Papel de dípteros muscóides como potenciais vetores de agentes bacterianos em fazendas de leite da região norte do Paraná

Abstract

Synanthropic flies are recognized as an important factor for the dissemination of infectious diseases to humans and animals. The aim of the present study was to determine the frequency of isolations and antimicrobial profile of Escherichia coli, Salmonella spp. and Staphylococcus spp. isolated from synanthropic flies captured with entomological traps, near of the in milk site of 30 dairy farms located in northern Paraná, Brazil. Surface washed and internal contents of 192 flies were submitted to microbiological analysis. In the 30 farms surveyed, the frequencies of caches of Muscidae (21/30 = 70%) and Calliphoridae (27/30 = 90%) were higher than Sarcophagidae (7/30 = 23.3%). E. coli was isolated only from Muscidae (14.3%) and Calliphoridae (33.3%). Salmonella spp. was isolated from 9.5% of Muscidae, 7.4% of Calliphoridae and 14.29% of Sarcophagidae. Staphylococcus spp. was only isolated from 28.5% of Muscidae and 29.6% of Calliphoridae. Isolates of E. coli were more common in flies captured on farms that kept domestic chickens near to the site milking (p = 0.031), and that did not use cane sugar for animal feed (p = 0.042). Two of the 27 strains (7.4%) of Staphylococcus spp. were coagulase-positive. Ceftriaxone, ciprofloxacin, enrofloxacin and gentamicin were the most effective antimicrobials against E. coli and Salmonella spp., and tetracycline was the less effective for the same microbial agents. None of the Staphylococcus spp. strains demonstrate resistance to oxacillin. It is concluded that the flies in the region are potential mechanical vectors of microbial agents that are able to cause enteritis in calves, mastitis in cows and contamination of dairy products produced on farms.