Microbiological and Molecular Characterization of Bacterial Communities in Domestic Water Sources in Nabuti Village, MukonoDistrict, Central Uganda

Abstract

Access to clean and safe water is crucial for community well-being. Water samples from storage tank water (STW) and municipal tap water (MTW) were aseptically collected, and total bacterial and coliform counts were determined. Isolates were Gram-stained, and conventional biochemical tests were conducted. Antibiotic susceptibility testing was performed using Kirby–Bauer’s disk diffusion technique. Selected isolates were confirmed through Sanger sequencing of amplified 16S rRNA genes. Polymerase chain reaction and gel electrophoresis techniques were used to determine the presence of quinolone and beta-lactam resistance genes. A total of 50 water samples were analyzed. The mean total coliform counts (TCCs) were 5.75 for STW and 5.5 for MTW. In total, 43 and 13 bacterial isolates were recovered from STW and MTW, respectively, with Gram-negative bacteria being more prevalent 58.14% (25/43) in STW and 81.82% (9/11) in MTW. The isolates appeared to belong to seven different presumptive bacterial genera on biochemical tests. The 16S rRNA gene amplicon Sanger sequencing of 38 isolates revealed 15 different species. A total of 38 isolates tested for resistance genes revealed that 47.37%, 31.58%, 21.05%, 10.53%, 28.95%, and 13.16% harbored gyrB, parC, gyrA, parE, blaSHV, and blaTEM genes, respectively. Antibiotic susceptibility profiling revealed a predominance of multidrug-resistant (MDR) strains among the bacterial isolates from both water sources. Regular monitoring and enhanced water treatment are critical to protect the public health and reduce the spread of potential pathogenic and antibiotic-resistant bacterial strains in household water systems.