Formigas como carreadoras de microrganismos no Hospital Escola da Universidade Federal do Triângulo Mineiro.

Abstract

Ants have not always been seen as harmful insects and their connection with the possible transport of microorganisms has turned them into an object of study. This study aimed at getting to know the fauna of ants present at Hospital Escola (HE), Universidade Federal do Triângulo Mineiro, Uberaba/MG, and on Campus I. It also focused on the species of microorganisms transported by the HE s ants, besides identifying the resistance pattern of such microorganisms. In order to attract ants, labeled sheets of paper containing honey were exposed for a three-hour period. After that the ants were triaged and sent to experts for identification. At HE, 10 autoclaved tubes containing honey were used. The tubes which attracted ants were assigned test group and the ones which did not were assigned control group. Afterwards, sensitivity tests and identification of the microorganisms were performed. 11 species were identified on Campus I, 10 of which belong to the tramp ants species. The most frequent genera were Brachymyrmex (69.2%), Paratrechina (61.5%), Pheidole (46.1%) and Tapinoma (30.7%). When analyzing seasonal variation in density, diversity and species crichness, higher richness in June and higher density in March were noticed. Concerning diversity, it reached the highest values in May, September and December 2005. Only the species of T. melanocephalum was sampled at HE. Seasonal variation of density was found to be higher in November, May and September. Microorganisms of T. melanocephalum samples were isolated and 59 microorganisms were identified, among which 7 Gram-positive bacilli, 14 Gram-negative bacilli, 22 Gram-positive cocci and 17 filamentous fungi. Pseudomonas, Staphylococcus and Group D Streptococcus were the microorganisms which showed higher resistance to antibiotics. There was 9% of similarity between the fauna inside and outside the hospital. Epidemiologically, ants must be regarded as an important vector of infections due to their transport of microorganisms. On the other hand, it is not possible to define the exact role of ants in hospital infections. It is known that there is this risk; therefore, it must be closely investigated by hospital infection control committees.