Incidence and antimicrobial susceptibility testing of Listeria monocytogenes in four street-food vending sites in Gaborone, Botswana

Abstract

Listeria monocytogenes is widely distributed in nature and a significant foodborne pathogen. Where outbreaks of listeriosis have occurred, high fatalities ensue especially among the immune suppressed, pregnant women and their fetuses. The current study investigated the occurrence of the L. monocytogenes in various foods sold by street vendors in four geographical areas of Gaborone from October 2011 to March 2012. From a total of 396 ready-to-eat street foods cultured, 60 (15.2%) tested positive for the organism. Out of the 60 confirmed isolates of Listeria monocytogenes, 48 (12.1%), 6 (1.5%) and 6 (1.5%) were isolated from vegetable, protein and starch food portions, respectively. From the four geographical areas selected for sampling in this study, the UB area recorded the highest number 24 (6.1%) of positive isolates while the bus station area recorded the least, 6 (1.5%). Thirty per cent of the positive isolates were resistant to tetracycline, 10% were resistant streptomycin, chloramphenicol and erythromycin each. The outcomes of the present investigation revealed the presence of L. monocytogenes in foods sold by street food vendors in Gaborone.