Incidence of pathogenic bacteria in the Asejire Lake, western Nigeria

Abstract

The incidence of pathogenic bacteria in Asejire Lake, Ibadan, Nigeria was studied. Water samples were collected weekly in sterile bottles from five stations for eight weeks. These samples were inoculated in double and single strength MacConkey Broth, containing inverted Durham's tubes, incubated at 37oC for 48 hours. They were examined for the presence of acid and gas. Those culture tubes showing positive results were compared with those of MacConkey's Probability Table. Results from this study indicate that the lake has been contaminated with faecal matter. This was implied as a result of the presence of the bacteria (Escherichia coli) in this freshwater lake; other bacteria isolated include Pseudomonas and Micrococcus species. This water body is therefore considered unsuitable for drinking.


KEY WORDS: Feacal contamination, presumptive coliform count, coliform bacteria population, pathogenic bacteria, commensal bacteria.


Tropical Freshwater Biology, 10 (2001) 75 - 80