Antimicrobial resistance is a natural mechanism in microorganisms, making the treatment of infections more complex in human and veterinary medicine. Global exotic and ornamental bird markets have significantly increased, and the close relationship between pets and humans makes exploring the potential role of these birds as vectors for the spread of antimicrobial-resistant bacteria imperative. This study aimed to use culture-dependent methods to investigate cloacal bacteria and the presence of antibiotic-resistant bacteria in four breeding stocks of ornamental birds. Cloacal swab samples were collected from 53 birds (canaries = 32, cockatiels = 17, and budgies = 4) and used for culturing and isolating facultative anaerobic and/or obligatory aerobic Gram-positive and Gram-negative bacteria. The antimicrobial susceptibility profile of each isolate was determined by the disk diffusion method. Thirty-four isolates were obtained, most of which belonged to the Staphylococcus genus. Bacterial richness was higher in canaries and in one of the breeding stockings, where Gram-negative bacteria were more abundant than in the others. In addition, canaries exhibited a predominance of resistant isolates, particularly multidrug-resistant strains, probably due to prophylactic antimicrobial usage. Most Gram-negative bacteria were resistant to at least one drug tested. A vancomycin-resistant Enterococcus faecalis strain was isolated. Most Staphylococcus strains were resistant to gentamycin, followed by penicillin. Eight strains were cefoxitin-resistant, including oxacillin-resistant S. epidermidis, in which the mecA gene was detected. Understanding the prevalence of resistance in avian species is crucial in the collaborative pursuit of maintaining antibiotic effectiveness and strengthening public health defense against emerging infectious risks. A resistência antimicrobiana é um mecanismo natural dos microrganismos, complicando o tratamento de infecções na medicina humana e veterinária. O mercado global de aves exóticas e ornamentais cresceu significativamente, e a relação próxima entre esses animais e humanos destaca a necessidade de investigar o papel das aves na disseminação de bactérias resistentes. Este estudo utilizou métodos dependentes de cultura para examinar bactérias cloacais e a presença de resistência a antibióticos em quatro plantéis de aves ornamentais. Amostras de suabe cloacal foram coletadas de 53 aves (canários = 32, calopsitas = 17, periquitos = 4) e usadas para cultivar e isolar bactérias Gram-positivas e Gram-negativas, facultativas anaeróbias e aeróbias obrigatórias. A suscetibilidade antimicrobiana foi determinada pelo método de difusão em disco. Foram obtidos 34 isolados, principalmente do gênero Staphylococcus. A riqueza bacteriana foi maior nos canários e em um dos plantéis, onde houve aumento de Gram-negativos. Canários mostraram predominância de isolados resistentes, especialmente cepas multirresistentes, provavelmente devido ao uso profilático de antimicrobianos. A maioria das bactérias Gram-negativas foi resistente a pelo menos um fármaco testado. Um Enterococcus faecalis resistente à vancomicina foi isolado. A maioria dos Staphylococcus foi resistente à gentamicina e penicilina; oito cepas foram resistentes à cefoxitina, incluindo S. epidermidis resistente à oxacilina com o gene mecA detectado. Compreender a prevalência de resistência em aves é crucial para manter a eficácia dos antibióticos e fortalecer a saúde pública contra riscos infecciosos emergentes.

In both aquaculture and scientific experimentation, fish handling often requires anesthesia to facilitate immobilization and minimize handling-associated disturbances. This study aimed to compare the anesthetic performance of different anesthetic agents in Astyanax lacustris, assessing induction, recovery, and safety to support protocol selection for tropical freshwater fish. A total of 114 yellowtail tetra Astyanax lacustris were used, including 54 fish in a preliminary experiment and 60 fish in the main experiment, with 10 fish per concentration in each anesthetic treatment during the main experiment. Fish were exposed to different concentrations of propofol (5.0 and 6.5 mg L⁻¹), eugenol (40 and 50 mg L⁻¹), and MS-222 (120 and 130 mg L⁻¹). Anesthetic efficacy and complementary physiological responses were assessed through induction and recovery times, responsiveness during recovery, opercular beat rate (OBR), hematological parameters, and plasma concentrations of glucose, lactate, and cortisol. Data were analyzed using analysis of covariance (ANCOVA) followed by appropriate post hoc tests (p < 0.05). All anesthetics successfully induced stage IV anesthesia at the evaluated concentrations, although distinct induction and recovery profiles were observed. MS-222 promoted significantly faster progression to deep anesthesia and shorter recovery times, whereas propofol induced prolonged recovery and marked reduction in OBR, with residual ventilatory depression after recovery. Eugenol showed an intermediate anesthetic profile associated with pronounced excitation during induction and an altered recovery pattern. Hematological parameters and plasma lactate concentrations did not differ significantly among anesthetic types or concentrations. Plasma glucose concentrations increased at higher anesthetic concentrations, whereas plasma cortisol concentrations differed significantly between propofol and eugenol groups (p < 0.05). Overall, the findings demonstrate that propofol, eugenol, and MS-222 produce distinct anesthetic and ventilatory responses in A. lacustris, highlighting the importance of selecting anesthetic protocols according to the intended experimental or handling procedure.