Staphylococcus aureus resistente à meticilina (MRSA): tipificação do cassete cromossômico SCCmec e resistência a antimicrobianos em pacientes com fibrose cística assistidos em dois centros no Rio de Janeiro

• Autor(a) principal: Brazão, Nathalia Brito Veloso
• Data de Publicação: 2012
• 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/1/14423
• topic: Cystic Fibrosis; Staphylococcus aureus; SCCmec; Fibrose cística; Staphylococcus aureus; SCCmec; Fibrose cística; Staphylococcus aureus; Infecções estafilocócicas; CNPQ::CIENCIAS BIOLOGICAS::MICROBIOLOGIA

Bacterial lung infections are the major cause of morbidity and mortality in CF patients. Staphylococcus aureus is one of the most common pathogens isolated from colonization/infection in pediatric patients particulary when it shows methicillin resistance (MRSA), causing problems to a choice of antimicrobial therapy. This samples MRSA are classified either genotypically or phenotypically in CA-MRSA (community acquired MRSA) or HA-MRSA (hospital acquired MRSA). However, this phenotypic classification is controverse and is based on criteria epidemiological features or antimicrobial susceptibility. In the other hand, genotypic classification based on the diversity of the cassette chromosomal, wich harbours gene mecA (responsible for methicillin resistant). Currently, there are 11 SCCmec. types Types I to III and VIII are related with HA-MRSA genotype and types IV to XI with CA-MRSA genotype. Classicaly, CA-MRSA is able to produce the Panton-Valentine Leukocidin toxin that is encoded by genes luk-S and luk-F. This toxin is associated to necrotizant pneumonia and soft tissue infections and in FC patients with pulmonary exacerbation. In Brazil, the are few studies envolving SCCmec characterization. Thus the main purpose of this study was to determine the presence of SCCmec types and the antimicrobial susceptibility profiles of MRSA strains recover from patients with CF attended at Hospital Universitário Pedro Ernesto (HUPE) - UERJ and Instituto Fernandes Figueiras (IFF) FIOCRUZ. One hundred and eight MRSA isolates from FC patients were studied in a period of two years (2008-2010). Ninety and four isolates belongs to pediatric patients treated in IFF and 14 from adults patients from HUPE. We found high rates of resistance to antimicrobials such as oxacillin, cefoxitin and erythromycin. All isolates were susceptible to vancomycin and linezolid by the microdilution testing. 82.4% of the isolates where typed by multiplex PCR and 64 % belonged to CA-MRSA. No statistical difference were detected between samples CA-MRSA and HA-MRSA. The SCCmec types I, IIII, IV and V were detected, and the types I and IV were the most frequent. 34,2% of the isolates harbored the PVL gene. This is the first in Brazil detecting the PVL toxin gene and high rates of CA-MRSA isolates among CF patients. Furthermore, we find luk-S gene HA-MRSA isolates from CF patients. The few national studies, as well as the differences between studies, reflecting the need for more improved knowledge of MRSA involved in lung infections of CF patients.