute to the widespread of beta-lactams resistance, and acquisition of non-resistant determinants can lead to changes in the susceptibility profile of A. baumannii strains.
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Affiliation(s)
- Sara Domingues
- Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal; Centre for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.
| | - Natasha Rosário
- Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Hadhemi Ben Cheikh
- Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal; Faculty of Science, Bizerta Carthage University, Bizerta, Tunisia; Laboratory of Contagious Disease and Biologically Active Substances LR99-ES27 at Monastir's Pharmacy Faculty, Monastir, Tunisia
| | - Gabriela Jorge Da Silva
- Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal; Centre for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
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Juan C, Torrens G, González-Nicolau M, Oliver A. Diversity and regulation of intrinsic β-lactamases from non-fermenting and other Gram-negative opportunistic pathogens. FEMS Microbiol Rev 2018; 41:781-815. [PMID: 29029112 DOI: 10.1093/femsre/fux043] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 08/18/2017] [Indexed: 01/22/2023] Open
Abstract
This review deeply addresses for the first time the diversity, regulation and mechanisms leading to mutational overexpression of intrinsic β-lactamases from non-fermenting and other non-Enterobacteriaceae Gram-negative opportunistic pathogens. After a general overview of the intrinsic β-lactamases described so far in these microorganisms, including circa. 60 species and 100 different enzymes, we review the wide array of regulatory pathways of these β-lactamases. They include diverse LysR-type regulators, which control the expression of β-lactamases from relevant nosocomial pathogens such as Pseudomonas aeruginosa or Stenothrophomonas maltophilia or two-component regulators, with special relevance in Aeromonas spp., along with other pathways. Likewise, the multiple mutational mechanisms leading to β-lactamase overexpression and β-lactam resistance development, including AmpD (N-acetyl-muramyl-L-alanine amidase), DacB (PBP4), MrcA (PPBP1A) and other PBPs, BlrAB (two-component regulator) or several lytic transglycosylases among others, are also described. Moreover, we address the growing evidence of a major interplay between β-lactamase regulation, peptidoglycan metabolism and virulence. Finally, we analyse recent works showing that blocking of peptidoglycan recycling (such as inhibition of NagZ or AmpG) might be useful to prevent and revert β-lactam resistance. Altogether, the provided information and the identified gaps should be valuable for guiding future strategies for combating multidrug-resistant Gram-negative pathogens.
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Affiliation(s)
- Carlos Juan
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases-Instituto de Investigación Sanitaria de Baleares (IdISBa), 07120 Palma, Illes Balears, Spain
| | - Gabriel Torrens
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases-Instituto de Investigación Sanitaria de Baleares (IdISBa), 07120 Palma, Illes Balears, Spain
| | - Mar González-Nicolau
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases-Instituto de Investigación Sanitaria de Baleares (IdISBa), 07120 Palma, Illes Balears, Spain
| | - Antonio Oliver
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases-Instituto de Investigación Sanitaria de Baleares (IdISBa), 07120 Palma, Illes Balears, Spain
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Molecular Epidemiology and Mechanism of Sulbactam Resistance in Acinetobacter baumannii Isolates with Diverse Genetic Backgrounds in China. Antimicrob Agents Chemother 2018; 62:AAC.01947-17. [PMID: 29311074 DOI: 10.1128/aac.01947-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 12/15/2017] [Indexed: 01/03/2023] Open
Abstract
Sulbactam is a plausible option for treating Acinetobacter infections because of its intrinsic antibacterial activity against the members of the Acinetobacter genus, but the mechanisms of sulbactam resistance have not been fully studied in Acinetobacter baumannii In this study, a total of 2,197 clinical A. baumannii isolates were collected from 27 provinces in China. Eighty-eight isolates with various MICs for sulbactam were selected on the basis of their diverse clonality and underwent multilocus sequence typing (MLST), antimicrobial susceptibility testing, and resistance gene screening. The copy number and relative expression of blaTEM-1D and ampC were measured via quantitative PCR and quantitative reverse transcription-PCR, respectively. The genetic structure of multicopy blaTEM-1D was determined using the whole-genome sequencing technology. The cefoperazone-sulbactam resistance rate of the 2,197 isolates was 39.7%. The rate of positivity for blaTEM-1D or ISAba1-ampC in the sulbactam-nonsusceptible group (64.91% and 78.95%, respectively) was significantly higher than that in the sulbactam-susceptible group (0% and 0%, respectively; P < 0.001). The MIC of sulbactam (P < 0.001) varied considerably between the groups expressing ampC with or without upstream ISAba1 Notably, the genetic structure of the multicopy blaTEM-1D gene in strain ZS3 revealed that blaTEM-1D was embedded within four tandem copies of the cassette IS26-blaTEM-1D-Tn3-IS26 Therefore, blaTEM-1D and ISAba1-ampC represent the prevalent mechanism underlying sulbactam resistance in clinical A. baumannii isolates in China. The structure of the four tandem copies of blaTEM-1D first identified may increase sulbactam resistance.
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ESBL-producing Escherichia coli
and Its Rapid Rise among Healthy People. Food Saf (Tokyo) 2017; 5:122-150. [PMID: 32231938 DOI: 10.14252/foodsafetyfscj.2017011] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 12/11/2017] [Indexed: 02/06/2023] Open
Abstract
Since around the 2000s, Escherichia coli (E. coli) resistant to both oxyimino-cephalosporins and fluoroquinolones has remarkably increased worldwide in clinical settings. The kind of E. coli is also identified in patients suffering from community-onset infectious diseases such as urinary tract infections. Moreover, recoveries of multi-drug resistant E. coli from the feces of healthy people have been increasingly documented in recent years, although the actual state remains uncertain. These E. coli isolates usually produce extended-spectrum β-lactamase (ESBL), as well as acquisition of amino acid substitutions in the quinolone-resistance determining regions (QRDRs) of GyrA and/or ParC, together with plasmid-mediated quinolone resistance determinants such as Qnr, AAC(6')-Ib-cr, and QepA. The actual state of ESBL-producing E. coli in hospitalized patients has been carefully investigated in many countries, while that in healthy people still remains uncertain, although high fecal carriage rates of ESBL producers in healthy people have been reported especially in Asian and South American countries. The issues regarding the ESBL producers have become very complicated and chaotic due to rapid increase of both ESBL variants and plasmids mediating ESBL genes, together with the emergence of various "epidemic strains" or "international clones" of E. coli and Klebsiella pneumoniae harboring transferable-plasmids carrying multiple antimicrobial resistance genes. Thus, the current state of ESBL producers outside hospital settings was overviewed together with the relation among those recovered from livestock, foods, pets, environments and wildlife from the viewpoint of molecular epidemiology. This mini review may contribute to better understanding about ESBL producers among people who are not familiar with the antimicrobial resistance (AMR) threatening rising globally.
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Ruppé E, Cherkaoui A, Lazarevic V, Emonet S, Schrenzel J. Establishing Genotype-to-Phenotype Relationships in Bacteria Causing Hospital-Acquired Pneumonia: A Prelude to the Application of Clinical Metagenomics. Antibiotics (Basel) 2017; 6:antibiotics6040030. [PMID: 29186015 PMCID: PMC5745473 DOI: 10.3390/antibiotics6040030] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/17/2017] [Accepted: 11/20/2017] [Indexed: 01/20/2023] Open
Abstract
Clinical metagenomics (CMg), referred to as the application of next-generation sequencing (NGS) to clinical samples, is a promising tool for the diagnosis of hospital-acquired pneumonia (HAP). Indeed, CMg allows identifying pathogens and antibiotic resistance genes (ARGs), thereby providing the information required for the optimization of the antibiotic regimen. Hence, provided that CMg would be faster than conventional culture, the probabilistic regimen used in HAP could be tailored faster, which should lead to an expected decrease of mortality and morbidity. While the inference of the antibiotic susceptibility testing from metagenomic or even genomic data is challenging, a limited number of antibiotics are used in the probabilistic regimen of HAP (namely beta-lactams, aminoglycosides, fluoroquinolones, glycopeptides and oxazolidinones). Accordingly, based on the perspective of applying CMg to the early diagnostic of HAP, we aimed at reviewing the performances of whole genomic sequencing (WGS) of the main HAP-causing bacteria (Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter baumannii, Stenotrophomonas maltophilia and Staphylococcus aureus) for the prediction of susceptibility to the antibiotic families advocated in the probabilistic regimen of HAP.
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Affiliation(s)
- Etienne Ruppé
- Genomic Research Laboratory, Geneva University Hospitals, CMU-9F, Rue Michel Servet 1, CH-1211 Geneva 14, Switzerland.
| | - Abdessalam Cherkaoui
- Laboratory of Bacteriology, University Hospitals, Rue Gabrielle Perret-Gentil 4, CH-1211 Geneva 14, Switzerland.
| | - Vladimir Lazarevic
- Genomic Research Laboratory, Geneva University Hospitals, CMU-9F, Rue Michel Servet 1, CH-1211 Geneva 14, Switzerland.
| | - Stéphane Emonet
- Service of Infectious Diseases, Geneva University Hospitals, Rue Gabrielle Perret-Gentil 4, CH-1211 Geneva 14, Switzerland.
| | - Jacques Schrenzel
- Genomic Research Laboratory, Geneva University Hospitals, CMU-9F, Rue Michel Servet 1, CH-1211 Geneva 14, Switzerland.
- Laboratory of Bacteriology, University Hospitals, Rue Gabrielle Perret-Gentil 4, CH-1211 Geneva 14, Switzerland.
- Service of Infectious Diseases, Geneva University Hospitals, Rue Gabrielle Perret-Gentil 4, CH-1211 Geneva 14, Switzerland.
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Alharbe R, Almansour A, Kwon DH. Antibacterial activity of exogenous glutathione and its synergism on antibiotics sensitize carbapenem-associated multidrug resistant clinical isolates of Acinetobacter baumannii. Int J Med Microbiol 2017; 307:409-414. [PMID: 28781060 DOI: 10.1016/j.ijmm.2017.07.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 06/27/2017] [Accepted: 07/20/2017] [Indexed: 10/19/2022] Open
Abstract
A major clinical impact of A. baumannii is hospital-acquired infections including ventilator-associated pneumonia. The treatment of this pathogen is often difficult due to its innate and acquired resistance to almost all commercially available antibiotics. Infections with carbapenem-associated multidrug resistant A. baumannii is the most problematic. Glutathione is a tripeptide thiol-antioxidant and antibacterial activity of exogenous glutathione was reported in some bacteria. However, clinical relevance and molecular details of the antibacterial activity of glutathione are currently unclear. Seventy clinical isolates of A. baumannii including 63 carbapenem-associated multidrug resistant isolates and a type strain A. baumannii ATCC 19606 were used to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Fractional inhibitory concentration (FIC) and time-killing activity with meropenem and/or glutathione were also determined in the carbapenem-associated multidrug resistant isolates. In addition, the roles of exogenous glutathione in multidrug efflux pumps and β-lactamase production were examined. Levels of MIC and MBC were ranged from 10 to 15mM of exogenous glutathione. All tested carbapenem-associated multidrug resistant isolates were sensitized by all tested antibiotics in combination with subinhibitory concentrations of glutathione. FIC levels of glutathione with carbapenem (meropenem) were all<0.5 and the carbapenem-associated multidrug resistant isolates were killed by subinhibitory concentrations of both glutathione and meropenem at>2log10 within 12h, suggesting glutathione synergistically interacts with meropenem. The roles of multidrug efflux pumps and β-lactamase production were excluded for the glutathione-mediated antibiotic susceptibility. Overall results demonstrate that the antibacterial activity of glutathione is clinically relevant and its synergism on antibiotics sensitizes clinical isolates of A. baumannii regardless of their resistance or susceptibility to antibiotics. This finding suggests that exogenous glutathione alone and/or in combination with existing antibiotics may be applicable to treat infections with carbapenem-associated multidrug resistant A. baumannii.
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Affiliation(s)
- Roaa Alharbe
- Department of Biology, Long Island University, Brooklyn, NY 11201, United States
| | - Ayidh Almansour
- Department of Biology, Long Island University, Brooklyn, NY 11201, United States
| | - Dong H Kwon
- Department of Biology, Long Island University, Brooklyn, NY 11201, United States; Department of Medicine, Michael E. DeBakey VA Medical Center, Baylor College of Medicine, Houston, TX 77030, United States, United States.
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Karah N, Jolley KA, Hall RM, Uhlin BE. Database for the ampC alleles in Acinetobacter baumannii. PLoS One 2017; 12:e0176695. [PMID: 28459877 PMCID: PMC5411055 DOI: 10.1371/journal.pone.0176695] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 04/14/2017] [Indexed: 11/19/2022] Open
Abstract
Acinetobacter baumannii is a troublesome opportunistic pathogen with a high capacity for clonal dissemination. We announce the establishment of a database for the ampC locus in A. baumannii, in which novel ampC alleles are differentiated based on the occurrence of ≥ 1 nucleotide change, regardless of whether it is silent or missense. The database is openly accessible at the pubmlst platform for A. baumannii (http://pubmlst.org/abaumannii/). Forty-eight distinctive alleles of the ampC locus have so far been identified and deposited in the database. Isolates from clonal complex 1 (CC1), according to the Pasteur multilocus sequence typing scheme, had a variety of the ampC locus alleles, including alleles 1, 3, 4, 5, 6, 7, 8, 13, 14, 17, and 18. On the other hand, isolates from CC2 had the ampC alleles 2, 3, 19, 20, 21, 22, 23, 24, 26, 27, 28, and 46. Allele 3 was characteristic for sequence types ST3 or ST32. The ampC alleles 10, 16, and 25 were characteristic for CC10, ST16, and CC25, respectively. Our study points out that novel gene databases, in which alleles are numbered based on differences in their nucleotide identities, should replace traditional records that use amino acid substitutions to define new alleles.
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Affiliation(s)
- Nabil Karah
- The Laboratory for Molecular Infection Medicine Sweden (MIMS) and Department of Molecular Biology, Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
- * E-mail:
| | - Keith A. Jolley
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Ruth M. Hall
- School of Life and Environmental Sciences, University of Sydney, Sydney, Australia
| | - Bernt Eric Uhlin
- The Laboratory for Molecular Infection Medicine Sweden (MIMS) and Department of Molecular Biology, Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
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Structure and Function of the PiuA and PirA Siderophore-Drug Receptors from Pseudomonas aeruginosa and Acinetobacter baumannii. Antimicrob Agents Chemother 2017; 61:AAC.02531-16. [PMID: 28137795 DOI: 10.1128/aac.02531-16] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 01/27/2017] [Indexed: 01/06/2023] Open
Abstract
The outer membrane of Gram-negative bacteria presents an efficient barrier to the permeation of antimicrobial molecules. One strategy pursued to circumvent this obstacle is to hijack transport systems for essential nutrients, such as iron. BAL30072 and MC-1 are two monobactams conjugated to a dihydroxypyridone siderophore that are active against Pseudomonas aeruginosa and Acinetobacter baumannii Here, we investigated the mechanism of action of these molecules in A. baumannii We identified two novel TonB-dependent receptors, termed Ab-PiuA and Ab-PirA, that are required for the antimicrobial activity of both agents. Deletion of either piuA or pirA in A. baumannii resulted in 4- to 8-fold-decreased susceptibility, while their overexpression in the heterologous host P. aeruginosa increased susceptibility to the two siderophore-drug conjugates by 4- to 32-fold. The crystal structures of PiuA and PirA from A. baumannii and their orthologues from P. aeruginosa were determined. The structures revealed similar architectures; however, structural differences between PirA and PiuA point to potential differences between their cognate siderophore ligands. Spontaneous mutants, selected upon exposure to BAL30072, harbored frameshift mutations in either the ExbD3 or the TonB3 protein of A. baumannii, forming the cytoplasmic-membrane complex providing the energy for the siderophore translocation process. The results of this study provide insight for the rational design of novel siderophore-drug conjugates against problematic Gram-negative pathogens.
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Lee CR, Lee JH, Park M, Park KS, Bae IK, Kim YB, Cha CJ, Jeong BC, Lee SH. Biology of Acinetobacter baumannii: Pathogenesis, Antibiotic Resistance Mechanisms, and Prospective Treatment Options. Front Cell Infect Microbiol 2017; 7:55. [PMID: 28348979 PMCID: PMC5346588 DOI: 10.3389/fcimb.2017.00055] [Citation(s) in RCA: 496] [Impact Index Per Article: 70.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/13/2017] [Indexed: 12/27/2022] Open
Abstract
Acinetobacter baumannii is undoubtedly one of the most successful pathogens responsible for hospital-acquired nosocomial infections in the modern healthcare system. Due to the prevalence of infections and outbreaks caused by multi-drug resistant A. baumannii, few antibiotics are effective for treating infections caused by this pathogen. To overcome this problem, knowledge of the pathogenesis and antibiotic resistance mechanisms of A. baumannii is important. In this review, we summarize current studies on the virulence factors that contribute to A. baumannii pathogenesis, including porins, capsular polysaccharides, lipopolysaccharides, phospholipases, outer membrane vesicles, metal acquisition systems, and protein secretion systems. Mechanisms of antibiotic resistance of this organism, including acquirement of β-lactamases, up-regulation of multidrug efflux pumps, modification of aminoglycosides, permeability defects, and alteration of target sites, are also discussed. Lastly, novel prospective treatment options for infections caused by multi-drug resistant A. baumannii are summarized.
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Affiliation(s)
- Chang-Ro Lee
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea
| | - Jung Hun Lee
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea
| | - Moonhee Park
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji UniversityYongin, South Korea; DNA Analysis Division, Seoul Institute, National Forensic ServiceSeoul, South Korea
| | - Kwang Seung Park
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea
| | - Il Kwon Bae
- Department of Dental Hygiene, College of Health and Welfare, Silla University Busan, South Korea
| | - Young Bae Kim
- Biotechnology Program, North Shore Community College Danvers, MA, USA
| | - Chang-Jun Cha
- Department of Systems Biotechnology, College of Biotechnology and Natural Resources, Chung-Ang University Anseong, South Korea
| | - Byeong Chul Jeong
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea
| | - Sang Hee Lee
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea
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Plasmid borne Carbapenem-Hydrolyzing Class D β-Lactamases (CHDLs) and AdeABC efflux pump conferring carbapenem-tigecycline resistance among Acinetobacter baumannii isolates harboring TnAbaRs. Microb Pathog 2017; 104:310-317. [DOI: 10.1016/j.micpath.2017.01.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 01/22/2017] [Accepted: 01/24/2017] [Indexed: 12/18/2022]
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31
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Werner JP, Mitchell JM, Taracila MA, Bonomo RA, Powers RA. Exploring the potential of boronic acids as inhibitors of OXA-24/40 β-lactamase. Protein Sci 2017; 26:515-526. [PMID: 27997706 DOI: 10.1002/pro.3100] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 12/08/2016] [Accepted: 12/08/2016] [Indexed: 01/01/2023]
Abstract
β-lactam antibiotics are crucial to the management of bacterial infections in the medical community. Due to overuse and misuse, clinically significant bacteria are now resistant to many commercially available antibiotics. The most widespread resistance mechanism to β-lactams is the expression of β-lactamase enzymes. To overcome β-lactamase mediated resistance, inhibitors were designed to inactivate these enzymes. However, current inhibitors (clavulanic acid, tazobactam, and sulbactam) for β-lactamases also contain the characteristic β-lactam ring, making them susceptible to resistance mechanisms employed by bacteria. This presents a critical need for novel, non-β-lactam inhibitors that can circumvent these resistance mechanisms. The carbapenem-hydrolyzing class D β-lactamases (CHDLs) are of particular concern, given that they efficiently hydrolyze potent carbapenem antibiotics. Unfortunately, these enzymes are not inhibited by clinically available β-lactamase inhibitors, nor are they effectively inhibited by the newest, non-β-lactam inhibitor, avibactam. Boronic acids are known transition state analog inhibitors of class A and C β-lactamases, and are not extensively characterized as inhibitors of class D β-lactamases. Importantly, boronic acids provide a novel way to potentially inhibit class D β-lactamases. Sixteen boronic acids were selected and tested for inhibition of the CHDL OXA-24/40. Several compounds were identified as effective inhibitors of OXA-24/40, with Ki values as low as 5 μM. The X-ray crystal structures of OXA-24/40 in complex with BA3, BA4, BA8, and BA16 were determined and revealed the importance of interactions with hydrophobic residues Tyr112 and Trp115. These boronic acids serve as progenitors in optimization efforts of a novel series of inhibitors for class D β-lactamases.
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Affiliation(s)
- Josephine P Werner
- Department of Chemistry, Grand Valley State University, Allendale, Michigan, 49401
| | - Joshua M Mitchell
- Department of Chemistry, Grand Valley State University, Allendale, Michigan, 49401
| | - Magdalena A Taracila
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, 44106.,Departments of Medicine, Pharmacology, Biochemistry and Molecular Biology, and Microbiology, Case Western Reserve University, Cleveland, Ohio, 44106
| | - Robert A Bonomo
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, 44106.,Departments of Medicine, Pharmacology, Biochemistry and Molecular Biology, and Microbiology, Case Western Reserve University, Cleveland, Ohio, 44106
| | - Rachel A Powers
- Department of Chemistry, Grand Valley State University, Allendale, Michigan, 49401
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32
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Liu C, Wang X, Chen Y, Hao H, Li X, Liang J, Duan R, Li C, Zhang J, Shao S, Jing H. Three Yersinia enterocolitica AmpD Homologs Participate in the Multi-Step Regulation of Chromosomal Cephalosporinase, AmpC. Front Microbiol 2016; 7:1282. [PMID: 27588018 PMCID: PMC4988969 DOI: 10.3389/fmicb.2016.01282] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 08/03/2016] [Indexed: 11/29/2022] Open
Abstract
In many gram negative bacilli, AmpD plays a key role in both cell well-recycling pathway and β-lactamase regulation, inactivation of the ampD causes the accumulation of 1,6-anhydromuropeptides, and results in the ampC overproduction. In Yersinia enterocolitica, the regulation of ampC expression may also rely on the ampR-ampC system, the role of AmpD in this species is still unknown. In this study, three AmpD homologs (AmpD1, AmpD2, and AmpD3) have been identified in complete sequence of strain Y. enterocolitica subsp. palearctica 105.5R(r). To understand the role of three AmpD homologs, several mutant strains were constructed and analyzed where a rare ampC regulation mechanism was observed: low-effective ampD2 and ampD3 cooperate with the high-effective ampD1 in the three levels regulation of ampC expression. Enterobacteriaceae was used to be supposed to regulate ampC expression by two steps, three steps regulation was only observed in Pseudomonas aeruginosa. In this study, we first reported that Enterobacteriaceae Y. enterocolitica can also possess a three steps stepwise regulation mechanism, regulating the ampC expression precisely.
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Affiliation(s)
- Chang Liu
- Department of Pathogenic Biology, School of Medical Science, Jiangsu UniversityZhenjiang, China; National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious DiseasesBeijing, China
| | - Xin Wang
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases Beijing, China
| | - Yuhuang Chen
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases Beijing, China
| | - Huijing Hao
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases Beijing, China
| | - Xu Li
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases Beijing, China
| | - Junrong Liang
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases Beijing, China
| | - Ran Duan
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases Beijing, China
| | - Chuchu Li
- Department of Pathogenic Biology, School of Medical Science, Jiangsu UniversityZhenjiang, China; National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious DiseasesBeijing, China
| | - Jing Zhang
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases Beijing, China
| | - Shihe Shao
- Department of Pathogenic Biology, School of Medical Science, Jiangsu University Zhenjiang, China
| | - Huaiqi Jing
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases Beijing, China
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Mutations Decreasing Intrinsic β-Lactam Resistance Are Linked to Cell Division in the Nosocomial Pathogen Acinetobacter baumannii. Antimicrob Agents Chemother 2016; 60:3751-8. [PMID: 27067318 DOI: 10.1128/aac.00361-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 04/03/2016] [Indexed: 12/18/2022] Open
Abstract
Transposon mutagenesis was used to identify novel determinants of intrinsic β-lactam resistance in Acinetobacter baumannii An EZ-Tn5 transposon insertion in a gene corresponding to the A1S_0225 sequence resulted in a 4-fold decrease in resistance to ampicillin, cefotaxime, imipenem, and ceftriaxone but did not alter resistance to other classes of antibiotics. Based on this phenotype, the gene was designated blhA (β-lactam hypersusceptibility). The blhA::EZ-Tn5 mutation conferred a similar phenotype in A. baumannii strain ATCC 17978. The wild-type blhA gene complemented the blhA::EZTn5 insertion and restored β-lactam resistance levels back to wild-type levels. The blhA mutation also increased β-lactam susceptibility in an adeB adeJ double mutant, indicating that the blhA mutation acted independently of these efflux systems to mediate susceptibility. In addition, mRNA levels for the blaOXA and blaADC β-lactamase genes were not altered by the blhA mutation. The blhA mutation resulted in a prominent cell division and morphological defect, with cells exhibiting a highly elongated phenotype, combined with large bulges in some cells. The blhA gene is unique to Acinetobacter and likely represents a novel gene involved in cell division. Three additional mutations, in zipA, zapA, and ftsK, each of which encode predicted cell division proteins, also conferred increased β-lactam susceptibility, indicating a common link between cell division and intrinsic β-lactam resistance in A. baumannii.
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Diversity of mechanisms conferring resistance to β-lactams among OXA-23–producing Acinetobacter baumannii clones. Diagn Microbiol Infect Dis 2016; 85:90-7. [DOI: 10.1016/j.diagmicrobio.2016.01.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 01/18/2016] [Accepted: 01/25/2016] [Indexed: 11/16/2022]
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Kim SH, Park C, Chun HS, Lee DG, Choi JK, Lee HJ, Cho SY, Park SH, Choi SM, Choi JH, Yoo JH. Pilot Screening to Determine Antimicrobial Synergies in a Multidrug-Resistant Bacterial Strain Library. Microb Drug Resist 2016; 22:372-8. [PMID: 26974861 PMCID: PMC4939386 DOI: 10.1089/mdr.2015.0251] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
With the rise in multidrug-resistant (MDR) bacterial infections, there has been increasing interest in combinations of ≥2 antimicrobial agents with synergistic effects. We established an MDR bacterial strain library to screen for in vitro antimicrobial synergy by using a broth microdilution checkerboard method and high-throughput luciferase-based bacterial cell viability assay. In total, 39 MDR bacterial strains, including 23 carbapenem-resistant gram-negative bacteria, 9 vancomycin-intermediate Staphylococcus aureus, and 7 vancomycin-resistant Enterococcus faecalis, were used to screen for potential antimicrobial synergies. Synergies were more frequently identified with combinations of imipenem plus trimethoprim-sulfamethoxazole for carbapenem-resistant Acinetobacter baumannii in the library. To verify this finding, we tested 34 A. baumannii clinical isolates resistant to both imipenem and trimethoprim-sulfamethoxazole by the checkerboard method. The imipenem plus trimethoprim-sulfamethoxazole combination showed synergy in the treatment of 21 (62%) of the clinical isolates. The results indicate that pilot screening for antimicrobial synergy in the MDR bacterial strain library could be valuable in the selection of combination therapeutic regimens to treat MDR bacterial infections. Further studies are warranted to determine whether this screening system can be useful to screen for the combined effects of conventional antimicrobials and new-generation antimicrobials or nonantimicrobials.
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Affiliation(s)
- Si-Hyun Kim
- 1 Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea.,2 Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea , Incheon St. Mary's Hospital, Incheon, Republic of Korea.,3 Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea
| | - Chulmin Park
- 1 Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea
| | - Hye-Sun Chun
- 1 Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea
| | - Dong-Gun Lee
- 1 Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea.,3 Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea
| | - Jae-Ki Choi
- 1 Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea.,3 Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea
| | - Hyo-Jin Lee
- 1 Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea.,3 Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea
| | - Sung-Yeon Cho
- 1 Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea.,3 Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea
| | - Sun Hee Park
- 1 Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea.,3 Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea
| | - Su-Mi Choi
- 1 Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea.,3 Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea
| | - Jung-Hyun Choi
- 1 Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea.,2 Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea , Incheon St. Mary's Hospital, Incheon, Republic of Korea.,3 Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea
| | - Jin-Hong Yoo
- 1 Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea.,3 Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea , Seoul, Republic of Korea
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Sun X, Liu B, Chen Y, Huang H, Wang G, Li F, Ni Z. Molecular characterization of Ambler class A to D β-lactamases, ISAba1, and integrons reveals multidrug-resistant Acinetobacter spp. isolates in northeastern China. J Chemother 2016; 28:469-475. [PMID: 27077928 DOI: 10.1080/1120009x.2015.1133014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The prevalence of various Ambler class A to D β-lactamases, ISAba1, and class 1 and 2 integrons as well as the clonal relatedness in 105 Acinetobacter spp. isolates found in northeastern China was investigated. All 105 Acinetobacter spp. isolates were determined to be multidrug resistant (MDR), and the resistance rates to carbapenem agents were approximately 50%. PER, IMP, AmpC, and OXA-23 were found to be dominant β-lactamases belonging to different classes, respectively. This is the first report of the coexistence of blaPER, blaIMP, blaAmpC, and blaOXA-23-like genes in Acinetobacter spp. isolates from northeastern China. ISAba1 was found upstream of the blaOXA-23-like gene in 87.8% (36/41) strains and upstream of the blaOXA-51-like gene in 26.5% (13/49) strains. ISAba3-like element was found upstream of the blaOXA-58-like gene in one blaOXA-58-like-positive strain. The presence of IntI1 was detected in 63.8% (67/105) of the isolates and the most prevalent gene cassettes were aacA4, aadA1, and catB8. The highly prevalent isolates belong to international clonal lineage (ICL)-II. These results indicate that the wide horizontal and clonal spread of MDR Acinetobacter spp. isolates harbouring multiple β-lactamase genes has become a serious problem in northeastern China.
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Affiliation(s)
- Xiaoyu Sun
- a Key Laboratory of Zoonosis, Ministry of Education, Department of Pathogenobiology , College of Basic Medical Science, Jilin University , Changchun , P.R. China
| | - Bin Liu
- b Cardiovascular Disease Center, The First Hospital of Jilin University , Changchun , P.R. China
| | - Yan Chen
- c Department of Neurosurgery , The Second Hospital of Jilin University , Changchun , P.R. China
| | - Honglan Huang
- a Key Laboratory of Zoonosis, Ministry of Education, Department of Pathogenobiology , College of Basic Medical Science, Jilin University , Changchun , P.R. China
| | - Guoqing Wang
- a Key Laboratory of Zoonosis, Ministry of Education, Department of Pathogenobiology , College of Basic Medical Science, Jilin University , Changchun , P.R. China
| | - Fan Li
- a Key Laboratory of Zoonosis, Ministry of Education, Department of Pathogenobiology , College of Basic Medical Science, Jilin University , Changchun , P.R. China
| | - Zhaohui Ni
- a Key Laboratory of Zoonosis, Ministry of Education, Department of Pathogenobiology , College of Basic Medical Science, Jilin University , Changchun , P.R. China
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Lean SS, Yeo CC, Suhaili Z, Thong KL. Comparative Genomics of Two ST 195 Carbapenem-Resistant Acinetobacter baumannii with Different Susceptibility to Polymyxin Revealed Underlying Resistance Mechanism. Front Microbiol 2016; 6:1445. [PMID: 26779129 PMCID: PMC4700137 DOI: 10.3389/fmicb.2015.01445] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 12/03/2015] [Indexed: 01/19/2023] Open
Abstract
Acinetobacter baumannii is a Gram-negative nosocomial pathogen of importance due to its uncanny ability to acquire resistance to most antimicrobials. These include carbapenems, which are the drugs of choice for treating A. baumannii infections, and polymyxins, the drugs of last resort. Whole genome sequencing was performed on two clinical carbapenem-resistant A. baumannii AC29 and AC30 strains which had an indistinguishable ApaI pulsotype but different susceptibilities to polymyxin. Both genomes consisted of an approximately 3.8 Mbp circular chromosome each and several plasmids. AC29 (susceptible to polymyxin) and AC30 (resistant to polymyxin) belonged to the ST195 lineage and are phylogenetically clustered under the International Clone II (IC-II) group. An AbaR4-type resistance island (RI) interrupted the comM gene in the chromosomes of both strains and contained the bla OXA-23 carbapenemase gene and determinants for tetracycline and streptomycin resistance. AC29 harbored another copy of bla OXA-23 in a large (~74 kb) conjugative plasmid, pAC29b, but this gene was absent in a similar plasmid (pAC30c) found in AC30. A 7 kb Tn1548::armA RI which encodes determinants for aminoglycoside and macrolide resistance, is chromosomally-located in AC29 but found in a 16 kb plasmid in AC30, pAC30b. Analysis of known determinants for polymyxin resistance in AC30 showed mutations in the pmrA gene encoding the response regulator of the two-component pmrAB signal transduction system as well as in the lpxD, lpxC, and lpsB genes that encode enzymes involved in the biosynthesis of lipopolysaccharide (LPS). Experimental evidence indicated that impairment of LPS along with overexpression of pmrAB may have contributed to the development of polymyxin resistance in AC30. Cloning of a novel variant of the bla AmpC gene from AC29 and AC30, and its subsequent expression in E. coli also indicated its likely function as an extended-spectrum cephalosporinase.
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Affiliation(s)
- Soo-Sum Lean
- Faulty of Science, Institute of Biological Sciences, Universiti Malaya Kuala Lumpur, Malaysia
| | - Chew Chieng Yeo
- Faculty of Medicine, Biomedical Research Centre, Universiti Sultan Zainal Abidin Kuala Terengganu, Malaysia
| | - Zarizal Suhaili
- Faculty of Bioresources and Food Industry, Universiti Sultan Zainal Abidin Kuala Terengganu, Malaysia
| | - Kwai-Lin Thong
- Faulty of Science, Institute of Biological Sciences, Universiti Malaya Kuala Lumpur, Malaysia
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Esterly JS, Richardson CL, Eltoukhy NS, Qi C, Scheetz MH. Genetic Mechanisms of Antimicrobial Resistance of Acinetobacter baumannii. Ann Pharmacother 2015; 45:218-28. [PMID: 21304033 DOI: 10.1345/aph.1p084] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE To summarize published data identifying known genetic mechanisms of antibiotic resistance in Acinetobacter baumannii and the correlating phenotypic expression of antibiotic resistance. DATA SOURCES MEDLINE databases (1966-July 15, 2010) were searched to identify original reports of genetic mechanisms of antibiotic resistance in A. baumannii. DATA SYNTHESIS Numerous genetic mechanisms of resistance to multiple classes of antibiotics are known to exist in A. baumannii, a gram-negative bacterium increasingly implicated in nosocomial infections. Mechanisms may be constitutive or acquired via plasmids, integrons, and transposons. Methods of resistance include enzymatic modification of antibiotic molecules, modification of antibiotic target sites, expression of efflux pumps, and downregulation of cell membrane porin channel expression. Resistance to β-lactams appears to be primarily caused by β-lactamase production, including extended spectrum β-lactamases (b/aTEM, blaSHV, b/aTX-M,b/aKPC), metallo-β-lactamases (blaMP, blaVIM, bla, SIM), and most commonly, oxacillinases (blaOXA). Antibiotic target site alterations confer resistance to fluoroquinolones (gyrA, parC) and aminoglycosides (arm, rmt), and to a much lesser extent, β-lactams. Efflux pumps (tet, ade, abe) contribute to resistance against β-lactams, tetracyclines, fluoroquinolones, and aminoglycosides. Finally, porin channel deletion (carO, oprD) appears to contribute to β-lactam resistance and may contribute to rarely seen polymyxin resistance. Of note, efflux pumps and porin deletions as solitary mechanisms may not render clinical resistance to A. baumannii. CONCLUSIONS A. baumannii possesses copious genetic resistance mechanisms. Knowledge of local genotypes and expressed phenotypes for A. baumannii may aid clinicians more than phenotypic susceptibilities reported in large epidemiologic studies.
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Affiliation(s)
- John S Esterly
- John S Esterly PharmD BCPS, at time of writing, Infectious Diseases Pharmacotherapy Fellow, Department of Pharmacy Practice, College of Pharmacy, Midwestern University Chicago, Downers Grove, IL; now, Assistant Professor of Pharmacy Practice, College of Pharmacy, Chicago State University, Chicago, IL; Infectious Diseases Pharmacist, Northwestern Memorial Hospital, Chicago
| | - Chad L Richardson
- Chad L Richardson PharmD, at time of writing, Infectious Diseases Pharmacotherapy Resident, Department of Pharmacy Practice, College of Pharmacy, Midwestern University Chicago; now, Solid Organ Transplant Pharmacist, Northwestern Memorial Hospital
| | - Noha S Eltoukhy
- Noha S Eltoukhy PharmD BCPS, at time of writing, Infectious Diseases Pharmacy Resident, Department of Pharmacy Practice, College of Pharmacy, Midwestern University Chicago; Rush University Medical Center, Chicago; now, Infectious DIseases Clinical Pharmacy Specialist, St. Mary Medical Center, Langhorne, PA
| | - Chao Qi
- Chao Qi PhD, Assistant Professor of Pathology, Feinberg School of Medicine, Northwestern University; Assistant Director, Clinical Microbiology Laboratory, Northwestern Memorial Hospital, Chicago
| | - Marc H Scheetz
- Marc H Scheetz PharmD MSc BCPS, Assistant Professor of Pharmacy Practice, College of Pharmacy, Midwestern University Chicago; Infectious Diseases Pharmacist, Northwestern Memorial Hospital
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Farshadzadeh Z, Hashemi FB, Rahimi S, Pourakbari B, Esmaeili D, Haghighi MA, Majidpour A, Shojaa S, Rahmani M, Gharesi S, Aziemzadeh M, Bahador A. Wide distribution of carbapenem resistant Acinetobacter baumannii in burns patients in Iran. Front Microbiol 2015; 6:1146. [PMID: 26539176 PMCID: PMC4611150 DOI: 10.3389/fmicb.2015.01146] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 10/05/2015] [Indexed: 11/14/2022] Open
Abstract
Antimicrobial resistance in carbapenem non-susceptible Acinetobacter baumannii (CNSAb) is a major public health concern globally. This study determined the antibiotic resistance and molecular epidemiology of CNSAb isolates from a referral burn center in Tehran, Iran. Sixty-nine CNSAb isolates were tested for susceptibility to antimicrobial agents using the E test methodology. Multiple locus variable number tandem repeat analysis (MLVA), Multilocus sequence typing (MLST) and multiplex PCR were performed. PCR assays tested for ambler classes A, B, and D β-lactamases. Detection of ISAba1, characterization of integrons, and biofilm formation were investigated. Fifty-three (77%) isolates revealed XDR phenotypes. High prevalence of blaOXA-23-like (88%) and blaPER-1 (54%) were detected. ISAba1 was detected upstream of blaADC, blaOXA-23-like and blaOXA51-like genes in, 97, 42, and 26% of isolates, respectively. Thirty-one (45%) isolates were assigned to international clone (IC) variants. MLVA identified 56 distinct types with six clusters and 53 singleton genotypes. Forty previously known MLST sequence types forming 5 clonal complexes were identified. The Class 1 integron (class 1 integrons) gene was identified in 84% of the isolates. The most prevalent (33%) cassette combination was aacA4-catB8-aadA1. The IC variants were predominant in the A. baumannii lineage with the ability to form strong biofilms. The XDR-CNSAb from burned patients in Iran is resistant to various antimicrobials, including tigecycline. This study shows wide genetic diversity in CNSAb. Integrating the new Iranian A. baumannii IC variants into the epidemiologic clonal and susceptibility profile databases can help effective global control measures against the XDR-CNSAb pandemic.
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Affiliation(s)
- Zahra Farshadzadeh
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences Tehran, Iran
| | - Farhad B Hashemi
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences Tehran, Iran
| | - Sara Rahimi
- Department of Microbiology, School of Medicine, Bushehr University of Medical Sciences Bushehr, Iran
| | - Babak Pourakbari
- Pediatrics Infectious Diseases Research Center, School of Medicine, Tehran University of Medical Sciences Tehran, Iran
| | - Davoud Esmaeili
- Molecular Biology Research Center, Baqiyatallah University of Medical Sciences Tehran, Iran
| | - Mohammad A Haghighi
- Department of Microbiology, School of Medicine, Bushehr University of Medical Sciences Bushehr, Iran
| | - Ali Majidpour
- Anti-microbial Resistance Research Center, Iran University of Medical Sciences Tehran, Iran
| | - Saeed Shojaa
- Department of Microbiology, Faculty of Medicine, Hormozgan University of Medical Sciences Bandar Abbas, Iran
| | - Maryam Rahmani
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences Tehran, Iran
| | - Samira Gharesi
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences Tehran, Iran
| | - Masoud Aziemzadeh
- Department of Microbiology, School of Medicine, Bushehr University of Medical Sciences Bushehr, Iran
| | - Abbas Bahador
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences Tehran, Iran
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Chang Y, Luan G, Xu Y, Wang Y, Shen M, Zhang C, Zheng W, Huang J, Yang J, Jia X, Ling B. Characterization of carbapenem-resistant Acinetobacter baumannii isolates in a Chinese teaching hospital. Front Microbiol 2015; 6:910. [PMID: 26388854 PMCID: PMC4555021 DOI: 10.3389/fmicb.2015.00910] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 08/19/2015] [Indexed: 01/02/2023] Open
Abstract
Carbapenem-resistant Acinetobacter baumannii (CRAB) presents a serious therapeutic and infection control challenge. In this study, we investigated the epidemiological and molecular differences of CRAB and the threatening factors for contributing to increased CRAB infections at a hospital in western China. A total of 110 clinical isolates of A. baumannii, collected in a recent 2-year period, were tested for carbapenem antibiotic susceptibility, followed by a molecular analysis of carbapenemase genes. Genetic relatedness of the isolates was characterized by multilocus sequence typing. Sixty-seven of the 110 isolates (60.9%) were resistant to carbapenems, 80.60% (54/67) of which carried the blaOXA-23 gene. Most of these CRAB isolates (77.62%) were classified as clone complex 92 (CC92), and sequence type (ST) 92 was the most prevalent STs, followed by ST195, ST136, ST843, and ST75. One CRAB isolate of ST195 harbored plasmid pAB52 from a Chinese patient without travel history. This plasmid contains toxin–antitoxin elements related to adaptation for growth, which might have emerged as a common vehicle indirectly mediating the spread of OXA-23 in CRAB. Thus, CC92 A. baumannii carrying OXA-23 is a major drug-resistant strain spreading in China. Our findings indicate that rational application of antibiotics is indispensable for minimizing widespread of drug resistance.
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Affiliation(s)
- Yaowen Chang
- Small Molecule Drugs Sichuan Key Laboratory, Institute of Materia Medica, Chengdu Medical College Chengdu, China
| | - Guangxin Luan
- Non-coding RNA and Drug Discovery Laboratory, Chengdu Medical College Chengdu, China
| | - Ying Xu
- Clinical Laboratory, The First Affiliated Hospital, Chengdu Medical College Chengdu, China
| | - Yanhong Wang
- Non-coding RNA and Drug Discovery Laboratory, Chengdu Medical College Chengdu, China
| | - Min Shen
- Non-coding RNA and Drug Discovery Laboratory, Chengdu Medical College Chengdu, China
| | - Chi Zhang
- Small Molecule Drugs Sichuan Key Laboratory, Institute of Materia Medica, Chengdu Medical College Chengdu, China
| | - Wei Zheng
- Small Molecule Drugs Sichuan Key Laboratory, Institute of Materia Medica, Chengdu Medical College Chengdu, China
| | - Jinwei Huang
- Institute of Antibiotics, The Fifth Affiliated Hospital, Wenzhou Medical University Lishui, China
| | - Jingni Yang
- Non-coding RNA and Drug Discovery Laboratory, Chengdu Medical College Chengdu, China
| | - Xu Jia
- Non-coding RNA and Drug Discovery Laboratory, Chengdu Medical College Chengdu, China
| | - Baodong Ling
- Small Molecule Drugs Sichuan Key Laboratory, Institute of Materia Medica, Chengdu Medical College Chengdu, China
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41
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Liu Y, Liu X. Detection of AmpC β-lactamases in Acinetobacter baumannii in the Xuzhou region and analysis of drug resistance. Exp Ther Med 2015; 10:933-936. [PMID: 26622417 DOI: 10.3892/etm.2015.2612] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 07/02/2015] [Indexed: 11/06/2022] Open
Abstract
The aim of the present study was to determine the prevalence and related drug resistance of AmpC β-lactamases in Acinetobacter baumannii in tertiary-level hospitals in the Xuzhou region in China. A total of 134 clinical isolates of non-repetitive Acinetobacter baumannii were collected from different hospitals in the Xuzhou region, and multiplex polymerase chain reaction (PCR) was employed to determine the genotype of AmpC. The PCR products were purified and sequenced. The susceptibility to antibiotics was tested using the biometrics automated microbiological-assay system, VITEK-2. Amongst the 134 isolated strains, 96 strains were found to produce AmpC β-lactamases, and the positive rate was 72%, all of which carried acinetobacter-derived cephalosporinase (ADC) type AmpC resistance genes. The drug sensitivity tests indicated that the positive Acinetobacter baumannii strains were resistant to the majority of extended-spectrum β-lactam antibiotics, but were only sensitive to polymyxin. In conclusion, the incidence of AmpC enzymes in Acinetobacter baumannii strains in tertiary-level hospitals in the Xuzhou area is relatively high, and resistance to the majority of extended-spectrum β-lactam antibiotics may be related to the ADC type of AmpC.
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Affiliation(s)
- Yongrui Liu
- Department of Respiration, The First People's Hospital of Jining, Shandong 272002, P.R. China
| | - Xiangqun Liu
- Department of Respiration, Xuzhou City Hospital Affiliated to Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China
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42
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Viehman JA, Nguyen MH, Doi Y. Treatment options for carbapenem-resistant and extensively drug-resistant Acinetobacter baumannii infections. Drugs 2015; 74:1315-33. [PMID: 25091170 DOI: 10.1007/s40265-014-0267-8] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Acinetobacter baumannii is a leading cause of healthcare-associated infections worldwide. Because of various intrinsic and acquired mechanisms of resistance, most β-lactam agents are not effective against many strains, and carbapenems have played an important role in therapy. Recent trends show many infections are caused by carbapenem-resistant or even extensively drug-resistant (XDR) strains, for which effective therapy is not well established. Evidence to date suggests that colistin constitutes the backbone of therapy, but the unique pharmacokinetic properties of colistin have led many to suggest the use of combination antimicrobial therapy. However, the combination of agents and dosing regimens that delivers the best clinical efficacy while minimizing toxicity is yet to be defined. Carbapenems, sulbactam, rifampin and tigecycline have been the most studied in the context of combination therapy. Most data regarding therapy for invasive, resistant A. baumannii infections come from uncontrolled case series and retrospective analyses, though some clinical trials have been completed and others are underway. Early institution of appropriate antimicrobial therapy is shown to consistently improve survival of patients with carbapenem-resistant and XDR A. baumannii infection, but the choice of empiric therapy in these infections remains an open question. This review summarizes the most current knowledge regarding the epidemiology, mechanisms of resistance, and treatment considerations of carbapenem-resistant and XDR A. baumannii.
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Affiliation(s)
- J Alexander Viehman
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical Center, S319 Falk Medical Building, 3601 Fifth Avenue, Pittsburgh, PA, 15213, USA
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Valdezate S, Garrido N, Carrasco G, Villalón P, Medina-Pascual MJ, Saéz-Nieto JA. Resistance gene pool to co-trimoxazole in non-susceptible Nocardia strains. Front Microbiol 2015; 6:376. [PMID: 25972856 PMCID: PMC4412068 DOI: 10.3389/fmicb.2015.00376] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 04/12/2015] [Indexed: 01/11/2023] Open
Abstract
The soil-borne pathogen Nocardia sp. causes severe cutaneous, pulmonary, and central nervous system infections. Against them, co-trimoxazole (SXT) constitutes the mainstay of antimicrobial therapy. However, some Nocardia strains show resistance to SXT, but the underlying genetic basis is unknown. We investigated the presence of genetic resistance determinants and class 1–3 integrons in 76 SXT-resistant Nocardia strains by PCR and sequencing. By E test, these clinical strains showed SXT minimum inhibitory concentrations of ≥32:608 mg/L (ratio of 1:19 for trimethoprim: sulfamethoxazole). They belonged to 12 species, being the main representatives Nocardia farcinica (32%), followed by N. flavorosea (6.5%), N. nova (11.8%), N. carnea (10.5%), N. transvalensis (10.5%), and Nocardia sp. (6.5%). The prevalence of resistance genes in the SXT-resistant strains was as follows: sul1 and sul2 93.4 and 78.9%, respectively, dfrA(S1) 14.7%, blaTEM-1 and blaZ 2.6 and 2.6%, respectively, VIM-2 1.3%, aph(3′)-IIIa 40.8%, ermA, ermB, mefA, and msrD 2.6, 77.6, 14.4, and 5.2%, respectively, and tet(O), tet(M), and tet(L) 48.6, 25.0, and 3.9%, respectively. Detected amino acid changes in GyrA were not related to fluoroquinolone resistance, but probably linked to species polymorphism. Class 1 and 3 integrons were found in 93.42 and 56.57% strains, respectively. Class 2 integrons and sul3 genes were not detected. Other mechanisms, different than dfrA(S1), dfrD, dfrF, dfrG, and dfrK, could explain the strong trimethoprim resistance shown by the other 64 strains. For first time, resistance determinants commonly found in clinically important bacteria were detected in Nocardia sp. sul1, sul2, erm(B), and tet(O) were the most prevalent in the SXT-resistant strains. The similarity in their resistome could be due to a common genetic platform, in which these determinants are co-transferred.
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Affiliation(s)
- Sylvia Valdezate
- Servicio de Bacteriología and Taxonomía, Centro Nacional de Microbiología, Instituto de Salud Carlos III Madrid, Spain
| | - Noelia Garrido
- Servicio de Bacteriología and Taxonomía, Centro Nacional de Microbiología, Instituto de Salud Carlos III Madrid, Spain
| | - Gema Carrasco
- Servicio de Bacteriología and Taxonomía, Centro Nacional de Microbiología, Instituto de Salud Carlos III Madrid, Spain
| | - Pilar Villalón
- Servicio de Bacteriología and Taxonomía, Centro Nacional de Microbiología, Instituto de Salud Carlos III Madrid, Spain
| | - María J Medina-Pascual
- Servicio de Bacteriología and Taxonomía, Centro Nacional de Microbiología, Instituto de Salud Carlos III Madrid, Spain
| | - Juan A Saéz-Nieto
- Servicio de Bacteriología and Taxonomía, Centro Nacional de Microbiología, Instituto de Salud Carlos III Madrid, Spain
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Potron A, Poirel L, Nordmann P. Emerging broad-spectrum resistance in Pseudomonas aeruginosa and Acinetobacter baumannii: Mechanisms and epidemiology. Int J Antimicrob Agents 2015; 45:568-85. [PMID: 25857949 DOI: 10.1016/j.ijantimicag.2015.03.001] [Citation(s) in RCA: 451] [Impact Index Per Article: 50.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 03/05/2015] [Indexed: 02/07/2023]
Abstract
Multidrug resistance is quite common among non-fermenting Gram-negative rods, in particular among clinically relevant species including Pseudomonas aeruginosa and Acinetobacter baumannii. These bacterial species, which are mainly nosocomial pathogens, possess a diversity of resistance mechanisms that may lead to multidrug or even pandrug resistance. Extended-spectrum β-lactamases (ESBLs) conferring resistance to broad-spectrum cephalosporins, carbapenemases conferring resistance to carbapenems, and 16S rRNA methylases conferring resistance to all clinically relevant aminoglycosides are the most important causes of concern. Concomitant resistance to fluoroquinolones, polymyxins (colistin) and tigecycline may lead to pandrug resistance. The most important mechanisms of resistance in P. aeruginosa and A. baumannii and their most recent dissemination worldwide are detailed here.
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Affiliation(s)
- Anaïs Potron
- Laboratoire de Bactériologie, Faculté de Médecine-Pharmacie, Centre Hospitalier Régional Universitaire, Université de Franche-Comté, Besançon, France
| | - Laurent Poirel
- Emerging Antibiotic Resistance Medical and Molecular Microbiology Unit, Department of Medicine, Faculty of Science, University of Fribourg, Fribourg, Switzerland.
| | - Patrice Nordmann
- Emerging Antibiotic Resistance Medical and Molecular Microbiology Unit, Department of Medicine, Faculty of Science, University of Fribourg, Fribourg, Switzerland; HFR - Hôpital Cantonal de Fribourg, Fribourg, Switzerland
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45
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Villalón P, Valdezate S, Cabezas T, Ortega M, Garrido N, Vindel A, Medina-Pascual MJ, Saez-Nieto JA. Endemic and epidemic Acinetobacter baumannii clones: a twelve-year study in a tertiary care hospital. BMC Microbiol 2015; 15:47. [PMID: 25887224 PMCID: PMC4352537 DOI: 10.1186/s12866-015-0383-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 02/11/2015] [Indexed: 11/22/2022] Open
Abstract
Background Nosocomial outbreaks of multidrug-resistant Acinetobacter baumannii are of worldwide concern. Using pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and multiple locus variable number tandem repeat sequence (VNTR) analysis (MLVA), the present work examines the genetic diversity of the endemic and epidemic A. baumannii clones isolated in a single hospital over a twelve-year period. Results PFGE analysis of 405 A. baumannii-calcoaceticus complex isolates detected 15 A. baumannii endemic/epidemic PFGE types (EE1 to EE15) that grouped into five clusters: EE1-EE8, EE9, EE10, EE11 and EE12-EE15. The MLST sequence type (ST) distributions were: international clone II (ST-2) 60%, international clone III (ST-3) 26.7%, ST-15 6.7%, and ST-80 6.7%. MLVA-8Orsay returned 17 allelic profiles. The large (L) VNTR marker profiles were fully concordant with the detected STs, and concordant with 14 up to 15 PFGE types. Imipenem resistance was detected in five PFGE types; the prevalence of the blaOXA-58-like and blaOXA-40-like genes was 60% and 40% respectively. Conclusions PFGE proved to be a vital tool for analysis of the temporal and spatial distribution of the clones. MLST and the VNTR L-markers grouped the isolates into clonal clusters. The wide diversity of MLVA small (S)-markers, however, did not permit clustering. The present results demonstrate the persistence of several endemic PFGE types in the hospital, the involvement of some of them in outbreaks, and the inter hospital transmission of extensively drug-resistant ST-15 and ST-80.
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Affiliation(s)
- Pilar Villalón
- Laboratorio de Taxonomía, Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda-Pozuelo km2, 28220, Madrid, Majadahonda, Spain.
| | - Sylvia Valdezate
- Laboratorio de Taxonomía, Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda-Pozuelo km2, 28220, Madrid, Majadahonda, Spain.
| | - Teresa Cabezas
- Laboratorio de Biotecnología Hospital de Poniente El Ejido, Almería, Spain.
| | - Montserrat Ortega
- Laboratorio de Taxonomía, Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda-Pozuelo km2, 28220, Madrid, Majadahonda, Spain.
| | - Noelia Garrido
- Laboratorio de Taxonomía, Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda-Pozuelo km2, 28220, Madrid, Majadahonda, Spain.
| | - Ana Vindel
- Laboratorio de Infecciones Intrahospitalarias Servicio de Bacteriología, Centro Nacional de Microbiología Instituto de Salud Carlos III, Majadahonda, Madrid, Spain.
| | - María J Medina-Pascual
- Laboratorio de Taxonomía, Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda-Pozuelo km2, 28220, Madrid, Majadahonda, Spain.
| | - Juan A Saez-Nieto
- Laboratorio de Taxonomía, Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda-Pozuelo km2, 28220, Madrid, Majadahonda, Spain.
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Doi Y, Murray GL, Peleg AY. Acinetobacter baumannii: evolution of antimicrobial resistance-treatment options. Semin Respir Crit Care Med 2015; 36:85-98. [PMID: 25643273 DOI: 10.1055/s-0034-1398388] [Citation(s) in RCA: 174] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The first decade of the 20th century witnessed a surge in the incidence of infections due to several highly antimicrobial-resistant bacteria in hospitals worldwide. Acinetobacter baumannii is one such organism that turned from an occasional respiratory pathogen into a major nosocomial pathogen. An increasing number of A. baumannii genome sequences have broadened our understanding of the genetic makeup of these bacteria and highlighted the extent of horizontal transfer of DNA. Animal models of disease combined with bacterial mutagenesis have provided some valuable insights into mechanisms of A. baumannii pathogenesis. Bacterial factors known to be important for disease include outer membrane porins, surface structures including capsule and lipopolysaccharide, enzymes such as phospholipase D, iron acquisition systems, and regulatory proteins. A. baumannii has a propensity to accumulate resistance to various groups of antimicrobial agents. In particular, carbapenem resistance has become commonplace, accounting for the majority of A. baumannii strains in many hospitals today. Carbapenem-resistant strains are often resistant to all other routinely tested agents. Treatment of carbapenem-resistant A. baumannii infection therefore involves the use of combinations of last resort agents such as colistin and tigecycline, but the efficacy and safety of these approaches are yet to be defined. Antimicrobial-resistant A. baumannii has high potential to spread among ill patients in intensive care units. Early recognition and timely implementation of appropriate infection control measures is crucial in preventing outbreaks.
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Affiliation(s)
- Yohei Doi
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Gerald L Murray
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Anton Y Peleg
- Department of Microbiology, Monash University, Melbourne, Australia
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Biglari S, Alfizah H, Ramliza R, Rahman MM. Molecular characterization of carbapenemase and cephalosporinase genes among clinical isolates of Acinetobacter baumannii in a tertiary medical centre in Malaysia. J Med Microbiol 2014; 64:53-58. [PMID: 25381148 DOI: 10.1099/jmm.0.082263-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Antimicrobial resistance in Acinetobacter baumannii is a growing public health concern and an important pathogen in nosocomial infections. We investigated the genes involved in resistance to carbapenems and cephalosporins in clinical A. baumannii isolates from a tertiary medical centre in Malaysia. A. baumannii was isolated from 167 clinical specimens and identified by sequencing of the 16S rRNA and rpoB genes. The MIC for imipenem, meropenem, ceftazidime and cefepime were determined by the E-test method. The presence of carbapenemase and cephalosporinase genes was investigated by PCR. The isolates were predominantly nonsusceptible to carbapenems and cephalosporins (>70 %) with high MIC values. ISAba1 was detected in all carbapenem-nonsusceptible A. baumannii harbouring the blaOXA-23-like gene. The presence of blaOXA-51-like and ISAba1 upstream of blaOXA-51 was not associated with nonsusceptibility to carbapenems. A. baumannii isolates harbouring ISAba1-blaADC (85.8 %) were significantly associated with nonsusceptibility to cephalosporins (P<0.0001). However, ISAba1-blaADC was not detected in a minority (<10 %) of the isolates which were nonsusceptible to cephalosporins. The acquired OXA-23 enzymes were responsible for nonsusceptibility to carbapenems in our clinical A. baumannii isolates and warrant continuous surveillance to prevent further dissemination of this antibiotic resistance gene. The presence of ISAba1 upstream of the blaADC was a determinant for cephalosporin resistance. However, the absence of this ISAba1-blaADC in some of the isolates may suggest other resistance mechanisms and need further investigation.
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Affiliation(s)
- Shirin Biglari
- Department of Medical Microbiology and Immunology, Universiti Kebangsaan Malaysia Medical Centre, Jalan Yaacob Latif, Bandar Tun Razak, 56000 Cheras, Kuala Lumpur, Malaysia
| | - Hanafiah Alfizah
- Department of Medical Microbiology and Immunology, Universiti Kebangsaan Malaysia Medical Centre, Jalan Yaacob Latif, Bandar Tun Razak, 56000 Cheras, Kuala Lumpur, Malaysia
| | - Ramli Ramliza
- Department of Medical Microbiology and Immunology, Universiti Kebangsaan Malaysia Medical Centre, Jalan Yaacob Latif, Bandar Tun Razak, 56000 Cheras, Kuala Lumpur, Malaysia
| | - Md Mostafizur Rahman
- Department of Medical Microbiology and Immunology, Universiti Kebangsaan Malaysia Medical Centre, Jalan Yaacob Latif, Bandar Tun Razak, 56000 Cheras, Kuala Lumpur, Malaysia
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Jeon JH, Hong MK, Lee JH, Lee JJ, Park KS, Karim AM, Jo JY, Kim JH, Ko KS, Kang LW, Lee SH. Structure of ADC-68, a novel carbapenem-hydrolyzing class C extended-spectrum β-lactamase isolated from Acinetobacter baumannii. ACTA ACUST UNITED AC 2014; 70:2924-36. [PMID: 25372683 DOI: 10.1107/s1399004714019543] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 08/28/2014] [Indexed: 11/10/2022]
Abstract
Outbreaks of multidrug-resistant bacterial infections have become more frequent worldwide owing to the emergence of several different classes of β-lactamases. In this study, the molecular, biochemical and structural characteristics of an Acinetobacter-derived cephalosporinase (ADC)-type class C β-lactamase, ADC-68, isolated from the carbapenem-resistant A. baumannii D015 were investigated. The blaADC-68 gene which encodes ADC-68 was confirmed to exist on the chromosome via Southern blot analysis and draft genome sequencing. The catalytic kinetics of β-lactams and their MICs (minimum inhibitory concentrations) for A. baumannii D015 and purified ADC-68 (a carbapenemase obtained from this strain) were assessed: the strain was resistant to penicillins, narrow-spectrum and extended-spectrum cephalosporins, and carbapenems, which were hydrolyzed by ADC-68. The crystal structure of ADC-68 was determined at a resolution of 1.8 Å. The structure of ADC-68 was compared with that of ADC-1 (a non-carbapenemase); differences were found in the central part of the Ω-loop and the C-loop constituting the edge of the R1 and R2 subsites and are close to the catalytic serine residue Ser66. The ADC-68 C-loop was stabilized in the open conformation of the upper R2 subsite and could better accommodate carbapenems with larger R2 side chains. Furthermore, a wide-open conformation of the R2-loop allowed ADC-68 to bind to and hydrolyze extended-spectrum cephalosporins. Therefore, ADC-68 had enhanced catalytic efficiency against these clinically important β-lactams (extended-spectrum cephalosporins and carbapenems). ADC-68 is the first reported enzyme among the chromosomal class C β-lactamases to possess class C extended-spectrum β-lactamase and carbapenemase activities.
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Affiliation(s)
- Jeong Ho Jeon
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University, 116 Myongjiro, Yongin, Gyeonggido 449-728, Republic of Korea
| | - Myoung Ki Hong
- Institute for Cellular and Structural Biology of Sun Yat-Sen University, Guangzhou, Peoples Republic of China
| | - Jung Hun Lee
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University, 116 Myongjiro, Yongin, Gyeonggido 449-728, Republic of Korea
| | - Jae Jin Lee
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University, 116 Myongjiro, Yongin, Gyeonggido 449-728, Republic of Korea
| | - Kwang Seung Park
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University, 116 Myongjiro, Yongin, Gyeonggido 449-728, Republic of Korea
| | - Asad Mustafa Karim
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University, 116 Myongjiro, Yongin, Gyeonggido 449-728, Republic of Korea
| | - Jeong Yeon Jo
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University, 116 Myongjiro, Yongin, Gyeonggido 449-728, Republic of Korea
| | - Ji Hwan Kim
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University, 116 Myongjiro, Yongin, Gyeonggido 449-728, Republic of Korea
| | - Kwan Soo Ko
- Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Lin Woo Kang
- Institute for Cellular and Structural Biology of Sun Yat-Sen University, Guangzhou, Peoples Republic of China
| | - Sang Hee Lee
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University, 116 Myongjiro, Yongin, Gyeonggido 449-728, Republic of Korea
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Durante-Mangoni E, Utili R, Zarrilli R. Combination therapy in severe Acinetobacter baumannii infections: an update on the evidence to date. Future Microbiol 2014; 9:773-89. [DOI: 10.2217/fmb.14.34] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
ABSTRACT: Acinetobacter baumannii is a drug-resistant Gram-negative pathogen increasingly causing hospital-acquired infections in critically ill patients. In this review, we summarize the current mechanisms of antimicrobial resistance in A. baumannii and describe in detail recent in vitro and in vivo experimental data on the activity of antimicrobial combinations against this microorganism. We then introduce the rationale for the use of combination antibiotic therapy in resistant A. baumannii infections. Finally, we present and critically discuss both uncontrolled clinical studies and the few randomized clinical trials of combination antimicrobial therapy for these infections, with a special focus on ongoing multinational trials and optimal approach to future research in this field.
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Affiliation(s)
- Emanuele Durante-Mangoni
- Internal Medicine, University of Naples S.U.N. & AORN dei Colli, Monaldi Hospital, Via L. Bianchi, Naples, Italy
| | - Riccardo Utili
- Internal Medicine, University of Naples S.U.N. & AORN dei Colli, Monaldi Hospital, Via L. Bianchi, Naples, Italy
| | - Raffaele Zarrilli
- Department of Public Health, University of Naples Federico II, Naples, Italy
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Pérez A, Pérez-Llarena FJ, García P, Kerff F, Beceiro A, Galleni M, Bou G. New mutations in ADC-type β-lactamases from Acinetobacter spp. affect cefoxitin and ceftazidime hydrolysis. J Antimicrob Chemother 2014; 69:2407-11. [PMID: 24845871 DOI: 10.1093/jac/dku163] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Two natural variants of ADC-type β-lactamases of Acinetobacter spp., ADC-1 and ADC-5, differ by nine mutations in their protein sequence. ADC-5 hydrolyses cefoxitin better than ADC-1 and the opposite is true for ceftazidime. We produced single and combined mutations in ADC-5 and characterized the variants microbiologically and biochemically to determine which amino acid residues are involved in the hydrolysis of β-lactam antibiotics in this family of β-lactamases. METHODS Site-directed mutagenesis, with blaADC-5 as a source of DNA, was used to generate nine single mutated and three combined mutated enzymes. The proteins (wild-type and derivatives) were then expressed in isogenic conditions in Escherichia coli. MICs of β-lactams were determined using Etest strips. ADC-1, ADC-5, ADC-5-P167S and ADC-5-P167S/D242G/Q163K/G342R were also purified and the kinetic parameters determined for ceftazidime, cefoxitin, cefalotin and ampicillin. RESULTS Single mutations did not significantly convert the hydrolysis spectrum of the ADC-5 enzyme into that of the ADC-1 enzyme, although among all studied mutants only the quadruple mutant (ADC-5-P167S/D242G/Q163K/G342R) displayed microbiological and biochemical properties consistent with those of ADC-1. CONCLUSIONS Although some single mutations are known to affect cefepime hydrolysis in ADC-type β-lactamases, little is known about ceftazidime and cefoxitin hydrolysis in this family of β-lactamases. Hydrolysis of these antibiotics appears to be positively and negatively affected, respectively, by the Q163K, P167S, D242G and G342R amino acid replacements.
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Affiliation(s)
- Astrid Pérez
- Servicio de Microbiología-INIBIC, Complejo Hospitalario Universitario A Coruña, A Coruña, Spain
| | | | - Patricia García
- Servicio de Microbiología-INIBIC, Complejo Hospitalario Universitario A Coruña, A Coruña, Spain
| | - Frédéric Kerff
- Centre d'Ingénierie des Protéines, Université de Liège, Liège, Belgium
| | - Alejandro Beceiro
- Servicio de Microbiología-INIBIC, Complejo Hospitalario Universitario A Coruña, A Coruña, Spain
| | - Moreno Galleni
- Centre d'Ingénierie des Protéines, Université de Liège, Liège, Belgium
| | - Germán Bou
- Servicio de Microbiología-INIBIC, Complejo Hospitalario Universitario A Coruña, A Coruña, Spain
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