Necrotizing fasciitis caused by community-associated methicillin-resistant Staphylococcus aureus (MRSA) is an emerging clinical entity. This study reports 14 cases of necrotizing fasciitis or myositis caused by community-associated MRSA in Los Angeles between 2003 and 2004. The median age of patients was 46 years, and 71% were men. Most patients had risk factors such as injection-drug use, diabetes, or chronic hepatitis C. All patients received combined medical and surgical therapy and survived, though they experienced serious complications, including the need for reconstructive surgery and prolonged ICU stays. Wound cultures were monomicrobial for MRSA in 86% of cases, and 40% of patients with blood cultures had positive results. All MRSA isolates were susceptible to clindamycin, trimethoprim-sulfamethoxazole, and rifampin. All isolates belonged to the same genotype (ST8, USA300, SCCmecIV) and carried the pvl, lukD, and lukE genes. Community-associated MRSA infections have become increasingly common, particularly in urban areas like Los Angeles. These infections are often caused by skin and soft tissue infections, but necrotizing fasciitis caused by community-associated MRSA is rare. The study highlights the importance of including antibiotics active against MRSA in empirical therapy for suspected necrotizing fasciitis. The MRSA strain identified in this study, ST8:S, is associated with outbreaks in correctional facilities and is known for carrying the pvl gene, which is linked to severe infections. The study also found that the majority of isolates carried multiple adhesin genes associated with pathogenicity. However, toxin genes other than pvl, lukD, and lukE were not detected. The findings suggest that community-associated MRSA may be less virulent than other pathogens in causing necrotizing fasciitis. The study underscores the need for further research to understand the pathogenesis of this severe infection and to improve empirical treatment strategies.Necrotizing fasciitis caused by community-associated methicillin-resistant Staphylococcus aureus (MRSA) is an emerging clinical entity. This study reports 14 cases of necrotizing fasciitis or myositis caused by community-associated MRSA in Los Angeles between 2003 and 2004. The median age of patients was 46 years, and 71% were men. Most patients had risk factors such as injection-drug use, diabetes, or chronic hepatitis C. All patients received combined medical and surgical therapy and survived, though they experienced serious complications, including the need for reconstructive surgery and prolonged ICU stays. Wound cultures were monomicrobial for MRSA in 86% of cases, and 40% of patients with blood cultures had positive results. All MRSA isolates were susceptible to clindamycin, trimethoprim-sulfamethoxazole, and rifampin. All isolates belonged to the same genotype (ST8, USA300, SCCmecIV) and carried the pvl, lukD, and lukE genes. Community-associated MRSA infections have become increasingly common, particularly in urban areas like Los Angeles. These infections are often caused by skin and soft tissue infections, but necrotizing fasciitis caused by community-associated MRSA is rare. The study highlights the importance of including antibiotics active against MRSA in empirical therapy for suspected necrotizing fasciitis. The MRSA strain identified in this study, ST8:S, is associated with outbreaks in correctional facilities and is known for carrying the pvl gene, which is linked to severe infections. The study also found that the majority of isolates carried multiple adhesin genes associated with pathogenicity. However, toxin genes other than pvl, lukD, and lukE were not detected. The findings suggest that community-associated MRSA may be less virulent than other pathogens in causing necrotizing fasciitis. The study underscores the need for further research to understand the pathogenesis of this severe infection and to improve empirical treatment strategies.