Profile of antimicrobial resistance of bacteria isolated from cockroaches (Periplaneta americana) in a Brazilian health care institution

RESUMO

Cockroaches carry microorganisms to sterilized materials, equipment and non-contaminated food in hospitals and in homes. Hence, they are regarded as major microbial vectors. We isolated and identified microorganisms from living cockroaches captured from a Brazilian health care institution and we determined the antimicrobial susceptibility profile of the isolates. Following collection, cockroaches were immobilized at 4°C for 10 to 20 minutes, immersed in 0.8 percent saline solution and then homogenized. Next, the suspension was seeded in culture media brain and heart agar infusion, MacConkey agar, Naito agar, and they were incubated for up to 48 hours at 37°C. Sabouraud agar cultures were incubated at ambient temperature. The microbial colonies were analyzed with a stereomicroscope to count and phenotypically identify the colony-forming units (cfu). The discdiffusion method was used to determine the profile of susceptibility to antimicrobials. Among the 103 cockroaches analyzed, fungi were found in 97 percent, enterobacteria in 74.6 percent and coagulase-negative staphylococci (CNS) in 25.40 percent. Among the enterobacteria, 96 percent were resistant to gentamicin, 84 percent to ampicillin, 75.3 percent to caphalothin, 66.7 percent to ampicillin-sulbactam, 50 percent to aztreonam and 30 percent to chloramphenicol. Among the CNS, 61 percent were resistant to oxacillin. We concluded that cockroaches carry organisms associated with nosocomial infections and that are resistant to antimicrobials. This fact contributes to the epidemiological chain, complicating therapeutics, and consequently, medical costs are increased.