Cockroaches as vectors of pathogenic bacteria

One hundred and thirty two cockroaches of species Blattella germanica--96 from hospital ward (test group) and 36 from residential areas (control group) were caught during Nov. 1985 to Nov. 1986. A variety of pathogenic and non-pathogenic bacteria were isolated from test and control group of insects. Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus faecalis, and Micrococci were isolated only from the test group of cockroaches. A high percentage (98.95 per cent) of test cockroaches were found to be carriers of various microorganisms as compared to the control group (80.55 per cent), the difference being statistically significant (p less than 0.001). Quantitative analysis in this study revealed that higher number of microorganisms are carried by test group of insects in the hospital environment. This, thereby suggests that these insects can play an important role in the etiology of hospital acquired infections.