1
|
Zhou Q, Tang M, Zhang X, Lu J, Tang X, Gao Y. Detection of AmpC β-lactamases in gram-negative bacteria. Heliyon 2022; 8:e12245. [PMID: 36582676 PMCID: PMC9793173 DOI: 10.1016/j.heliyon.2022.e12245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 07/12/2022] [Accepted: 12/01/2022] [Indexed: 12/14/2022] Open
Abstract
AmpC β-lactamase genes are clinically important because they often confer resistance to most β-lactams other than 4th-generation cephalosporins and carbapenems. However, traditional and existing detection methods are expensive, labor-intensive and range-limited. We established an efficient multiplex PCR method to simultaneously identify six families of ampC β-lactamase genes, ACC, EBC, CIT, DHA, MOX and FOX, and evaluated the sensitivity and specificity of this assay. The multiplex method could accurately identify ACC, EBC, CIT, DHA, MOX and FOX variants among a total of 175 ampC β-lactamase genes. The minimum concentration of genomic DNA that could be detected was 1.0×103 copies/μL. We subsequently used this method to analyze 2 Salmonella spp. with carrying CMY-2 and DHA-1, and 167 Enterobacteriaceae isolates in blinded PCR testing. Positive isolates produced bright bands that corresponded with their genotype. Results were in concordance with those of the traditional method but showed increased sensitivity and accuracy. This indicates that the newly developed multiplex PCR system could be used as a diagnostic tool to accurately distinguish the six families of ampC β-lactamase genes with high efficiency, wide range, easy operation and good discrimination.
Collapse
|
2
|
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.
Collapse
|
3
|
Russ D, Glaser F, Shaer Tamar E, Yelin I, Baym M, Kelsic ED, Zampaloni C, Haldimann A, Kishony R. Escape mutations circumvent a tradeoff between resistance to a beta-lactam and resistance to a beta-lactamase inhibitor. Nat Commun 2020; 11:2029. [PMID: 32332717 PMCID: PMC7181632 DOI: 10.1038/s41467-020-15666-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Accepted: 03/13/2020] [Indexed: 11/09/2022] Open
Abstract
Beta-lactamase inhibitors are increasingly used to counteract antibiotic resistance mediated by beta-lactamase enzymes. These inhibitors compete with the beta-lactam antibiotic for the same binding site on the beta-lactamase, thus generating an evolutionary tradeoff: mutations that increase the enzyme's beta-lactamase activity tend to increase also its susceptibility to the inhibitor. Here, we investigate how common and accessible are mutants that escape this adaptive tradeoff. Screening a deep mutant library of the blaampC beta-lactamase gene of Escherichia coli, we identified mutations that allow growth at beta-lactam concentrations far exceeding those inhibiting growth of the wildtype strain, even in the presence of the enzyme inhibitor (avibactam). These escape mutations are rare and drug-specific, and some combinations of avibactam with beta-lactam drugs appear to prevent such escape phenotypes. Our results, showing differential adaptive potential of blaampC to combinations of avibactam and different beta-lactam antibiotics, suggest that it may be possible to identify treatments that are more resilient to evolution of resistance.
Collapse
Affiliation(s)
- Dor Russ
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Fabian Glaser
- Lorry I. Lokey Interdisciplinary Center for Life Sciences and Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Einat Shaer Tamar
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Idan Yelin
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Michael Baym
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA
| | - Eric D Kelsic
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Claudia Zampaloni
- Roche Pharma Research and Early Development, Immunology, Infectious Diseases, and Ophthalmology, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Andreas Haldimann
- Roche Pharma Research and Early Development, Immunology, Infectious Diseases, and Ophthalmology, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Roy Kishony
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel. .,Faculty of Computer Science, Technion-Israel Institute of Technology, Haifa, Israel.
| |
Collapse
|
4
|
Arakawa Y. Systematic research to overcome newly emerged multidrug-resistant bacteria. Microbiol Immunol 2020; 64:231-251. [PMID: 32068266 DOI: 10.1111/1348-0421.12781] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 01/05/2020] [Accepted: 02/08/2020] [Indexed: 11/30/2022]
Abstract
In the 1980s, I found that the chromosomal β-lactamase of Klebsiella pneumoniae LEN-1 showed a very high similarity to the R-plasmid-mediated penicillinase TEM-1 on the amino acid sequence level, and this strongly suggested the origination of TEM-1 from the chromosomal penicillinases of K. pneumoniae or related bacteria. Moreover, the chromosomal K1 β-lactamase (KOXY) of Klebsiella oxytoca was found to belong to the class A β-lactamases that include LEN-1 and TEM-1, although KOXY can hydrolyze cefoperazone (CPZ) like the chromosomal AmpC-type cephalosporinases of various Enterobacteriaceae that can hydrolyze several cephalosporins including CPZ. Furthermore, my collaborators and I found plural novel serine-type β-lactamases, such as MOX-1, SHV-24, TEM-91, CTX-M-64, CMY-9, CMY-19, GES-3, GES-4, and TLA-3, mediated by plasmids. Besides these serine-type β-lactamases, we also first identified exogenously acquired metallo-β-lactamases (MBLs), IMP-1 and SMB-1, in imipenem-resistant Serratia marcescens, and the IMP-1-producing S. marcescens TN9106 became the index case for carbapenemase-producing Enterobacteriaceae. I developed the sodium mercaptoacetic acid (SMA)-disk test for the simple identification of MBL-producing bacteria. We were also the first to identify a variety of plasmid-mediated 16S ribosomal RNA methyltransferases, RmtA, RmtB, RmtC, and NpmA, from various Gram-negative bacteria that showed very high levels of resistance to a wide range of aminoglycosides. Furthermore, we first found plasmid-mediated quinolone efflux pump (QepA) and fosfomycin-inactivating enzymes (FosA3 and FosK). We also first characterized penicillin reduced susceptible Streptococcus agalactiae, macrolide-resistant Mycoplasma pneumoniae, as well as Campylobacter jejuni, and Helicobacter pylori, together with carbapenem-resistant Haemophilus influenzae. We constructed a PCR-based open reading frame typing method for rapid identification of Acinetobacter baumannii international clones.
Collapse
Affiliation(s)
- Yoshichika Arakawa
- Department of Bacteriology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| |
Collapse
|
5
|
Sawa T, Kooguchi K, Moriyama K. Molecular diversity of extended-spectrum β-lactamases and carbapenemases, and antimicrobial resistance. J Intensive Care 2020; 8:13. [PMID: 32015881 PMCID: PMC6988205 DOI: 10.1186/s40560-020-0429-6] [Citation(s) in RCA: 103] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 01/13/2020] [Indexed: 12/16/2022] Open
Abstract
Along with the recent spread of multidrug-resistant bacteria, outbreaks of extended-spectrum β-lactamase (ESBL) and carbapenemase-producing bacteria present a serious challenge to clinicians. β-lactam antibiotics are the most frequently used antibacterial agents and ESBLs, and carbapenemases confer resistance not only to carbapenem antibiotics but also to penicillin and cephem antibiotics. The mechanism of β-lactam resistance involves an efflux pump, reduced permeability, altered transpeptidases, and inactivation by β-lactamases. Horizontal gene transfer is the most common mechanism associated with the spread of extended-spectrum β-lactam- and carbapenem resistance among pathogenic bacterial species. Along with the increase in antimicrobial resistance, many different types of ESBLs and carbapenemases have emerged with different enzymatic characteristics. For example, carbapenemases are represented across classes A to D of the Ambler classification system. Because bacteria harboring different types of ESBLs and carbapenemases require specific therapeutic strategies, it is essential for clinicians to understand the characteristics of infecting pathogens. In this review, we summarize the current knowledge on carbapenem resistance by ESBLs and carbapenemases, such as class A carbapenemases, class C extended-spectrum AmpC (ESAC), carbapenem-hydrolyzing class D β-lactamases (CHDLs), and class B metallo-β-lactamases, with the aim of aiding critical care clinicians in their therapeutic decision making.
Collapse
Affiliation(s)
- Teiji Sawa
- 1Department of Anesthesiology, School of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo, Kyoto, 602-8566 Japan
| | - Kunihiko Kooguchi
- 2Department of Intensive Care, Kyoto City Hospital, 1-2 Higashitakada-cho, Mibu, Nakagyo, Kyoto, 604-8845 Japan
| | - Kiyoshi Moriyama
- 3Department of Anesthesiology, School of Medicine, Kyorin University, 6-20-2 Shinkawa, Mitaka, Tokyo 181-8611 Japan
| |
Collapse
|
6
|
San N, Aung MS, Urushibara N, San T, Maw WW, Lwin MM, Mar TT, Myint YY, Thu PP, Hlaing MS, Ganesh B, Kobayashi N. Genetic Diversity of CMY Beta-Lactamase Genes in Clinical Isolates of Escherichia coli in Myanmar: Identification of Three Novel Types and Updated Phylogenetic Classification of blaCMY. Microb Drug Resist 2019; 26:497-504. [PMID: 31738628 DOI: 10.1089/mdr.2019.0234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The dissemination of CMY-type enzymes, one of the plasmid-mediated AmpC beta-lactamases, among Enterobacteriaceae has become an important public health concern. In this study, genetic diversity of CMY beta-lactamase genes was investigated for 50 blaCMY-positive isolates detected from 426 clinical isolates of Escherichia coli in Yangon, Myanmar. CMY genes were differentiated into 9 types, with blaCMY-42 being predominant (22 isolates, 44%), followed by blaCMY-2, blaCMY-6, blaCMY-146, and included three novel types (CMY-156, CMY-158, CMY-159). Among E. coli harboring blaCMY, phylogenetic group D-sequence type (ST)405 and A-ST410 were the most common genotypes, and blaCTX-M-15 was detected in 72% (36/50) of isolates. blaCMY-42 was distributed to phylogenetic groups A, B1, and D E. coli with 11 STs, which included 10 isolates harboring carbapenemase genes (blaNDM-4, blaNDM-5, or blaNDM-7). Phylogenetic analysis of all the blaCMY genes reported to date, including the three novel types in the present study, revealed the presence of at least four distinct genetic groups, that is, CMY-1, CMY-2, CMY-70, and CMY-98 group, showing less than 91% nucleotide sequence identities among different groups. CMY-2 group beta-lactamase genes, which contained by far the largest number of CMY types (89.7%) with extensive diversity, were divided into two clusters (I and II). While eight CMY types identified in the present study were classified into CMY-2 group cluster I, novel type CMY-159 was assigned into CMY-98 group with a Citrobacter freundii strain in Thailand.
Collapse
Affiliation(s)
- Nilar San
- Department of Microbiology, University of Medicine 2, Yangon, Myanmar
| | - Meiji Soe Aung
- Department of Hygiene, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Noriko Urushibara
- Department of Hygiene, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Thida San
- Yangon Children's Hospital, Ministry of Health and Sports, Yangon, Myanmar
| | - Win Win Maw
- Department of Microbiology, University of Medicine 2, Yangon, Myanmar
| | - Mya Mya Lwin
- Department of Microbiology, University of Medicine 2, Yangon, Myanmar
| | - Thin Thin Mar
- Department of Microbiology, University of Medicine 2, Yangon, Myanmar
| | - Yi Yi Myint
- Department of Microbiology, University of Medicine 2, Yangon, Myanmar
| | - Pyae Phyo Thu
- Department of Microbiology, University of Medicine 2, Yangon, Myanmar
| | - Myat Su Hlaing
- Department of Microbiology, University of Medicine 2, Yangon, Myanmar
| | | | - Nobumichi Kobayashi
- Department of Hygiene, Sapporo Medical University School of Medicine, Sapporo, Japan
| |
Collapse
|
7
|
Schutzius G, Nguyen M, Navab-Daneshmand T. Antibiotic resistance in fecal sludge and soil in Ho Chi Minh City, Vietnam. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:34521-34530. [PMID: 31643014 DOI: 10.1007/s11356-019-06537-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 09/13/2019] [Indexed: 06/10/2023]
Abstract
This study investigated the prevalence of antibiotic-resistant bacteria and genes in fecal sludge and soil in Ho Chi Minh City, Vietnam, and identified the factors contributing to the survival of antibiotic-resistant bacteria in soil. Sludge and soil samples (n = 24 and 55, respectively) were collected from residential septic systems and environmental reservoirs (i.e., canals, rivers, and parks) in twelve districts of Ho Chi Minh City and tested against a library of 12 antibiotic-resistant genes and 1 integron gene. The susceptibility of isolated Escherichia coli from sludge and soil (n = 104 and 129, respectively) was tested against nine antibiotics. Over 60% of sludge and soil samples harbored sul1, ere(A), intI1, cmIA, and tet(A) genes. The three most common phenotypic resistances found in E. coli isolated from sludge and soil were to ampicillin, tetracycline, and sulfamethoxazole/trimethoprim. In a temporal microcosm study of antibiotic-susceptible and multi-drug-resistant E. coli inoculated in soil, temperature (21.4 vs. 30 °C), resistance phenotype, and soil background microbial community were associated with E. coli decay rates over 73 days. This is the first study that provides insights into the high prevalence of antibiotic resistance in septic systems and environmental reservoirs in Ho Chi Minh City, Vietnam. Findings highlight that the fecal sludge and soil environments in Vietnam are likely reservoirs for dissemination of and human exposure to antibiotic resistance.
Collapse
Affiliation(s)
- Genevieve Schutzius
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, 105 SW 26th St, 116 Johnson Hall, Corvallis, OR, 97331, USA
| | - Mi Nguyen
- Nguyen Tat Thanh Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam
| | - Tala Navab-Daneshmand
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, 105 SW 26th St, 116 Johnson Hall, Corvallis, OR, 97331, USA.
| |
Collapse
|
8
|
Guiral E, Pons MJ, Vubil D, Marí-Almirall M, Sigaúque B, Soto SM, Alonso PL, Ruiz J, Vila J, Mandomando I. Epidemiology and molecular characterization of multidrug-resistant Escherichia coli isolates harboring blaCTX-M group 1 extended-spectrum β-lactamases causing bacteremia and urinary tract infection in Manhiça, Mozambique. Infect Drug Resist 2018; 11:927-936. [PMID: 30013375 PMCID: PMC6037150 DOI: 10.2147/idr.s153601] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Background The emergence and spread of extended-spectrum β-lactamases (ESBLs), especially CTX-M, is an important public health problem with serious implications for low-income countries where second-line treatment is often unavailable. Knowledge of the local prevalence of ESBL is critical to define appropriate empirical therapeutic strategies for multidrug-resistant (MDR) organisms. This study aimed to assess and characterize the presence of ESBL and especially CTX-M-producing Escherichia coli MDR isolates from patients with urinary tract infections (UTIs) and bacteremia in a rural hospital in Mozambique. Materials and methods One hundred and fifty-one E. coli isolates from bacteremia and UTI in children were screened for CTX-M, TEM, SHV and OXA β-lactamases by polymerase chain reaction and sequencing. Isolates carrying CTX-M group 1 β-lactamases were further studied. The resistance to other antibiotic families was determined by phenotypic and genotypic methods, the location of the blaCTX-M gene and the epidemiology of the isolates were studied, and extensive plasmid characterization was performed. Results Approximately 11% (17/151) of E. coli isolates causing bacteremia and UTI were ESBL producers. CTX-M-15 was the most frequently detected ESBL, accounting for 75% of the total isolates characterized. The blaCTX-M gene is located in different plasmids belonging to different incompatibility groups and can be found in non-epidemiologically related isolates, indicating the high capacity of this resistance determinant to spread widely. Conclusion Our data suggest the presence of a co-selection of third-generation cephalosporin-resistant determinants in the study area despite limited access to these antibiotics. This highlights the importance of continuous surveillance of antimicrobial resistance of both genetic elements of resistance and resistant isolates in order to monitor the emergence and trends of ESBL-producing isolates to promote adequate therapeutic strategies for the management of MDR bacterial infections.
Collapse
Affiliation(s)
- Elisabet Guiral
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - Maria Jesús Pons
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - Delfino Vubil
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique,
| | - Marta Marí-Almirall
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - Betuel Sigaúque
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique, .,Instituto Nacional de Saúde (INS), Ministério da Saúde, Maputo, Mozambique,
| | - Sara Maria Soto
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - Pedro Luís Alonso
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique,
| | - Joaquim Ruiz
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - Jordi Vila
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.,Microbiology Department, Hospital Clínic, School of Medicine, University of Barcelona, Barcelona, Spain
| | - Inácio Mandomando
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique, .,Instituto Nacional de Saúde (INS), Ministério da Saúde, Maputo, Mozambique,
| |
Collapse
|
9
|
In Vivo Evolution of CMY-2 to CMY-33 β-Lactamase in Escherichia coli Sequence Type 131: Characterization of an Acquired Extended-Spectrum AmpC Conferring Resistance to Cefepime. Antimicrob Agents Chemother 2015; 59:7483-8. [PMID: 26392491 DOI: 10.1128/aac.01804-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Accepted: 09/13/2015] [Indexed: 11/20/2022] Open
Abstract
Cefepime is frequently prescribed to treat infections caused by AmpC-producing Gram-negative bacteria. CMY-2 is the most common plasmid-mediated AmpC (pAmpC) β-lactamase. Unfortunately, CMY variants conferring enhanced cefepime resistance have been reported. Here, we describe the evolution of CMY-2 to an extended-spectrum AmpC (ESAC) in clonally identical Escherichia coli isolates obtained from a patient. The CMY-2-producing E. coli isolate (CMY-2-Ec) was isolated from a wound. Thirty days later, one CMY-33-producing E. coli isolate (CMY-33-Ec) was detected in a bronchoalveolar lavage fluid sample. Two weeks before the isolation of CMY-33-Ec, the patient received cefepime. CMY-33-Ec and CMY-2-Ec were identical by repetitive extragenic palindromic-PCR (rep-PCR), being of hyperepidemic sequence type 131 (ST131) but showing different β-lactam MICs (e.g., cefepime MIC, 16 and ≤ 0.5 μg/ml for CMY-33-Ec and CMY-2-Ec, respectively). Identical CMY-2-Ec isolates were also found in a rectal swab. CMY-33 differs from CMY-2 by a Leu293-Ala294 deletion. Expressed in E. coli strain DH10B, both CMYs conferred resistance to ceftazidime (≥ 256 μg/ml), but the cefepime MICs were higher for CMY-33 than CMY-2 (8 versus 0.25 μg/ml, respectively). The kcat/Km or inhibitor complex inactivation (kinact)/Ki app (μM(-1) s(-1)) indicated that CMY-33 possesses an extended-spectrum β-lactamase (ESBL)-like spectrum compared to that of CMY-2 (e.g., cefoxitin, 0.2 versus 0.4; ceftazidime, 0.2 versus not measurable; cefepime, 0.2 versus not measurable; and tazobactam, 0.0018 versus 0.0009, respectively). Using molecular modeling, we show that a widened active site (∼ 4-Å shift) may play a significant role in enhancing cefepime hydrolysis. This is the first in vivo demonstration of a pAmpC that under cephalosporin treatment expands its substrate spectrum, resembling an ESBL. The prevalence of CMY-2-Ec isolates is rapidly increasing worldwide; therefore, awareness that cefepime treatment may select for resistant isolates is critical.
Collapse
|
10
|
Porres-Osante N, Sáenz Y, Somalo S, Torres C. Characterization of Beta-lactamases in Faecal Enterobacteriaceae Recovered from Healthy Humans in Spain: Focusing on AmpC Polymorphisms. MICROBIAL ECOLOGY 2015; 70:132-40. [PMID: 25501887 DOI: 10.1007/s00248-014-0544-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 11/26/2014] [Indexed: 05/21/2023]
Abstract
The intestinal tract is a huge reservoir of Enterobacteriaceae, some of which are opportunist pathogens. Several genera of these bacteria harbour intrinsic antibiotic resistance genes, such as ampC genes in species of Citrobacter, Enterobacter or Escherichia genera. In this work, beta-lactamases and other resistance mechanisms have been characterized in Enterobacteriaceae isolates recovered from healthy human faecal samples, focusing on the ampC beta-lactamase genes. Fifty human faecal samples were obtained, and 70 Enterobacteriaceae bacteria were isolated: 44 Escherichia coli, 4 Citrobacter braakii, 9 Citrobacter freundii, 8 Enterobacter cloacae, 1 Proteus mirabilis, 1 Proteus vulgaris, 1 Klebsiella oxytoca, 1 Serratia sp. and 1 Cronobacter sp. A high percentage of resistance to ampicillin was detected (57%), observing the AmpC phenotype in 22 isolates (31%) and the ESBL phenotype in 3 isolates. AmpC molecular characterization showed high diversity into bla CMY and bla ACT genes from Citrobacter and Enterobacter species, respectively, and the pulsed-field gel electrophoresis (PFGE) analysis demonstrated low clonality among them. The prevalence of people colonized by strains carrying plasmid-mediated ampC genes obtained in this study was 2%. The unique plasmid-mediated bla AmpC identified in this study was the bla CMY-2 gene, detected in an E. coli isolate ascribed to the sequence type ST405 which belonged to phylogenetic group D. The hybridization and conjugation experiments demonstrated that the ISEcp1-bla CMY-2-blc structure was carried by a ~78-kb self-transferable IncK plasmid. This study shows a high polymorphism among beta-lactamase genes in Enterobacteriaceae from healthy people microbiota. Extensive AmpC-carrier studies would provide important information and could allow the anticipation of future global health problems.
Collapse
Affiliation(s)
- Nerea Porres-Osante
- Área de Bioquímica y Biología Molecular, Universidad de La Rioja, Logroño, Spain
| | | | | | | |
Collapse
|
11
|
SMB-1, a novel subclass B3 metallo-beta-lactamase, associated with ISCR1 and a class 1 integron, from a carbapenem-resistant Serratia marcescens clinical isolate. Antimicrob Agents Chemother 2011; 55:5143-9. [PMID: 21876060 DOI: 10.1128/aac.05045-11] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A carbapenem-resistant Serratia marcescens strain, 10mdr148, was identified in a Japanese hospital in 2010. The carbapenem resistance of this strain was attributed to the production of a novel metallo-β-lactamase (MBL), named SMB-1 (Serratia metallo-β-lactamase). SMB-1 possessed a zinc binding motif, H(Q)XHXDH (residues 116 to 121), H196, and H263 and was categorized as a member of subclass B3 MBL. SMB-1 has 75% amino acid identity with the most closely related MBL, AMO1, of uncultured bacterium, recently identified through the metagenomic analysis of apple orchard soil. The introduction of bla(SMB-1) into Escherichia coli conferred resistance to a variety of β-lactam antibiotics, penicillins, cephalosporins, and carbapenems, but not aztreonam, a resistance pattern consistent with those of other MBLs. SMB-1 demonstrated high k(cat) values of >500 s(-1) for carbapenems, resulting in the highest hydrolyzing efficiency (k(cat)/K(m)) among the agents tested. The hydrolyzing activity of SMB-1 was well inhibited by chelating agents. The bla(SMB-1) gene was located on the chromosome of S. marcescens strain 10mdr148 and at the 3' end of the ISCR1 element in complex with a typical class 1 integron carrying aac(6')-Ib and catB3 gene cassettes. Downstream of bla(SMB-1), the second copy of the 3'conserved segment and ISCR1 were found. To our knowledge, this is the first subclass B3 MBL gene associated with an ISCR1 element identified in an Enterobacteriaceae clinical isolate. A variety of antibiotic resistance genes embedded with ISCR1 have been widely spread among Enterobacteriaceae clinical isolates, thus the further dissemination of bla(SMB-1) mediated by ISCR1 transposition activity may become a future concern.
Collapse
|
12
|
Scientific Opinion on the public health risks of bacterial strains producing extended-spectrum β-lactamases and/or AmpC β-lactamases in food and food-producing animals. EFSA J 2011. [DOI: 10.2903/j.efsa.2011.2322] [Citation(s) in RCA: 202] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
|
13
|
Naseer U, Sundsfjord A. The CTX-M Conundrum: Dissemination of Plasmids andEscherichia coliClones. Microb Drug Resist 2011; 17:83-97. [DOI: 10.1089/mdr.2010.0132] [Citation(s) in RCA: 169] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Umaer Naseer
- Research Group for Host-Microbe Interactions, Department of Medical Biology, University of Tromsø, Tromsø, Norway
| | - Arnfinn Sundsfjord
- Research Group for Host-Microbe Interactions, Department of Medical Biology, University of Tromsø, Tromsø, Norway
- Reference Centre for Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| |
Collapse
|
14
|
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.
Collapse
Affiliation(s)
- Yu-lin Zhu
- Department of Infectious Diseases, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Laboratory surveillance for prospective plasmid-mediated AmpC beta-lactamases in the Kinki region of Japan. J Clin Microbiol 2010; 48:3267-73. [PMID: 20610688 DOI: 10.1128/jcm.02111-09] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Extended-spectrum beta-lactamases, plasmid-mediated AmpC beta-lactamases (PABLs), and plasmid-mediated metallo-beta-lactamases confer resistance to many beta-lactams. In Japan, although several reports exist on the prevalence of extended-spectrum beta-lactamases and metallo-beta-lactamases, the prevalence and characteristics of PABLs remain unknown. To investigate the production of PABLs, a total of 22,869 strains of 4 enterobacterial species, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, and Proteus mirabilis, were collected during six 6-month periods from 17 clinical laboratories in the Kinki region of Japan. PABLs were detected in 29 (0.13%) of 22,869 isolates by the 3-dimensional test, PCR analysis, and DNA sequencing analysis. PABL-positive isolates were detected among isolates from 13 laboratories. Seventeen of 13,995 (0.12%) E. coli isolates, 8 of 5,970 (0.13%) K. pneumoniae isolates, 3 of 1,722 (0.17%) K. oxytoca isolates, and 1 of 1,182 (0.08%) P. mirabilis isolates were positive for PABLs. Of these 29 PABL-positive strains, 20 (69.0%), 6 (20.7%), 2 (6.9%), and 1 (3.4%) carried the genes for CMY-2, DHA-1, CMY-8, and MOX-1 PABLs, respectively. Pattern analysis of randomly amplified polymorphic DNA and pulsed-field gel electrophoretic analysis revealed that the prevalence of CMY-2-producing E. coli strains was not due to epidemic strains and that 3 DHA-1-producing K. pneumoniae strains were identical, suggesting their clonal relatedness. In conclusion, the DHA-1 PABLs were predominantly present in K. pneumoniae strains, but CMY-2 PABLs were predominantly present in E. coli strains. The present findings will provide significant information to assist in preventing the emergence and further spread of PABL-producing bacteria.
Collapse
|
16
|
Mallo S, Pérez-Llarena FJ, Kerff F, Soares NC, Galleni M, Bou G. A tripeptide deletion in the R2 loop of the class C beta-lactamase enzyme FOX-4 impairs cefoxitin hydrolysis and slightly increases susceptibility to beta-lactamase inhibitors. J Antimicrob Chemother 2010; 65:1187-94. [PMID: 20382725 DOI: 10.1093/jac/dkq115] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES A natural variant of the AmpC enzyme from Escherichia coli HKY28 with a tripeptide deletion (Gly-286/Ser-287/Asp-288) was recently described. The isolate produced an inhibitor-sensitive AmpC beta-lactamase variant that also conferred higher than usual levels of resistance to ceftazidime in the E. coli host. To demonstrate whether this is true in other class C beta-lactamase enzymes, we deleted the equivalent tripeptide in the FOX-4 plasmid-mediated class C beta-lactamase. METHODS By site-directed mutagenesis, we deleted the tripeptide Gly-306/Asn-307/Ser-308 of FOX-4, thus generating FOX-4(DeltaGNS). The enzymes (FOX-4 wild-type and DeltaGNS) were purified and kinetic parameters (kcat, Km, kcat/Km) as well as IC50 values of several beta-lactams were assessed. Modelling studies were also performed. RESULTS FOX-4(DeltaGNS) did not increase the catalytic efficiency towards ceftazidime, although it conferred a slight increase in the susceptibility to beta-lactamase inhibitors. There was also a noteworthy decrease in the cefoxitin MIC with the FOX-4(DeltaGNS) mutant (from 512 to 16 mg/L) as well as a 10-fold decrease in kcat/Km towards imipenem, which revealed specific structural features. CONCLUSIONS Although deletions in the R2-loop are able to extend the substrate spectrum of class C enzymes, the present results do not confirm this hypothesis in FOX-4. The FOX-4 R2 site would already be wide enough to accommodate antibiotic molecules, and thus any amino acid replacement or deletion at this location would not affect the hydrolytic efficiency towards beta-lactams and would have a less drastic effect on the susceptibility to beta-lactamase inhibitors.
Collapse
Affiliation(s)
- Susana Mallo
- Laboratorio de Microbiología-INIBIC, Complejo Hospitalario Universitario La Coruña, Xubias de Arriba s/n, 15006 La Coruña, Spain
| | | | | | | | | | | |
Collapse
|
17
|
Lin CF, Hsu SK, Chen CH, Huang JR, Lo HH. Genotypic detection and molecular epidemiology of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in a regional hospital in central Taiwan. J Med Microbiol 2010; 59:665-671. [PMID: 20150317 DOI: 10.1099/jmm.0.015818-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
This study was conducted to detect the genes encoding extended-spectrum beta-lactamases (ESBLs) and determine the epidemiological relatedness of 69 Escherichia coli and 33 Klebsiella pneumoniae isolates collected from a regional hospital in central Taiwan, mostly from inpatients (E. coli 87.0%; K. pneumoniae 88.0%). The phenotypes of these isolates were examined according to the combination disc method recommended by the Clinical and Laboratory Standards Institute. Most of the ESBL-producing E. coli and K. pneumoniae isolates (98.6% and 97%, respectively) could be detected using cefotaxime discs with and without clavulanate. Genotyping was performed by PCR with type-specific primers. CTX-M-14 type (53.6%) was the most prevalent ESBL among E. coli isolates while SHV type (57.6%) was the most dominant among K. pneumoniae isolates. Six E. coli and three K. pneumoniae isolates did not carry genes encoding ESBLs of types TEM, SHV, CTX-M-3, CTX-M-14, CMY-2 and DHA-1. The co-existence of two or more kinds of ESBL in a single isolate was common, occurring in 40.6% and 72.7% of E. coli and K. pneumoniae isolates, respectively. PFGE analysis revealed that ESBL producers isolated in this setting were genetically divergent.
Collapse
Affiliation(s)
- Chin-Fu Lin
- Department of Clinical Microbiology Laboratory, Taichung Veterans General Hospital, Taichung, Taiwan, ROC
| | - Shih-Kuang Hsu
- Department of Dental Technology and Materials, Central Taiwan University of Science and Technology, Taichung, Taiwan, ROC
| | - Chao-Hsien Chen
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan, ROC
| | - Jr-Rung Huang
- Department of Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan, ROC
| | - Hsueh-Hsia Lo
- Department of Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan, ROC
| |
Collapse
|
18
|
Abstract
Two classification schemes for beta-lactamases are currently in use. The molecular classification is based on the amino acid sequence and divides beta-lactamases into class A, C, and D enzymes which utilize serine for beta-lactam hydrolysis and class B metalloenzymes which require divalent zinc ions for substrate hydrolysis. The functional classification scheme updated herein is based on the 1995 proposal by Bush et al. (K. Bush, G. A. Jacoby, and A. A. Medeiros, Antimicrob. Agents Chemother. 39:1211-1233, 1995). It takes into account substrate and inhibitor profiles in an attempt to group the enzymes in ways that can be correlated with their phenotype in clinical isolates. Major groupings generally correlate with the more broadly based molecular classification. The updated system includes group 1 (class C) cephalosporinases; group 2 (classes A and D) broad-spectrum, inhibitor-resistant, and extended-spectrum beta-lactamases and serine carbapenemases; and group 3 metallo-beta-lactamases. Several new subgroups of each of the major groups are described, based on specific attributes of individual enzymes. A list of attributes is also suggested for the description of a new beta-lactamase, including the requisite microbiological properties, substrate and inhibitor profiles, and molecular sequence data that provide an adequate characterization for a new beta-lactam-hydrolyzing enzyme.
Collapse
|
19
|
Scientific Advisory Group on Antimi. Reflection paper on the use of third and fourth generation cephalosporins in food producing animals in the European Union: development of resistance and impact on human and animal health. J Vet Pharmacol Ther 2009; 32:515-33. [DOI: 10.1111/j.1365-2885.2009.01075.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
20
|
Wachino JI. [Novel molecular mechanisms of antibiotic resistance found in clinically isolated pathogenic bacteria]. Nihon Saikingaku Zasshi 2009; 64:357-64. [PMID: 19721338 DOI: 10.3412/jsb.64.357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Jun-ichi Wachino
- Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo, Japan
| |
Collapse
|
21
|
Kotsakis SD, Papagiannitsis CC, Tzelepi E, Tzouvelekis LS, Miriagou V. Extended-spectrum properties of CMY-30, a Val211Gly mutant of CMY-2 cephalosporinase. Antimicrob Agents Chemother 2009; 53:3520-3. [PMID: 19470510 PMCID: PMC2715598 DOI: 10.1128/aac.00219-09] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Revised: 05/03/2009] [Accepted: 05/17/2009] [Indexed: 01/25/2023] Open
Abstract
CMY-30, a Val211Gly mutant of CMY-2 cephalosporinase, was derived by mutagenesis. The hydrolytic efficiency of CMY-30 against expanded-spectrum cephalosporins was higher than that of CMY-2 due to increased k(cat) values. Findings indicate a role of the Omega loop residue 211 in determining the substrate specificities of CMYs also corroborated by modeling studies.
Collapse
Affiliation(s)
- Stathis D Kotsakis
- Laboratory of Bacteriology, Hellenic Pasteur Institute, Vas. Sofias 127, Athens 11521, Greece
| | | | | | | | | |
Collapse
|
22
|
|
23
|
Reduced susceptibility to cefepime among Escherichia coli clinical isolates producing novel variants of CMY-2 beta-lactamase. Antimicrob Agents Chemother 2009; 53:3159-61. [PMID: 19414578 DOI: 10.1128/aac.00133-09] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Here we describe three Escherichia coli clinical isolates with reduced susceptibility to cefepime. Sequencing of the bla(CMY) genes revealed two novel variants (CMY-33 and -44) with two- to four-amino-acid deletions in the H-10 helix. The deletions were responsible for 12- to 24-fold increases in the MICs of cefepime.
Collapse
|
24
|
|
25
|
Abstract
SUMMARY AmpC beta-lactamases are clinically important cephalosporinases encoded on the chromosomes of many of the Enterobacteriaceae and a few other organisms, where they mediate resistance to cephalothin, cefazolin, cefoxitin, most penicillins, and beta-lactamase inhibitor-beta-lactam combinations. In many bacteria, AmpC enzymes are inducible and can be expressed at high levels by mutation. Overexpression confers resistance to broad-spectrum cephalosporins including cefotaxime, ceftazidime, and ceftriaxone and is a problem especially in infections due to Enterobacter aerogenes and Enterobacter cloacae, where an isolate initially susceptible to these agents may become resistant upon therapy. Transmissible plasmids have acquired genes for AmpC enzymes, which consequently can now appear in bacteria lacking or poorly expressing a chromosomal bla(AmpC) gene, such as Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis. Resistance due to plasmid-mediated AmpC enzymes is less common than extended-spectrum beta-lactamase production in most parts of the world but may be both harder to detect and broader in spectrum. AmpC enzymes encoded by both chromosomal and plasmid genes are also evolving to hydrolyze broad-spectrum cephalosporins more efficiently. Techniques to identify AmpC beta-lactamase-producing isolates are available but are still evolving and are not yet optimized for the clinical laboratory, which probably now underestimates this resistance mechanism. Carbapenems can usually be used to treat infections due to AmpC-producing bacteria, but carbapenem resistance can arise in some organisms by mutations that reduce influx (outer membrane porin loss) or enhance efflux (efflux pump activation).
Collapse
|
26
|
Cefotaxime and ceftriaxon resistantKlebsiella pneumoniae associated with SHV-11 hyperproduction. ANN MICROBIOL 2008. [DOI: 10.1007/bf03175582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
|
27
|
Harada S, Ishii Y, Yamaguchi K. Extended-spectrum β-Lactamases: Implications for the Clinical Laboratory and Therapy. Ann Lab Med 2008; 28:401-12. [DOI: 10.3343/kjlm.2008.28.6.401] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Sohei Harada
- Department of Microbiology and Infectious Diseases, School of Medicine, Faculty of Medicine, Toho University, Tokyo, Japan
- Division of Infectious Diseases2, The University of Tokyo Hospital, Tokyo, Japan
| | - Yoshikazu Ishii
- Department of Microbiology and Infectious Diseases, School of Medicine, Faculty of Medicine, Toho University, Tokyo, Japan
| | - Keizo Yamaguchi
- Department of Microbiology and Infectious Diseases, School of Medicine, Faculty of Medicine, Toho University, Tokyo, Japan
| |
Collapse
|
28
|
Endimiani A, Perez F, Bonomo RA. Cefepime: a reappraisal in an era of increasing antimicrobial resistance. Expert Rev Anti Infect Ther 2008; 6:805-24. [PMID: 19053894 PMCID: PMC2633657 DOI: 10.1586/14787210.6.6.805] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cefepime is a 'fourth-generation' cephalosporin with an in vitro extended-spectrum of activity against Gram-negative and Gram-positive pathogens. Cefepime is approved for the treatment of moderate-to-severe infections, such as pneumonia, uncomplicated and complicated urinary tract infections, skin and soft-tissue infections, intra-abdominal infections and febrile neutropenia. In this article, we provide a critical review of pharmacodynamics, clinical management, pharmacokinetics, metabolism, pharmacodynamic target analyses, clinical efficacy, safety and tolerability of cefepime after more than a decade of clinical use.
Collapse
Affiliation(s)
- Andrea Endimiani
- Department of Medicine, Section of Infectious Diseases, Case Western Reserve University, School of Medicine, Cleveland, OH, USA.
| | | | | |
Collapse
|
29
|
Identification of plasmid-mediated AmpC beta-lactamases in Escherichia coli, Klebsiella spp., and proteus species can potentially improve reporting of cephalosporin susceptibility testing results. J Clin Microbiol 2008; 47:294-9. [PMID: 19036936 DOI: 10.1128/jcm.01797-08] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The goal of this study was to determine if the interpretations of extended-spectrum and advanced-spectrum cephalosporins (ESCs and ASCs, respectively) for isolates of Enterobacteriaceae would be impacted by the results of aminophenylboronic acid (APBA) testing. Fifty-three isolates of Escherichia coli, 21 Klebsiella species, and 6 Proteus species that were resistant to at least one ESC were tested by disk diffusion with ceftazidime and cefotetan disks with and without APBA. Ceftazidime disks with and without clavulanic acid (CLAV) were also tested to confirm extended-spectrum beta-lactamase (ESBL) carriage. Twenty-nine (36.3%) isolates were only APBA test positive, 27 were only CLAV test positive, 2 were positive with both substrates, and 22 were negative with both substrates. Thirteen (41.9%) of the 31 APBA-test-positive isolates (all E. coli) tested susceptible to cefotaxime, ceftriaxone, or ceftazidime. Since clinical data suggest that AmpC-producing isolates should be reported as resistant to all ESCs, APBA testing can be helpful in identifying such organisms. Screening for AmpC-producing organisms using nonsusceptibility to cefoxitin and amoxicillin-clavulanate was less specific than APBA testing; it identified ESBL as well as AmpC-producing organisms. Only 18 of 31 APBA-positive isolates were positive by PCR for an AmpC beta-lactamase gene. Thus, testing with APBA could improve the accuracy of reporting ESCs, especially for E. coli. However, results of APBA and CLAV testing did not correlate well for isolates containing both AmpC beta-lactamases and ESBLs. Thus, additional data are needed before formal recommendations can be made on changing the reporting of ASC test results.
Collapse
|
30
|
Novel chimeric beta-lactamase CTX-M-64, a hybrid of CTX-M-15-like and CTX-M-14 beta-lactamases, found in a Shigella sonnei strain resistant to various oxyimino-cephalosporins, including ceftazidime. Antimicrob Agents Chemother 2008; 53:69-74. [PMID: 18955524 DOI: 10.1128/aac.00227-08] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The plasmid-mediated novel beta-lactamase CTX-M-64 was first identified in Shigella sonnei strain UIH-1, which exhibited resistance to cefotaxime (MIC, 1,024 microg/ml) and ceftazidime (MIC, 32 microg/ml). The amino acid sequence of CTX-M-64 showed a chimeric structure of a CTX-M-15-like beta-lactamase (N- and C-terminal moieties) and a CTX-M-14-like beta-lactamase (central portion, amino acids 63 to 226), suggesting that it originated by homologous recombination between the corresponding genes. The introduction of a recombinant plasmid carrying bla(CTX-M-64) conferred resistance to cefotaxime in Escherichia coli, and the activities of cefotaxime and ceftazidime were restored in the presence of clavulanic acid. Of note, CTX-M-64 production could also confer consistent resistance to ceftazidime, which differs from the majority of CTX-M-type enzymes, which poorly hydrolyze ceftazidime. These results were consistent with the kinetic parameters determined with the purified CTX-M-64 enzyme. The bla(CTX-M-64) gene was flanked upstream by an ISEcp1 sequence and downstream by an orf477 sequence. The sequence of the 45-bp spacer region between the right inverted repeat (IRR) of ISEcp1 and bla(CTX-M-64) was exactly identical to that of ISEcp1-bla(CTX-M-15-like). Moreover, the presence of a putative IRR of ISEcp1 at the right end of truncated orf477 is indicative of an ISEcp1-mediated transposition event in the bla(CTX-M-64) gene. The emergence of CTX-M-64 by probable homologous recombination would suggest the natural potential of an alternative mechanism for the diversification of CTX-M-type beta-lactamases.
Collapse
|
31
|
Su LH, Chu C, Cloeckaert A, Chiu CH. An epidemic of plasmids? Dissemination of extended-spectrum cephalosporinases among Salmonella and other Enterobacteriaceae. ACTA ACUST UNITED AC 2007; 52:155-68. [PMID: 18093140 DOI: 10.1111/j.1574-695x.2007.00360.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
CTX-M- and AmpC-type beta-lactamases comprise the two most rapidly growing populations among the extended-spectrum cephalosporinases. The evolution and dissemination of resistance genes encoding these enzymes occur mostly through the transmission of plasmids. The high prevalence of clinical isolates of Enterobacteriaceae producing the plasmid-mediated extended-spectrum cephalosporinases resembles an epidemic of plasmids, and has generated serious therapeutic problems. This review describes the emergence and worldwide spread of various classes of plasmid-mediated extended-spectrum cephalosporinases in Salmonella and other Enterobacteriaceae, the transfer mechanism of the plasmids, detection methods, and therapeutic choices.
Collapse
Affiliation(s)
- Lin-Hui Su
- Department of Clinical Pathology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | | | | | | |
Collapse
|
32
|
Nordmann P, Mammeri H. Extended-spectrum cephalosporinases: structure, detection and epidemiology. Future Microbiol 2007; 2:297-307. [PMID: 17661704 DOI: 10.2217/17460913.2.3.297] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Extended-spectrum AmpC beta-lactamases of Enterobacteriaceae, which are chromosomally or plasmid-encoded, possess structural modifications in the vicinity of the active site compared with their progenitors. They display an increased catalytic efficiency against extended-spectrum beta-lactams, such as ceftazidime, cefotaxime, cefepime, cefpirome and, in some cases, also against imipenem. An overview of the molecular and biochemical characterization of this recently identified mechanism of resistance to beta-lactams is provided as well as its prevalence and possible clinical significance.
Collapse
Affiliation(s)
- Patrice Nordmann
- Service de Bactériologie-Virologie, Hôpital de Bicêtre, Le Kremlin-Bicêtre, France.
| | | |
Collapse
|
33
|
Hee Lee S, Lee JH, Heo MJ. Exact location of the region responsible for the extended substrate spectrum in class C beta-lactamases. Antimicrob Agents Chemother 2007; 51:3778-9; author reply 3779. [PMID: 17890420 PMCID: PMC2043277 DOI: 10.1128/aac.00633-07] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Sang Hee Lee
- Phone: 82 31 330 6195, Fax: 82 31 335 8249, E-mail:
| | | | | |
Collapse
|
34
|
Lee JH, Jeong SH, Cha SS, Lee SH. A lack of drugs for antibiotic-resistant Gram-negative bacteria. Nat Rev Drug Discov 2007. [DOI: 10.1038/nrd2201-c1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
35
|
Doi Y, Paterson DL. Detection of plasmid-mediated class C β-lactamases. Int J Infect Dis 2007; 11:191-7. [PMID: 17339123 DOI: 10.1016/j.ijid.2006.07.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2006] [Revised: 07/18/2006] [Accepted: 07/27/2006] [Indexed: 10/23/2022] Open
Abstract
Plasmid-mediated class C beta-lactamases are reported from Enterobacteriaceae with increasing frequency. They likely originate from chromosomal AmpC of certain Gram-negative bacterial species and subsequently are mobilized onto transmissible plasmids. There are reports of unfavorable clinical outcomes in patients infected with these organisms and treated with broad-spectrum cephalosporins. However, unlike class A extended-spectrum beta-lactamases (ESBLs), no screening and confirmatory tests have been uniformly established for strains that produce class C beta-lactamases. Reduced susceptibility to cefoxitin is a sensitive but not specific indicator of class C beta-lactamase production. Simple confirmatory tests including tests using boronic acid compounds as specific class C beta-lactamase inhibitors have recently been developed. Their utilization will enable clinical microbiology laboratories to report those strains producing plasmid-mediated class C beta-lactamases as being resistant to all broad-spectrum cephalosporins, thus allowing physicians to prescribe appropriate antimicrobial therapy.
Collapse
Affiliation(s)
- Yohei Doi
- Division of Infectious Diseases, University of Pittsburgh Medical Center, Falk Medical Building Suite 3A, 3601 Fifth Avenue, Pittsburgh, PA 15213, USA
| | | |
Collapse
|
36
|
Nakano R, Okamoto R, Nagano N, Inoue M. Resistance to gram-negative organisms due to high-level expression of plasmid-encoded ampC β-lactamase blaCMY-4 promoted by insertion sequence ISEcp1. J Infect Chemother 2007; 13:18-23. [PMID: 17334724 DOI: 10.1007/s10156-006-0483-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2006] [Accepted: 10/10/2006] [Indexed: 10/23/2022]
Abstract
A Klebsiella pneumoniae strain, KU6500, which showed resistance to extended-spectrum beta-lactams and produced the plasmid-encoded AmpC beta-lactamase CMY-4, was identified from clinical isolates in Japan. The aim of this study was to identify the mechanism of the high-level expression of blaCMY-4. Sequence analysis indicated that the promoter element of Citrobacter freundii was conserved, but the insertion sequence ISEcp1 coding with the putative promoter element, was inserted into the AmpR binding site. We determined the influence of the promoter on blaCMY-4 expression and beta-lactam resistance. Two recombinant plasmids containing the entire blaCMY-4 gene, with or without the ISEcp1-mediated promoter sequences, were constructed and named pMWampC and pMWISEcp1, respectively. Escherichia coli DH5alpha (pMWISEcp1) was resistant to almost all beta-lactams tested and E. coli DH5alpha (pMWampC) was susceptible to all, except for cephalothin. In addition, the activity of each promoter was measured by subcloning the element into a promoterless luciferase plasmid pGL3-Basic vector. The expression of the putative promoter of ISEcp1 was 18.9-fold higher than that of C. freundii. These results suggest that the putative promoter element of ISEcp1 is necessary for the high-level expression of blaCMY-4 to confer resistance to extended-spectrum cephalosporins.
Collapse
Affiliation(s)
- Ryuichi Nakano
- School of Medicine and Environmental Infectious Diseases, Graduate School of Medical Sciences, Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa 228-8555, Japan.
| | | | | | | |
Collapse
|
37
|
Abstract
The emergence of mutations in nucleic acids is one of the major factors underlying evolution, providing the working material for natural selection. Most bacteria are haploid for the vast majority of their genes and, coupled with typically short generation times, this allows mutations to emerge and accumulate rapidly, and to effect significant phenotypic changes in what is perceived to be real-time. Not least among these phenotypic changes are those associated with antibiotic resistance. Mechanisms of horizontal gene spread among bacterial strains or species are often considered to be the main mediators of antibiotic resistance. However, mutational resistance has been invaluable in studies of bacterial genetics, and also has primary clinical importance in certain bacterial species, such as Mycobacterium tuberculosis and Helicobacter pylori, or when considering resistance to particular antibiotics, especially to synthetic agents such as fluoroquinolones and oxazolidinones. In addition, mutation is essential for the continued evolution of acquired resistance genes and has, e.g., given rise to over 100 variants of the TEM family of beta-lactamases. Hypermutator strains of bacteria, which have mutations in genes affecting DNA repair and replication fidelity, have elevated mutation rates. Mutational resistance emerges de novo more readily in these hypermutable strains, and they also provide a suitable host background for the evolution of acquired resistance genes in vitro. In the clinical setting, hypermutator strains of Pseudomonas aeruginosa have been isolated from the lungs of cystic fibrosis patients, but a more general role for hypermutators in the emergence of clinically relevant antibiotic resistance in a wider variety of bacterial pathogens has not yet been proven.
Collapse
Affiliation(s)
- N Woodford
- Antibiotic Resistance Monitoring and Reference Laboratory, Centre for Infections, Health Protection Agency, London, UK.
| | | |
Collapse
|
38
|
Rossolini GM, Docquier JD. New β-lactamases: a paradigm for the rapid response of bacterial evolution in the clinical setting. Future Microbiol 2006; 1:295-308. [PMID: 17661642 DOI: 10.2217/17460913.1.3.295] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Production of β-lactamases is one of the most common mechanisms of bacterial resistance to β-lactam antibiotics. In the clinical setting, the introduction of new classes of β-lactams has invariably been followed by the emergence of new β-lactamases capable of degrading them, as a paradigmatic example of rapid bacterial evolution under a rapidly changing selective environment. The scope of this article is to provide an overview on the recent evolution of β-lactamase-mediated resistance among bacterial pathogens. Focus is on the mechanisms of evolution and dissemination of enzymes of greater clinical impact, including the extended-spectrum β-lactamases, the AmpC-type β-lactamases and the carbapenemases, which are currently responsible for emerging resistance to the most recent and powerful β-lactams (the expanded-spectrum cephalosporins and the carbapenems) among major Gram-negative pathogens such as Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter.
Collapse
Affiliation(s)
- Gian Maria Rossolini
- University of Siena, Department of Molecular Biology, Section of Microbiology, Policlinico Santa Maria alle Scotte, Siena, Italy.
| | | |
Collapse
|