Aim: Biofilm formation is a developmental process with intercellular signals that regulate growth. Biofilms contaminate catheters, ventilators, and medical implants; they act as a source of disease for humans, animals, and plants. In this study we have done a quantitative assessment of biofilm formation in bacterial isolates, associated with the drinking water distribution system, in tryptic soya broth, with different incubation times. Materials and Methods: The study was carried out on 104 samples of water from different systems. The bacterial isolates were processed as per the microtiter plate method with only tryptic soya broth, and with varying concentrations of glucose, and were observed in response to time. Results: Out of the total of 104 samples of water, 63 were found to be bacteriologically positive and 24 of them were biofilm formers. Enterobacter spp. and Pseudomonas were maximally found to be biofilm producing. Conclusion: Biofilm formation depends on adherence of bacteria to various surfaces. Overhead plastic tanks and metal taps were the most common sources being infected. We must have a regular policy to get them clean so as to have affordable and safe drinking water.
Key words: Biofilm, bacteria, drinking water system, microtiter plate method