Inventory of Extended-Spectrum-β-Lactamase-Producing Enterobacteriaceae in France as Assessed by a Multicenter Study.

Area of Science:

• Clinical Microbiology
• Molecular Epidemiology
• Antimicrobial Resistance

Background:

• Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae are a significant cause of hospital-acquired infections.
• Understanding the mechanisms of ESBL diffusion is crucial for infection control and antibiotic stewardship.

Purpose of the Study:

• To inventory ESBL-producing Enterobacteriaceae isolates from French hospitals.
• To assess the genetic mechanisms driving the diffusion of ESBLs.
• To investigate the association between ESBL types, bacterial species, and plasmid characteristics.

Main Methods:

• Multicenter collection of 200 nonredundant ESBL-producing Enterobacteriaceae strains from clinical samples.
• Identification of antibiotic resistance genes via PCR and sequencing.
• Clonal relatedness analysis using DiversiLab system.
• Plasmid characterization through PCR-based replicon typing and multilocus sequence typing.

Main Results:

• CTX-M-15, CTX-M-1, CTX-M-14, and SHV-12 were the most prevalent ESBLs.
• Specific ESBL types showed distinct prevalences in Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae.
• Plasmid-mediated resistance genes (qnrB, aac(6')-Ib-cr, aac(3)-II) were common.
• Molecular typing revealed limited clonal diffusion but suggested the spread of specific ESBL-encoding plasmids.

Conclusions:

• Plasmid spread is a key determinant in the epidemiology of ESBL-producing Enterobacteriaceae.
• The association between ESBL-encoding plasmids and specific bacterial hosts influences observed resistance patterns.
• ESBL subtype prevalence varies significantly across different Enterobacteriaceae species.