Genetic Diversity and Antibiotic Resistance Patterns in aCampylobacterPopulation Isolated from Poultry Farms in Switzerland

Abstract

The diversity and genetic interrelation of Campylobacter jejuni and C. coli isolated from Swiss poultry were assessed by three independent typing methods. Samples were derived prior to slaughter from 100 randomly selected flocks (five birds per flock) raised on three different farm types. The observed flock prevalence was 54% in total, with 50% for conventional and 69% for free-range farms. Birds held on farms with a confined roaming area had the lowest prevalence of 37%. Campylobacter isolates were characterized by amplified fragment length polymorphism (AFLP), restriction fragment length polymorphism of flaA PCR fragments (flaA-RFLP), and disk diffusion testing for eight antimicrobial agents that are commonly used in veterinary or human medicine in Switzerland. Analysis of the genotypic results indicates that the Campylobacter population in Swiss poultry is genetically highly diverse. Nevertheless, occasionally, isolates with identical or nearly identical characteristics were isolated from different farms or farm types in different locations. Genetic typing by AFLP and flaA-RFLP was found to be complementary. The majority of isolates (67%) were susceptible to all tested antibiotics; however, single, double, and triple resistances were observed in 7%, 23%, and 2% of the strains, respectively. There was no correlation between genotype and antibiotic resistance. Surprisingly, sulfonamide resistance was frequently found together with streptomycin resistance. Our findings illustrate the results of common genetic exchange in the studied bacterial population.

Genotype and Antibiotic Resistance Analyses of Campylobacter Isolates from Ceca and Carcasses of Slaughtered Broiler Flocks

“…Statistical analysis indicated that this is a highly significant association and that the majority of samples obtained from the neck skin originated from the slaughtered flock itself. Given the fact that only single colonies were analyzed and that both species and various genotypes can be present in the flock, the true number of self-contaminated carcasses can be quite large (5,52). The remaining nonmatching isolates that were obtained from the neck skin could have come from other contaminated sources, such as previously slaughtered batches, equipment, working surfaces, or water (19,36,49).…”

Multiplex Strategy for Multilocus Sequence Typing, fla Typing, and Genetic Determination of Antimicrobial Resistance of Campylobacter jejuni and Campylobacter coli Isolates Collected in Switzerland

“…Phenotypically characterized C. jejuni (180) and C. coli (141) isolates from the collection at the Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland, were used. The strain set contained human isolates from patients suffering from clinical campylobacteriosis sampled between 1993 and 2003 at the Swiss National Reference Centre for Enteropathogenic Bacteria, cattle isolates collected from healthy dairy cows during December 2001 and January 2002, pet isolates collected from healthy dogs and cats from 2002 to 2003, and poultry and pig isolates collected in 2002 (27,38,40 The isolates were stored at Ϫ80°C until they were cultivated on tryptone soya agar plates with sheep blood (Oxoid, Hampshire, United Kingdom) for 24 to 48 h at 42°C under microaerophilic conditions.…”

Antibiotic Resistance Characteristics of Environmental Bacteria from an Oxytetracycline Production Wastewater Treatment Plant and the Receiving River

“…Some elements, including class I integrons, conjugative plasmids, and transposons, are frequently linked to antibiotic resistance as they harbor rather diverse resistance genes and possibly promote the distribution of these genes in phylogenetically diverse bacteria (29). In light of the potential health risk, many studies have focused on antibiotic-resistant bacteria recovered from various ecosystems (1,18,45). Environments that contain antibiotic residues are particularly worrisome because antibiotics could exert selective pressure and might contribute to the appearance of resistant bacteria.…”