Bacterial diversity and biofilm formation potential in well water sources

Access to clean and safe drinking water is a major public health concern, particularly in communities where well water serves as a primary source. This study aimed to assess the bacterial diversity and biofilm formation potential in well water from three sources (designated as Wells A, B, and C) in Gida Dubu, Dutse, Jigawa State, Nigeria. Water samples were collected at three time points (morning, midday, and evening) over five days. Bacterial isolation was performed using the membrane filtration technique. Isolated bacteria were identified based on colony morphology, Gram reaction, and biochemical characteristics. The biofilm-forming potential of the isolates was evaluated using the crystal violet staining assay. The bacterial species identified included Escherichia coli (12.5%), Enterobacter sp. (16.0%), Pseudomonas sp. (14.6%), Klebsiella sp. (10.4%), Salmonella sp. (8.3%), Aeromonas sp. (11.1%), Citrobacter sp. (10.4%), Shigella sp. (6.3%), Serratia sp. (6.3%), Yersinia sp. (2.1%), and Proteus sp. (2.1%). Enterobacter was the most prevalent species across all wells (23 occurrences), followed by Pseudomonas (21 occurrences) and E. coli (18 occurrences). Well B exhibited the highest bacterial diversity. The study further revealed that Enterobacter sp., Pseudomonas sp., E. coli, and Aeromonas sp. were the most prominent biofilm formers, with Enterobacter sp. showing the highest frequency of strong biofilm formation (12 occurrences). Conversely, Yersinia sp. and Proteus sp. exhibited weak or no biofilm formation. The findings demonstrate the presence of a diverse array of potentially pathogenic bacteria in the well water sources, with significant biofilm formation potential among certain species, indicating a possible risk to water quality and public health.