THE SIGNIFICANCE OF COCKROACHES AS CARRIE RS OF PATHOGEN BACTERIA

Cockroaches are insects which can be found in areas of food production , kitchens, social welfare institutions etc. Their significance in con nection with the contamination by pathogenic microorganisms was examin ed. In the course of pilot tests a special technique of application of bacteria suspensions to cockroaches has been worked out and a box for collecting the cockroach droppings has been constructed. The quantita tive examination of the different strains of bacteria (E. coli, S. aur eus, L. monocytogenes, S. enteritidis) were performed by standard meth ods. The course of bacterial counts in the digestive tract as well as in the droppings within 14 days has been shown. Experimental fed germs are detectable in the droppings of male Blatta orientalis one to two weeks after the feeding regime. E. coli can also be obtained from faec es on the 14(th) day after feeding this strain. Up to the 3(rd) day af ter the input the different bacteria could be isolated from the digest ive tract in order to 3,20 to 4,40 log units. Fed germs could not be f ound in the digestive-tract-samples on the 14(th) day after bacteria-i ntake. After a single contamination of the laboratory cockroaches the bacteria persisted only for a short period. A reproduction of microorg anisms in the digestive-tract of B. orientals did not take place.