Almost 65% of pathogenic bacteria that isolated from cockroaches were caught from hospital Q and the student dormitory. The prevalence of pathogenic bacteria was similarly high in B. germanica (98%). The most frequent species of bacteria (>82%) both internally and externally on American and German cockroaches at all three sampled places in Shiraz was Pseudomonas. At all locations, the gastrointestinal tract as well as the external surfaces were
maximally (>82%) infected with at least one species of bacteria (Figure 1).