Young Lisa M, Price Connie S
Department of Medicine, Division of Infectious Diseases, University of Colorado Health Sciences Center, Denver, Colorado., USA.
Surg Infect (Larchmt). 2008 Aug;9(4):469-74. doi: 10.1089/sur.2007.052.
Necrotizing fasciitis (NF) is an uncommon fulminant soft tissue infection characterized by extensive fascial necrosis. Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) isolates producing the Panton-Valentine leukocidin (PVL) cytotoxin have been associated with serious necrotizing infections, but NF caused by CA-MRSA has been described only recently. We reviewed our NF experience at Denver Health Medical Center, where CA-MRSA accounts for more than 50% of community S. aureus clinical isolates.
Patients treated for NF from January 2004 to February 2006 were identified by review of pathology records and diagnostic codes, and their medical records were reviewed. Isolates of MRSA from monomicrobial NF underwent testing for the PVL gene and pulsed-field gel electrophoresis to determine relatedness to CA-MRSA strains.
Five of 30 NF cases during the study period, all involving the extremities, were caused by MRSA. Monomicrobial MRSA NF accounted for three cases, with all of the patients reporting a distinct "spider bite" lesion 2-3 days prior to admission. The median age was 32 years (range 28-55 years). Resistance to erythromycin and levofloxacin was present in four isolates. None of the isolates displayed inducible clindamycin resistance. Within 12 hours of admission, all patients received empiric antibiotics to which their isolate was susceptible. Patients required a median of six surgical procedures (range 2-7 operations). All patients survived. The MRSA isolates tested positive for PVL and had the USA 300 CA-MRSA deoxyribonucleic acid banding pattern.
Community-acquired MRSA is an important cause of NF in our region, accounting for > 15% of NF cases. This infection was associated with significant morbidity necessitating multiple surgical interventions. Given the propensity of PVL-positive CA-MRSA to cause severe necrotizing infections, it is reasonable to administer empiric MRSA coverage for NF in endemic locations.
坏死性筋膜炎（NF）是一种罕见的暴发性软组织感染，其特征为广泛的筋膜坏死。产生杀白细胞素（PVL）细胞毒素的社区获得性耐甲氧西林金黄色葡萄球菌（CA-MRSA）分离株与严重的坏死性感染有关，但由CA-MRSA引起的NF直到最近才被描述。我们回顾了丹佛健康医疗中心的NF治疗经验，在该中心，CA-MRSA占社区金黄色葡萄球菌临床分离株的50%以上。
通过查阅病理记录和诊断编码，确定2004年1月至2006年2月期间接受NF治疗的患者，并查阅他们的病历。对单微生物NF的MRSA分离株进行PVL基因检测和脉冲场凝胶电泳，以确定与CA-MRSA菌株的相关性。
研究期间30例NF病例中有5例由MRSA引起，均累及四肢。单微生物MRSA NF占3例，所有患者在入院前2 - 3天均报告有明显的“蜘蛛咬伤”损伤。中位年龄为32岁（范围28 - 55岁）。4株分离株对红霉素和左氧氟沙星耐药。所有分离株均未显示诱导型克林霉素耐药。入院后12小时内，所有患者均接受了其分离株敏感的经验性抗生素治疗。患者平均需要进行6次外科手术（范围2 - 7次手术）。所有患者均存活。MRSA分离株PVL检测呈阳性，具有USA 300 CA-MRSA脱氧核糖核酸条带模式。
社区获得性MRSA是我们地区NF的重要病因，占NF病例的15%以上。这种感染与严重的发病率相关，需要多次外科干预。鉴于PVL阳性CA-MRSA易于引起严重的坏死性感染，在流行地区对NF进行经验性MRSA覆盖是合理的。
