Prevalence and antimicrobial profiles of Salmonella serovars from vegetables in Maiduguri, North eastern Nigeria

Abstract

This study determined the occurrence of Salmonella from vegetables, the prevailing serovars, and the antimicrobial susceptibility profile of the serovars. A total of 300 samples of vegetable comprising spinach (Amaranthus hybridus spp.), Corchorus olitorus spp., sorrel (Hibiscus sabdariffa), bitter leaf (Vernonia amygadalina spp.), and water leaf (Talinum triangulares spp.) were collected from five different farms and Maiduguri central market from May to August, 2009. Presumptive Salmonella isolates were determined by using the conventional biochemical tests, Serovars were confirmed by serotyping, using slide agglutination technique. Antimicrobial susceptibility test was performed with 17 antimicrobial agents using the minimum inhibition concentration tests (MIC) method. Out of the 300 samples analyzed, 19 were positive for Salmonella, which represent a prevalence of 6.3%. The serovars obtained were Salmonella Hadar, 13(4.3%), Salmonella serovar 47: mt:-, 5(1.7%), and Salmonella Vinohrady, 1(0.3%). Most of the serovars were susceptible to antimicrobial agents with the exception of Salmonella Hadar that exhibited multiple resistances to streptomycin, trimethoprim, sulfamethoxazole, and neomycin. Salmonella represents a major contaminant of vegetables consumed in Maiduguri, North-eastern Nigeria. Therefore, vegetables can serve as a route for the transmission of Salmonella to humans. This constitutes a serious health risk to the human population, and there is a need for specific Salmonella control program to be instituted as part of a national food safety strategy.

Keywords: Antimicrobial profiles, MIC, North eastern Nigeria, Prevalence, Salmonella serovars, Vegetables