Role of the Ser-287-Asn Replacement in the Hydrolysis Spectrum Extension of AmpC β-Lactamases in
            <i>Escherichia coli</i>

Mammeri, Hedi; Galleni, Moreno; Nordmann, Patrice

doi:10.1128/aac.00608-08

Cited by 20 publications

(17 citation statements)

References 13 publications

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“…Antimicrobial agents contribute to selection pressure in commensals E. coli [50]. While some phylogenetic groups (A and some D group strains) of E. coli are more permissive to develop resistance to third generation cephalosporins whereas group B2 strains are less likely to develop resistance compared to the other groups [51–53]. This variability influences the strain structures of E. coli in hosts frequently exposed to antimicrobials [4].…”

Section: Discussionmentioning

confidence: 99%

Temporal variations in patterns ofEscherichia colistrain diversity and antimicrobial resistance in the migrant Egyptian vulture

Sharma

Maherchandani

Shringi

et al. 2018

Infection Ecology & Epidemiology

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Aims: Multiple antimicrobial resistance in Escherichia coli of wild vertebrates is a global concern with scarce assessments on the subject from developing countries that have high human-wild species interactions. We studied the ecology of E. coli in a wintering population of Egyptian Vultures in India to understand temporal changes in both E. coli strains and patterns of antimicrobial resistance. Methods and Results: We ribotyped E. coli strains and assessed antimicrobial resistance from wintering vultures at a highly synanthropic carcass dump in north-west India. Both E. coli occurence (90.32%) and resistance to multiple antimicrobials (71.43%) were very high. Clear temporal patterns were apparent. Diversity of strains changed and homogenized at the end of the Vultures’ wintering period, while the resistance pattern showed significantly difference inter-annually, as well as between arrival and departing individuals within a wintering cycle. Significance of study: The carcass dump environment altered both E. coli strains and multiple antimicrobial resistance in migratory Egyptian Vultures within a season. Long-distance migratory species could therefore disseminate resistant E. coli strains across broad geographical scales rendering regional mitigation strategies to control multiple antimicrobial resistance in bacteria ineffective.

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Section: Discussionmentioning

confidence: 99%

Temporal variations in patterns ofEscherichia colistrain diversity and antimicrobial resistance in the migrant Egyptian vulture

Sharma

Maherchandani

Shringi

et al. 2018

Infection Ecology & Epidemiology

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“…Clinical isolates Escherichia coli ECB1 and ECB2 produced ACC-1 and CMY-2 ␤-lactamases, respectively (17); recombinant strains E. coli DH10B (pPON-1) and E. coli EC6 produced DHA-1 enzyme and the AmpC B2 ␤-lactamase, respectively, which is the chromosomal wild-type cephalosporinase of E. coli (18,25); the transformant strain E. coli (pGLK1) produced FOX-1 enzyme (10); and the strain Enterobacter asburiae CIP 105006 (Pasteur Institute, Paris, France) produced ACT-1 ␤-lactamase (30). All of these strains were used as sources of ampC genes.…”

Section: Methodsmentioning

confidence: 99%

Phenotypic and Biochemical Comparison of the Carbapenem-Hydrolyzing Activities of Five Plasmid-Borne AmpC β-Lactamases

Mammeri

Guillon

et al. 2010

Antimicrob Agents Chemother

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The CMY-2, ACT-1, DHA-1, ACC-1, and FOX-1 enzymes are representative of five plasmid-mediated AmpC (pAmpC) ␤-lactamase clusters. Resistance to imipenem has been reported in Enterobacteriaceae as a result of pAmpC expression combined with decreased outer membrane permeability. The aim of this study was to determine the role of different pAmpCs in carbapenem resistance and to define the structure/activity relationship supporting carbapenemase activity. The ampC genes encoding the five pAmpCs and the chromosomal AmpC of Escherichia coli EC6, which was used as a reference cephalosporinase, were cloned and introduced into wild-type E. coli TOP10 and OmpC/OmpF porin-deficient E. coli HB4 strains. The MICs of ␤-lactams for the recombinant strains revealed that CMY-2, ACT-1, and DHA-1 ␤-lactamases conferred a high level of resistance to ceftazidime and cefotaxime once expressed in E. coli TOP10 and reduced significantly the susceptibility to imipenem once expressed in E. coli HB4. In contrast, FOX-1 and ACC-1 enzymes did not confer resistance to imipenem. Biochemical analysis showed that CMY-2 ␤-lactamase and, to a lesser extent, ACT-1 exhibited the highest catalytic efficiency toward imipenem and showed low K m values. A modeling study revealed that the large R2 binding site of these two enzymes may support the carbapenemase activity. Therefore, CMY-2-type, ACT-1-type, and DHA-1-type ␤-lactamases may promote the emergence of carbapenem resistance in porin-deficient clinical isolates.The class C (AmpC) ␤-lactamases constitute a group of enzymes widely distributed in Enterobacteriaceae. They preferentially inactivate narrow-spectrum cephalosporins and, to a lesser extent, expanded-spectrum cephalosporins (ESCs), such as ceftazidime and cefotaxime. Zwitterionic cephalosporins, such as cefepime, and carbapenems, such as imipenem, ertapenem, and meropenem, which penetrate very efficiently through the native outer membrane of Gram negatives and are poor substrates of AmpC ␤-lactamases, remain active in vitro against enterobacterial isolates that overproduce chromosome-encoded cephalosporinase (24).Plasmid-mediated AmpC (pAmpC) ␤-lactamases, which originated from chromosomal AmpC of different Gram-negative bacteria, has emerged since the 1980s (24). They can be divided into five clusters: the Citrobacter freundii cluster, represented by CMY-2, the Enterobacter cluster with MIR-1 and ACT-1, the Morganella morganii group with DHA-1, the Hafnia alvei cluster represented by ACC-1, and the Aeromonas cluster with MOX-1 (also called CMY-1) and FOX-1 enzymes, which constitute two distinct subgroups (24). pAmpC ␤-lactamases, whose constitutive expression often is triggered by strong promoters (29), confer a phenotype of resistance similar to that displayed by chromosomal AmpC-overproducing strains.Modifications of the membrane permeability can markedly change the susceptibility profile of pAmpC-producing isolates. By reducing the antibiotic concentration inside the periplasm, porin change may amplify the ␤-lactamase effects toward wea...

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“…Extended-spectrum AmpCs were first identified in Serratia marcescens and Enterobacter spp. (10,143,153) and, most recently, in E. coli (141,142). Amino acid modifications near the active sites of these enzymes can lead to FIG.…”

Section: Ampc-mediated Resistancementioning

confidence: 99%

Antibacterial-ResistantPseudomonas aeruginosa: Clinical Impact and Complex Regulation of Chromosomally Encoded Resistance Mechanisms

2009

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SUMMARY Treatment of infectious diseases becomes more challenging with each passing year. This is especially true for infections caused by the opportunistic pathogen Pseudomonas aeruginosa, with its ability to rapidly develop resistance to multiple classes of antibiotics. Although the import of resistance mechanisms on mobile genetic elements is always a concern, the most difficult challenge we face with P. aeruginosa is its ability to rapidly develop resistance during the course of treating an infection. The chromosomally encoded AmpC cephalosporinase, the outer membrane porin OprD, and the multidrug efflux pumps are particularly relevant to this therapeutic challenge. The discussion presented in this review highlights the clinical significance of these chromosomally encoded resistance mechanisms, as well as the complex mechanisms/pathways by which P. aeruginosa regulates their expression. Although a great deal of knowledge has been gained toward understanding the regulation of AmpC, OprD, and efflux pumps in P. aeruginosa, it is clear that we have much to learn about how this resourceful pathogen coregulates different resistance mechanisms to overcome the antibacterial challenges it faces.

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Role of the Ser-287-Asn Replacement in the Hydrolysis Spectrum Extension of AmpC β-Lactamases in Escherichia coli

Cited by 20 publications

References 13 publications

Temporal variations in patterns ofEscherichia colistrain diversity and antimicrobial resistance in the migrant Egyptian vulture

Temporal variations in patterns ofEscherichia colistrain diversity and antimicrobial resistance in the migrant Egyptian vulture

Phenotypic and Biochemical Comparison of the Carbapenem-Hydrolyzing Activities of Five Plasmid-Borne AmpC β-Lactamases

Antibacterial-ResistantPseudomonas aeruginosa: Clinical Impact and Complex Regulation of Chromosomally Encoded Resistance Mechanisms

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