Detection and Prevalence Rate of American Cockroaches (Periplaneta americana) Bacterial Infections in Human Dwellings

Background: In hospitals, it has been clarified that Periplaneta americana can operate as possible vectors of nosocomial infections, chiefly for the transmission of drug-resistant bacteria. Also, these domestic insects have a role in transmitting food-borne diseases. The bacterial loads of these insects have been reported as seven million in each excretion dropping and up to 14 million on their cuticle. Their presence decreases human health and sanitary standards. Objectives: This descriptive study was carried out to confirm that Periplaneta americana L. (Dictyoptera; Blattidae) carry pathogenic bacteria in residential areas, by bacteriological analysis of the cuticles of this insect. Materials and Methods: In this research we caught 25 American cockroaches from human dwelling localities of Ahvaz province during 2008 and 2009. Cockroaches were collected using sticky traps, vacuum cleaners and direct collection. The collected cockroaches were brought to the laboratory and were identified as P. americana. They were examined for the presence of bacteria on their external surfaces using specific standard methods for bacterial infection. Results: One hundred percent of cockroaches had bacterial infections. Culturing of the external parts wash homogenates resulted in the isolation of Escherichia coli, Proteus, Serratia, Klebsiella, Enterobacter, Pseudomonas, Staphylococcus aureus, Streptococcus, Enterococcus, Citrobacter, Micrococcus. Conclusions: The results showed that P. americana is a possible reservoir and potential vector of some pathogenic agents.