Epidemiological role of arthropods detectable in health facilities.

A total of 161 arthropod specimens were collected from 55 sites in a health care facility during July and September 1990. Of the 116 bacterial isolates obtained from their body surfaces 6% were from parasites (mosquitoes), 59% from eusynanthropic arthropods (Tenebrionid beetles, flies, German cockroaches, wasps), 16% from hemisynanthropic arthropods (ants, spiders) and 19% from occasionally encountered insects (non-biting midges, moths, beetles). Most (88%) of the isolated bacteria were Gram-negative rods of the species E. coli, Enterobacter, Klebsiella, Citrobacter, Proteus, Serratia, Pseudomonas and Acinetobacter. Gram-positive cocci accounted for 13% of isolates and were primarily represented by coagulase-negative staphylococci. The highest isolation rates were from body surfaces of flies, German cockroaches, non-biting midges (Chironomids) and Tenebrionid beetles. About one third of all isolates were resistant to more than three antimicrobials using a standard disc diffusion assay. The presence of multiple resistance to antibiotics was observed in two thirds of Enterobacter isolates, namely those of Enterobacter cloacae from the body surface of Germany cockroaches, in 13% of Citrobacter spp and in 8% of Klebsiella spp as well as Acinetobacter calcoaceticus strains. Strains of Morganella and Hafnia species were very infrequent but all of them shared resistance to the antibiotics tested. In contrast, strains of Serratia spp were relatively antibiotic-sensitive. The group of isolated Gram-positive organisms was represented by two strains of Staphylococcus hominis and one strain of Enterococcus sp, all of them were multiply-resistant to antimicrobials.