Bacteriological Quality and Prevalence of Multidrug Resistant Gram-negative Bacteria from Surface and Underground Domestic Water Sources in Selected Locations in Ibadan, Oyo State, Nigeria

Aim: To examine the bacteriological quality and prevalence of multidrug resistant (MDR) Gram-negative bacteria in surface and underground domestic water sources standard methods and antibiotic susceptibility testing was by disc-diffusion method. Results: The mean values of the total viable counts for the first water sample collection ranged from 3.1×10 2 to 6.2×10 4 cfu/mL and 2.4×10 2 to 6.1×10 4 cfu/mL for the second collection with the mean difference statistically significant for samples from sites AJR, DDR, ADM, EDM, WW-B and WW-G (P > .05). Most Probable Number of Coliforms ranged from 20 to >180/100 mL. A total of 7 bacteria genera including E. coli , Klebsiella spp., Proteus spp., Pseudomonas spp., Serratia spp., Providencia spp. and Enterobacter spp. were isolated. Among the isolates, 100% showed resistance to ampicillin, over 80% to amoxicillin, amoxicillin-clavulanic acid, cefuroxime and cefotaxime, 60% to ceftazidime, over 50% to ciprofloxacin and aztreonam, <40% to ofloxacin, nitrofurantoin and gentamicin while 100% were susceptible to the carbapenems. A total of 90.9% exhibited MDR phenotype. Conclusion: In this study, the presence of high level of coliforms with MDR phenotype in surface and underground water used domestically in Ibadan signifies a public health hazard that requires urgent attention.