Distribution and Factors Associated with Occurrence of Listeria monocytogenes in Table Size African Catfish, Pond Water and Sediment in Two Ecological Zones in Nigeria

Occurrence of Listeria monocytogenes (LM) and associated factors affecting its distribution in Oyo state, Nigeria was investigated in 2016. A total number of 972 (756 fish organs, 108 water and 108 sediments) samples were collected and examined for LM using molecular method. Descriptive statistics, t-test, Manny-Whitney U test and ANOVA were employed to analysed the data generated. It was found out, among other that 61 out of 972 samples had listeria infection. Forest zone had higher percentage of infection (66.67%) than the derived savannah zone (25.93%). However, there was no significant difference in LM occurrence between the sexes (p=0.333) of the fish. Although, there was significant difference in body weight (p=0.005). Out of 61 biochemically characterized isolates, only 18(29.51%) using iap primer and 12(19.67%) using hly-A primer were confirmed to be L. monocytogenes by PCR method. There was significant difference in the occurrence of L. monocytogenes in organs (p=0.001) with the spleen having the highest occurrence. Thus, the study concluded that LM was well distributed in fish farms in the ecological zones. Also, the highest occurrence was observed in forest zone revealing body weight and fish length as possible predisposing factors.