Unseen Threats in Our Water: Assessing Bacterial Contamination in Institutional Tap Water and Vended Water (Meruwa) in Otuogidi-Ogbia and Ogbia Main Town, Bayelsa State, Nigeria

Rationale: Safe drinking water is essential for human health, yet bacterial contamination remains a pervasive challenge in resource-limited settings. In the Niger Delta region of Nigeria, aging infrastructure, environmental degradation, and inadequate water quality monitoring contribute to persistent waterborne disease burden. However, no prior study has systematically characterized and compared bacterial contamination in both institutional tap water and informal vended water (Meruwa) in this region, leaving critical evidence gaps for policy and intervention. Objectives: This study aimed to: (i) assess the presence, types, and levels of bacterial contamination in tap water from Bayelsa State College of Health Technology and vended water from Ogbia Main Town; (ii) compare contamination levels and bacterial species distribution between the two water sources; (iii) evaluate compliance with World Health Organization (WHO) drinking water standards; and (iv) provide evidence-based recommendations for water safety interventions. Methods: A total of 47 water samples were analyzed, 23 tap water samples from six campus points and 24 vended water samples from vendors in Ogbia Main Town. Total bacterial counts (TBC) and total coliform counts (TCC) were determined using the plate count method on nutrient agar and MacConkey agar, respectively. Bacterial isolates were identified through Gram staining and biochemical characterization (catalase, coagulase, oxidase, citrate, urease, indole, Kligler iron agar, motility). Compliance was assessed against WHO guidelines (0 CFU/100 mL for coliforms;