Abstract
This study was aimed at determining the level of Listeria contaminants and subsequently
detects some resistance genes among the isolated Listeria species from lettuce sold in some
vegetable markets in Benin City, Nigeria. Twenty-four lettuce samples were purchased from
three vegetable markets in Benin City, Nigeria and examined using standard microbiological
methods. Microbial characterization revealed Listeria monocytogenes and L. grayi as the
predominant species isolated. Plate count analysis on Listeria selective agar revealed that
lettuce sold in Oba market and Forestry market had the highest and lowest mean count of
Listeria species 224.00 x 102 CFU/g and 83.00 x 102 CFU/g respectively. Most (63.75%) of
the Listeria species isolates were found to be susceptible to Ofloxacin (5 ?g), Ciprofloxacin
(10 ?g), Streptomycin (10 ?g), Gentamycin (10 ?g), Pefloxacin (5 ?g) whereas species
harbouring tetracycline (65%) and erythromycin (60%) resistant genes. The study provides
an evidence of the colonization of Listeria species in lettuce sold in Benin City which may
pose serious public health threat to the populace.