Enrofloxacin Alters Fecal Microbiota and Resistome Irrespective of Its Dose in Calves

Beyi, Ashenafi Feyisa
Brito-Goulart, Debra
Hawbecker, Tyler
Ruddell, Brandon
Hassall, Alan
Dewell, Renee
Sahin, Orhan
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Veterinary Microbiology and Preventive MedicineVeterinary Diagnostic and Production Animal MedicineCenter for Food Security and Public Health
Enrofloxacin is a fluoroquinolone drug used to prevent and control bovine respiratory disease (BRD) complex in multiple or single doses, ranging from 7.5 to 12.5 mg/kg body weight. Here, we examined the effects of high and low doses of a single subcutaneously injected enrofloxacin on gut microbiota and resistome in calves. Thirty-five calves sourced for this study were divided into five groups: control (n = 7), two low dose groups (n = 14, 7.5 mg/kg), and two high dose groups (n = 14, 12.5 mg/kg). One group in the low and high dose groups was challenged with Mannheimia haemolytica to induce BRD. Both alpha and beta diversities were significantly different between pre- and post-treatment microbial communities (q < 0.05). The high dose caused a shift in a larger number of genera than the low dose. Using metagenomic ProxiMeta Hi-C, 32 unique antimicrobial resistance genes (ARGs) conferring resistance to six antibiotic classes were detected with their reservoirs, and the high dose favored clonal expansion of ARG-carrying bacterial hosts. In conclusion, enrofloxacin treatment can alter fecal microbiota and resistome irrespective of its dose. Hi-C sequencing provides significant benefits for unlocking new insights into the ARG ecology of complex samples; however, limitations in sample size and sequencing depth suggest that further work is required to validate the findings.
This article is published as Beyi, Ashenafi Feyisa, Debora Brito-Goulart, Tyler Hawbecker, Brandon Ruddell, Alan Hassall, Renee Dewell, Grant Dewell, Orhan Sahin, Qijing Zhang, and Paul J. Plummer. "Enrofloxacin Alters Fecal Microbiota and Resistome Irrespective of Its Dose in Calves." Microorganisms 9, no. 10 (2021): 2162. DOI: 10.3390/microorganisms9102162. Copyright 2021 by the authors. Attribution 4.0 International (CC BY 4.0). Posted with permission.
antibiotic resistance, bovine respiratory disease complex, calves, fluoroquinolone/enrofloxacin, gut microbiota, resistome profiles