Cephaloridine resistance in gram-negative bacteria isolated in Scotland

Area of Science:

• Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Urinary tract infections (UTIs) are common, and antibiotic resistance poses a significant challenge to effective treatment.
• Cephaloridine and ampicillin are commonly prescribed antibiotics for UTIs, making resistance to these agents a key concern.

Purpose of the Study:

• To determine the incidence of cephaloridine and ampicillin resistance in UTI isolates from three Scottish cities.
• To investigate the mechanisms of resistance, specifically beta-lactamase production, in cephaloridine-resistant strains.

Main Methods:

• Antimicrobial susceptibility testing was performed to determine minimum inhibitory concentrations (MICs) for cephaloridine and ampicillin.
• Resistant isolates were further analyzed for beta-lactamase production using biochemical tests.

Main Results:

• Cephaloridine resistance ranged from 22.6% to 45.1% across Dundee, Edinburgh, and Glasgow.
• Ampicillin resistance was notably high, reaching 71.9% in Glasgow, the highest reported in the UK.
• Among cephaloridine-resistant strains, 50.8% produced chromosomal beta-lactamase, and 47.9% produced potentially plasmid-mediated beta-lactamases.

Conclusions:

• Significant levels of cephaloridine and ampicillin resistance exist in UTI pathogens in Scotland.
• Beta-lactamase production is a prevalent mechanism contributing to cephaloridine resistance in these isolates.
• The high ampicillin resistance rates, particularly in Glasgow, warrant urgent attention and potential changes in antibiotic prescribing strategies.