Epidemiologia molecular de Staphylococcus aureus resistentes à meticilina (MRSA) isolados de pacientes com Fibrose Cística

• Autor(a) principal: Lima, Danielle Ferreira
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/14431
• topic: Methicillin-resistant Staphylococcus aureus; Cystic Fibrosis; SCCmec; Resistance; PVL; MLST; Staphylococcus aureus resistentes à meticilina; Fibrose cística; SCCmec; Resistência; PVL; MLST; Fibrose cística; Staphylococcusaureus; Resistência à meticilina; Tipagem de sequências multilocus; CNPQ::CIENCIAS BIOLOGICAS::MICROBIOLOGIA::MICROBIOLOGIA APLICADA::MICROBIOLOGIA MEDICA

Methicillin-resistant Staphylococcus aureus (MRSA) is a major pulmonary pathogen in patients with cystic fibrosis (CF). It is characterized by resistance to all β-lactam antibiotics due to the presence of the mobile genetic element SCCmec which harbors the mecA gen. Furthermore, MRSA is recognized by several virulence factors, such as the toxin Panton-Valentine Leukocidin (PVL), pore-forming cytolysin in the host cell, and produces various epidemic clones involved in hospital outbreaks. The aim of this study was to characterize the epidemiology of MRSA, using phenotypic and genotypic methods of isolates from CF patients from two reference centers in Rio de Janeiro. A total of 57 MRSA isolates were tested by the Agar diffusion test for 11 antibiotics. SCCmec and the presence of the Luks-PV gene, responsible for encoding the PVL toxin, were evoluted by PCR, in order to establish a better epidemiological clone characterization by MLST (Multilocus Sequence Typing) technique. Non-β-lactam antimicrobials showed less than 50% of resistance, which included erythromycin with the highest percentage was 45.6%, beside, multirresistant profile was observed in 24.6% of isolates. We found SCCmec types I, III, IV and V with the corresponding percentage of 22.8% (n = 13), 7.1% (n = 4), 61.4% (n = 35) and 3.5% (n = 2) respectively and just 5.3% (n = 3) isolates were not typified. SCCmec II was not detected among our isolates. Twenty (35.1%) isolates showed amplification products consistent with the presence of the lukS gen, approximately half of these samples (55%) were correlated with SCCmec IV. Using MLST analysis, we obtained STs 1 (n = 1, 1.7%), 5 (n = 28, 49.1%), 30 (n = 11, 19.3%), 72 (n = 1, 1.7%), 398 (n = 1, 1.7%), 1635 (n = 7, 12.3%), 1661 (n = 2, 3.5%), 239 (n = 5, 8, 8%), and further identified a new ST (2732) present in one isolate. Associating MLST and SCCmec, it was possible to observe the presence of epidemic clones, such as, UK-EMRSA-3 (ST5, SCCmec I), USA800/pediatric (ST5, SCCmec IV), Oceania Southwest Pacific Clone - OSPC (ST30, SCCmec IV) and Brazilian Epidemic Clone - BEC (ST239, SCCmec III). In conclusion this study is the first one to characterize epidemic strains of MRSA in care centers of CF patients in Rio de Janeiro, that require constant monitoring in order to prevent the spread of these clones.