Rapid characterization of beta-lactamases by multiplex PCR

Area of Science:

• Clinical microbiology
• Molecular biology
• Antimicrobial resistance

Background:

• Rising prevalence of extended-spectrum beta-lactamases (ESBLs) and carbapenemases in Enterobacteriaceae, Pseudomonas spp., and Acinetobacter baumannii poses a significant global health challenge.
• These enzymes compromise therapeutic options and complicate patient management, necessitating rapid diagnostic methods.
• Timely identification of resistant strains in clinical laboratories is essential for prompt and appropriate treatment, ultimately reducing patient mortality.

Purpose of the Study:

• To describe multiplex PCR assays for the simultaneous detection of key antibiotic resistance genes.
• To provide tools for the rapid identification of bacteria producing ESBLs and carbapenemases.

Main Methods:

• Development and description of three multiplex PCR assays.
• Assays target genes encoding five families of CTX-M-type ESBLs (groups 1, 2, 8, 9, 25).
• Assays target genes encoding five families of metallo-carbapenemases (IMP, VIM, SPM, GIM, SIM) and four families of OXA-carbapenemases (OXA-23-like, OXA-40-like, OXA-51-like, OXA-58-like).

Main Results:

• CTX-M ESBLs are prevalent, particularly in Escherichia coli and Klebsiella spp.
• Metallo-carbapenemases are frequently found in Pseudomonas spp. and other non-fermenters, with emerging presence in Enterobacteriaceae.
• OXA-carbapenemases detected are primarily associated with Acinetobacter spp.

Conclusions:

• Multiplex PCR assays offer a rapid and effective method for detecting clinically significant beta-lactamase genes.
• These assays are suitable for national reference laboratories, regional centers, and tertiary hospitals.
• Prompt detection facilitates appropriate antimicrobial therapy and improves patient outcomes in the face of rising resistance.