| Autor: |
Goulart DB; Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA., Beyi AF; Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA., Wu Z; Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA., Adiguzel MC; Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA., Wilson S; Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA., Xu C; Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA., Pang J; Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA., Dewell R; Center for Food Security and Public Health, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA., Dewell GA; Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA., Plummer PJ; Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.; Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.; National Institute of Antimicrobial Resistance Research and Education, Iowa State University, Ames, IA 50010, USA., Zhang Q; Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA., Sahin O; Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA. |
| Abstrakt: |
Fluoroquinolone (FQ) resistance in a major foodborne bacterial pathogen, Campylobacter jejuni , derived from cattle has recently become prevalent and poses a significant public health concern. However, the underlying factors for this increase are not entirely clear. To evaluate the effect of enrofloxacin treatment on FQ-resistance development in C. jejuni , 35 commercial calves were equally divided into five groups (Groups 1-5) and were orally inoculated with FQ-susceptible (FQ-S) C. jejuni . Eight days later, Groups 4 and 5 were challenged with Mannheimia haemolytica via a transtracheal route to induce a respiratory disease; after 8 days, Groups 2, 3, 4, and 5 were injected subcutaneously with enrofloxacin (7.5 mg/kg for Groups 2 and 4, and 12.5 mg/kg for Groups 3 and 5). Colonization levels by FQ-resistant (FQ-R) and FQ-S Campylobacter in rectal feces were determined via differential culture throughout the experiment. Before oral inoculation with C. jejuni , only five calves were naturally colonized by Campylobacter , four of which were also colonized by FQ-R C. jejuni (three in Group 1 and one in Group 3). Soon after the oral inoculation, almost all calves in the groups became stably colonized by FQ-S C. jejuni (~3-6 log 10 CFU/g), except that the four calves that were pre-colonized before inoculation remained positive with both FQ-R and FQ-S C. jejuni . Following enrofloxacin administration, C. jejuni colonization declined sharply and rapidly in all treated groups to undetectable levels; however, the vast majority of the animals were recolonized by C. jejuni at comparable levels 72 h after the treatment. Notably, no FQ-R C. jejuni was detected in any of the calves that received enrofloxacin, regardless of the drug dose used or disease status of the animals. The lack of detection of FQ-R C. jejuni was likely due to the localized high concentration of the antibiotic in the intestine, which may have prevented the emergence of the FQ-R mutant. These findings indicate that single-dose enrofloxacin use in cattle poses a low risk for selection of de novo FQ-R mutants in C. jejuni . |
