Evaluation of Enterobacteriaceae Isolated from Ogbese River, Ovia North East LGA, Edo State

Ogbese River is about 150 meters from the Ogbese community in Ovia North East Local Government Area of Edo State, Nigeria. It serves as the major source of water to the inhabitants of the community. This is because it’s strategic location, makes it available for domestic, agricultural and industrial purposes. This study was aimed at evaluation of Enterobacteriaceae isolated from Ogbese River. Samples (27) were collected from three sampling points (upstream, midstream and downstream with 100 meters apart) into sterile containers and were immediately transported to the laboratory on ice packs. Standard bacteriological methods such as most probable number (MPN) and standard plate counts were employed to isolate and enumerate bacterial species. Identification of the Enterobacteriaceae was done by using biochemical and molecular methods. Kirby-Bauer disk diffusion technique was employed for evaluation of antibacterial sensitivity against standard antibiotics and the multiple antibiotic resistance index was evaluated. The data were analyzed using SPSS (Version 26) and MS Excel (2019) employing basic descriptive statistics. The results revealed that total heterotrophic bacterial counts ranged from 4.52 ±2.12 cfu/ml – 51.50 ±4.94 cfu/ml, while the total coliform counts ranged from 0.33 ±0.03 cfu/ml – 17 ±1.55 cfu/ml. The molecular identification of the bacterial isolates revealed the presence of Enterobacter hormaechei, Proteus vulgaris, Salmonella bongori, Escherichia coli, Serratia liquefasciens, and Shigella flexneri. The phenotypic virulence properties revealed that all isolates were beta-hemolytic. The antibiotic sensitivity tests revealed that all isolates were resistant to tetracycline and erythromycin but were susceptible to ciprofloxacin and meropenem. The values of the multiple antibiotic resistance (MAR) index of all the isolates were greater than 0.2 which is the permissible limit. This suggests that the isolates are of public health significance as a risk factor to consumption of water from Ogbese river hence relevant authorities should set up regulatory teams to monitor the quality of the river.