Occurrence and Spread of Quinolone-Resistant Escherichia coli on Dairy Farms

Abstract

Quinolone-resistant Escherichia coli (QREC) is common in feces from young calves, but the prevalence and genetic diversity of QREC in groups of cattle of other ages and the farm environment are unknown. The aims of the study were to obtain knowledge about the occurrence of QREC on dairy farms, the genetic diversity of QREC within and between farms, and how these relate to the number of purchased animals and geographic distances between farms. We analyzed the within-sample prevalence of QREC in individual fecal samples from preweaned dairy calves and postpartum cows and in environmental samples from 23 Swedish dairy farms. The genetic diversity of the QREC isolates on 10 of these farms was assessed. In general, QREC was more prevalent in the dairy farm environment and in postpartum cows if QREC was commonly found in calves than if QREC was rare in calves. In particular, we found more QREC organisms in feed and water troughs and in environments that may come into contact with young calves. Thus, the results suggest that QREC circulates between cattle and the farm environment and that calves are important for the maintenance of QREC. Some genotypes of QREC were widespread both within and between farms, indicating that QREC has spread within the farms and likely also between farms, possibly through purchased animals. Farms that had purchased many animals over the years had greater within-farm diversity than farms with more closed animal populations. Finally, animals on more closely located farms were more likely to share the same genotype than animals on farms located far apart. IMPORTANCEThis study investigates the occurrence of a specific type of antimicrobial-resistant bacterium on dairy farms. It contributes to increased knowledge about the occurrence and spread of these bacteria, and the results pave the way for actions or further studies that could help mitigate the spread of these bacteria on dairy farms and in the community as a whole.

Antimicrobial use policy change in pre-weaned dairy calves and its impact on antimicrobial resistance in commensal Escherichia coli: a cross sectional and ecological study

“…Fluoroquinolone treatment is known to suppress Enterobacteriaceae , but this is followed some days or weeks later by increased prevalence in quinolone resistant Enterobacteriaceae [23]. Another explanation for quinolone resistance could be that quinolone resistant E. coli are common in the feces of pre-weaned dairy calves and the farm environment, hence, calves can acquire exogenous strains from the farm environment [24].…”

Prevalence and molecular detection of fluoroquinolone-resistant genes (qnrA and qnrS) in Escherichia coli isolated from healthy broiler chickens

“…In Bangladesh, few previous studies were carried out to investigate the occurrence and characterization of fluoroquinolone- and quinolone-resistant E. coli in human [7,8]. Quinolone-resistant E. coli has also been detected in healthy cattle and other animals from many other countries [9,10]. Recently, in a study in Bangladesh, quinolone-resistant E. coli was detected from apparently healthy cattle [11].…”

Role played by the environment in the emergence and spread of antimicrobial resistance (AMR) through the food chain

“…A Swedish study on dairy farms found that environmental samples (feed and water troughs in calving areas) collected from farms with high levels of quinolone resistant E. coli , showed greater contamination with these organisms than other sample types. Water and feed contamination therefore appeared to play a role in the dissemination of these organisms within the farms (Duse et al., 2016). The frequency of water trough disinfection was negatively correlated with the prevalence of cefotaxime‐resistant bacteria in calves in a study in the US, suggesting transmission of ARB between animals through contaminated drinking water troughs (Markland et al., 2019).…”