Prevalence and Molecular Detection of Quinolone-Resistant E. coli in Rectal Swab of Apparently Healthy Cattle in Bangladesh

Emergence of antibiotic resistance is a serious health problem both in human and animal all over the world. In this study, we investigated the prevalence of quinolone-resistant E. coli isolated from apparently healthy cattle in Mymensingh district, Bangladesh. A total of 137 rectal swabs was screened among which 95 was found positive for E. coli. Confirmation of isolation of E. coli was done by PCR targeting 16S rRNA gene of E. coli (prevalence 69.3%). Resistance against quinolone is primarily due to activities of qnrS and qnrA gene products. Among these E. coli quinolone-resistant gene qnrS was detected in 11 isolates. None of the isolates were found positive for qnr Agene. The overall prevalence of qnrS positive E. coli was 8.0%. Many of these quinolone-resistant E. coli was multidrug-resistant. Nucleotide sequence analysis of qnrS gene showed homology with the qnrS gene detected in China, Nigeria, Taiwan, Russia, Turkey and USA. All isolates that were resistant to multiple quinolones were found highly sensitive to imipenem, ertapenem and meropenem. The results of this study indicated that apparently healthy cattle harbor quinolone-resistant E. coli which have both clinical and public health significance. If strict regulation on the use of quinolones in food animals is not maintained, these quinolone-resistant E. coli may be transmitted to humans and other animals and may cause serious health problems in future. To the best of our knowledge, this is the first report on the molecular detection of quinolone-resistant E. coli in cattle in Bangladesh.