molecular epidemiology of methicillin-resistant staphylococcus hominis (mrsho) low clonality and reservoirs of sccmec structural elements分子流行病学的耐甲氧西林金黄色葡萄hominis(mrsho)单克隆和水库低sccmec结构元素.pdfVIP

Molecular Epidemiology of Methicillin-Resistant Staphylococcus hominis (MRSHo): Low Clonality and Reservoirs of SCCmec Structural Elements 1,2 2 1,3 1 Ons Bouchami , Assia Ben Hassen , Herminia de Lencastre , Maria Miragaia * ´ ´ ´ 1 Laboratory of Molecular Genetics, Instituto de Tecnologia Quımica e Biologica (ITQB), Oeiras, Portugal, 2 Bone Marrow Transplant Centre of Tunisia, Tunis, Tunısia, 3 Laboratory of Microbiology, The Rockefeller University, New York, New York, United States of America Abstract Background: Methicillin resistant Staphylococcus hominis (MRSHo) are important human pathogens in immunocompro- mised patients. However, little is known regarding its population structure and staphylococcal chromosomal cassette mec (SCCmec) content. Methodology/Principal Findings: To assess the population structure and the SCCmec content of S. hominis, 34 MRSHo and 11 methicillin-susceptible S. hominis (MSSHo) from neutropenic patients collected over a 3-year period were studied. The genetic backgrounds of S. hominis isolates were analyzed by pulsed-field gel electrophoresis (PFGE) and SCCmec types were determined by PCR. Cassette chromosome recombinases (ccr) were characterized by PCR and ccrB sequencing. The 34 S. hominis isolates were classified into as many as 28 types and 32 subtypes (SID = 99.82%); clonal dissemination was occasionally observed. The main SCCmec structures identified were SCCmec type VI (4B) (20%), SCCmec VIII (4A) (15%), and a new SCCmec composed of mec complex A in association with