Optimization of the rapid carbapenem inactivation method for use with AmpC hyperproducers.

Objectives: Detection of carbapenemase-producing Enterobacterales (CPEs) is sometimes difficult with AmpC-hyperproducing Enterobacterales (AHEs), as they may falsely be classified as CPEs. Here, we present a rapid Carbapenem Inactivation Method (rCIM) optimized for AmpC producers (rCIM-A) that allows rapid and easy discrimination between AHEs and CPEs.

Methods: Enterobacterales (n = 249), including natural AmpC producers, AHEs, CPEs and non-carbapenemase-producing carbapenem-resistant control strains were evaluated, using Carba NP, rCIM and rCIM-A.

Evaluation of a colorimetric test for the rapid detection of carbapenemase activity in Gram negative bacilli: the MAST® PAcE test.

The MAST Carba PAcE test is a colorimetric test used to detect carbapenemase-producing Gram-negative bacilli from cultured colonies. The performances of this test were compared to β-CARBA™, Carba NP test and RAPIDEC CARBA NP tests using a collection of 280 characterized isolates. Sensitivity and specificity of the MAST Carba PAcE test were 79.

Polyclonal Dissemination of NDM-1- and NDM-9-Producing Escherichia coli and Klebsiella pneumoniae in French Polynesia.

The whole-genome sequencing analysis revealed a polyclonal dissemination of NDM-1 and NDM-9 variants in ( = 20) and ( = 2) in Tahiti since 2015 via interspecies transfer of three different -carrying plasmids (IncR, IncHI2, and IncF) and patient-to-patient cross-transmission. It highlights the potential risk of importation of NDM producers in France, where French Polynesia is not considered a foreign country from which repatriated patients have to be screened.

First Occurrence of the OXA-198 Carbapenemase in .

A carbapenem-resistant sp. was recovered from routine screening of multidrug-resistant bacteria. This isolate coproduced OXA-48 and OXA-198.

Evaluation of the BD MAX Check-Points CPO Assay for the Detection of Carbapenemase Producers Directly from Rectal Swabs.

A novel real-time multiplex PCR assay, BD MAX Check-Points CPO, was evaluated to detect carbapenemase-producing organisms in clinical settings on the BD MAX system. A total of 175 well-characterized isolates (including 123 carbapenemase producers) and 128 rectal swab specimens (including 83 positives) of patients considered at high risk for carriage of carbapenemase producers were included. Bacterial suspensions were used to spike true-negative rectal swabs to mimic a clinical sample.

False-Positive Carbapenem-Hydrolyzing Confirmatory Tests Due to ACT-28, a Chromosomally Encoded AmpC with Weak Carbapenemase Activity from Enterobacter kobei.

In complex (ECC), the overproduction of the chromosome-encoded cephalosporinase (cAmpC) associated with decreased outer membrane permeability may result in carbapenem resistance. In this study, we have characterized ACT-28, a cAmpC with weak carbapenemase activity, from a single lineage. ECC clinical isolates were characterized by whole-genome sequencing (WGS), susceptibility testing, and MIC, and carbapenemase activity was monitored using diverse carbapenem hydrolysis methods.

Development and validation of a multiplex polymerase chain reaction assay for detection of the five families of plasmid-encoded colistin resistance.

Plasmid-mediated colistin resistance is increasingly described worldwide in Enterobacteriaceae from animal and human isolates. Diffusion of these resistance traits among carbapenem-resistant enterobacterial isolates is of particular concern as colistin has become the last resort antibiotic for treating human infections with these organisms. Therefore, being able to monitor the presence of these transferable colistin resistance genes (mcr-1 to mcr-5-variants) is crucial.

Diversity of Carbapenemase-Producing Escherichia coli Isolates in France in 2012-2013.

With the dissemination of carbapenemase-producing (CPE) strains worldwide, carbapenem-hydrolyzing enzymes are increasingly reported among isolates of , the first hospital and community-acquired opportunistic pathogen. Here, we have performed an epidemiological survey of carbapenemase-producing (CP-) isolates received at the French National Reference Centre (F-NRC) in 2012 and 2013. Antimicrobial susceptibilities for last-resort antibiotics and antimicrobial compounds commonly used to treat urinary tract infections were determined by broth microdilution.

Evaluation of the rapid carbapenem inactivation method (rCIM): a phenotypic screening test for carbapenemase-producing Enterobacteriaceae.

Objectives: Fast and accurate diagnostic tests to identify carbapenemase-producing Enterobacteriaceae (CPE) are mandatory for proper antimicrobial therapy and implementing infection control measures. Here, we have developed a rapid Carbapenem Inactivation Method (rCIM) for CPE detection.

Methods: The rCIM consists of the incubation of a potential carbapenemase producer with meropenem discs and use of the resulting supernatant to challenge a susceptible indicator strain.

Genomic Insights into Colistin-Resistant Klebsiella pneumoniae from a Tunisian Teaching Hospital.

The emergence of colistin-resistant (CoR) is a public health concern, since this antibiotic has become the last line of treatment for infections caused by multidrug-resistant (MDR) Gram negatives. In this study, we have investigated the molecular basis of colistin resistance in 13 MDR strains isolated from 12 patients in a teaching hospital in Sousse, Tunisia. Whole-genome sequencing (WGS) was used to decipher the molecular mechanism of colistin resistance and to identify the resistome of these CoR isolates.

Real-time PCR for detection of blaOXA-48 genes from stools.

Objectives: Outbreaks of OXA-48-like carbapenemase producers are increasingly reported in many European countries and are often the result of difficulties in detection, especially for isolates with MICs of carbapenems that remain in the susceptibility range.

Methods: An in-house real-time quantitative PCR (qPCR) assay using TaqMan chemistry to detect bla(OXA-48-like) genes was compared with bacterial culturing on ChromID ESBL and SUPERCARBA media of spiked stool samples with several species producing OXA-48 variants.

Results: qPCR amplification using plasmid DNA was linear over 10 log dilutions (r(2) = 0.