Screening and Identification of Antibiotic Resistant Gene int1 in Coliforms Isolated From Drinking Water

Abstract

Antibiotic-resistance genes carried by coliforms in drinking water is a concerning issue for public health in Bangladesh. This research was carried out to identify coliforms in drinking water and to understand the importance of the int1 gene of coliforms in the spread of resistance to bacterial antibiotics through consumption of contaminated water. A total of 31 drinking water samples were collected from restaurants ( n = 18), health center ( n = 9), and residences ( n = 4) located in Chattogram City, Bangladesh. The isolation and identification of coliforms was performed on selective media with a combination of biochemical and molecular analysis. PCR amplification of the LacZ, uidA and int1 genes was carried out for the identification of the coliform and fecal coliform and antibiotic resistant gene, respectively. Antimicrobial susceptibility test was performed according to the Kirby-Bauer disk diffusion method with McFarland standard against three selective antibiotics including co-trimoxazole, ciprofloxacin, and ampicillin. Of 31 drinking water samples, coliforms were detected within 32% ( n = 10) of the water samples, nine samples were collected in restaurants and one sample in a residence. But no coliform was detected in the drinking water of the health center. Among the identified coliforms, the prevalence of fecal coliforms and the int1 gene was 60% ( n = 6) and 40% ( n = 4), relatively. All isolates containing the int1 microbial-resistance gene were resistant to ampicillin.This study shows that drinking water consumed in different restaurants located in Chattogram, Bangladesh is contaminated by antibiotic-resistant gene bearing coliforms that not only increase the risk of water-borne disease, but also may be the major cause of antibiotic resistance transmission in this part of Bangladesh.