Approaches to the antimicrobial susceptibility testing of Campylobacter to monitor the spread of antibiotic-resistant strains

Abstract

Introduction. Campylobacteriosis is one of the most common diarrhea-associated infections over the world. The situation is getting worse along with increasing cases of the disease caused by the Campylobacter spp. pathogen resistant to antimicrobials (AMPs). Preventing the disease requires monitoring the spread of resistant Campylobacter strains isolated from both sick people and animals, food, and water. 
 Aim of the study is to evaluate the results of the antimicrobial susceptibility testing of Campylobacter according to the requirements of the EUCAST and CLSI methodologies using Russia-made nutrient media. 
 Materials and methods. Collected and freshly isolated strains of C. jejuni, C. coli, C. fetus and C. lari were used. Campylobacter cultures were subcultured on Campylobacter Agar Base (HiMedia), Preston laboratory-produced medium and iron-erythritol blood agar (Obolensk). Their sensitivity to AMPs was determined by three methods as ffollows: disc diffusion, gradient diffusion and microdilutions using Mueller-Hinton agar, and broth of two manufacturers (BD BBL and Obolensk) according to EUCAST and CLSI.
 Results. Using Russian-made and imported Mueller-Hinton agar and broth allowed obtaining identical results for AMPs susceptibility of Campylobacter spp. The campylobacter strains were attributed to the same susceptibility category by all three methods in frame of any methodology (EUCAST or CLSI) when interpreting results. Due to differences in cutoffs of MIC and inhibition zone diameters in the EUCAST and CLSI standards, there were some differences in the interpretation of the results.
 Limitations. Eight strains of four species Campylobacter were tested for their susceptibility to three antimicrobials by three methods according to EUCAST and CLSI methodology.
 Conclusion. The results obtained confirm the possibility of applying a complex of domestic nutrient media for cultivating and monitoring the spread of antibiotic resistant strains of Campylobacter spp. This is especially important in view of implementing the import substitution program.