Antimicrobial resistance in ESBL-producing Escherichia coli Isolated from layer and pig farms in Thailand

ABSTRACT

Background: Study of drug resistance of commensal bacteria in both humans and animals can determine the scale of the drug resistance problem. Usage of antimicrobials to treat infections in humans and animals has generated extensive antimicrobial pressure not only on targeted pathogens but also on commensal bacteria. Commensal Escherichia coli appears to be the major reservoir for resistant genes implicated in the transmission of genetic traits from one bacterium to another. Antimicrobial resistance in Enterobacteriaceae has increased dramatically worldwide in the last decade. An increasing number of community-onset extended-spectrum beta-lactamase (ESBL)-producing bacterial infections, especially those caused by ESBL-producing E. coli, have been reported in many countries, including Thailand. Moreover, ESBL-producing E. coli have been widely detected in food-producing animals and the environment. The increased use of ESBLs in food animals is a serious public health problem. The objective of the study was to determine the prevalence and antimicrobial resistance pattern of ESBL-producing E. coli isolated from pigs, layers, farm workers and stagnant water, in order to increase awareness about antimicrobial usage on farms and to minimize the expansion of the antimicrobial resistance phenomenon in farm settings.Materials, Methods & Results: A total of 588 samples were collected from 107 pig farms and 89 layer farms in Chiang Mai–Lamphun and Chon Buri provinces during May 2015-April 2016. Double-disk diffusion method according to EUCAST (European Committee on Antimicrobial Susceptibility Testing) guidelines was used for detection. The results demonstrated that 36.7% (216/588) of samples were ESBL-producing E. coli-positive, including rectal swabs 74.8% (80/107), pig farm worker stool swabs 57.0% (61/107), stagnant water on pig farms 21.5% (23/107), healthy layer rectal swabs 6.7% (6/89) and layer farm worker stool swabs 51.7% (46/89).[...](AU)