Antimicrobial-resistant Staphylococcus spp. and Mammaliicoccus sciuri isolated from rehabilitating wild mammals in northeastern Brazil: implications for microbiological surveillance and biosafety in wildlife care facilities

Antimicrobial resistance (AMR) among Staphylococcus and Mammaliicoccus species is a growing concern in wildlife care settings, as rehabilitation centers may represent contact points among wild animals, captive environments, and human handlers. This study characterized antimicrobial resistance profiles, multiple antibiotic resistance (MAR) indices, and biofilm formation in Staphylococcus spp. and Mammaliicoccus sciuri isolated from wild mammals housed at a wildlife screening and rehabilitation center in Pernambuco, northeastern Brazil. Oropharyngeal and rectal swabs were collected from 84 individuals representing 15 species. Isolates were identified using MALDI-TOF MS, and susceptibility to oxacillin, cefoxitin, clindamycin, erythromycin, gentamicin, norfloxacin, and tetracycline was assessed by disk diffusion. Multidrug resistance (MDR) and MAR indices were determined, and the resistance genes mecA , mecC , norA , msrA , tet(38) , and tetM were investigated by PCR. Bacterial growth on mannitol salt agar was obtained from samples collected from 63/84 (75.0%) animals, yielding 63 confirmed isolates. Mammaliicoccus sciuri was the most frequently identified species, accounting for 29/63 (46.0%) isolates, followed by Staphylococcus aureus , Staphylococcus felis , and Staphylococcus simulans , with 5/63 (7.9%) isolates each. Overall, 50/63 (79.4%) isolates were resistant to at least one antimicrobial category, and 13/63 (20.6%) were classified as MDR. Resistance was most frequently observed to oxacillin (68.3%), followed by cefoxitin (28.6%), erythromycin (27.0%), tetracycline (25.4%), clindamycin (22.2%), norfloxacin (11.1%), and gentamicin (11.1%). MAR indices ranged from 0.00 to 1.00, with a mean value of 0.28. Resistance genes were detected in a subset of isolates, including mecA (4/63; 6.3%), norA (2/63; 3.2%), and msrA (1/63; 1.6%), whereas mecC , tet(38) , and tetM were not detected. Biofilm formation was observed in 33/63 (52.4%) isolates, predominantly among weak and moderate producers. These findings provide baseline evidence supporting systematic microbiological surveillance, antimicrobial stewardship, and biosafety measures in wildlife rehabilitation facilities within a One Health framework.