Dissemination of carbapenemase-producing Enterobacteriaceae in France, 2012

Objectives Carbapenem-resistant Enterobacteriaceae isolates (n = 1485) were received at the French Associated National Reference Center for Antibiotic Resistance in 2012 and were characterized for their mechanism of resistance to carbapenems. Methods Carbapenemase production was detected using the biochemical-based Carba NP test, based on the detection of in vitro hydrolysis of imipenem. All isolates with a positive Carba NP test result were characterized by PCR and sequencing. Results Carbapenemase production was identified in 23.1% of the isolates. The main carbapenemase type identified was OXA-48 and derivatives (75.5%). An overseas source was clearly demonstrated for only 27.6% of the isolates. Conclusions OXA-48 and derivatives are now the most prevalent carbapenemases in France, with a possible spread of these producers in the communit

Dissemination of carbapenemase-producing Enterobacteriaceae in France, 2012

Objectives: Carbapenem-resistant Enterobacteriaceae isolates (n = 1485) were received at the French Associated National Reference Center for Antibiotic Resistance in 2012 and were characterized for their mechanism of resistance to carbapenems.Methods: Carbapenemase production was detected using the biochemical-based Carba NP test, based on the detection of in vitro hydrolysis of imipenem. All isolates with a positive Carba NP test result were characterized by PCR and sequencing.Results: Carbapenemase production was identified in 23.1% of the isolates. The main carbapenemase type identified was OXA-48 and derivatives (75.5%). An overseas source was clearly demonstrated for only 27.6% of the isolates.Conclusions: OXA-48 and derivatives are now the most prevalent carbapenemases in France, with a possible spread of these producers in the communit

First identification of novel NDM carbapenemase, NDM-7, in Escherichia coli in France.

BACKGROUND: The NDM-1 carbapenemase has been identified in 2008 in Enterobacteriaceae. Since then, several reports have emphasized its rapid dissemination throughout the world. The spread of NDM carbapenemases involve several bla NDM gene variants associated with various plasmids among several Gram negative species. METHODOLOGY: A multidrug-resistant E. coli isolate recovered from urine of a patient who had travelled to Burma has been characterized genetically and biochemically. PRINCIPAL FINDINGS: E. coli COU was resistant to all antibiotics tested except amikacin, tigecycline, fosfomycin, and chloramphenicol. Analysis of the antibiotic resistance traits identified a metallo-ß-lactamase, a novel NDM variant, NDM-7. It differs from NDM-4 by a single amino acid substitution sharing an identical extended spectrum profile towards carbapenems. The bla NDM-7 gene was located on an untypeable conjugative plasmid and associated with a close genetic background similar to those described among the bla NDM-1 genes. The isolate also harbours bla CTXM-15 and bla OXA-1 genes and belonged to ST167. SIGNIFICANCE: This study highlights that spread of NDM producers correspond to spread of multiple bla NDM genes and clones and therefore will be difficult to control

Prospective evaluation of an algorithm for the phenotypic screening of carbapenemase-producing Enterobacteriaceae

International audienceThe objective of this study was to assess the performance of an algorithm based on the disc diffusion method for the screening of carbapenemase-producing Enterobacteriaceae (CPE) referred to the French National Reference Centre for Antibiotic Resistance

In vivo selection of imipenem-resistant producing extended-spectrum β-lactamase CTX-M-15 and plasmid-encoded DHA-1 cephalosporinase

International audienceFour isolates (KP1–4) were recovered sequentially from an infected patient. Whilst KP1–3 were resistant to all β-lactams except carbapenems, KP4 recovered after 24 days of imipenem-containing treatment showed additional resistance to carbapenems. No carbapenem hydrolysis could be identified in KP4. Molecular characterisation revealed that KP1–4 were indistinguishable by pulsed-field gel electrophoresis, contained a 95-kb self-transferable plasmid harbouring and genes and a 65-kb plasmid that was not transferred by conjugation into , and harboured the plasmid-mediated AmpC β-lactamase gene. In addition, KP4 failed to express OmpK36 owing to a point mutation leading to a premature stop of the protein. This study demonstrates development of carbapenem resistance related to loss of OmpK36 expression in a isolate harbouring extended-spectrum β-lactamse and plasmid-mediated cephalosporinase genes following prolonged imipenem exposure

Evaluation of a DNA microarray for the rapid detection of extended-spectrum β-lactamases (TEM, SHV and CTX-M), plasmid-mediated cephalosporinases (CMY-2-like, DHA, FOX, ACC-1, ACT/MIR and CMY-1-like/MOX) and carbapenemases (KPC, OXA-48, VIM, IMP and NDM).

The 'Check-MDR CT103 array' is a powerful high-throughput tool for rapid identification of ESBL, pAmpC and carbapenemase producers in culture. Because of its rapid performance, this platform is a valuable tool for epidemiological or infection control studies

Evaluation of a DNA Microarray (Check-MDR CT102) for Rapid Detection of TEM, SHV, and CTX-M Extended-Spectrum β-Lactamases and of KPC, OXA-48, VIM, IMP, and NDM-1 Carbapenemases▿

The Check-MDR CT102 microarray, aimed at identifying bacteria producing extended-spectrum β-lactamase (ESBL) (SHV, TEM, and CTX-M) and carbapenemase (KPC, OXA-48, VIM, IMP, and NDM-1), was evaluated on a total of 144 Gram-negative strains expressing various β-lactamases. The sensitivity and specificity were 100% for most tested genes, suggesting that this assay allows accurate identification of common ESBL and carbapenemase producers from bacterial cultures

Alignment of the amino acid sequences of the seven NDM variants.

<p>Conserved residues of the active site of the metallo-ß-lactamase are denoted with asterisks.</p

Schematic representation of different genetic structures surrounding <i>bla</i>_NDM genes identified in <i>E. coli</i>.

<p>(A) pHKNDM encoding <i>bla</i>_NDM-1 gene described in <i>E. coli</i> isolate from Hong-Kong (accession number HQ451074) (11); (B) pGUE-NDM encoding <i>bla</i>_NDM-1 gene described in <i>E. coli</i> isolate from India (accession number JQ364967) (12); (C) p271A encoding <i>bla</i>_NDM-1 gene described in <i>E. coli</i> isolate from Bangladesh (accession number JF785549) (25); and (D) genetic structure surrounding the new <i>bla</i>_NDM-7 gene from <i>E. coli</i> COU. Genes and their transcription orientations are indicated by arrows.</p