Hsueh P R, Teng L J, Yang P C, Pan H J, Chen Y C, Wang L H, Ho S W, Luh K T
Departments of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan.
J Clin Microbiol. 1999 Mar;37(3):504-9. doi: 10.1128/JCM.37.3.504-509.1999.
From December 1997 to March 1998, 25 methicillin-resistant Staphylococcus aureus (MRSA) isolates exhibiting negative Staphylase (Oxoid Ltd., Basingstoke, England) reactions were identified from various clinical specimens from 13 patients in six intensive care units (ICUs) or in wards following a stay in an ICU at the National Taiwan University Hospital. The characteristics of these isolates have not been previously noted in other MRSA isolates from this hospital. Colonies of all these isolates were grown on Trypticase soy agar supplemented with 5% sheep blood and were nonhemolytic and unpigmented. Seven isolates, initially reported as Staphylococcus haemolyticus (5 isolates) and Staphylococcus epidermidis (2 isolates) by the routine identification scheme and with the Vitek GPI system (bioMerieux Vitek, Inc., Hazelwood, Mo.), were subsequently identified as S. aureus by positive tube coagulase tests, standard biochemical reactions, and characteristic cellular fatty acid chromatograms. The antibiotypes obtained by the E test, coagulase types, restriction fragment length polymorphism profiles of the staphylococcal coagulase gene, and random amplified polymorphic DNA patterns generated by arbitrarily primed PCR of the isolates disclosed that two major clones disseminated in the ICUs. Clone 1 (16 isolates) was resistant to clindamycin and was susceptible to trimethoprim-sulfamethoxazole (TMP-SMZ) and was coagulase type II. Clone 2 (eight isolates) was resistant to clindamycin and TMP-SMZ and was coagulase type IV. These two epidemic clones from ICUs are unique and underline the need for caution in identifying MRSA strains with colonial morphologies not of the typical type and with negative Staphylase reactions.
1997年12月至1998年3月期间，在台湾大学医院的6个重症监护病房（ICU）或ICU住院后的病房中，从13名患者的各种临床标本中鉴定出25株表现出葡萄球菌凝固酶（Oxoid有限公司，英国贝辛斯托克）反应阴性的耐甲氧西林金黄色葡萄球菌（MRSA）分离株。这些分离株的特征在该医院其他MRSA分离株中尚未见报道。所有这些分离株的菌落均在添加5%羊血的胰蛋白胨大豆琼脂上生长，无溶血现象且无色素。最初通过常规鉴定方案和Vitek GPI系统（bioMerieux Vitek公司，密苏里州黑兹尔伍德）报告为溶血葡萄球菌（5株）和表皮葡萄球菌（2株）的7株分离株，随后通过阳性试管凝固酶试验、标准生化反应和特征性细胞脂肪酸色谱图鉴定为金黄色葡萄球菌。通过E试验获得的抗菌谱、凝固酶类型、葡萄球菌凝固酶基因的限制性片段长度多态性图谱以及分离株的任意引物PCR产生的随机扩增多态性DNA模式显示，两个主要克隆在ICU中传播。克隆1（16株）对克林霉素耐药，对甲氧苄啶 - 磺胺甲恶唑（TMP - SMZ）敏感，凝固酶类型为II型。克隆2（8株）对克林霉素和TMP - SMZ耐药，凝固酶类型为IV型。来自ICU的这两个流行克隆是独特的，强调了在鉴定具有非典型菌落形态和葡萄球菌凝固酶反应阴性的MRSA菌株时需要谨慎。
