Phenotypic and Genotypic Virulence Potentials of Listeria monocytogenes Isolated from Different Food Samples in Yola

Aim: the aim of this work is to determine the Phenotypic and Genotypic Virulence Potentials of Listeria monocytogenes Isolated from Different Food Samples in Yola.

Study Design: the study was a randomized study; the samples (sources of organisms) were collected at random from different market and shops within the study area.

Place and Duration of Study: the study was carried out in Yola, the capital of Adamawa State, north eastern Nigeria.

Methodology: phenotypic virulence potentials of the isolates was determined by haemolytic activity on 5% sheep blood agar and biofilm formation ability, using Christensen’s tube method and microtiter plate method for the qualitative and quantitative biofilm formation respectively. Genotypic virulence determination was done by polymerase chain reaction amplification of plcB, hlyA and actA genes.

Results: All the isolates (100%) were beta haemolytic on 5% sheep blood agar and all the isolates were biofilm formers but with different degree of biofilm formation abilities. Genotypically all the isolates (100%) indicated the presence of all the three virulence genes amplified.

Conclusion: food samples isolates analyzed are potentially virulence pathogenic of L. monocytogenes that can pose food borne listeriosis to high risk individuals in the study area.