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Background and Aim: The production of beta-lactamase enzymes, such as extended-spectrum beta-lactamase (ESBL), adenosine-monophosphate-cyclic (AmpC), and Klebsiella pneumoniae carbapenemase (KPC), is one of the most important mechanisms of bacterial resistance to antimicrobials. Gram-negative bacteria show significant resistance due to various intrinsic and acquired factors. These intrinsic factors include low permeability of the outer membrane, various efflux systems, and the production of beta-lactamases, while acquired factors include chromosomal mutation and acquisition of resistance genes by horizontal transfer. Mobile elements such as plasmids, integrative conjugative elements, mobilizable islands, or transposable elements are involved in horizontal transfer. At present, the Gram-negative pathogens of most concern are Acinetobacter baumannii, Pseudomonas aeruginosa, and those belonging to the Enterobacteriaceae family (e.g., Escherichia coli, K. pneumoniae, and Proteus mirabilis). This study aimed to evaluate the profile of antimicrobial resistance and the production of the enzymes ESBL, AmpC, and KPC, in 21 gram-negative bacteria isolated from domestic animals treated at the University Veterinary Hospital (HVU) of the Federal University of Western Bahia (UFOB). Materials and Methods: The biological samples (21) were inoculated to brain heart infusion broth, blood agar, and MacConkey agar and incubated for 24-72 h at 37°C. Gram staining and identification through biochemical tests and matrixassociated laser desorption/ionization time-of-flight mass spectrometry were conducted. To evaluate the antimicrobial resistance profile, the disk diffusion method was used, and 25 antibiotics were employed. For the detection of ESBL, the disk approximation method was applied using chromogenic agar. The presence of KPC was observed using chromogenic agar and the Hodge test. For AmpC evaluation, the disk approximation method was used. Results: The most isolated agent was E. coli (66.66%, 14/21), followed by K. pneumoniae and P. mirabilis (both 14.29%, 3/21), and then Pasteurella spp. (4.76%, 1/21). The bacterial isolates showed high levels of resistance against clindamycin, penicillin, imipenem, polymyxin, cefoxitin, gentamycin, cefotaxime, ceftazidime, cephalothin, ceftriaxone, ciprofloxacin, trimethoprim/sulfamethoxazole, chloramphenicol, and tetracycline. The best effectiveness rates were observed for cefepime, streptomycin, amoxicillin-clavulanate, aztreonam, nalidixic acid, tobramycin, levofloxacin, amikacin, and meropenem. All biological isolates showed multiple resistance to at least three of the antibiotics tested (3/25), and some showed resistance to 24 of the antibiotics tested (24/25). Among the 21 pathogens analyzed, 8 were ESBL producers (38.09%); of these, 6 were identified as E. coli (28.57%), and 2 were identified as K. pneumoniae (9.52%). Two strains of K. pneumoniae produced both ESBL and KPC. None of the isolates were producers of AmpC. Conclusion: The results found in the present work raise concern about the level of antimicrobial resistance among pathogens isolated from domestic animals in Brazil. The results highlight the need for the development and implementation of antiresistance strategies to avoid the dissemination of multiresistant pathogens, including the prudent use of antimicrobials and the implementation of bacterial culture, antimicrobial sensitivity, and phenotypic tests for the detection of beta-lactamase enzymes in bacteria isolated from animals. [ABSTRACT FROM AUTHOR]

Background: Staphylococcus pseudintermedius is an opportunistic pathogen, belonging to the genus Staphylococcus. The methicillin-resistant Staphylococci have the mecA-gene, which confers them with the ability of becoming resistant to methicillin and multiple classes of antimicrobials, which makes the treatment of the affections caused by these specimens difficult. This work describes a case of systemic infection and death by methicillin-resistant S. pseudintermedius, in a canine. Case: A crossbred bitch (Canis lupus familiaris), was admitted to the University Veterinary Hospital of the Federal University of Western Bahia (HVU-UFOB). The main complaint reported by the owner was the presence of mammary nodules and constant nasal secretion. During the clinical examination was observed reactivity in the popliteal and left submandibular lymph nodes, pale mucous membranes, stomatitis, bilateral mucopurulent nasal secretion, abdominal pustules, serous secretion in the inguinal mammary gland and focal alopecia on the dorsum. On auscultation, was identified only arrhythmia and the other physiological parameters of the animal were within normality for the species. Samples of the nasal secretion and of the secretion from the abdominal pustules were collected, and sent to the Veterinary Microbiology Laboratory of the same institution. The samples collected were sown in 5% Blood Agar (BA), Sabouraud Agar (SAB) and MacConkey Agar (MCK), after 24 h was observed in BA the growth of macroscopically white colonies, with a humid aspect, creamy consistency, with presence of catalase and a-hemolysis. Microscopically, was observed the presence of Gram-positive cocci, suggestive of Staphylococcus sp. Microscopically, was observed the presence of Gram-positive cocci, suggestive of Staphylococcus sp. In the MALDI-TOF mass spectrometry, was identified S. pseudintermedius. Enrofloxacin [Enrotrat tab® 25 mg, 5 mg/kg, SID, PO, 5 days] was prescribed and a follow-up consultation was requested. Two weeks after leaving the University Veterinary Hospital, the animal was admitted in emergency and was submitted to the support protocol and died during the procedure. After the owner's authorization, the anatomopathological examination was carried out, and fragments of the liver, lung and kidney were collected, in addition to sample of the liquid of the abdominal cavity for microbiological examination, and was evidenced the growth of S. pseudintermedius in all the specimens. The bacterium's susceptibility to 19 antibiotics was tested, and a high degree of resistance was found, with sensitivity only to amoxicillin+ clavulanate (20-10 µg), chloramphenicol (30 µg) and vancomycin (30 µg). Given the detection of MRSP in Chromogenic Agar and in cefoxitin disks, all the specimens were MRSP positive. Discussion: The diagnosis based on the bacteriological culture and anatomopathological findings were essential for the confirmation of the clinical presentation of septicemia. The isolation of S. pseudintermedius in all the analyzed samples, associated to the identification by MALDI-TOF Mass Spectrometry confirmed the clinical suspicion of systemic infection. Based on the result of Antimicrobial susceptibility testing (AST) and phenotypic tests, it was evidenced that all the isolates were MRSP positive, presenting multiple resistance to antibiotics, which may have interfered in the efficiency of the treatment. The results obtained in this report are worrying and signal the need for the implementation of phenotypical researches associated to anti-microbial susceptibility tests in bacteria isolated from animals attended in veterinary clinics and hospitals, in order to monitor and avoid the dissemination of pathogens with a multi-resistant profile. [ABSTRACT FROM AUTHOR]