Dissemination of diarrheagenic bacteria in community-based natural water sources and wastewater environments: A comprehensive analysis in University of Nigeria, Nsukka and its metropolis

Abstract

The presence of pathogenic strains abounds in our environment, arising from many sources. The study was aimed at identifying Vibrio species, E. coli, and other coliforms in various water sources within a university setting and its metropolis. Approximately 20 samples from roof-collected rainwater, municipal piped tap water, borehole water and 60 samples of sewage effluent from the central effluent water of University of Nigeria, Nsukka were systematically collected at intervals and subjected to bacteriological analysis. The samples underwent dilutions, and aliquots were inoculated on chromocult and thiosulfatecitrate-bile salts-sucrose (TCBS) agar. Simultaneously, 100 ml of each natural water sample underwent membrane filtration, followed by the inoculation of TCBS agar plates in duplicates. Both sets of culture plates were incubated at 37 °C for 24 h. Further biochemical characterization was performed after microscopy. Susceptibility profile was done using disk diffusion assay. Descriptive statistics were used in the aggregation of the results where necessary. Results revealed that each sample, when plated on chromocult agar, yielded a substantial number of colonies of E. coli (bluish colour) and other coliforms (pink-red colonies). Notably, wastewater gave a maximum yield of Vibrio cholera. Conversely, all significant pathogenic Vibrio species were recovered on TCBS agar inoculated with natural water samples, wastewater and sewage effluent, with isolation rates appearing independent of both time (in weeks) and collection points. Antimicrobial susceptibility studies disclosed that some of the isolates exhibited antibiotic resistance. The study underscores the need to install appropriate measures to mitigate the contamination of the environment.

Keywords

• Wastewater, Vibrio, Antimicrobial, Chromocult, Pathogen, Sewage