Antimicrobial Resistance In Indicator Bacteria Research Articles

Food-borne zoonotic pathogens and antimicrobial resistance of indicator bacteria in urban wild boars in Barcelona, Spain

Wildlife is increasingly abundant in urban environments, but little is known about the zoonotic pathogens carried by these populations. Urban wild boars are of particular concern because this species is well-known as a pathogen reservoir, and thus, we studied selected zoonotic pathogens in urban wild boars in Barcelona, Spain (n=41). Salmonella enterica was found in 5.00% (95% CI 0.61–16.91) and Campylobacter coli in 4.88% (95% CI 0.6–16.53) of the animals. E. coli O157:H7 and C. jejuni were not found. Other thermophilic Campylobacter were moderately prevalent (19.51%, 95% CI 8.82–34.87). Additionally, we screened for antimicrobial resistance in indicator bacteria: resistance was most frequent in Enterococcus faecium (95% of the isolates were resistant to at least one antimicrobial agent), followed by Enterococcus faecalis (50%) and Escherichia coli (10%). For the first time resistance to linezolid in bacteria carried by wildlife is reported. These findings pose a concern for public health, and thus, further research is needed on wildlife in urban environments.

Antimicrobial Resistance in Swiss Laying Hens, Prevalence and Risk Factors

Antimicrobial resistance is an emerging concern to public health, and food-producing animals are known to be a potential source for transmission of resistant bacteria to humans. As legislation of the European Union requires to ban conventional cages for the housing of laying hens on the one hand, and a high food safety standard for eggs on the other hand, further investigations about the occurrence of antimicrobial resistance in alternative housing types are required. In this study, we determined antimicrobial resistance in indicator bacteria from 396 cloacal swabs from 99 Swiss laying hen farms among four alternative housing types during a cross-sectional study. On each farm, four hens were sampled and exposure to potential risk factors was identified with a questionnaire. The minimal inhibitory concentration was determined using broth microdilution in Escherichia coli (n=371) for 18 antimicrobials and in Enterococcus faecalis (n=138) and Enterococcus faecium (n=153) for 16 antimicrobials. All antimicrobial classes recommended by the European Food Safety Authority for E. coli and enterococci were included in the resistance profile. Sixty per cent of the E. coli isolates were susceptible to all of the considered antimicrobials and 30% were resistant to at least two antimicrobials. In E. faecalis, 33% of the strains were susceptible to all tested antimicrobials and 40% were resistant to two or more antimicrobials, whereas in E. faecium these figures were 14% and 39% respectively. Risk factor analyses were carried out for bacteria species and antimicrobials with a prevalence of resistance between 15% and 85%. In these analyses, none of the considered housing and management factors showed a consistent association with the prevalence of resistance for more than two combinations of bacteria and antimicrobial. Therefore we conclude that the impact of the considered housing and management practices on the egg producing farms on resistance in laying hens is low.