Effect of Danofloxacin Treatment on the Development of Fluoroquinolone Resistance in <i>Campylobacter jejuni</i> in Calves

• Main Authors: Debora Brito Goulart (Author), Ashenafi Feyisa Beyi (Author), Zuowei Wu (Author), Mehmet Cemal Adiguzel (Author), Anastasia Schroeder (Author), Kritika Singh (Author), Changyun Xu (Author), Melda Meral Ocal (Author), Renee Dewell (Author), Grant A. Dewell (Author), Paul J. Plummer (Author), Qijing Zhang (Author), Orhan Sahin (Author)
• Format: Book
• Published: MDPI AG, 2022-04-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 10.3390/antibiotics11040531; 2079-6382
• Keywords: <i>Campylobacter</i>; cattle; colonization; rectal feces; bovine respiratory disease (BRD); fluoroquinolone/danofloxacin treatment; Therapeutics. Pharmacology; RM1-950
• Source: Antibiotics, Vol 11, Iss 4, p 531 (2022)

<i>Campylobacter</i> is a leading cause of foodborne gastroenteritis. Recent studies have indicated a rise in fluoroquinolone-resistant (FQ-R) <i>Campylobacter</i> in cattle, where FQ is used to control bovine respiratory disease (BRD). To assess the effect of danofloxacin treatment on the development of FQ-resistance in <i>C. jejuni</i>, 30 commercial calves were divided into Group 1, Group 2, and Group 3 (<i>n</i> = 10), and were all inoculated orally with FQ-susceptible (FQ-S) <i>C. jejuni</i>; seven days later, Group 3 was challenged with transtracheal <i>Mannheimia haemolytica</i>, and one week later, Group 2 and Group 3 were injected subcutaneously with danofloxacin. Rectal feces were collected to determine relative percentages of FQ-R <i>Campylobacter</i> via culture. Before oral inoculation with <i>C. jejuni</i>, 87% of calves were naturally colonized by FQ-R <i>C. jejuni</i>. Two days after the inoculation, FQ-R <i>C. jejuni</i> decreased substantially in the majority of calves. Within 24 h of danofloxacin injection, almost all <i>C. jejuni</i> populations shifted to an FQ-R phenotype in both FQ-treated groups, which was only transitory, as FQ-S strains became predominant during later periods. Genotyping indicated that the spike seen in FQ-R <i>C. jejuni</i> populations following the injection was due mainly to enrichment of preexisting FQ-R <i>C. jejuni</i>, rather than development of de novo FQ resistance in susceptible strains. These results provide important insights into the dynamic changes of FQ-resistant <i>Campylobacter</i> in cattle in response to FQ treatment.