Bacteriological Quality and antimicrobial susceptibility of some isolates of Well Waters Used for Drinking in Jimma Town, Southwest Ethio

Abstract

Well waters could be polluted with fecal materials due to inadequate protection, depth of wells, distance and position relative to latrine house, unhygienic practice at the source and poor environmental sanitation. The objectives of this study were to assess the current bacteriological safety of well waters being used for drinking and other domestic uses; and also to evaluate the antibiotic susceptibility patterns of bacterial species isolated from some of the wells in Jimma town, southwestern Ethiopia. Accordingly, bacteriological quality and safety, as well as physico-chemical properties of water samples collected from 30 purposively selected wells were assessed following the standard microbiological methods. Pure isolates were characterized to species level using API 20 E kit and evaluated for resistance patterns towards ten antimicrobial agents being used for human medication. The finding of the study showed that the mean pH (6.64- 6.8) of all the studied well water samples was within acceptable range (pH= 6.5-8.5), while the mean temperature was not. Likewise, the mean microbial counts (cfu/ml) of the samples were beyond the value recommended by World Health Organization. Accordingly, the mean count (cfu/ml) of aerobic mesophilic bacteria (AMB) was 908 (360 – 1490), while those of Entrobacteriaceae and coliforms were 332 and 234, respectively. A total of 15 representative bacterial species including Aeromonas hydrophilia (3), Enterobacter cloacae(1), Serratia liqueofaciens(1), Enterobacter sakazaki(1), Serratia marcesense(1), Klebsella orithinolytica(4), and Escherichia coli(1) were identified to species level. All isolates were sensitive to Amikacin (AK), Norfloxacin (Nx), Kanamycin (K), Bacitracin (B) and Tetracyclin (T). On the other hand, all isolates were resistant to Methicillin (M) and Pencillin G (P). Stains of Klebsella ornithinolytica showed the highest resistance against most of the antibiotics tested. In general, the well water samples analyzed in this study were found in unacceptable condition in terms of bacteriological quality. Moreover, the identification of Escherichia coli in some of the wells indicates the safety problem of the water for human consumption. Therefore, it calls for proper disinfection and monitoring of the water sources besides awareness creation to the well owners.