Cockroaches as Reservoirs and Vectors of Drug Resistant Salmonella spp

Cockroaches were collected from hospitals, houses and poultry sheds in various parts of Isfahan (Iran) and identified to species. In total, seven species of cockroaches in seven genera were identified: Blatta lateralis, Polyphaga aegyptiaca, Arenivaga roseni and Parcoblatta spp. Three species Periplaneta americana, Blattella germanica and Supella longipalpa (Blattidae and Blattellidae) were more abundant than the others. In another study, forty cockroaches were collected from hospitals in two experiments and were studied for the presence of Salmonella spp. Salmonella (Black colonies on SS agar with urease negative) were isolated from about 70 percent of the cockroaches collected from hospitals. Some of the isolated Salmonella were resistant to antibacterial drugs in a susceptibility test. Isolation of Salmonella from cockroaches collected from hospitals suggests that cockroaches act as natural reservoirs of Salmonella. A second study was conducted to determine if individual B. germanica could transfer Salmonella from an infected food source and then infects uncontaminated colony members. The results showed that the inoculation of 10 CFU of Salmonella into cockroaches via their food could infect the uncontaminated cockroaches. These contaminated cockroaches transfer infection to other colony members. Salmonella is stable in cockroaches for more than 10 months. Iran. Biomed. J. 7 (1): 35-38, 2003