Isolation of antibiotic resistant bacteria from rivers in Terengganu, Malaysia

Abstract

Infectious disease cause by antibiotic resistant bacteria has been more difficult to treat because the ability of these bacteria to avoid the effect of antibiotic medication. Nowadays, water environment especially river has become the reservoir for the dissemination of antibiotic resistant bacteria due to antibiotic contamination derived from human activities. The exposure to antibiotic resistance bacteria in water increase the health risks associated with the waterborne bacteria in animals and humans. Therefore, this study was carried out to investigate the presence of antibiotic resistant bacteria from two rivers in Terengganu; Ibai River and Terengganu River. A total of 24 bacterial strains were isolated from both rivers. Antibiotic susceptibility of the bacteria isolates were assayed according to the Kirby-Bauer disk diffusion method using six types of antibiotics; ampicillin, rifampicin, gentamicin, tetracycline, ciprofloxacin and chloramphenicol. The results of this study indicate that 100% of bacterial strains were resistant to at least two antibiotics tested. The multiple antibiotic resistant (MAR) index of these bacteria was calculated and 23 bacterial strains show MAR index of more than 20%. These bacteria were selected for further characterization using 16S rRNA gene sequencing. Among the 23 isolates, a total of 10 bacterial strains (2A, 2B, 2C, 2I, 3A, 3B, 4A, 4C, 4D and 4E) were successfully identified as Chromobacterium violaceum, Enterobacter tabaci, Bacillus wiedmannii, Acinetobacter baumannii, Klebsiella quasipneumoniae subsp. quasipneumoniae, Chromobacterium aquaticum, Cupriavidus metallidurans, Weeksella massiliensis, Cupriavidus necator and Acinetobacter nosocomialis. The results from this study show that both of the rivers are exposed to high level of antibiotics compound which may lead the bacteria to develop mechanism of antibiotic resistant. This may cause a serious threat to the public health and environment.