Effect of enrofloxacin treatment on the prevalence of fluoroquinolone resistant Campylobacter in cattle
99th Conference of Research Workers in Animal Diseases, Chicago, United States Of America, 2 - 08 December 2018, pp.132, (Full Text)
- Publication Type: Conference Paper / Full Text
- City: Chicago
- Country: United States Of America
- Page Numbers: pp.132
- Çukurova University Affiliated: Yes
Abstract
Objective
Cattle are significant reservoirs for Campylobacter, a major foodborne pathogen. Recent studies have shown a rise in fluoroquinolone-resistant (FQ-R) Campylobacter in cattle, but it is unclear if this is directly related to FQ use in cattle. The aim of this study is to assess the effect of Enrofloxacin treatment on FQ resistance in cattle.
Methods
Calves derived from commercial farms were inoculated with FQ-susceptible (FQ-S) strains of C. jejuni, followed by treatment with a single dose
of Enrofloxacin (12.5 mg/kg by injection). Fecal samples were collected during the course of study for isolation and identification of
Campylobacter. Interestingly, the calves were naturally infected with FQ-R C. jejuni prior to inoculation with the laboratory strains.
Results
After the inoculation, FQ-R Campylobacter decreased, which was accompanied by increase of FQ-S Campylobacter. However, after Enrofloxacin treatment was given, the calves were recolonized by FQ-R Campylobacter. Pulsed field gel electrophoresis and multilocus sequence typing revealed genetic diversity of the isolates, but certain genotypes dominated during different stages of the study. Prior to
inoculation, the calves were predominantly colonized by FQ-R cluster A (ST982). After inoculation, the predominant genotypes changed to FQ-S clusters C (ST929) and D (ST61). Following the treatment with Enrofloxacin, the primary genotypes shifted to FQ-R clusters A (ST982) and B (ST922).
Conclusions
These results indicate that commercial cattle harbor genetically diverse FQ-R Campylobacter and a single treatment with Enrofloxacin enriched pre-existing FQ-R populations, but had little effect on de novo selection of FQ-R Campylobacter from the inoculated strains.