Mongkolrattanothai Kanokporn, Boyle Susan, Kahana Madelyn D, Daum Robert S
Section of Pediatric Infectious Diseases, University of Chicago, Department of Pediatrics, Chicago, Illinois 60637, USA.
Clin Infect Dis. 2003 Oct 15;37(8):1050-8. doi: 10.1086/378277. Epub 2003 Sep 23.
We investigated the genetic relatedness of 5 community-acquired (CA) Staphylococcus aureus isolates obtained from 4 consecutive pediatric patients presenting with sepsis syndrome and severe pneumonia during a 3-week period in 2000. Two patients were infected with methicillin-susceptible S. aureus (MSSA), and 2 were infected with methicillin-resistant S. aureus (MRSA). The pulsed-field gel electrophoresis patterns for the 2 CA-MRSA isolates were identical to each other, as were the patterns for the 3 CA-MSSA isolates. A 2-band difference reflecting the presence of a staphylococcal cassette chromosome mec (SCCmec) element distinguished the CA-MRSA isolates from the CA-MSSA isolates. The small, mobile type IV SCCmec element was present in the CA-MRSA isolates. These data suggest that an insertion or, less likely, a deletion of the SCCmec type IV element occurred in a highly virulent S. aureus background. Staphylococcal toxin genes sea, seh, lukS-PV, and lukF-PV were detected in all isolates. Also, in all isolates, was a partial homolog of seo (seo'). The relationship among these patient isolates strengthens the assumption that CA-MRSA infections may be caused by isolates closely related to MSSA isolates.
我们调查了2000年3周内从4例连续出现脓毒症综合征和重症肺炎的儿科患者中分离出的5株社区获得性（CA）金黄色葡萄球菌的遗传相关性。2例患者感染了甲氧西林敏感金黄色葡萄球菌（MSSA），2例感染了耐甲氧西林金黄色葡萄球菌（MRSA）。2株CA-MRSA分离株的脉冲场凝胶电泳图谱彼此相同，3株CA-MSSA分离株的图谱也相同。反映葡萄球菌盒式染色体mec（SCCmec）元件存在的2条带差异区分了CA-MRSA分离株和CA-MSSA分离株。小型可移动IV型SCCmec元件存在于CA-MRSA分离株中。这些数据表明，在高毒力金黄色葡萄球菌背景中发生了IV型SCCmec元件的插入，不太可能是缺失。在所有分离株中均检测到葡萄球菌毒素基因sea、seh、lukS-PV和lukF-PV。此外，在所有分离株中均存在seo的部分同源物（seo'）。这些患者分离株之间的关系强化了这样一种假设，即CA-MRSA感染可能由与MSSA分离株密切相关的分离株引起。
