Recreational water quality in the river Mahaweli, Sri Lanka: Enumeration and antibiotic sensitivity of <em>Escherichia coli</em> and sociological aspects

Although recreational water quality affects health, in Sri Lanka, recreational water quality is hardly assessed. Faecal contamination of water poses health risks as faeces are a source of pathogens. The current study aimed to investigate Escherichia coli in recreational water by enumerating and assessing antibiotic sensitivity, and to conduct a sociological survey. Water samples (n = 72) were collected from six bathing locations along the river Mahaweli during rainy and dry periods, and subjected to membrane filtration. Typical blue colonies on m-FC agar were enumerated. An antibiotic sensitivity test was performed on E. coli isolates using seven antibiotics commonly used in Sri Lanka. Escherichia coli counts in 95.0% of water samples exceeded the permissible limit (235 CFU/100 mL). Mean E. coli counts were significantly higher (p < 0.05) during the rainy period compared to the dry period. In both periods, mean counts were significantly higher (p < 0.05) in more populated locations than less populated locations. Antibiotic resistant E. coli were present in varying degrees in all locations. Isolates were resistant to ciprofloxacin (56.5%), cefotaxime (4.8%), amoxicillin-clavulanate (4.2%), amikacin (3.0%), and ticarcillin-clavulanate (0.6%). None were resistant to imipenem or meropenem. The percentages of isolates resistant to amikacin, amoxicillin-clavulanate, and ciprofloxacin were significantly higher in less populated locations compared to more populated locations (p < 0.05), while the percentage for cefotaxime was higher in more populated locations. According to the sociological survey (n = 60), inadequate sewage facilities and urban runoff are likely reasons of pollution. Elevated E. coli counts and the presence of antibiotic-resistant E. coli render the water unsuitable for recreational purposes.