Detecção de Salmonella spp., Escherichia coli e Staphylococcus spp. em ardeídeos: investigação de potenciais reservatórios

Abstract

Ardeids are birds of the Order Pelecaniformes, which move over great distances and form dense nests in natural and urban environments. Its synanthropic behavior can facilitate the spread of zoonotic pathogens and antimicrobial-resistant microorganisms. The research aims to investigate whether the Pelecaniformes from a nest located in the urban area of Lavras, within the Campus of the Federal University of Lavras (UFLA), built in the area of a stream that crosses the city, are carriers of Salmonella spp., E. coli and Staphylococcus spp. and to correlate the infections with the occurrence of macro and microscopic lesions in the examined birds. In the 2021 breeding season, daily visits were made to a nest of Pelecaniformes located on the UFLA campus. Puppies found dead were collected and sent to the UFLA SPV for examination. Cubs found fallen from the nests and dying were also collected, weighed, anesthetized and euthanized. A macroscopic evaluation of the organs and tissues was carried out, with a description and photographic record of the alterations found. Organ and tissue fragments were collected and stored in 10% formalin, processed, stained with hematoxylin and eosin for histological analysis and evaluated under an optical microscope. Intracloacal excreta were collected from all cadavers, as well as swabs from organs with macroscopic lesions suggestive of the microorganisms of interest. One swab of each material collected was stored in a tube containing buffered peptone water and another in Stuart transport medium, with identification of the tubes according to the necropsy record. Samples were sent to LEM - UFLA for isolation of Salmonella spp., E. coli and Staphylococcus spp. Up to five isolated colonies characteristic of each microorganism of interest were submitted to preliminary tests of evaluation of the microscopic morphology by Gram-stained smears; catalase and coagulase tests for characterization of Staphylococcus spp. and biochemical tests for samples suggestive of Salmonella spp. PCR tests were performed using specific primers for each of the microorganisms. Ten Great Egrets (Ardea alba) and five Cattle Egrets (Bubulcus ibis) were evaluated, most of these birds (92.85%) were young, with a prevalence of 42.85% of Salmonella spp. and 64.28% E. coli. No birds were detected with S. aureus. The vast majority of isolates were obtained by cloacal swab, which means that the agents were being eliminated by the birds' excreta and represent a significant public health concern. pathogens in different areas.