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

Abstract

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.

Comparisons of plasma and fecal pharmacokinetics of danofloxacin and enrofloxacin in healthy and Mannheimia haemolytica infected calves

“…Subcutaneously administered enrofloxacin to calves achieved the intestinal concentration that could decrease intestinal bacteria 42 . Further, our metagenomic studies 21 , 22 have revealed that the fecal microbial diversity has been significantly changed in calves; some bacterial taxa responded differently to the low and high enrofloxacin doses. The fecal resistome profiles have been affected remarkably in FQs administered groups compared to the control groups 21 , 22 .…”

“…In this study, there were four groups of calves: low-dose control, low-dose BRD, high-dose control, and high-dose BRD. The animal study was detailed in our recent publication 22 .…”

Extended-Spectrum Beta-Lactamases Producing Enterobacteriaceae in the USA Dairy Cattle Farms and Implications for Public Health

“…Both experimental and observational studies indicated that antibiotic use and thus, the resultant selection pressure is an important factor driving the emergence and persistence of ARB and their resistance genes [ 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 ]. Mastitis is the most frequent disease of dairy cattle; and ceftiofur is the most commonly used antimicrobial drug used to manage it [ 5 , 68 ].…”

Effect of time of sample collection after onset of diarrhea on fecal microbiota composition of calves

“…The importance of the gut microbiota has led to an increase in the number of studies investigating the role of bacterial communities on the health and disease of neonatal calves. The impact of different intervention and management practices (eg, antimicrobial drugs, colostrum, or probiotic administration) on the gut microbiota has also been frequently investigated 1‐5 . Most of these studies explore the variation on fecal characteristics and microbiota over time by collecting samples on a weekly basis 2,6‐8 .…”

“…The impact of different intervention and management practices (eg, antimicrobial drugs, colostrum, or probiotic administration) on the gut microbiota has also been frequently investigated. 1 , 2 , 3 , 4 , 5 Most of these studies explore the variation on fecal characteristics and microbiota over time by collecting samples on a weekly basis. 2 , 6 , 7 , 8 During such weekly visits, researchers collect feces from all animals enrolled in the study.…”