Microflora and Antibiotic Susceptibility Pattern of Some Microbes from Aquaculture Waste-water from Lagos, Nigeria

Aquaculture is the fastest growing food industry in the world. It can be practiced on a small, medium or large scale. The proliferation of fish ponds and the indiscriminate discharge of waste water from aquaculture into the environment without adequate treatment are of a great environmental and public health concern.

Waste water were collected from seven fish farms around Lagos, the samples were analyzed for total heterotrophic bacteria, fungi, total coliform , faecal coliform and other bacteria of public health importance. The antibiotic susceptibility of the isolates obtained was also carried out.

A total of about one hundred and twenty-nine (129) bacteria isolates were obtained. The total heterotrophic bacterial count ranged between 1.00 x 10⁴ and 2.32 x 10⁶cfuml^-1 while the total fungi count ranged between 1.31 x 10⁴ and 6.25 x 10⁴cfuml^-1 . The bacterial isolates were identified to belong to the genera Pseudomonas, Micrococcus, Bacillus, Staphylococcus and Enterobacteriacea. The fungal isolates encountered include Aspergillus sp, Mucor sp, Rhizopus sp, Penicillium sp and Fusarium sp. The isolates obtained exhibited varying levels (7.14 – 100%) of resistance to all the eleven antibiotics tested, however, the resistance of the isolates to cloxacillin (100%) and erythromycin (85.7%) is noteworthy.

The microbiological quality of the fish pond effluents and the level of multiple antibiotics resistance demonstrated by the isolates suggest a need for comprehensive waste management system in our aquaculture practice.

Key words: Fish, fish ponds, waste water, microorganisms, antibiotic susceptibility, aquaculture.