n engl j med 352;14 www.nejm.org april 7, 2005 The new england journal of medicine 1445 original article Necrotizing Fasciitis Caused by Community-Associated Methicillin-Resistant Staphylococcus aureus in Los Angeles Loren G. Miller, M.D., M.P.H., Francoise Perdreau-Remington, Ph.D.,Gunter Rieg, M.D., Sheherbano Mehdi, M.D., Josh Perlroth, M.D.,Arnold S. Bayer, M.D., Angela W. Tang, M.D., Tieu O. Phung, M.D.,and Brad Spellberg, M.D. From the Divisions of Infectious Diseasesand HIV Medicine (L.G.M., G.R., A.S.B.,B.S.) and the Department of InternalMedicine (L.G.M., G.R., J.P., A.S.B., B.S.),Harbor–UCLA Medical Center and the LosAngeles Biomedical Institute at Harbor–UCLA, Torrance; the University of Califor-nia, San Francisco (F.P.-R.); and St. MaryMedical Center, Long Beach (S.M., A.W.T.,T.O.P.) — all in California. N Engl J Med 2005;352:1445-53. Copyright © 2005 Massachusetts Medical Society. background Necrotizing fasciitis is a life-threatening infection requiring urgent surgical and medicaltherapy. Staphylococcus aureus has been a very uncommon cause of necrotizing fasciitis, butwe have recently noted an alarming number of these infections caused by community-associated methicillin-resistant S. aureus (MRSA). methods We reviewed the records of 843 patients whose wound cultures grew MRSA at ourcenter from January 15, 2003, to April 15, 2004. Among this cohort, 14 were identifiedas patients presenting from the community with clinical and intraoperative findings ofnecrotizing fasciitis, necrotizing myositis, or both. results The median age of the patients was 46 years (range, 28 to 68), and 71 percent weremen. Coexisting conditions or risk factors included current or past injection-drug use(43 percent); previous MRSA infection, diabetes, and chronic hepatitis C (21 percenteach); and cancer and human immunodeficiency virus infection or the acquired im-munodeficiency syndrome (7 percent each). Four patients (29 percent) had no seriouscoexisting conditions or risk factors. All patients received combined medical and sur-gical therapy, and none died, but they had serious complications, including the needfor reconstructive surgery and prolonged stay in the intensive care unit. Wound cultureswere monomicrobial for MRSA in 86 percent, and 40 percent of patients (4 of 10) forwhom blood cultures were obtained had positive results. All MRSA isolates were sus-ceptible in vitro to clindamycin, trimethoprim–sulfamethoxazole, and rifampin. Allrecovered isolates belonged to the same genotype (multilocus sequence type ST8,pulsed-field type USA300, and staphylococcal cassette chromosome mec type IV[SCC mec IV]) and carried the Panton–Valentine leukocidin ( pvl ), lukD, and lukE genes,but no other toxin genes were detected. conclusions Necrotizing fasciitis caused by community-associated MRSA is an emerging clinicalentity. In areas in which community-associated MRSA infection is endemic, empiricaltreatment of suspected necrotizing fasciitis should include antibiotics predictably ac-tive against this pathogen.abstractCopyright © 2005 Massachusetts Medical Society. All rights reserved. Downloaded from www.nejm.org at Stanford University on September 20, 2005 .n engl j med 352;14 www.nejm.org april 7 , 2005 The new england journal of medicine 1446 taphylococcus aureus is a ubiqui- tous pathogen and one of the most commoncauses of severe community-associated (alsoreferred to as community-acquired) infections ofskin and soft tissue. 1-4 Until recently, S. aureus strainsfrom community-associated infections were almostuniformly susceptible to penicillinase-resistant b -lactam antibiotics (i.e., methicillin and oxacillin).However, over the past few years, community-associated infections caused by methicillin-resistant S. aureus (MRSA) have become commonplace inmultiple locales in the United States and world-wide 5-10 ; at our center, 62 percent of community-associated S. aureus infections are due to MRSA. 11 The majority of community-associated MRSA in-fections have been skin and soft-tissue infec-tions. 7,10,12 In urban regions, such as Los AngelesCounty, such infections appear to have become en-demic. 5,7,12,13 In such settings, it is recommend-ed that empirical therapy for serious community-associated S. aureus infections include antibioticsdirected against MRSA. 14 Necrotizing fasciitis is a rapidly progressive, life-threatening infection involving the skin, soft tissue,and deep fascia. 15-18 These infections are typicallycaused by group A streptococcus, Clostridium perfrin-gens, or a mixture of aerobic and anaerobic organ-isms, typically including group A streptococcus, theEnterobacteriaceae, anaerobes, and S. aureus . 17-21 S. aureus has not been described as a monomicrobi-al cause of necrotizing fasciitis in major clinical re-views of the topic or in published microbiologicstudies of the disease. 17,19-22 Owing to the frequent-ly polymicrobial nature of necrotizing fasciitis, mostauthorities recommend the use of broad-spectrumempirical antimicrobial therapy for suspected cases.However, therapy directed against MRSA, such asvancomycin, is not recommended in current stan-dard guides, presumably because of the rarity ofthis pathogen as a cause of necrotizing fasciitis. 22-24 To date, MRSA has been reported to be associ-ated with necrotizing fasciitis in only one case ofsubacute, polymicrobial infection 25 and as a mono-microbial cause of an iatrogenic, surgery-associated“necrotizing fasciitis–like” infection and bactere-mia. 26 At our medical center in Los Angeles Coun-ty, we noted a number of cases of monomicrobialnecrotizing fasciitis caused by community-associ-ated MRSA beginning in 2003. Because of the veryunusual nature of these infections and their impor-tant clinical effect on empirical therapy for necro-tizing fasciitis, we sought to identify all cases at ourmedical center and to characterize clinical andorganism-specific features of these infections.We identified all wound cultures that were positivefor MRSA from January 15, 2003, through April 15,2004, at Harbor–UCLA Medical Center and re-viewed the case records of patients with positivewound cultures that also contained a surgical re-port. All surgical reports were reviewed to deter-mine the preoperative diagnosis, intraoperativefindings, and postoperative diagnosis. If both theintraoperative and postoperative diagnoses werenecrotizing fasciitis, myositis, or both, the