Bacteriological Quality Assessment and Antibiogram Profile of Bacteria Associated with Sachet Drinking Water Sold at Zaria, Northern Nigeria

Aims: Bacteriological quality assessment and antibiogram profile of bacteria associated with sachet drinking water was carried out with view to determine the bacterial load and fitness of the water sold in the study area for human consumption.

Materials and Methods: Ten samples of different brands were aseptically collected and analyzed using heterotrophic count and most probable number technique. The isolated bacteria were microscopically and biochemically characterized and finally confirmed using Box™ Easygel® E. coli Quantitube™ Test Kit (Micrology Laboratories manufactures, Easygel®, USA) biotyping. Physicochemical analysis of the samples was done using standard methods. The isolated bacteria were screened for antimicrobial susceptibility using Kirby-Bauer disc diffusion technique.

Results: The total heterotrophic bacterial count ranged from 1.0×102 to 3.0×102 cfu/ml, with MPN/100ml values ranged from <0.03 to 1.2. The temperature ranged from 8 to 18°C, at the pH range of 5.0 to 7.6. The findings showed that, high temperatures and pH was associated with high bacterial counts. There was no statistical relationship between microbial loads and the temperature (p= 0.454) of the analyzed sachet water. Also, there was no statistical relationship between microbial loads and pH (p= 0.446) of the sachet water. The bacteria isolated were Escherichia coli, Enterobacter aerogenes, Salmonella sp, Citrobacter freundii and Proteus vulgaris. Most 9 (90%) of the water analyzed fell within the statutory limits. While, the remaining 1 (10%) fell within the contamination level, which recorded high bacterial counts beyond the standard of safe drinking water set by water and food regulatory bodies.

Conclusion: The isolation of E. coli and Salmonella sp. in sample brand “A” in this study is an indication that if not promptly checked, an outbreak could occur in the near future. All the isolates are susceptible to variety of antibiotics used, except Enterobacter aerogenes, Salmonella sp. and Citrobacter freundii which recorded resistance to amoxicillin, and Proteus vulgaris which recorded multidrug resistance.