Physicochemical and Antibacterial Susceptibility Profile of Fish Pond Waters in Anambra State, Nigeria

Abstract

Fishes are good source of dietary protein, reared in artificial ponds in most countries. Poor sanitary condition predisposes the fishes to infestation by pathogenic microorganisms. This study was aimed at evaluating the bacteriological and physicochemical characteristics of fish pond waters in three senatorial zones in Anambra State, Nigeria and the antibiogram of the isolates determined. A total of 480 fish pond water samples collected from different fish farms during May to October 2016 (Rainy season) and November to April, 2017 (Dry season) were cultured and their physicochemical properties examined. Susceptibility of the isolates to conventional antibiotics was determined. Bacterial isolates recovered were identified based on their biochemical features. They include genera of Vibrio, Aeromonas, Pseudomonas, Lactobacillus, Staphylococcus, Microbacterium, Serratia, Proteus, Bacillus, Streptococcus, Citrobacter, Micrococcus, Enterococcus, Enterobacter, Paenalcaligenes, Lysinibacillus, Acinetobacter and Escherichia. The most occurring organism in the pond water in both seasons was Staphylococcus sp. The physicochemical parameters of the pond water samples showed that there was significant difference (p value 0.05) was observed in turbidity, phosphate and biological oxygen demand (BOD). Based on estimated marginal means, BOD, DO and alkalinity were higher during rainy season, while temperature, pH, conductivity, turbidity, nitrite, phosphate and sulphate were higher during dry season. Bacterial load obtained in the fish pond water samples, during dry and rainy seasons and in the three senatorial zones vary significantly (p value < 0.05). Percentage susceptibility of isolates to antibiotics was highest with chloramphenicol, vancomycin, ciprofloxacin and trimethoprim (93.3%), and least with erythromycin (66.7%). This study showed high bacterial contamination of fish pond waters, physicochemical parameters at variance with the WHO standard and presence of antibiotic resistant organisms. Therefore, proper sanitary measures are necessary to prevent disease outbreak among fish consumers.