ESBL-producing Klebsiella sp. isolated from raw milk of healthy cow in small holder dairy farms of Mymensingh district in Bangladesh

Abstract

Background: The emergence of extended-spectrum beta-lactamase (ESBL) bacteria such as Klebsiella sp. in milk is a serious public health concern. Antibiotic resistance profile and molecular characterization of ESBL-producing Klebsiella sp. (ESBL-Kleb) from milk of healthy cow have not yet been reported in Bangladesh. This study aims to detect and characterize ESBL-Kleb from milk samples of the healthy cow in the smallholder dairy farm of Mymensingh district, Bangladesh. Methods: A total of 100 milk samples were collected from apparently healthy cows of smallholder dairy farms. Klebsiella sp. was isolated from milk samples as per standard methods. The detection of ESBL-Kleb was done phenotypically by a double-disc synergy test. Subsequently, ESBL gene grouping of the isolates was done by multiplex PCR. Antimicrobial susceptibility testing of the ESBL-Kleb isolates was done using the common 15 antimicrobials by the disc diffusion method. Results: In this study, Klebsiella sp. was isolated from 30 (30%) samples whereas 20 (67%) of the isolate was ESBL producer both phenotypically and genotypically with the presence of blaTEM and blaSHV individually or combined (blaTEM plusblaSHV). The ESBL-positive isolates were highly resistant against commonly used antibiotics such as ampicillin, cefotaxime, gentamicin (100%), ceftazidime (80%), cotrimoxazole/trimethoprim (40%), and oxytetracycline (30%). Most importantly multidrug resistance (MDR) was found in a high number of the ESBL-Kleb isolates. However, the isolates were 100% sensitive to drugs such as ceftriaxone imipenem, azithromycin, chloramphenicol, and cefepime. To the best of our knowledge, this is the first report of detection of ESBL-Kleb in raw milk of healthy cow of smallholder dairy farm in Bangladesh. Conclusion: The presence of a high number of MDR ESBL-Kleb in raw milk of healthy cows of smallholder dairy farms might be alarming for public health.