Formation of the Resistance of Campylobacter jejuni to Macrolide Antibiotics

Area of Science:

• Microbiology
• Antimicrobial Resistance
• Food Safety

Background:

• Macrolide resistance in Campylobacter spp. poses a significant public health threat.
• Existing resistance to fluoroquinolones and tetracyclines is widespread in Campylobacter.
• Campylobacteriosis is a common foodborne illness requiring effective antibiotic treatment.

Purpose of the Study:

• To determine the prevalence of macrolide resistance in Campylobacter jejuni strains.
• To identify the genetic mechanisms conferring macrolide resistance in these strains.
• To assess the potential for transmission of resistance mechanisms.

Main Methods:

• Phenotypic screening for erythromycin and azithromycin resistance in 40 Campylobacter jejuni isolates.
• Isolation of strains from raw milk, poultry products, and processing plant equipment.
• Molecular detection of genes associated with macrolide resistance, including ribosomal protection proteins and CmeABC efflux pump genes.
• Analysis of chromosomal mutations in the 23S rRNA sequence.

Main Results:

• 27.5% of C. jejuni strains exhibited phenotypic resistance to erythromycin.
• 10% of strains were resistant to azithromycin.
• Ribosomal protection protein genes were found in 45% of strains, and CmeABC efflux pump genes in 36%, indicating transmissible resistance mechanisms.
• Chromosomal mutations in 23S rRNA were detected in 18% of strains.

Conclusions:

• Macrolide resistance, particularly to erythromycin, is prevalent in Campylobacter jejuni.
• Transmissible genetic mechanisms, including ribosomal protection and efflux pumps, are the primary drivers of macrolide resistance.
• While less common, chromosomal mutations in 23S rRNA also contribute to resistance.