ISOLATION AND IDENTIFICATION OF VARIOUS BACTERIA IN DRINKING WATER IN BAHAWALPUR CITY, PAKISTAN.

Introduction: Waterborne diseases remain a major global public health concern, especially in low- and middle-income countries like Pakistan. Contamination of drinking water due to poor sanitation and unhygienic storage practices contributes significantly to the disease burden. Bacterial pathogens such as Escherichia coli, Salmonella typhi, Staphylococcus aureus, and Pseudomonas aeruginosa have been frequently isolated from drinking water in affected regions. Objective: To isolate and identify bacterial contaminants in drinking water samples from various residential colonies of Bahawalpur City, Pakistan. Methods: This cross-sectional study was conducted from January 2024 to August 2024 after ethical approval from the Bahawalpur Medical and Dental College, Bahawalpur. A total of 250 water samples were collected from different colonies using sterilized 250 ml glass bottles. Samples were transported and stored under strict aseptic and cold chain conditions. Water was cultured on MacConkey, CLED, Blood, and Chocolate agar media. Bacterial isolates were identified using Gram staining and standard biochemical tests. Results: Public filtration plant water samples showed no microbial growth. In contrast, water with added market ice revealed mixed growth of E. coli and Salmonella. Water stored in plastic tanks was found to contain Salmonella, Pseudomonas, and Staph. aureus. Filtered dispenser water was free from contamination. Poor households storing water in earthen pots showed bacterial contamination. Overall, E. coli (60%) and Salmonella typhi (54%) were the most frequently isolated organisms. Conclusion: Unsafe storage and handling practices, along with poverty and illiteracy, contribute significantly to microbial contamination of drinking water. Community education and improved sanitation are essential to reduce disease transmission.