A study on bacteria carried on the teguments of cockroaches in urban environment of Bangkok, showed that numbers of pathogenic bacteria liked in hospital areas and food handling establishments, while human dwellings contained a negligible bacterial flora[7]. Besides, a favored isolation bacteria from cockroaches relates to the existing materials and instruments.
This issue may be the important cause for diversities among various studies. In our study, results of culture media exhibited that 90% of cockroaches were positive to the bacteria. In Vahabi’s study, all the American cockroaches and 70% of German cockroaches were infected to at least one bacterium[3]