Community Acquired MRSA Skin and Soft Tissue Infection and its Possible Relationship With IgG Deficiency and CD4 Lymphopenia

Abstract

Staphylococcus aureus is the most common pathogen associated with infections of skin and soft tissue structures Staphylococcus aureus colonizes the skin of approximately 35% of Americans of which approximately 1% is methicillin resistant Staphylococcus aureus (MRSA). The vast majority of skin and soft tissue infections have been associated with Community acquired-MRSA strains, but other presentations such as pneumonia, necrotizing fascitis and on rare occasions, septicemia have occurred 4,5 . Risk factors for CA-MRSA infections include being a child, an athlete, a member of the armed forces or an intravenous drug user with the majority of these being immunocompetent 6,7 . CA-MRSA infections have also been reported in patients with immunodeficiency states such as HIV, cancer etc . This study was performed to identify any existing correlations between CA-MRSA skin infections and immunocompromised conditions, as assessed by IgG deficiency and CD4 lymphopenia and to define the local epidemiology of (CA-MRSA) skin infections in El Paso, Texas in an Infectious Disease Clinic over a 3 year period. MATERIAL AND METHODS Data was collected prospectively from the medical and laboratory records of outpatients seen at a Infectious Disease Clinic in El Paso, Texas between 2006 -2009. Inclusion criteria for analysis included: (1) Documented skin and soft tissue infections (SSTIs) , (2) Positive wound cultures obtained just prior to or at the time of evaluation, (3) No known previous history of MRSA colonization or infections, and (4) No recent history of hospitalization, nursing home admission, dialysis, surgery, indwelling catheter or devices that pass through the skin in the past year. Data collected included age, gender, complete blood count (CBC), IgG level and CD4 count. Possible confounders including diabetes, steroid use, cancer or other immunecompromised states and sick contacts were assessed. Description of the lesions included site and characteristics of the infection, as well as the clinical course including surgical intervention, antibiotic therapy and relapses or recurrences. If family members were susupected of having the same presentation, phone interviews or face to face contact was established to determine if they had a reasonable probability of having MRSA skin infections. Any cultures that were done on them by other physicians were reviewed. Patients were followed for an average of 2 years following their initial presentation. The definition of a cure was no further skin and soft tissue infections at the end of the 2 year period.