Campylobacter genome analysis: an alternative to classical antibiograms?

Summary Bacteria of the genus Campylobacter are bacteria involved in human pathology, most often in intestinal infections of the enteritis type and originate, in the majority of cases, from farm animals (poultry, pigs) consumed in the diet. Antibiotic treatment of these enteric infections, although not systematic, is often conducted with macrolides or fluoroquinolones but systemic infections may require the use of aminoglycosides such as gentamicin. Recent studies report an increased incidence of gentamicin-resistant strains of Campylobacter. Moreover, such strains frequently present multiple associated resistances which limits the therapeutic alternatives. Analysis of twelve whole genomes of multi-resistant Campylobacter has identified new genes coding for aminoglycoside-modifying enzymes and a probable new lincomycin resistance gene. In addition, known resistance genes in other bacterial genera were identified for the first time in Campylobacter. The correlation between genotype and phenotype is 100% for tetracyclines, quinolones, ampicillin, erythromycin and aminoglycosides suggesting that the analysis of the Campylobacter genome is a very powerful tool for the monitoring of antibiotic resistance and could be a substitute for antibiotic susceptibility testing in the future. On the other hand, conjugation tests have shown that these resistance genes, when carried by a plasmid, can diffuse from one Campylobacter strain to another by horizontal transmission and thus contribute to their dissemination and to the emergence of multi-resistant strains.