Community-acquired methicillin-resistant Staphylococcus aureus emerging as an important cause of necrotizing fasciitis.
BACKGROUND
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Young
Lisa M
LM
Department of Medicine, Division of Infectious Diseases, University of Colorado Health Sciences Center, Denver, Colorado., USA. Young.Lisa@yahoo.com
Price
Connie S
CS
D000328:Adult; D001427:Bacterial Toxins / Q000235:genetics; D003120:Colorado / Q000453:epidemiology; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000382:microbiology; D005098:Exotoxins / Q000235:genetics; D019115:Fasciitis, Necrotizing / Q000453:epidemiology / Q000382:microbiology; D005260:Female; D006801:Humans; D007956:Leukocidins / Q000235:genetics; D008297:Male; D016106:Methicillin Resistance; D008875:Middle Aged; D015995:Prevalence; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
D001427:Bacterial Toxins; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin