Cockroach-associated food-borne bacterial pathogens from some hospitals and restaurants in Hosur, Tamilnadu : distribution and antibiograms

The association of cockroaches with various pathogens is well documented and this study assessed the role of cockroaches as potential vectors of food-borne bacterial pathogens in Hosur, Tamilnadu, India. A total of 160 adult cockroaches, captured aseptically from four hospitals and two restaurants, were identified as Blattela germanica. Culturing external surface wash and gut homogenates by pooling cockroaches in batches of ten resulted in the isolation of 12 Salmonella spp., two Shigella flexneri, two Escherichia coli, 17 Staphylococcus aureus, and 25 Bacillus cereus. The analysis of isolates for antimicrobial susceptibility demonstrated that most of the isolates, belonging to the various genera, developed multiple drug resistance to up to 12 antimicrobials. To evaluate survival in and shedding of pathogens by B. germanica, Salmonella Group B, S. flexneri and S. aureus were separately fed to B. germanica at a level of 106 cfu/g of contaminated food. Cultural examination of faecal pellets from B. germanica showed that Salmonella and Staphylococcus aureus could be excreted for 35 and 14 days, respectively. Shigella flexneri was not shed by cockroaches during the experiment. The results indicated that B. germanica is a possible reservoir and potential vector of some food-borne pathogens and may spread multiple drug resistance in hospitals and food catering establishments