Staph infections resistant to antibiotics, previously only associated with hospitalization or prior contact with the healthcare system, are now widespread in the community and coming home.
A study from Emory University School of Medicine and Grady Memorial Hospital, published in the Annals of Internal Medicine, reports on a dramatic rise in antibiotic resistant community-acquired methicillin-resistant Staphylococcus aureus ( MRSA ), making it the primary cause of skin and soft tissue infections.
An editorial accompanying the article notes, " the number of populations at risk for community-acquired MRSA infections is steadily expanding ", making it a " remarkable epidemic."

The bacterium Staphyloccus aureus ( staph ) normally resides on skin and in noses, and typically infects tissues through cuts or rashes. Those infections can remain minor, or lead to illnesses ranging from boils or abscesses to necrotizing skin infections, pneumonia and sometimes blood stream infections.
The Centers for Disease Control and Prevention ( CDC ) reports that staph is one of the leading causes of skin infections in the United States.

Previously, researchers have categorized staph into two main types: antibiotic resistant ( MRSA ), and methicillin-susceptible Staphyloccus aureus ( MSSA ), which can be treated by antibiotics in the Penicillin or related groups ( i.e, beta-lactam antibiotics ). Previously, MRSA infections were usually restricted to hospital or healthcare-associated infections. This is clearly no longer the case.

Henry M. Blumberg, senior author of the study, and at Emory University School of Medicine, says, " We have seen an explosion of community-acquired MRSA infections among the urban patient populations served by the Grady Health System. Community-acquired MRSA infections are no longer restricted to certain risk groups but appear to be wide spread in the Atlanta community. "

The study demonstrated that 72 percent of community-onset Staph skin and soft tissue infections among patients receiving care at the Grady Health System ( Grady Memorial Hospital and its affiliated outpatient clinics in Atlanta ) are now due to MRSA. The vast majority of these MRSA skin and soft tissue infections are due to a single clone or strain of MRSA called USA300. As noted in the accompanying editorial, MRSA appears to have emerged as a cause of community-acquired skin infections in other U.S. communities as well.

As noted by Blumberg and other Emory and Grady authors, " Empirical use of antibiotics active against community-acquired MRSA is warranted, especially for patients presenting with serious skin and soft-tissue infections." This represents a major change in prescribing practices for community-onset skin and soft tissue infections.

The recognition of community-acquired MRSA as a primary cause of skin and soft tissue infections offers implications for prevention and treatment.
In the past, Blumberg says, " skin and soft tissue infections occurring in the community were generally MSSA, and that is how antibiotic therapy was targeted." Currently, many doctors may assume that community-acquired staph infections will not be resistant to antibiotics similar to Methicillin and patients may be prescribed ineffective antibiotics.

Source: Emory University Health Sciences Center, 2006


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