A study of bacterial antibiotic resistance in four major waterways in a taiwanese city

Abstract

This study tested water samples from four major waterways (Luchuan Canal, Liuchuan Canal, Meichuan Canal, and Mayuantou River) in the center of Taichung, Taiwan, so as to know the viable count of Gram-negative bacteria (VCGB), bacterial resistance patterns, and drug-resistant strains. The samples were collected from the upper, middle, and lower reaches of the waterways, and spread on the MacConkey (MAC) agar plates without antibiotics and with ampicillin (Ap), kanamycin (Km), or tetracycline (Tc). The colonies formed (CFU) were calculated, the colony appearance was observed, and the drug resistance patterns were recorded. Results showed that VCGB in Luchuan Canal, Liuchuan Canal, Meichuan Canal, and Mayuantou River ranged from 12,200 to 56,600 CFU/ml, 6,760 to 44,400 CFU/ml, 11,200 to 21,800 CFU/ml, and 6,800 to 54,800 CFU/ml, respectively. The lactose-fermenting intestinal bacteria (LFIB) accounted for 11.6% to 81.8% of the VCGB. In addition, the drug-resistant microorganisms exist in waters universally. The strains resistant to the aforesaid three antibiotics were identifi ed as Escherichia coli, Klebsiella, Providencia stuwartii, and Aeromonas. A lot of untreated effl uent might be discharged into the rivers fl owing across Taichung, seriously threatening human health. The fi ndings highlight the importance of building sewage disposal systems.