Occurrences of antibiotic resistant bacteria in a tropical river impacted by anthropogenic activities in Ho Chi Minh City

Antibiotic resistance causes serious health problems associated with an increase in hospitalization time, treatment cost, and mortality. In this study, the contamination levels of antibiotic resistant bacteria were determined in the Saigon River, which is impacted by different anthropogenic activities in Ho Chi Minh City. Five target antibiotics were supplemented to the R2A medium at the concentration of amoxicillin (9.6 µg/ml) / clavulanic acid (4.8 µg/ml), amikacin (19.2 µg/ml), cefixime (1.2 µg/ml), ciprofloxacin (1.2 µg/ml), and trimethoprim (2.4 µg/ml)/ sulfamethoxazole (45.6 µg/ml). As the results, the antibiotic resistant bacteria were found in all the sampling sites and at the highest concentration at the sites impacted by wastewater from both industrial and residential activities. Enterobacteriaceae was the most abundant family with 23.8% of total isolates of the antibiotic resistant bacteria. Human opportunistic pathogens and pathogens such as Klebsiella pneumoniae (6.74%), Enterobacter sp. (4.15%), Escherichia coli (6.63%), Stenotrophomonas maltophilia (3.11%), Aeromonas Caviae (4.66%) were identified in all surface water samples. Correlation analysis suggested that the pollutions of dissolved salt, organic matter, and wastewaters may facilitate the antibiotic resistant bacteria in the aquatic environments.