ISOLATION AND MOLECULAR CHARACTERIZATION OF Escherichia coli PATHOTYPES FROM LETTUCE PLANTS ISOLATED FROM OGUDU, LAGOS STATE, NIGERIA

Abstract

Recently, there has been an increase in the consumption of vegetables such as lettuce worldwide in a bid to maintain a healthy diet. However, along with this increase is an increase in reports of foodborne outbreaks. The common pathogen associated with these outbreaks reported is the bacteria, Escherichia coli. Consumption of lettuce contaminated with this pathogenic E. coli could result in several manifestations of Diarrhea and in severe cases Hemorrhagic colitis. Research has been ongoing in the isolation and characterization of this pathogen in lettuce samples and samples from infected patients in various parts of the world. Nevertheless, there has not been notable research done in the isolation and characterization of this pathogen in Africa, specifically, Nigeria considering the severity of infections caused by it. Data has also shown that most cases reported in Nigeria have not been related to the ingestion of food products from non-bovine origin such as lettuce. As a result, this study was aimed at the isolation and characterization of E. coli pathotypes from a farm in Ogudu, Lagos state, Nigeria. First, the morphological characteristics of the isolates were observed on MacConkey agar and Sorbitol MacConkey agar to provide a primary means of identification. Subsequently biochemical tests were done for further characterization which were all consistent with the characteristics of E. coli. However, its pathogenicity was not well defined. The characterization proceeded with the use of Multiplex Polymerase chain reaction (PCR) to give an insight into the specific pathotypes based on the amplified genes. The results produced indicated that some of the lettuce samples were contaminated with the pathotypes, Enterotoxingenic E. coli (ETEC) and Enterohaemorrhagic E. coli (EHEC). The pathotypes are very dangerous when consumed due to the toxins they secrete. This is a very serious issue and it must be treated with utmost importance, as it poses great hazard to all members of the population especially old people and children.