Spectrum of invasive staphylococcus aureus infection in HIV-infected patients

Invasive S. aureus infections in HIV+ patients have been increasingly reported. The role of underlying HIV infection in the clinical manifestation and prognosis of S. aureus infection is not known. We report a retrospective analysis of invasive 5. aureus infections in HIV+ and HIV- patients during a ten-year period at GWUMC. Of the 68 HIV+ patients in whom 71 episodes of invasive S aureus infections occurred, 80% had bacteremia, 9% had soft-tissue abscess, 4% had septic arthritis, 4% had pneumonia, 1% had UTI, and 41% had mixed infections. The HIV+ patients had central venous catheters (31% vs. 10%, p=0.012) and presented with bacteremia (80% vs. 45%, p<0.001) more frequently when compared with HIV- patients. Lower WBC count at presentation (median 5.3 vs. 12.0, p<0.001) and higher rate of antibiotic (abx) toxicity (17% vs. 0%) during hospitalization were also noted. There was no significant difference between the two groups with regard to infectious complications, length of hospitalization, and death. Within the group of HIV+ patients, the strongest predictors of death were history of OI's (52% of survivors had history of OI's vs. 100% of non-survivors, p=0.004) and initiation of anti-staphylococcal abx later than day 0 (28% of survivors had delayed abx initiation vs. 70% of non-survivors, p=0.009). Death was not affected by age, HIV risk factors, site of infection, WBC count, and choice of abx. In summary, indwelling central venous catheter is the biggest risk factor for invasive S. aureus infection in HIV+ patients. These patients commonly present with bacteremia and WBC in the normal range. Although overall prognosis is favorable, advanced immunosuppression and delayed initiation of appropriate abx are strong independent predictors of death.