台中地區水域環境的細菌抗藥性之研究

Bacterial antibiotic-resistance in water bodies in the Taichung area

目標：抗生素的大量使用，已導致細菌抗藥性的問題日趨嚴重。本研究檢測台中地區的一些「封閉式」水域環境，以及流經都市的「開放式」水路，以瞭解其中之含菌量、細菌抗藥型態及抗藥菌種。方法：於各水域環境中共採集23個樣本。採樣後，檢測水質酸鹼度，再分別塗抹於不含抗生素，以及含安必西林(Ap)、卡那黴素(Km)及四環素(Tc)之培養基上，計算菌落數量(CFU)，觀察菌落外觀，分析抗藥型態，並鑑定多重抗藥之菌種。結果：「封閉式」水域環境中的菌量介於0至11,800 CFU/ml；「開放式」水路的水樣菌量介於3,900至79,200 CFU/ml。抗藥性微生物普遍存在於水域中，尤其是「開放式」水域環境。在檢測的水樣中，對安必西林與卡那黴素具抗性的菌種最普及。對上述三種抗生素皆具抗性的菌種包含6種革蘭氏陰性菌。結論：可能有大量未經處理的污水排放於流經台中市的河川，其中包含具多重抗藥性之大腸桿菌，對人體健康具威脅。研究結果突顯台中市亟須建立污水處理系統之必要性。

Objectives: Extensive use of antibiotics has caused an increase in bacterial drug resistance. Unfortunately, bacteria get into various water bodies easily. The purpose of this study was to determine the amounts and drug-resistance patterns of bacteria present in the closed water bodies and the streams flowing through Taichung City. Methods: A total of 23 water samples were collected. After measuring the pH values, viable bacterial counts (expressed as colony forming units [CFU]) were determined in the samples, as well as resistance to antibiotics, including ampicillin (Apr), kanamycin (Kmr), and tetracycline (Tcr), and morphology of the colonies. Results: The total viable counts in the samples obtained from the closed water bodies and streams ranged between 0 and 11,800 CFU/ml and 3,900 and 79,200 CFU/ml, respectively. Drug-resistant microorganisms were commonly found, especially in the streams, with Apr, Kmr, Tcs strains the most prevalent and Aps, Kmr, Tcr strains the least common. Species identification revealed that the Apr, Kmr, Tcr strains included Escherichia coli, Klebsiella rhinoscleromatis, K. pneumoniae, Serratia plymuthica, Proteus mirabilis, and one kind of glucose non-fermenting gram-negative bacilli. Conclusions: The presence of high levels of bacteria indicates that streams flowing through Taichung City are receiving large volumes of untreated sewage discharge. More importantly, high levels of multiple drug-resistant bacteria, especially coliforms, pose a high risk to human health. Based on these findings, establishment of sewage treatment systems for Taichung City is highly recommended.