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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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Prendergast DM, O'Doherty Á, Burgess CM, Howe N, McMahon F, Murphy D, Leonard F, Morris D, Harrington C, Carty A, Moriarty J, Gutierrez M. Critically important antimicrobial resistant Enterobacteriaceae in Irish farm effluent and their removal in integrated constructed wetlands. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:151269. [PMID: 34710415 DOI: 10.1016/j.scitotenv.2021.151269] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 10/22/2021] [Accepted: 10/22/2021] [Indexed: 06/13/2023]
Abstract
This study investigated the ability of Integrated Constructed Wetlands (ICWs) to remove critically important antimicrobial resistant organisms (AROs) from farm wastewater. Influent samples from the untreated farm waste and effluent samples taken at the end of the ICW system were collected monthly from four ICWs, serving four different farm types (suckler, dairy, dairy & poultry and pig). Using selective media to screen for the presence of carbapenemase resistant organisms, plasmid mediated and AmpC β-Lactamase producing organisms (ESBL/pAmpC) and fluoroquinolone resistant organisms, a total of 82 AROs were obtained with the majority being E. coli (n = 79). Statistically significant were the differences on the number of AROs isolated from influent (higher) compared to effluent, as well as a seasonal effect, with less AROs recovered during winter in comparison to other seasons (P < 0.05). On the other hand, there was no significant differences in the recovery of AROs on different farms. The majority of isolates from each of the farms (99%) were multi drug resistant, with 65% resistant to seven or more antimicrobials. A high incidence of tetracycline, trimethoprim/sulfamethoxazole, and ampicillin resistance was common to the isolates from all four farms but there were differences in ESBL levels with 63% of the isolates recovered from Farm 4 (piggery) being ESBLs compared to 18%, 36% and 4.5% recovered from Farms 1 (suckler), 2 (dairy) and 3 (dairy & poultry), respectively. No carbapenemase producing organisms were isolated. Our results showed that ICWs are effective in removing critically important AROs from farm wastewater on all four farm types.
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Affiliation(s)
- Deirdre M Prendergast
- Department of Agriculture, Food and the Marine, Backweston Complex, Celbridge, Co. Kildare, Ireland.
| | - Áine O'Doherty
- Department of Agriculture, Food and the Marine, Backweston Complex, Celbridge, Co. Kildare, Ireland
| | | | - Nicole Howe
- Department of Agriculture, Food and the Marine, Backweston Complex, Celbridge, Co. Kildare, Ireland
| | - Frederick McMahon
- Department of Agriculture, Food and the Marine, Backweston Complex, Celbridge, Co. Kildare, Ireland
| | - Declan Murphy
- Department of Agriculture, Food and the Marine, Backweston Complex, Celbridge, Co. Kildare, Ireland
| | - Finola Leonard
- School of Veterinary Medicine, Veterinary Science Centre, University College Dublin, Belfield, Dublin 4, Ireland
| | - Dearbháile Morris
- Antimicrobial Resistance and Microbial Ecology Group, NUI Galway, Ireland
| | | | - Aila Carty
- VESI Environmental Ltd., Little Island, Cork, Ireland
| | - John Moriarty
- Department of Agriculture, Food and the Marine, Backweston Complex, Celbridge, Co. Kildare, Ireland
| | - Montserrat Gutierrez
- Department of Agriculture, Food and the Marine, Backweston Complex, Celbridge, Co. Kildare, Ireland
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Girlich D, Bonnin RA, Dortet L, Naas T. Genetics of Acquired Antibiotic Resistance Genes in Proteus spp. Front Microbiol 2020; 11:256. [PMID: 32153540 PMCID: PMC7046756 DOI: 10.3389/fmicb.2020.00256] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 02/03/2020] [Indexed: 01/30/2023] Open
Abstract
Proteus spp. are commensal Enterobacterales of the human digestive tract. At the same time, P. mirabilis is commonly involved in urinary tract infections (UTI). P. mirabilis is naturally resistant to several antibiotics including colistin and shows reduced susceptibility to imipenem. However higher levels of resistance to imipenem commonly occur in P. mirabilis isolates consecutively to the loss of porins, reduced expression of penicillin binding proteins (PBPs) PBP1a, PBP2, or acquisition of several antibiotic resistance genes, including carbapenemase genes. In addition, resistance to non-β-lactams is also frequently reported including molecules used for treating UTI infections (e.g., fluoroquinolones, nitrofurans). Emergence and spread of multidrug resistant P. mirabilis isolates, including those producing ESBLs, AmpC cephalosporinases and carbapenemases, are being more and more frequently reported. This review covers Proteus spp. with a focus on the different genetic mechanisms involved in the acquisition of resistance genes to multiple antibiotic classes turning P. mirabilis into a dreadful pandrug resistant bacteria and resulting in difficult to treat infections.
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Affiliation(s)
- Delphine Girlich
- EA7361 "Structure, dynamic, function and expression of broad spectrum β-lactamases", LabEx Lermit, Faculty of Medicine, Université Paris-Saclay, Le Kremlin-Bicêtre, France.,Associated French National Reference Center for Antibiotic Resistance: Carbapenemase-producing Enterobacteriaceae, Le Kremlin-Bicêtre, France.,Evolution and Ecology of Resistance to Antibiotics Unit, Institut Pasteur - APHP - Université Paris-Saclay, Paris, France
| | - Rémy A Bonnin
- EA7361 "Structure, dynamic, function and expression of broad spectrum β-lactamases", LabEx Lermit, Faculty of Medicine, Université Paris-Saclay, Le Kremlin-Bicêtre, France.,Associated French National Reference Center for Antibiotic Resistance: Carbapenemase-producing Enterobacteriaceae, Le Kremlin-Bicêtre, France.,Evolution and Ecology of Resistance to Antibiotics Unit, Institut Pasteur - APHP - Université Paris-Saclay, Paris, France
| | - Laurent Dortet
- EA7361 "Structure, dynamic, function and expression of broad spectrum β-lactamases", LabEx Lermit, Faculty of Medicine, Université Paris-Saclay, Le Kremlin-Bicêtre, France.,Associated French National Reference Center for Antibiotic Resistance: Carbapenemase-producing Enterobacteriaceae, Le Kremlin-Bicêtre, France.,Evolution and Ecology of Resistance to Antibiotics Unit, Institut Pasteur - APHP - Université Paris-Saclay, Paris, France
| | - Thierry Naas
- EA7361 "Structure, dynamic, function and expression of broad spectrum β-lactamases", LabEx Lermit, Faculty of Medicine, Université Paris-Saclay, Le Kremlin-Bicêtre, France.,Associated French National Reference Center for Antibiotic Resistance: Carbapenemase-producing Enterobacteriaceae, Le Kremlin-Bicêtre, France.,Evolution and Ecology of Resistance to Antibiotics Unit, Institut Pasteur - APHP - Université Paris-Saclay, Paris, France
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Akata K, Muratani T, Yatera K, Naito K, Noguchi S, Yamasaki K, Kawanami T, Kido T, Mukae H. Induction of plasmid-mediated AmpC β-lactamase DHA-1 by piperacillin/tazobactam and other β-lactams in Enterobacteriaceae. PLoS One 2019; 14:e0218589. [PMID: 31283769 PMCID: PMC6613692 DOI: 10.1371/journal.pone.0218589] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Accepted: 06/06/2019] [Indexed: 01/10/2023] Open
Abstract
Chromosomal AmpC β-lactamase induction by several types of β-lactams has been reported, but not enough data are available on DHA-1 β-lactamase, a plasmid-mediated AmpC β-lactamase. Therefore, we evaluated the DHA-1 β-lactamase induction by various antibiotics including piperacillin/tazobactam (PIP/TZB) in this study. Six strains (Enterobacter cloacae 2 strains, Citrobacter freundii 1 strain, Serratia marcescens 2 strain, and Morganella morganii 1 strain) possessing chromosomal inducible AmpC β-lactamase were used as controls. Four strains (Escherichia coli 2 strains, Klebsiella pneumoniae 1 strain, and C. koseri 1 strain) possessing DHA-1 β-lactamase were used. The β-lactamase activities were determined by a spectrophotometer using nitrocefin. β-lactamase induction by PIP, PIP/TZB was not observed in any strains and β-lactamase induction by third- and fourth-generation cephems was not observed in most strains. The induction ratios of the chromosomal AmpC β-lactamase in the reference group by PIP/TZB were <1.51, and those of the DHA-1 β-lactamase were <1.36, except for K. pneumoniae Rkp2004 (2.22). The β-lactamase induction by first- and second-generation cephems, flomoxef, and carbapenem differed in each strain. Cefmetazole (CMZ) strongly induced β-lactamase. This study demonstrated that the induction of DHA-1 β-lactamase was similar to that of chromosomal AmpC using various Enterobacteriaceae, although the induction of β-lactamase in both groups by PIP/TZB was low. We also reported that the induction of PIP/TZB, a β-lactamase inhibitor combination antibiotic, against various AmpC-producing Enterobacteriaceae, including DHA-1 producers, was low.
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Affiliation(s)
- Kentaro Akata
- Department of Respiratory Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu City, Fukuoka, Japan
| | - Tetsuro Muratani
- Department of Clinical Microbiology, Kyurin Medical Laboratory, Kitakyushu City, Fukuoka, Japan
| | - Kazuhiro Yatera
- Department of Respiratory Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu City, Fukuoka, Japan
- * E-mail:
| | - Keisuke Naito
- Department of Respiratory Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu City, Fukuoka, Japan
| | - Shingo Noguchi
- Department of Respiratory Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu City, Fukuoka, Japan
| | - Kei Yamasaki
- Department of Respiratory Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu City, Fukuoka, Japan
| | - Toshinori Kawanami
- Department of Respiratory Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu City, Fukuoka, Japan
| | - Takashi Kido
- Department of Respiratory Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu City, Fukuoka, Japan
| | - Hiroshi Mukae
- Second Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki City, Nagasaki, Japan
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Probing the Mechanism of Inactivation of the FOX-4 Cephamycinase by Avibactam. Antimicrob Agents Chemother 2018; 62:AAC.02371-17. [PMID: 29439972 DOI: 10.1128/aac.02371-17] [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] [Received: 11/17/2017] [Accepted: 01/22/2018] [Indexed: 12/17/2022] Open
Abstract
Ceftazidime-avibactam is a "second-generation" β-lactam-β-lactamase inhibitor combination that is effective against Enterobacteriaceae expressing class A extended-spectrum β-lactamases, class A carbapenemases, and/or class C cephalosporinases. Knowledge of the interactions of avibactam, a diazabicyclooctane with different β-lactamases, is required to anticipate future resistance threats. FOX family β-lactamases possess unique hydrolytic properties with a broadened substrate profile to include cephamycins, partly as a result of an isoleucine at position 346, instead of the conserved asparagine found in most AmpCs. Interestingly, a single amino acid substitution at N346 in the Citrobacter AmpC is implicated in resistance to the aztreonam-avibactam combination. In order to understand how diverse active-site topologies affect avibactam inhibition, we tested a panel of clinical Enterobacteriaceae isolates producing blaFOX using ceftazidime-avibactam, determined the biochemical parameters for inhibition using the FOX-4 variant, and probed the atomic structure of avibactam with FOX-4. Avibactam restored susceptibility to ceftazidime for most isolates producing blaFOX; two isolates, one expressing blaFOX-4 and the other producing blaFOX-5, displayed an MIC of 16 μg/ml for the combination. FOX-4 possessed a k2/K value of 1,800 ± 100 M-1 · s-1 and an off rate (koff) of 0.0013 ± 0.0003 s-1 Mass spectrometry showed that the FOX-4-avibactam complex did not undergo chemical modification for 24 h. Analysis of the crystal structure of FOX-4 with avibactam at a 1.5-Å resolution revealed a unique characteristic of this AmpC β-lactamase. Unlike in the Pseudomonas-derived cephalosporinase 1 (PDC-1)-avibactam crystal structure, interactions (e.g., hydrogen bonding) between avibactam and position I346 in FOX-4 are not evident. Furthermore, another residue is not observed to be close enough to compensate for the loss of these critical hydrogen-bonding interactions. This observation supports findings from the inhibition analysis of FOX-4; FOX-4 possessed the highest Kd (dissociation constant) value (1,600 nM) for avibactam compared to other AmpCs (7 to 660 nM). Medicinal chemists must consider the properties of extended-spectrum AmpCs, such as the FOX β-lactamases, for the design of future diazabicyclooctanes.
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Fróes AM, da Mota FF, Cuadrat RRC, Dávila AMR. Distribution and Classification of Serine β-Lactamases in Brazilian Hospital Sewage and Other Environmental Metagenomes Deposited in Public Databases. Front Microbiol 2016; 7:1790. [PMID: 27895627 PMCID: PMC5108929 DOI: 10.3389/fmicb.2016.01790] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 10/25/2016] [Indexed: 01/09/2023] Open
Abstract
β-lactam is the most used antibiotic class in the clinical area and it acts on blocking the bacteria cell wall synthesis, causing cell death. However, some bacteria have evolved resistance to these antibiotics mainly due the production of enzymes known as β-lactamases. Hospital sewage is an important source of dispersion of multidrug-resistant bacteria in rivers and oceans. In this work, we used next-generation DNA sequencing to explore the diversity and dissemination of serine β-lactamases in two hospital sewage from Rio de Janeiro, Brazil (South Zone, SZ and North Zone, NZ), presenting different profiles, and to compare them with public environmental data available. Also, we propose a Hidden-Markov-Model approach to screen potential serine β-lactamases genes (in public environments samples and generated hospital sewage data), exploring its evolutionary relationships. Due to the high variability in β-lactamases, we used a position-specific scoring matrix search method (RPS-BLAST) against conserved domain database profiles (CDD, Pfam, and COG) followed by visual inspection to detect conserved motifs, to increase the reliability of the results and remove possible false positives. We were able to identify novel β-lactamases from Brazilian hospital sewage and to estimate relative abundance of its types. The highest relative abundance found in SZ was the Class A (50%), while Class D is predominant in NZ (55%). CfxA (65%) and ACC (47%) types were the most abundant genes detected in SZ, while in NZ the most frequent were OXA-10 (32%), CfxA (28%), ACC (21%), CEPA (20%), and FOX (19%). Phylogenetic analysis revealed β-lactamases from Brazilian hospital sewage grouped in the same clade and close to sequences belonging to Firmicutes and Bacteroidetes groups, but distant from potential β-lactamases screened from public environmental data, that grouped closer to β-lactamases of Proteobacteria. Our results demonstrated that HMM-based approach identified homologs of serine β-lactamases, indicating the specificity and high sensitivity of this approach in large datasets, contributing for the identification and classification of a large number of homologous genes, comprising possible new ones. Phylogenetic analysis revealed the potential reservoir of β-lactam resistance genes in the environment, contributing to understanding the evolution and dissemination of these genes.
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Affiliation(s)
- Adriana M Fróes
- Laboratório de Biologia Computacional e Sistemas, Instituto Oswaldo Cruz, FIOCRUZ Rio de Janeiro, Brazil
| | - Fábio F da Mota
- Laboratório de Biologia Computacional e Sistemas, Instituto Oswaldo Cruz, FIOCRUZ Rio de Janeiro, Brazil
| | - Rafael R C Cuadrat
- Laboratório de Biologia Computacional e Sistemas, Instituto Oswaldo Cruz, FIOCRUZ Rio de Janeiro, Brazil
| | - Alberto M R Dávila
- Laboratório de Biologia Computacional e Sistemas, Instituto Oswaldo Cruz, FIOCRUZ Rio de Janeiro, Brazil
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Comparative genomics of an IncA/C multidrug resistance plasmid from Escherichia coli and Klebsiella isolates from intensive care unit patients and the utility of whole-genome sequencing in health care settings. Antimicrob Agents Chemother 2014; 58:4814-25. [PMID: 24914121 DOI: 10.1128/aac.02573-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The IncA/C plasmids have been implicated for their role in the dissemination of β-lactamases, including gene variants that confer resistance to expanded-spectrum cephalosporins, which are often the treatment of last resort against multidrug-resistant, hospital-associated pathogens. A bla(FOX-5) gene was detected in 14 Escherichia coli and 16 Klebsiella isolates that were cultured from perianal swabs of patients admitted to an intensive care unit (ICU) of the University of Maryland Medical Center (UMMC) in Baltimore, MD, over a span of 3 years. Four of the FOX-encoding isolates were obtained from subsequent samples of patients that were initially negative for an AmpC β-lactamase upon admission to the ICU, suggesting that the AmpC β-lactamase-encoding plasmid was acquired while the patient was in the ICU. The genomes of five E. coli isolates and six Klebsiella isolates containing bla(FOX-5) were selected for sequencing based on their plasmid profiles. An ∼ 167-kb IncA/C plasmid encoding the FOX-5 β-lactamase, a CARB-2 β-lactamase, additional antimicrobial resistance genes, and heavy metal resistance genes was identified. Another FOX-5-encoding IncA/C plasmid that was nearly identical except for a variable region associated with the resistance genes was also identified. To our knowledge, these plasmids represent the first FOX-5-encoding plasmids sequenced. We used comparative genomics to describe the genetic diversity of a plasmid encoding a FOX-5 β-lactamase relative to the whole-genome diversity of 11 E. coli and Klebsiella isolates that carry this plasmid. Our findings demonstrate the utility of whole-genome sequencing for tracking of plasmid and antibiotic resistance gene distribution in health care settings.
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Papp-Wallace KM, Mallo S, Bethel CR, Taracila MA, Hujer AM, Fernández A, Gatta JA, Smith KM, Xu Y, Page MGP, Desarbre E, Bou G, Bonomo RA. A kinetic analysis of the inhibition of FOX-4 β-lactamase, a plasmid-mediated AmpC cephalosporinase, by monocyclic β-lactams and carbapenems. J Antimicrob Chemother 2013; 69:682-90. [PMID: 24235094 DOI: 10.1093/jac/dkt434] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Class C β-lactamases are prevalent among Enterobacteriaceae; however, these enzymes are resistant to inactivation by commercially available β-lactamase inhibitors. In order to find novel scaffolds to inhibit class C β-lactamases, the comparative efficacy of monocyclic β-lactam antibiotics (aztreonam and the siderophore monosulfactam BAL30072), the bridged monobactam β-lactamase inhibitor BAL29880, and carbapenems (imipenem, meropenem, doripenem and ertapenem) were tested in kinetic assays against FOX-4, a plasmid-mediated class C β-lactamase (pmAmpC). METHODS The FOX-4 β-lactamase was purified. Steady-state kinetics, electrospray ionization mass spectrometry (ESI-MS) and ultraviolet difference (UVD) spectroscopy were conducted using the β-lactam scaffolds described. RESULTS The K(i) values for the monocyclic β-lactams against FOX-4 β-lactamase were 0.04 ± 0.01 μM (aztreonam) and 0.66 ± 0.03 μM (BAL30072), and the Ki value for the bridged monobactam BAL29880 was 8.9 ± 0.5 μM. For carbapenems, the Ki values ranged from 0.27 ± 0.05 μM (ertapenem) to 2.3 ± 0.3 μM (imipenem). ESI-MS demonstrated the formation of stable covalent adducts when the monocyclic β-lactams and carbapenems were reacted with FOX-4 β-lactamase. UVD spectroscopy suggested the appearance of different chromophoric intermediates. CONCLUSIONS Monocyclic β-lactam and carbapenem antibiotics are effective mechanism-based inhibitors of FOX-4 β-lactamase, a clinically important pmAmpC, and provide stimulus for the development of new inhibitors to inactivate plasmidic and chromosomal class C β-lactamases.
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Affiliation(s)
- Krisztina M Papp-Wallace
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA
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Characterization of the new AmpC β-lactamase FOX-8 reveals a single mutation, Phe313Leu, located in the R2 loop that affects ceftazidime hydrolysis. Antimicrob Agents Chemother 2013; 57:5158-61. [PMID: 23877692 DOI: 10.1128/aac.00818-13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel class C β-lactamase (FOX-8) was isolated from a clinical strain of Escherichia coli. The FOX-8 enzyme possessed a unique substitution (Phe313Leu) compared to FOX-3. Isogenic E. coli strains carrying FOX-8 showed an 8-fold reduction in resistance to ceftazidime relative to FOX-3. In a kinetic analysis, FOX-8 displayed a 33-fold reduction in kcat/Km for ceftazidime compared to FOX-3. In the FOX family of β-lactamases, the Phe313 residue located in the R2 loop affects ceftazidime hydrolysis and alters the phenotype of E. coli strains carrying this variant.
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Zhu YL, Zhang XN, Gao F, Cheng J, Hu LF, Ma T, Yin J, Ye Y, Li JB. ACT-6, a novel plasmid-encoded class C β-lactamase in a Klebsiella pneumoniae isolate from China. J Antibiot (Tokyo) 2011; 64:317-20. [PMID: 21304534 DOI: 10.1038/ja.2011.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The purpose of this study was to investigate the phenotypic and molecular characterization of a novel plasmid-mediated AmpC-type β-lactamase in Klebsiella pneumoniae E701 isolated from Anhui province in China. In comparison with the ACT-1, sequence analysis revealed that there were 43 point mutations in the coding gene, and 10 of which led to amino-acid substitution. Resistance could be transferred by conjugation or transformation with plasmid DNA into E. coli JM109, which was due to the production of a β-lactamase with an isoelectric point of 8.4 named ACT-6. Cloning, expression, purification and kinetics were carried out to study the characterization of the novel AmpC-type β-lactamase. The results of MIC determinations and substrate profiles showed there was no significant difference in the activities of the novel enzyme and ACT-1. Moreover, the class 1 integron and the whole open reading frame of the novel AmpC-type β-lactamase from K.pneumoniae E701 were detectable in the same size plasmid. This is the first report on the emergence of the novel ACT-6 type β-lactamases in K. pneumoniae.
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Affiliation(s)
- Yu-lin Zhu
- Department of Infectious Diseases, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
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Al Muharrmi Z, Rafay AM, Balkhair A, Al-Tamemi S, Al Mawali A, Al Sadiri H. Extended-spectrum β-lactamase (ESBL) in Omani Children: Study of prevalence, risk factors and clinical outcomes at Sultan Qaboos University Hospital, Sultanate of Oman. Sultan Qaboos Univ Med J 2008; 8:171-177. [PMID: 21748055 PMCID: PMC3074824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Accepted: 03/31/2008] [Indexed: 05/31/2023] Open
Abstract
OBJECTIVES Antimicrobial resistance is a growing problem worldwide, which imposes difficulties in the selection of appropriate empirical antimicrobial therapy. This study evaluated extended-spectrum β-lactamase (ESBL) isolates in 2005 in The Department of Child Health at Sultan Qaboos University Hospital (SQUH), Oman. METHODS During the 12 month period from January 2005 to December 2005, ESBL isolates from paediatrics inpatients were identified and analysed. Risk factors for the patients who grew ESBLs were analysed. RESULTS 13.3% of E. coli and 16.6% of Klebsiella pneumoniae isolated were ESBL producers. Most of the ESBLs were from urine (46.2%) and blood (42.6%). The main risk factors for ESBL in these children were previous exposure to antimicrobials (100%), prolonged hospital stay, severe illness (92.3%) and female gender (84.6%). Sensitivity of 100% was observed to carbapenems whereas 92% of the isolates were susceptible to amikacin. The oximino-cephalosporins were 100% resistant. Klebsiella pneumoniae were 100% resistant to piperacillin-tazobactam and nitrofurantoin. E. coli was 100% resistant to trimethoprim-sulfamethoxazole and ciprofloxacin. No resistance was recorded for the following combinations: amikacin plus piperacillin-tazobactam, amikacin plus nitrofurantoin and gentamicin plus nitrofurantoin. CONCLUSION ESBL-producing organisms are becoming a major problem in Omani children. Exposure to antimicrobials and long admissions are modifiable risk factors that should be targeted for better control. Carbapenems are the most sensitive and reliable treatment options for infections caused by ESBLs. Amikacin plus piperacillin-tazobactam or nitrofurantoin are good alternatives.
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Affiliation(s)
| | | | | | - Salem Al-Tamemi
- Child Health, Sultan Qaboos University Hospital, Muscat, Oman
| | - Ali Al Mawali
- Medical Student, College of Medicine & Health Sciences, Sultan Qaboos University, Muscat, Oman
| | - Hilal Al Sadiri
- Medical Student, College of Medicine & Health Sciences, Sultan Qaboos University, Muscat, Oman
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VIM-15 and VIM-16, two new VIM-2-like metallo-beta-lactamases in Pseudomonas aeruginosa isolates from Bulgaria and Germany. Antimicrob Agents Chemother 2008; 52:2977-9. [PMID: 18519714 DOI: 10.1128/aac.00175-08] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two Pseudomonas aeruginosa urine isolates from Bulgaria and Germany produced two new VIM-2 variants. VIM-15 had one amino acid substitution (Tyr218Phe) which caused a significant increase in hydrolytic efficiency. The substitution Ser54Leu, characterizing VIM-16, showed no influence on enzyme activity. Both genes were part of class I integrons located in the chromosome.
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Schlüter A, Krause L, Szczepanowski R, Goesmann A, Pühler A. Genetic diversity and composition of a plasmid metagenome from a wastewater treatment plant. J Biotechnol 2008; 136:65-76. [PMID: 18603322 DOI: 10.1016/j.jbiotec.2008.03.017] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Revised: 03/14/2008] [Accepted: 03/31/2008] [Indexed: 11/24/2022]
Abstract
Plasmid metagenome nucleotide sequence data were recently obtained from wastewater treatment plant (WWTP) bacteria with reduced susceptibility to selected antimicrobial drugs by applying the ultrafast 454-sequencing technology. The sequence dataset comprising 36,071,493 bases (346,427 reads with an average read length of 104 bases) was analysed for genetic diversity and composition by using a newly developed bioinformatic pipeline based on assignment of environmental gene tags (EGTs) to protein families stored in the Pfam database. Short amino acid sequences deduced from the plasmid metagenome sequence reads were compared to profile hidden Markov models underlying Pfam. Obtained matches evidenced that many reads represent genes having predicted functions in plasmid replication, stability and plasmid mobility which indicates that WWTP bacteria harbour genetically stabilised and mobile plasmids. Moreover, the data confirm a high diversity of plasmids residing in WWTP bacteria. The mobile organic peroxide resistance plasmid pMAC from Acinetobacter baumannii was identified as reference plasmid for the most abundant replication module type in the sequenced sample. Accessory plasmid modules encode different transposons, insertion sequences, integrons, resistance and virulence determinants. Most of the matches to Transposase protein families were identified for transposases similar to the one of the chromate resistance transposon Tn5719. Noticeable are hits to beta-lactamase protein families which suggests that plasmids from WWTP bacteria encode different enzymes possessing beta-lactam-hydrolysing activity. Some of the sequence reads correspond to antibiotic resistance genes that were only recently identified in clinical isolates of human pathogens. EGT analysis thus proofed to be a very valuable method to explore genetic diversity and composition of the present plasmid metagenome dataset.
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Affiliation(s)
- Andreas Schlüter
- Department of Genetics, Bielefeld University, Postfach 100131, D-33501 Bielefeld, Germany.
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Van TTH, Chin J, Chapman T, Tran LT, Coloe PJ. Safety of raw meat and shellfish in Vietnam: an analysis of Escherichia coli isolations for antibiotic resistance and virulence genes. Int J Food Microbiol 2008; 124:217-23. [PMID: 18457892 DOI: 10.1016/j.ijfoodmicro.2008.03.029] [Citation(s) in RCA: 197] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2007] [Revised: 02/06/2008] [Accepted: 03/24/2008] [Indexed: 11/27/2022]
Abstract
This study was conducted to examine a current baseline profile of antimicrobial resistance and virulence of Escherichia coli isolated from foods commonly sold in the market place in Vietnam. E. coli were isolated from 180 samples of raw meat, poultry and shellfish and also isolated from 43 chicken faeces samples. Ninety-nine E. coli isolates recovered from all sources were selected for the investigation of their susceptibility to 15 antimicrobial agents by the disk diffusion method. Eighty-four percent of the isolates were resistant to one or more antibiotics, and multi-resistance, defined as resistance to at least 3 different classes of antibiotics, was detected in all sources. The rates of multi-resistance were up to 89.5% in chicken, 95% in chicken faeces and 75% in pork isolates. Resistance was most frequently observed to tetracycline (77.8%), sulfafurazole (60.6%), ampicillin (50.5%), amoxicillin (50.5%), trimethoprim (51.5%), chloramphenicol (43.4%), streptomycin (39.4%), nalidixic acid (34.3%) and gentamicin (24.2%). In addition, the isolates also displayed resistance to fluoroquinolones (ciprofloxacin 16.2%, norfloxacin 17.2%, and enrofloxacin 21.2%), with chicken isolates showing the highest rates of resistance to these antibiotics (52.6-63.2%). Thirty-eight multi-resistant isolates were selected for further the examination of antibiotic resistance genes and were also evaluated for virulence gene profiles by multiplex and uniplex polymerase chain reaction. The beta-lactam TEM gene and tetracycline resistance tetA, tetB genes were frequently detected in the tested isolates (84.2% and 89.5% respectively). Genes which are responsible for resistance to streptomycin (aadA) (68.4%), chloramphenicol (cmlA) (42.1%), sulfonamides (sulI) (39.5%), trimethoprim (dhfrV) (26.3%) and kanamycin (aphA-1) (23.7%) were also widely distributed. Plasmid-mediated ampC genes were detected in E. coli isolates from chicken and pork. The isolates were tested for the presence of 58 virulence genes for adhesins, toxins, capsule synthesis, siderophores, invasins and others from different E. coli pathotypes. All of the tested isolates contained at least one virulence gene and there were 16 genes detected. Virulence genes detected were fimH (92.1%), bmaE (84.2%), TSPE4.C2 (42.1%), aidA AIDA-I (orfB) (31.6%), east1 (26.3%), traT (23.7%), and others including fyuA, iutA, chuA, yjaA, iss, iroN(E. coli), ibeA, aah (orfA), iha and papG allele III (10.5-2.6%). Typical toxin genes produced by enterohemorrhagic and enterotoxigenic E. coli pathotypes (a heat-stable toxin (ST), heat-labile toxin (LT) and Shiga toxin stx1, stx2) were not detected in any of these 38 isolates. The study has revealed that E. coli in raw foods is a significant reservoir of resistance and virulence genes.
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Affiliation(s)
- Thi Thu Hao Van
- Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, Bundoora West Campus, Bundoora, Melbourne, VIC 3083, Australia
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Schneider I, Queenan AM, Bauernfeind A. Novel carbapenem-hydrolyzing oxacillinase OXA-62 from Pandoraea pnomenusa. Antimicrob Agents Chemother 2006; 50:1330-5. [PMID: 16569848 PMCID: PMC1426949 DOI: 10.1128/aac.50.4.1330-1335.2006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pandoraea spp. are gram-negative, glucose nonfermenting rods detectable in blood cultures and sputa of cystic fibrosis patients. They are resistant to various antibiotic groups, with imipenem being the only active beta-lactam. We isolated an imipenem-resistant (MIC, 64 microg/ml) Pandoraea pnomenusa strain from a cystic fibrosis patient. Cloning and sequencing identified two beta-lactamases of Bush group 2d, namely, the known OXA-33, located on an integron, and the novel carbapenem-hydrolyzing oxacillinase OXA-62. OXA-62 is only distantly related to other oxacillinases (OXA-50 being closest with 43% amino acid identity). It hydrolyzes penicillins, oxacillin, imipenem, and meropenem but not expanded-spectrum cephalosporins. The blaOXA-62 gene is chromosome located. No transposable elements were found in its genetic neighborhood. With OXA-62-specific primers, blaOXA-62 could be identified in all P. pnomenusa strains and appears to be species specific. This additional mechanism of carbapenem resistance further complicates the treatment of infections caused by P. pnomenusa.
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Affiliation(s)
- Ines Schneider
- MICOER Institute, Hesseloherstrasse 4, 80802 Munich, Germany
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Rodríguez-Martínez JM, Velasco C, Pascual A, García I, Martínez-Martínez L. Correlation of quinolone resistance levels and differences in basal and quinolone-induced expression from three qnrA-containing plasmids. Clin Microbiol Infect 2006; 12:440-5. [PMID: 16643520 DOI: 10.1111/j.1469-0691.2006.01389.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study investigated the effect of copy number and transcriptional level of the qnrA gene on plasmid-mediated quinolone resistance, and the effect of quinolones on qnrA expression, in three clinical isolates of Klebsiella pneumoniae and the corresponding Escherichia coli transconjugants. The copy number of plasmids containing qnrA was analysed and transcriptional studies were performed on transconjugants grown in the presence or absence of ciprofloxacin or moxifloxacin. None of the three clinical isolates was porin-deficient. One isolate contained a mutation in the quinolone resistance-determining region of the gyrA gene (Ser83Phe), but no gyrA mutations were present in the other two isolates, and no mutations were found in parC. Differences in qnrA copy number were observed in K. pneumoniae, but not in the corresponding E. coli transconjugants, although the qnrA gene was located in plasmids with similar mobility and Southern blot RFLP pattern. Differences in qnrA transcription, both at the basal level and following induction by quinolones, were observed among transconjugants. Expression of the qnrA gene correlated well with the level of quinolone (ciprofloxacin and moxifloxacin) resistance in E. coli transconjugants. These data suggest that the main factor determining the resistance level in the transconjugants analysed was the different levels of qnrA expression.
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Affiliation(s)
- J M Rodríguez-Martínez
- Department of Microbiology, School of Medicine, University of Seville, C/Sanchez Pizjuan s/n, 41009 Seville, Spain.
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Wu LT, Hung SW, Chuang YC, Chen HE, Jones RN, Yu WL. Identification of a novel cephalosporinase (DHA-3) in Klebsiella pneumoniae isolated in Taiwan. Clin Microbiol Infect 2005; 11:893-7. [PMID: 16216104 DOI: 10.1111/j.1469-0691.2005.01252.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A strain of Klebsiella pneumoniae resistant to cefoxitin and oxyimino-cephalosporins, but susceptible to cefepime, was isolated from an adult patient hospitalised in Taichung, Taiwan. Isoelectric focusing revealed three beta-lactamases with isoelectric points of 5.4, 8.2 and 7.9, respectively. Following PCR with plasmid DNA templates and gene sequencing, these enzymes were shown to correspond to TEM-1, SHV-5 and a novel DHA-1-like enzyme (designated DHA-3). The bla genes for TEM-1 and SHV-5 were transferable, but the bla(DHA-3) gene was non-self-transferable in conjugation experiments. All three bla genes were successfully introduced by electrotransformation into an Escherichia coli recipient (DH5alpha), resulting in a similar resistance profile to that observed in the original donor strain. Other K. pneumoniae strains producing DHA-1-like enzymes have been identified previously in Taiwan, and this report suggests that DHA-type beta-lactamases are continuing to emerge in this country.
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Affiliation(s)
- L-T Wu
- Institute of Medical Science and Department of Microbiology, China Medical University, Taiwan
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Briñas L, Moreno MA, Teshager T, Sáenz Y, Porrero MC, Domínguez L, Torres C. Monitoring and characterization of extended-spectrum beta-lactamases in Escherichia coli strains from healthy and sick animals in Spain in 2003. Antimicrob Agents Chemother 2005; 49:1262-4. [PMID: 15728945 PMCID: PMC549238 DOI: 10.1128/aac.49.3.1262-1264.2005] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genes encoding CTX-M-14, CTX-M-9, CTX-M-1, CTX-M-32, SHV-12, TEM-52, or CMY-2 beta-lactamases were detected in 21 Escherichia coli strains recovered during 2003 from sick animals (11 of 459 [2.4%] strains) and healthy animals (10 of 158 [6.3%] strains) in Spain. Twelve of these strains harbored bla(CTX-M) genes and showed unrelated pulsed-field gel electrophoresis patterns.
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Affiliation(s)
- Laura Briñas
- Area Bioquímica y Biología Molecular, Universidad de La Rioja, Madre de Dios 51, 26006 Logroño, Spain
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20
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Reisbig MD, Hanson ND. Promoter sequences necessary for high-level expression of the plasmid-associated ampC beta-lactamase gene blaMIR-1. Antimicrob Agents Chemother 2004; 48:4177-82. [PMID: 15504838 PMCID: PMC525406 DOI: 10.1128/aac.48.11.4177-4182.2004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Little is known about mechanisms involved in high-level expression of plasmid-associated ampC genes. The sequence for bla(MIR-1) has been elucidated, and the gene is not inducible. Although the sequence for the promoter (prA) that drives expression of Enterobacter cloacae chromosomal ampC is present upstream of bla(MIR-1), high-level expression from bla(MIR-1) is directed from a hybrid promoter (prB) located further upstream of prA. The purpose of this study was to determine the influence of each promoter on bla(MIR-1) expression and beta-lactam resistance. RNA expression by deletion clones with both promoters was measured and compared to that by clones in which -35 and/or -10 elements of prA and/or prB were altered. Primer extension revealed two start sites for bla(MIR-1) transcription. Expression of bla(MIR-1) in clones with both promoters was 171-fold higher than that in clones carrying only prA. In addition, bla(MIR-1) expression from prA increased 11-fold in the presence of the prB -10 element compared to expression driven from prA alone. Ceftazidime and cefotaxime MICs increased 42- and 64-fold, respectively, for the clone expressing bla(MIR-1) from both promoters compared to expression from prA alone. The upstream promoter prB of bla(MIR-1) is solely responsible for high-level expression required for cefotaxime and ceftazidime resistance. These data suggest that resistance to extended-spectrum cephalosporins mediated by noninducible plasmid-associated ampC genes requires the formation of novel promoter elements that are capable of increasing ampC expression.
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Affiliation(s)
- Mark D Reisbig
- Center for Research in Anti-Infectives and Biotechnology, Department of Microbiology and Immunology, Creighton University School of Medicine, 2500 California Pl., Omaha, NE 68178, USA
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Briñas L, Lantero M, Zarazaga M, Pérez F, Torres C. Outbreak of SHV-5 β-Lactamase-ProducingKlebsiella pneumoniaein a Neonatal-Pediatric Intensive Care Unit in Spain. Microb Drug Resist 2004; 10:354-8. [PMID: 15650382 DOI: 10.1089/mdr.2004.10.354] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The objective was to analyze the beta-lactamase genes and the clonal relationship in a series of 12 clinical Klebsiella pneumoniae strains resistant to ceftazidime or cefotaxime (MIC >/=16 microg/ml) recovered in the neonatalpediatric intensive care unit (ICU) ward of a Spanish hospital during a 1-year period. TEM, SHV, CTX-M, CMY, or FOX beta-lactamase genes were analyzed by PCR and sequencing. The clonal study was performed by pulsed-field gel electrophoresis (PFGE) using XbaI. All but one of the 12 K. pneumoniae strains harbored the bla (SHV-5) gene, and the bla TEM-1a gene was also detected in one of them. These 11 strains belonged to two different clonal types: A (9 strains) and B (2 strains) and were grouped in the subtypes A(1) (6 strains), A(2), A(3), A(4), B(1), and B(2) (1 strain each). The clonal type A strains were isolated from 9 patients (in five cases from blood) during a 6-month period. The remaining K. pneumoniae strain harbored both the bla (SHV-11) + bla (CTX-M-14) genes and showed the clonal type C. A nosocomial outbreak by a SHV-5-producing multiresistant K. pneumoniae is reported in Spain in a neonatal-pediatric ICU ward. This is the first description of a K. pneumoniae harboring both the bla (SHV-11) and bla (CTX-M-14) genes in Spain.
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Affiliation(s)
- Laura Briñas
- Area Bioquímica y Biología Molecular, Universidad La Rioja, 26006 Logroño, Spain
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22
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Burgess DS, Hall RG, Lewis JS, Jorgensen JH, Patterson JE. Clinical and microbiologic analysis of a hospital's extended-spectrum beta-lactamase-producing isolates over a 2-year period. Pharmacotherapy 2004; 23:1232-7. [PMID: 14594340 DOI: 10.1592/phco.23.12.1232.32706] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
STUDY OBJECTIVE To evaluate the microbiologic and clinical outcomes of patients with extended-spectrum beta-lactamase (ESBL)-producing isolates over a 2-year period. DESIGN Retrospective analysis. SETTING Tertiary care teaching hospital. PATIENTS Twenty-one patients with cultures of confirmed ESBL-producing Escherichia coli, Klebsiella pneumoniae, or Klebsiella oxytoca. MEASUREMENTS AND MAIN RESULTS Antimicrobial susceptibilities of piperacillin-tazobactam, cefotetan, carbapenems, aminoglycosides, fluoroquinolones, trimethoprim-sulfamethoxazole, and nitrofurantoin (nitrofurantoin for urinary isolates only) of confirmed ESBL producers at our institution were determined, as well as clinical outcomes of patients with ESBL-producing isolates. Microbiologic and medical records were reviewed for patient sex and age, antimicrobial susceptibilities, antimicrobial therapy, and clinical and microbiologic outcomes. From January 2000-December 2001, 31 isolates were confirmed as ESBL producers (6 E. coli, 11 K. pneumoniae, and 14 K. oxytoca). A statistically significant increase occurred over the 2-year period from 9 (0.6%) of 1414 isolates in 2000 to 22 (1.8%) of 1218 isolates in 2001 (p = 0.0055). All isolates were susceptible to carbapenems, and more than 88% were susceptible to amikacin, cefotetan, or nitrofurantoin. Less than 70% of isolates were susceptible to gentamicin, fluoroquinolones, piperacillin-tazobactam, or trimethoprim-sulfamethoxazole. All patients treated with a carbapenem experienced clinical cure. Piperacillin-tazobactam alone and in combination resulted in an overall clinical cure rate of 55%, with a 50% cure rate for isolates susceptible to piperacillin-tazobactam. All patients in whom antibiotic therapy failed had been treated with piperacillin-tazobactam or cefepime, either alone or in combination with a fluoroquinolone. CONCLUSION Carbapenems remain the treatment of choice for ESBL-producing pathogens. Piperacillin-tazobactam and cefepime should not be routinely administered for the treatment of these organisms.
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Briñas L, Moreno MA, Teshager T, Zarazaga M, Sáenz Y, Porrero C, Dominguez L, Torres C. Beta-lactamase characterization in Escherichia coli isolates with diminished susceptibility or resistance to extended-spectrum cephalosporins recovered from sick animals in Spain. Microb Drug Resist 2004; 9:201-9. [PMID: 12820806 DOI: 10.1089/107662903765826804] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A total of 1439 Escherichia coli isolates from sick animals were received from the Spanish Network of Veterinary Antimicrobial Resistance Surveillance (VAV) from 1997 to 2001. Antimicrobial susceptibility tests were performed and diminished susceptibility to cefotaxime and ceftazidime was identified in 2.5% and 2.8% of the isolates, respectively. Beta-lactamase characterization was carried out in the group of 20 E. coli isolates with both characteristics. The MIC ranges of different beta-lactams showed by these 20 isolates were as follows (in microg/ml): ampicillin (64-->256), amoxicillin-clavulanic acid (4-64), ticarcillin (8-->128), cefazolin (32-->256), cefoxitin (4-->128), cefotaxime (1-64), ceftazidime (2-->64), ceftriaxone (0.5-64), imipenem (< or = 0.06-0.25), and aztreonam (2-->32). TEM, SHV, CMY, and FOX beta-lactamase genes were analyzed by PCR and sequencing. The beta-lactamase genes detected were the following ones (number of isolates): bla(TEM-1b) (3), bla(TEM-1a) (1), bla(TEM-30f) (2), bla(TEM-1b) + bla(CMY-2) (2), and bla(SHV-12) (1). Sequences of the promoter and/or attenuator region of the chromosomal ampC gene were studied in all the 20 isolates. Mutations at position -42 or -32 were detected in 16 isolates and these mutations were associated with the presence of a TEM type beta-lactamase in 6 isolates. Besides, a high variety of plasmidic beta-lactamases was detected including TEM-30 and CMY-2. To our knowledge, this is the first time that TEM-30 beta-lactamase has been detected in E. coli isolates of animal origin.
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Affiliation(s)
- Laura Briñas
- Area de Bioquímica y Biología Molecular, Universidad de La Rioja, 26006 Logroño, Spain
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Briñas L, Moreno MA, Zarazaga M, Porrero C, Sáenz Y, García M, Dominguez L, Torres C. Detection of CMY-2, CTX-M-14, and SHV-12 beta-lactamases in Escherichia coli fecal-sample isolates from healthy chickens. Antimicrob Agents Chemother 2003; 47:2056-8. [PMID: 12760899 PMCID: PMC155838 DOI: 10.1128/aac.47.6.2056-2058.2003] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genes encoding the CMY-2, CTX-M-14, and SHV-12 beta-lactamases were detected in three of five Escherichia coli isolates from fecal samples from healthy chickens which showed resistance or diminished susceptibility to extended-spectrum cephalosporins. A -42 mutation at the promoter region of the ampC gene was detected in the other two isolates.
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Affiliation(s)
- Laura Briñas
- Area de Bioquímica y Biología Molecular, Universidad de La Rioja, 26006 Logroño, Spain
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Fosse T, Giraud-Morin C, Madinier I, Labia R. Sequence analysis and biochemical characterisation of chromosomal CAV-1 (Aeromonas caviae), the parental cephalosporinase of plasmid-mediated AmpC 'FOX' cluster. FEMS Microbiol Lett 2003; 222:93-8. [PMID: 12757951 DOI: 10.1016/s0378-1097(03)00253-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Aeromonas caviae CIP 74.32 was resistant to amoxicillin, ticarcillin and cephalothin, and susceptible to cefoxitin, cefotaxime, ceftazidime, aztreonam and imipenem. This strain produced a cephalosporinase (pI 7.2) and an oxacillinase (pI 8.5). The cephalosporinase gene cav-1 was cloned and sequenced. Unlike A. caviae donor, Escherichia coli pNCE50 transformant producing CAV-1 beta-lactamase was resistant to cefoxitin. The deduced protein sequence CAV-1 contained 382 amino acids, and shared >96% homology with FOX-1 to FOX-5 cephalosporinase. CAV-1 presented only two amino acid substitutions (Thr270Ser and Arg271Ala) with FOX-1. CAV-1 is the chromosomal putative ancestor of the FOX family, a cluster of class C/group 1 plasmidic cephalosporinases spreading in Klebsiella and E. coli clinical isolates via conjugative plasmids.
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Affiliation(s)
- Thierry Fosse
- Laboratoire de Bactériologie, Hôpital L'Archet 2, Centre Hospitalier Universitaire, B P 3079, 06202 Nice, Cedex 3, France.
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Briñas L, Zarazaga M, Sáenz Y, Ruiz-Larrea F, Torres C. Beta-lactamases in ampicillin-resistant Escherichia coli isolates from foods, humans, and healthy animals. Antimicrob Agents Chemother 2002; 46:3156-63. [PMID: 12234838 PMCID: PMC128764 DOI: 10.1128/aac.46.10.3156-3163.2002] [Citation(s) in RCA: 217] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
TEM-, SHV-, and OXA-type beta-lactamases were studied by PCR with 124 ampicillin-resistant (AMP(r)) Escherichia coli isolates recovered from foods of animal origin (n = 20) and feces of humans (n = 49) and healthy animals (n = 55). PCR showed that 103 isolates were positive for TEM and negative for SHV and OXA. Three E. coli isolates showed a positive reaction for OXA, and one showed a positive reaction for SHV. The remaining 17 E. coli isolates were negative for the three enzymes by PCR. Fifty-seven of the 103 bla(TEM) amplicons were sequenced. Different molecular variants of bla(TEM-1) were found in 52 isolates: bla(TEM-1a) (n = 9), bla(TEM-1b) (n = 36), bla(TEM-1c) (n = 6), and bla(TEM-1f) (n = 1). Four inhibitor-resistant TEM (IRT) beta-lactamase-encoding genes were also detected: bla(TEM-30c) (IRT-2), bla(TEM-34b) (IRT-6), bla(TEM-40b) (IRT-11), and bla(TEM-51a) (IRT-15). A new bla(TEM) gene, named bla(TEM-95b), which showed a mutation in amino acid 145 (P-->A) was detected. It was found in a food isolate of chicken origin (AMP(r), amoxicillin-clavulanic acid susceptible). The promoter region in 24 bla(TEM) amplicons was analyzed, and the weak P3 promoter was found in 23 of them (bla(TEM-1) in 20 amplicons and bla(TEM-51a), bla(TEM-30c), and bla(TEM-95b) in 1 amplicon each). The strong Pa/Pb promoter was found only in the bla(TEM-34b) gene. No extended-spectrum beta-lactamases were detected. Mutations at position -42 or -32 in the ampC gene promoter were demonstrated in 4 of 10 E. coli isolates for which the cefoxitin MIC was >/=16 micro g/ml. Different variants of bla(TEM-1) and IRT bla(TEM) genes were found among the AMP(r) E. coli isolates from foods and the feces of humans and healthy animals, and a new gene, bla(TEM-95b) (P3), was detected.
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Affiliation(s)
- Laura Briñas
- Area de Bioquímica y Biología Molecular, Universidad de La Rioja, 26006 Logroño, Spain
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28
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Abstract
Historically, it was thought that ampC genes encoding class C beta-lactamases were located solely on the chromosome but, within the last 12 years, an increasing number of ampC genes have been found on plasmids. These have mostly been acquired by ampC-deficient pathogenic bacteria, which consequently are supplied with new and additional resistance phenotypes. This review discusses the phylogenetic origin of the plasmid-encoded AmpC beta-lactamases, their occurrence, and mode of spread, as well as their hydrolytic properties.
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Affiliation(s)
- Jan Walther-Rasmussen
- Department of Clinical Microbiology, Rigshospitalet, National University Hospital, Copenhagen, Denmark.
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Rhimi-Mahjoubi F, Bernier M, Arlet G, Jemaa ZB, Jouve P, Hammami A, Philippon A. [Identification of plasmid-encoded cephalosporinase ACC-1 among various enterobacteria (Klebsiella pneumoniae, Proteus mirabilis, Salmonella) isolated from a Tunisian hospital (Sfax 997-2000)]. PATHOLOGIE-BIOLOGIE 2002; 50:7-11. [PMID: 11873633 DOI: 10.1016/s0369-8114(01)00260-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Because a multiresistant K. pneumoniae outbreak detected in an intensive care unit of a parisian hospital, combined to the production of the plasmid-encoded cephalosporinase ACC-1, a probable importation via a patient was suggested from another country (Tunisia). The investigation was conducted to examine 35 clinical strains of enterobacteria resistant to ceftazidime without synergy towards Augmentin. Other test of synergy with two inhibitors, BRL 42715, Ro 48-5545 was performed by diffusion method and deposit of 10 micrograms of inhibitor on disks containing ceftazidime, cefoxitin and cefotetan. Synergies were obtained suggesting a probable production of ACC-1 type among six isolates of K. pneumoniae (two), Proteus mirabilis (one) and Salmonella (three) issued from different units. The isoelectric focusing on gel revealed at least one band of beta-lactamase activity at 7.8 but also demonstrated the simultaneous production of several probable beta-lactamases including TEM-type, SHV-2 and ACC-1 among S. enterica ser. Livingstone. The PCR of the gene blaacc-1 was positive. The sequencing (1160 pb) of two products showed high identity (99-100%) with the gene blaacc-1 deposited in 1999. Finally the ACC-1 type reported in Tunisia was probably imported in France via a patient. Because a simultaneous synthesis of ESBL and ACC-1 type, its presence may be invisible and need more investigation.
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Affiliation(s)
- F Rhimi-Mahjoubi
- Service de bactériologie, CHU Habib Bourguiba, 3029 Sfax, Tunisie
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30
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Affiliation(s)
- Alain Philippon
- Service de Bactériologie, Université Paris V-Hôpital Cochin, Paris, France
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31
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Queenan AM, Jenkins S, Bush K. Cloning and biochemical characterization of FOX-5, an AmpC-type plasmid-encoded beta-lactamase from a New York City Klebsiella pneumoniae clinical isolate. Antimicrob Agents Chemother 2001; 45:3189-94. [PMID: 11600376 PMCID: PMC90802 DOI: 10.1128/aac.45.11.3189-3194.2001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Klebsiella pneumoniae 5064, isolated in New York, carried plasmid-mediated resistance to multiple beta-lactams and was unresponsive to clavulanic acid. The beta-lactamase gene responsible for cephalosporin resistance encoded FOX-5, with 96 to 97% amino acid identities to other members of the FOX family of beta-lactamases. The bla(FOX-5) coding region was located next to a transposase gene from the Aeromonas salmonicida insertion element ISAS2.
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Affiliation(s)
- A M Queenan
- The R.W. Johnson Pharmaceutical Research Institute, Raritan, New Jersey 08869, USA.
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32
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Leflon-Guibout V, Speldooren V, Heym B, Nicolas-Chanoine M. Epidemiological survey of amoxicillin-clavulanate resistance and corresponding molecular mechanisms in Escherichia coli isolates in France: new genetic features of bla(TEM) genes. Antimicrob Agents Chemother 2000; 44:2709-14. [PMID: 10991849 PMCID: PMC90140 DOI: 10.1128/aac.44.10.2709-2714.2000] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Amoxicillin-clavulanate resistance (MIC >16 microg/ml) and the corresponding molecular mechanisms were prospectively studied in Escherichia coli over a 3-year period (1996 to 1998) in 14 French hospitals. The overall frequency of resistant E. coli isolates remained stable at about 5% over this period. The highest frequency of resistant isolates (10 to 15%) was observed, independently of the year, among E. coli isolated from lower respiratory tract samples, and the isolation rate of resistant strains was significantly higher in surgical wards than in medical wards in 1998 (7.8 versus 2.8%). The two most frequent mechanisms of resistance for the 3 years were the hyperproduction of the chromosomal class C beta-lactamase (48, 38.4, and 39.7%) and the production of inhibitor-resistant TEM (IRT) enzymes (30.4, 37.2, and 41.2%). By using the single-strand conformational polymorphism-PCR technique and sequencing methods, we determined that 59 IRT enzymes corresponded to previously described IRT enzymes whereas 8 were new. Three of these new enzymes derived from TEM-1 by only one amino acid substitution (Ser130Gly, Arg244Gly, and Asn276Asp), whereas three others derived by two amino acid substitutions (Met69Leu and Arg244Ser, Met69Leu and Ile127Val, and Met69Val and Arg275Gln). The two remaining new IRTs showed three amino acid substitutions (Met69Val, Trp165Arg, and Asn276Asp and Met69Ile, Trp165Cys, and Arg275Gln). New genetic features were also found in bla(TEM) genes, namely, bla(TEM-1B) with either the promoters Pa and Pb, P4, or a promoter displaying a C-->G transversion at position 3 of the -35 consensus sequence and new bla(TEM) genes, notably one encoding TEM-1 but possessing the silent mutations originally described in bla(TEM-2) and then in some bla(TEM)-encoding IRT enzymes.
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Affiliation(s)
- V Leflon-Guibout
- Microbiology Department, Hôpital Ambroise-Paré, Université Paris V, 92100 Boulogne-Billancourt, France
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33
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Bou G, Oliver A, Ojeda M, Monzón C, Martínez-Beltrán J. Molecular characterization of FOX-4, a new AmpC-type plasmid-mediated beta-lactamase from an Escherichia coli strain isolated in Spain. Antimicrob Agents Chemother 2000; 44:2549-53. [PMID: 10952615 PMCID: PMC90105 DOI: 10.1128/aac.44.9.2549-2553.2000] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A clinical strain of Escherichia coli (Ec GCE) displayed resistance to cefoxitin, cefotetan, cefotaxime, and ceftazidime. Susceptibility was not restored by the addition of clavulanic acid. Two beta-lactamases with apparent pIs of 5.4 and 6.4 were identified; the beta-lactamase with a pI of 6.4 was transferred by conjugation and associated with a 40-kb plasmid. Analysis of the nucleotide sequence showed a new ampC beta-lactamase gene that is closely related to those encoding the FOX-3, FOX-2, and FOX-1 beta-lactamases but whose product has four novel amino acid mutations, at positions 11 (M-->T), 43 (A-->E), 233 (V-->A), and 280 (Y-->H). This first cephamycinase from Spain was named FOX-4.
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Affiliation(s)
- G Bou
- Servicio de Microbiología, Hospital Ramón y Cajal, Madrid, Spain
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34
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Coudron PE, Moland ES, Thomson KS. Occurrence and detection of AmpC beta-lactamases among Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis isolates at a veterans medical center. J Clin Microbiol 2000; 38:1791-6. [PMID: 10790101 PMCID: PMC86590 DOI: 10.1128/jcm.38.5.1791-1796.2000] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/1999] [Accepted: 02/18/2000] [Indexed: 11/20/2022] Open
Abstract
AmpC beta-lactamases are cephalosporinases that confer resistance to a wide variety of beta-lactam drugs and that may thereby create serious therapeutic problems. Although reported with increasing frequency, the true rate of occurrence of AmpC beta-lactamases in Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis remains unknown. We tested a total of 1,286 consecutive, nonrepeat isolates of these three species and found that, overall, 45 (3.5%) yielded a cefoxitin zone diameter less than 18 mm (screen positive) and that 16 (1.2%) demonstrated AmpC bands by isoelectric focusing. Based on the species, of 683 E. coli, 371 K. pneumoniae, and 232 P. mirabilis isolates tested, 13 (1.9%), 28 (7.6%), and 4 (1.7%), respectively, demonstrated decreased zone diameters and 11 (1.6%), 4 (1.1%), and 1 (0.4%), respectively, demonstrated AmpC bands. Cefoxitin resistance was transferred for all but 8 (E. coli) of the 16 AmpC producers. We also describe a three-dimensional extract test, which was used to detect phenotypically isolates that harbor AmpC beta-lactamase. Of the 45 cefoxitin-resistant isolates, the three-dimensional extract test accurately identified all 16 AmpC producers and 28 of 29 (97%) isolates as non-AmpC producers. Interestingly, most (86%) isolates in the latter group were K. pneumoniae isolates. These data confirm that, at our institution, E. coli, K. pneumoniae, and P. mirabilis harbor plasmid-mediated AmpC enzymes.
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Affiliation(s)
- P E Coudron
- Pathology and Laboratory Medicine Service/113, McGuire Veterans Affairs Medical Center, Richmond, Virginia 23249-0001, USA.
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35
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Tavío Pérez MM, Amicosante G, Franceschini N, Vila J, Ruiz J, Oratore A, Martín-Sánchez AM, Jiménez de Anta MT. Decreased production of AmpC-type beta-lactamases associated with the development of resistance to quinolones in Citrobacter freundii strains. Microb Drug Resist 2000; 5:235-40. [PMID: 10647079 DOI: 10.1089/mdr.1999.5.235] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The effect of fluoroquinolones in Citrobacter freundii strains that results in a decreased expression of cephalosporin-hydrolysing beta-lactamases was studied. Resistance to broad-spectrum cephalosporins and penicillins in two C. freundii clinical isolates was associated with moderate production of chromosomal AmpC-type-beta-lactamase in addition to changes in the outer membrane proteins profile with respect to wild-type C. freundii strains. Ten quinolone-resistant mutants were derived from the two clinical isolates using increasing fluoroquinolone concentrations. The level of susceptibility to cephalosporins and meropenem of these 10 mutants was increased and was associated with a 3.6-32% diminution in the hydrolyzing activity of their periplasmic extracts containing beta-lactamases on cephaloridine as compared with those from their parent strains. Susceptibility to cephalosporins and meropenem, as well as the expression of chromosomal AmpC-type-beta-lactamase in C. freundii strains, was influenced by the exposure to quinolones.
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Affiliation(s)
- M M Tavío Pérez
- Department of Clinical Sciences, School of Medicine, University of Las Palmas de G.C., Spain
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36
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Bou G, Martínez-Beltrán J. Cloning, nucleotide sequencing, and analysis of the gene encoding an AmpC beta-lactamase in Acinetobacter baumannii. Antimicrob Agents Chemother 2000; 44:428-32. [PMID: 10639377 PMCID: PMC89698 DOI: 10.1128/aac.44.2.428-432.2000] [Citation(s) in RCA: 140] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A clinical strain of Acinetobacter baumannii (strain Ab RYC 52763/97) that was isolated during an outbreak in our hospital and that was resistant to all beta-lactam antibiotics tested produced three beta-lactamases: a TEM-1-type (pI, 5.4) plasmid-mediated beta-lactamase, a chromosomally mediated OXA-derived (pI, 9.0) beta-lactamase, and a presumptive chromosomal cephalosporinase (pI, 9.4). The nucleotide sequence of the chromosomal cephalosporinase gene shows for the first time the gene encoding an AmpC beta-lactamase in A. baumannii. In addition, we report here the biochemical properties of this A. baumannii AmpC beta-lactamase.
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Affiliation(s)
- G Bou
- Servicio de Microbiología, Hospital Ramón y Cajal, 28034 Madrid, Spain.
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37
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Bauernfeind A, Schneider I, Jungwirth R, Sahly H, Ullmann U. A novel type of AmpC beta-lactamase, ACC-1, produced by a Klebsiella pneumoniae strain causing nosocomial pneumonia. Antimicrob Agents Chemother 1999; 43:1924-31. [PMID: 10428914 PMCID: PMC89392 DOI: 10.1128/aac.43.8.1924] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
A Klebsiella pneumoniae strain resistant to oxyimino cephalosporins was cultured from respiratory secretions of a patient suffering from nosocomial pneumonia in Kiel, Germany, in 1997. The isolate harbors a bla resistance gene located on a transmissible plasmid. An Escherichia coli transconjugant produces a beta-lactamase with an isoelectric point of 7.7 and a resistance phenotype characteristic of an AmpC (class 1) beta-lactamase except for low MICs of cephamycins. The bla gene was cloned and sequenced. It encodes a protein of 386 amino acids with the active site serine of the S-X-X-K motif at position 64, as is characteristic for class C beta-lactamases. Multiple alignment of the deduced amino acid sequence with 21 other AmpC beta-lactamases demonstrates only very distant homology, reaching at maximum 52.3% identity for the chromosomal AmpC beta-lactamase of Serratia marcescens SR50. The beta-lactamase of K. pneumoniae KUS represents a new type of AmpC-class enzyme, for which we propose the designation ACC-1 (Ambler class C-1).
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Affiliation(s)
- A Bauernfeind
- Max von Pettenkofer Institute, Munich, Federal Republic of Germany.
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38
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Abstract
Nosocomial infections (NIs) are among the most difficult problems confronting clinicians who deal with severely ill patients. The incidence of these hospital-acquired infections varies with the size of hospitals, with specialities of wards, and with many other factors such as length of hospital stay, local trends in antibiotic usage, nursing and hygiene conditions, hospital design and geographical distribution of patients at risk. An average incidence of NI can be estimated at 5 to 10%, with higher rates in large university hospitals, reaching up to 28% in the intensive care unit (ICU). Changing epidemiology of NI and emerging resistance problems have resulted in evolving strategies of antibiotic usage in patients at risk. Several recent antibiotic resistance problems have been identified, for instance in Gram-positive organisms, and have been surveyed, in addition to those previously well known in Gram-negative bacilli. The choice of empiric antibiotic therapy for the treatment of any NI before microbiology is available has become a difficult challenge, requiring: (i) surveillance data on a regular basis of predominant organisms in units at risk; (ii) surveillance of the current resistance patterns of these organisms; (iii) identification of outbreaks involving the prevalent organisms, using modern molecular techniques for typing the strain and assess cross-contamination. In documented infection, monotherapy vs combination therapy has been often discussed in the treatment of serious Gram-negative hospital infections, but these concepts vary with the site of infection, the nature of organism involved and its pattern of resistance, the kind of antibiotic which may more or less quickly select resistant mutants. Antibiotic therapy concepts vary significantly between countries, and combinations either empirical or based on laboratory data are often preferred in European countries than in the US. Frequent collaborative studies and an increasing communication between experts of different countries, make guidelines and consensus conferences, established in a particular country, useful elsewhere and may contribute to improvement in the management of NI. Guidelines for the prevention and the control of NI are well established in many developed countries and they may have resulted in the improvement of the prevention and the treatment of NI. However, there is still potential progress that should be made, including individual preventive practices, improvement in nursing practices, control of antibiotic use, trend to shorten the hospital stay and early discharge from hospital, which results in significant cost savings.
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Trépanier S, Knox JR, Clairoux N, Sanschagrin F, Levesque RC, Huletsky A. Structure-function studies of Ser-289 in the class C beta-lactamase from Enterobacter cloacae P99. Antimicrob Agents Chemother 1999; 43:543-8. [PMID: 10049265 PMCID: PMC89158 DOI: 10.1128/aac.43.3.543] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Site-directed mutagenesis of Ser-289 of the class C beta-lactamase from Enterobacter cloacae P99 was performed to investigate the role of this residue in beta-lactam hydrolysis. This amino acid lies near the active site of the enzyme, where it can interact with the C-3 substituent of cephalosporins. Kinetic analysis of six mutant beta-lactamases with five cephalosporins showed that Ser-289 can be substituted by amino acids with nonpolar or polar uncharged side chains without altering the catalytic efficiency of the enzyme. These data suggest that Ser-289 is not essential in the binding or hydrolytic mechanism of AmpC beta-lactamase. However, replacement by Lys or Arg decreased by two- to threefold the kcat of four of the five beta-lactams tested, particularly cefoperazone, cephaloridine, and cephalothin. Three-dimensional models of the mutant beta-lactamases revealed that the length and positive charge of the side chain of Lys and Arg could create an electrostatic linkage to the C-4 carboxylic acid group of the dihydrothiazine ring of the acyl intermediate which could slow the deacylation step or hinder release of the product.
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Affiliation(s)
- S Trépanier
- Département de Biologie Médicale, Pavillon Marchand, Université Laval, Ste-Foy, Québec, Canada
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40
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Verdet C, Arlet G, Ben Redjeb S, Ben Hassen A, Lagrange PH, Philippon A. Characterisation of CMY-4, an AmpC-type plasmid-mediated beta-lactamase in a Tunisian clinical isolate of Proteus mirabilis. FEMS Microbiol Lett 1998; 169:235-40. [PMID: 9868767 DOI: 10.1111/j.1574-6968.1998.tb13323.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
A strain of Proteus mirabilis resistant to beta-lactams, including cefoxitin, was isolated from the urine of a woman from Tunisia. Its antibiotic susceptibility pattern and that of the Escherichia coli transconjugant suggested the presence of an AmpC-type beta-lactamase. Two bands of beta-lactamase activity (pI 5.4 and 9.2) were detected by isoelectric focusing. The nucleotide sequence of the gene encoding the AmpC-type enzyme was determined. The deduced amino acid sequence was 98-99% identical to CMY-3 and to those of the plasmid-mediated AmpC-type beta-lactamases originated from Citrobacter freundii and 97% identical to the chromosome-encoded beta-lactamase of a Tunisian clinical isolate of C. freundii. This enzyme differs from CMY-2 by one substitution (Arg for Trp at position 221) and from CMY-3 by two substitutions (Glu for Gly at position 42 and Ser for Asn at position 363) and we propose the denomination CMY-4.
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Affiliation(s)
- C Verdet
- Service de Microbiologie, Université Paris VII Denis Diderot, Hôpital Saint-Louis, France
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41
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42
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Bush K, Miller GH. Bacterial enzymatic resistance: beta-lactamases and aminoglycoside-modifying enzymes. Curr Opin Microbiol 1998; 1:509-15. [PMID: 10066532 DOI: 10.1016/s1369-5274(98)80082-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Numerous novel beta-lactamases and aminoglycoside-modifying enzymes with altered substrate profiles continue to be identified. Plasmid-mediated transmission of many of these enzymes readily occurs due to inclusion of the encoding genes in mobile gene cassettes. Recent crystallographic determinations of the structures of metallo-beta-lactamases and aminoglycoside-modifying enzymes provide the opportunity for the rational design of inhibitors.
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Affiliation(s)
- K Bush
- RW Johnson Pharmaceutical Research Institute, 1000 Route 202, Raritan NJ 08869, USA.
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43
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Barnaud G, Arlet G, Verdet C, Gaillot O, Lagrange PH, Philippon A. Salmonella enteritidis: AmpC plasmid-mediated inducible beta-lactamase (DHA-1) with an ampR gene from Morganella morganii. Antimicrob Agents Chemother 1998; 42:2352-8. [PMID: 9736562 PMCID: PMC105832 DOI: 10.1128/aac.42.9.2352] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
DHA-1, a plasmid-mediated cephalosporinase from a single clinical Salmonella enteritidis isolate, conferred resistance to oxyimino-cephalosporins (cefotaxime and ceftazidime) and cephamycins (cefoxitin and moxalactam), and this resistance was transferable to Escherichia coli HB101. An antagonism was observed between cefoxitin and aztreonam by the diffusion method. Transformation of the transconjugant E. coli strain with plasmid pNH5 carrying the ampD gene (whose product decreases the level of expression of ampC) resulted in an eightfold decrease in the MIC of cefoxitin. A clone with the same AmpC susceptibility pattern with antagonism was obtained, clone E. coli JM101(pSAL2-ind), and its nucleotide sequence was determined. It contained an open reading frame with 98. 7% DNA sequence identity with the ampC gene of Morganella morganii. DNA sequence analysis also identified a gene upstream of ampC whose sequence was 97% identical to the partial sequence of the ampR gene (435 bp) from M. morganii. The gene encoded a protein with an amino-terminal DNA-binding domain typical of transcriptional activators of the LysR family. Moreover, the intercistronic region between the ampC and ampR genes was 98% identical to the corresponding region from M. morganii DNA. AmpR was shown to be functional by enzyme induction and a gel mobility-shift assay. An ampG gene was also detected in a Southern blot of DNA from the S. enteritidis isolate. These findings suggest that this inducible plasmid-mediated AmpC type beta-lactamase, DHA-1, probably originated from M. morganii.
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Affiliation(s)
- G Barnaud
- Service de Microbiologie, Hôpital Saint-Louis, Paris, France
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44
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Bauernfeind A, Hohl P, Schneider I, Jungwirth R, Frei R. Escherichia coli producing a cephamycinase (CMY-2) from a patient from the Libyan---Tunisian border region. Clin Microbiol Infect 1998; 4:168-170. [PMID: 11864315 DOI: 10.1111/j.1469-0691.1998.tb00384.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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45
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Marchese A, Arlet G, Schito GC, Lagrange PH, Philippon A. Characterization of FOX-3, an AmpC-type plasmid-mediated beta-lactamase from an Italian isolate of Klebsiella oxytoca. Antimicrob Agents Chemother 1998; 42:464-7. [PMID: 9527810 PMCID: PMC105438 DOI: 10.1128/aac.42.2.464] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Klebsiella oxytoca 1731, which showed a wide spectrum of resistance to beta-lactams, including cefoxitin, was isolated in 1994 from a patient in Genoa, Italy. This strain contained a plasmid-mediated AmpC beta-lactamase with a pI of 7.25. Sequencing of the corresponding DNA of K. oxytoca 1731 revealed 96 and 97% identities of the deduced amino acid sequence with FOX-1 and FOX-2, respectively.
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