Resumo

Studying antimicrobial resistance in wildlife represents a unique opportunity to understand the origin and spread of resistance determinants amongst microbial pathogens of veterinary and public health significance. The aim of this study was to investigate methicillin resistance in Staphylococcus spp. from non-migratory wildlife seabird populations living in the Fernando de Noronha Archipelago. Cloacal and oral swabs were collected from seabirds (n=18) from three different species: White-tailed tropic bird (Phaethon lepturus), Red-billed tropic bird (Phaethon aethereus) and Audubon's shearwater (Puffinus lherminieri). Samples were enriched in methicillin-supplemented BHI broth and streaked onto blood agar and mannitol-salt agar. Staphylococci isolates were confirmed biochemically and the minimum inhibitory concentration (MIC) was determined by microdilution test using a semi-automated system (Autoscan 4, Siemens). Out of the 18 sampled animals, 29 staphylococci organisms were isolated from 15 birds. Four Staphylococci species were detected: S. sciuri (11 birds); S. intermedius (3 birds), S. saprophyticus (1 bird), and S. haemolyticus (1 bird). Isolates were most resistant against ampicillin (100%), amoxicillin/clavulanate K (96.5%), ceftriaxone (96.5%) and oxacillin (86.2%). Pan susceptibility was observed for ampicillin/sulbactam, ciprofloxacin and nitrofurantoin, gentamicin, levofloxacin, linezolid, moxifloxacin, synercid, tetracycline, trimethoprim-sulfamethoxazole, and vancomycin. The detection of staphylococci isolates highly resistant against antimicrobials, especially beta-lactams, is noteworthy considering the investigated seabird species have virtually no contact with humans or domestic animals and, therefore, no antimicrobial selection pressures over those populations is expected. Those non-migratory birds live in an archipelago with strict conservations laws. Visitation of tourists or even habitants are not allowed in some of the islands were the birds were captured. In this sense, the present findings suggest that coagulase negative staphylococci could be natural reservoirs for methicillin resistance determinants. Further investigations about possible intrinsic mechanisms of resistance including staphylococcal cassette chromosome mec (SCCmec) characterization are required to test this hypothesis. Acknowledgements: Fapesp; CNPq; ICMBio; CEMAVE; Fire Department; PARNAMAR, APA and Administration of Fernando de Noronha.