South Asian Journal of Research in Microbiology

This study investigated the pattern of occurrence of antibiotic resistant bacteria in biofilms in water from groundwater sources in Ado-Ekiti, Nigeria. Water samples were collected from boreholes and wells within Ado-Ekiti metropolis over a period of 4 months (n = 100), and biofilm samples were taken at interval of seven days within the period of storage and subjected to microbiological analysis until the total bacterial counts were significant. Enumeration of bacteria in biofilms and antibiotic sensitivity of the bacterial isolates were carried out using standard microbiological methods and multiple antibiotic resistant indexes of the bacterial isolates were calculated. Results showed that a total of 202 bacterial isolates were obtained from the biofilms of the water samples and this include Streptococcus faecalis, Escherichia coli, Enterobacter aerogenes, Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus aureus, Salmonella typhi and Shigella dysenteriae. Of all the bacterial isolates, Streptococcus faecalis had the highest frequency of occurrence (90 %). The bacterial isolates from the biofilms in water from borehole had the highest bacterial count (1.11 × 10⁴ cfu/ml) and were more resistant to antibiotics, whereas those from well had the least bacterial count (0.78 × 10⁴ cfu/ml) and were less resistant to antibiotics. A total of 106 (52.5%) bacterial isolates displayed multiple antibiotic resistance (MAR) with indexes greater than 0.2. The findings from this study suggest high prevalence of MAR indexes indicating high source of contamination in areas where antibiotics are used in Ado-Ekiti. Water from the groundwater sources should be treated at point of use and should not be stored for too long before use to prevent the development of biofilms that may be of great significance to human health.