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ABSTRACT Introduction Pseudomonas aeruginosa infections are common worldwide, affecting mainly hospitalized patients and causing healthcare-associated infections (HAIs), with a high frequency of antibiotic resistance and complicated outcomes. Objective To investigate the P. aeruginosa frequency in HAIs in a medium/high-complexity hospital in Alagoas (Brazil) and the antibiotic susceptibility profiles of the strains. Methods A retrospective cross-sectional study was conducted from January 2013 to December 2014, when P. aeruginosa related-HAIs were evaluated after automated identification (Vitek®2) and documental analysis. Results Seventy-eight samples were positive for P. aeruginosa, with 37 (47.4%) isolates from patients of the general Intensive Care Unit (ICU) and 13 (16.7%) from the surgical unit. Tracheal secretion (25.6%), wound secretions (20.5%) and sputum (18.0%) were the main positive biological samples. Among 68 strains tested, 73.53% showed resistance to aztreonam, while cefepime, ceftriaxone and cefotaxime were not effective for any isolates (all resistant). High resistance to carbapenems imipenem (61.76%) and meropenem (55.88%) was observed, as well as 46 isolates resistant to piperacillin/tazobactam (67.64%); 47 (60.2%) from the general ICU and neonatal ICU were resistant to all antibiotics tested (MDR profile), except for colistin. Conclusion Our results indicated antibiotic-resistant P. aeruginosa highly present in ICU and the therapy with aminoglycosides and colistin as important choices in cases with failure against P. aeruginosa isolates. A constant screening of multidrug-resistant P. aeruginosa is necessary for the control in the hospital environment, evaluating the antibiotic susceptibility to guide the therapeutic choice.
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ABSTRACT: Methicillin resistance in the Staphylococcus intermedius group (SIG) has emerged in small animal practice. Methicillin-resistant SIG (MRSIG) members have been implicated as causes of infections in both companion animals and humans. Staphylococcal cassette chromosome mec (SCCmec) elements carry the mecA/C genes, which encode for the transpeptidase PBP2a (PBP2') responsible for β-lactam antibiotic resistance in staphylococci. This study examined the SCCmec types of MRSIG isolates from different clinical specimens of dogs that exhibited methicillin MIC ≥ 0.5 μg/mL by an automated identification and susceptibility system in a Center for Veterinary Diagnostics in São Paulo, Brazil. Susceptibility to methicillin was determined by broth microdilution testing, and Oxoid® M.I.C.Evaluator® strips. PBP2a production was detected using a latex agglutination assay. SCCmec typing was performed according to the International Working Group on the Classification of Staphylococcal Cassette Chromosome Elements (IWG-SCC) guidelines. SCCmec type II (2A), SCCmec type III (3A), composite SCC structures consisting of a class A mec gene complex in addition to multiple ccr gene complexes, and non-typable SCCmec elements were reported in these MRSIG isolates. SCCmec type variants differing from those so far acknowledged by IWG-SCC were found, indicating new rearrangements in the genetic context of mecA in these canine MRSIG isolates.
RESUMO: A resistência à meticilina no grupo Staphylococcus intermedius (GSI) tem aumentado na clínica de pequenos animais. Membros GSI resistentes à meticilina (GSIRM) têm sido causas de infecções tanto em animais de companhia e humanos. Cassetes cromossômicos estafilocócicos mec (SCCmec) carregam os genes mecA/C, que codificam a transpeptidase PBP2a (PBP2') responsável pela resistência aos antibióticos β-lactâmicos em estafilococos. Nosso objetivo foi investigar os elementos SCCmec de GSIRM isolados de diferentes amostras clínicas de cães que exibiram CIM de meticilina ≥ 0,5 μg/mL por meio de um sistema automatizado em um Centro Veterinário de Diagnósticos em São Paulo, Brasil. A sensibilidade à meticilina foi determinada por meio do teste de microdiluição em caldo e fitas Oxoid® M.I.C.Evaluator®. A produção de PBP2a foi detectada usando um ensaio de aglutinação de látex. A tipagem dos elementos SCCmec foi realizada de acordo com as diretrizes do International Working Group on the Classification of Staphylococcal Cassette Chromosome Elements (IWG-SCC). SCCmec tipo II (2A), SCCmec tipo III (3A), SCC compostos de um complexo mec de classe A com múltiplos complexos ccr, e elementos SCCmec não tipáveis foram encontrados nesses isolados GSIRM. Variantes que diferem dos elementos SCCmec reconhecidos até o momento pelo IWG-SCC foram encontradas, indicando novos rearranjos no contexto genético de mecA nesses isolados GSIRM caninos.