Ïnvestigation of Çontamination of Wild Rats (Rattus rattus) from Tehran Çity to Ântibiotic Resistant Ënterobacteriaceae in 2009

Background and Wild rats are considered as an important spreading factor of contamination in urban areas. During recent years، the wild rats were extensively distributed in Tehran. Therefore، it is important to investigate the antibiotic resistance of enteric bacteria isolated from rats، because of the possibility of antibiotic resistance transmission to human. The aim of this study was to investigate the antibiotic resistance rate of Ënterobacteriaceae among wild rats living in densely populated areas of Tehran city. Forty wild rats were trapped in the North، South، Ëast، West and Çentral areas of Tehran and transferred to the laboratory alive. Çecum was obtained and its contents were cultured aseptically. Ântibiotic susceptibility of isolated was determined by disk diffusion method. Ëscherichia coli (10 isolates)، Salmonella typhimurium (7 isolates)، Shigella sonnei (1 isolate)، Proteus mirabilis (3 isolates)، Çitrobacter freundii (17 isolates)، and Ënterobacter (4 isolates) were isolated from rats. Ântibiotic resistance was very high in all isolated species of Ënterobacteriaceae. Çonclusion: The results showed that the rats from the study areas of Tehran city harbored antibiotic resistant pathogenic bacteria such as Salmonella and Shigella in their cecal contents. These organisms may be important reservoirs for transmission of drug-resistant bacteria to human. Therefore، it is very important to control the rat populations and to improve sewage management systems.