Optimal phenotypic testing of AmpC beta-lactamases using boronic acid solutions

Area of Science:

• Microbiology
• Molecular Biology
• Clinical Diagnostics

Background:

• Plasmid-mediated class C beta-lactamases, particularly AmpC, are increasingly prevalent in Gram-negative bacteria like Escherichia coli and Klebsiella pneumoniae.
• The rise of these enzymes poses a significant challenge to antibiotic treatment due to resistance.
• Standardized screening and confirmatory tests for AmpC production are lacking.

Purpose of the Study:

• To evaluate the efficacy of two boronic acid derivatives, phenylboronic acid (PB) and 3-(N-Boc-amino)phenylboronic acid (APB), in detecting plasmid-mediated AmpC production.
• To compare the performance of PB and APB in conjunction with polymerase chain reaction (PCR) for identifying AmpC-producing Enterobacteriaceae.

Main Methods:

• Analysis of 51 clinical isolates of Enterobacteriaceae.
• Utilized polymerase chain reaction (PCR) for genetic detection.
• Compared the effectiveness of two boronic acid formulations: phenylboronic acid (PB) and 3-(N-Boc-amino)phenylboronic acid (APB).

Main Results:

• Phenylboronic acid (PB) exhibited better performance than 3-(N-Boc-amino)phenylboronic acid (APB) in the detection assays.
• The study successfully identified plasmid-mediated AmpC production in the tested clinical isolates.

Conclusions:

• Phenylboronic acid (PB) is a more effective reagent than APB for the PCR-based detection of plasmid-mediated AmpC beta-lactamases.
• Improved diagnostic methods are crucial for identifying and managing infections caused by AmpC-producing Enterobacteriaceae.