Epidemiological and clinical characteristics of methicillin sensitive Staphylococcus aureus (MSSA) bacteriuria

Objectives: To determine the frequency of MSSA bacteriuria in our hospital, ascertain nosocomial and community-acquired risk factors, identify specific epidemiological characteristics among bacteriuric patients with/without MSSA bacteremia. Methods: Adult patients with MSSA bacteriuria during 44 months identified retrospectively; their files reviewed for demographics, Charlson Comorbidity Index, urinary tract infection, clinical data, predisposing factors, urinary catheter data, treatment, and outcome. Results: 106 patients (mean age 56 (SD 22) years; 43% females) with MSSA bacteriuria were identified, comprising 0.18% of bacteriurias in our hospital during the study period. Only 6.6% were admitted from long-term care facilities. 30% were hospital-acquired, with crude mortality rate 28% vs. 8% in community-acquired bacteriuria (P < 0.05). Charlson Comorbidity Index was 2.7 (SD 3.2). 41% had a Foley urinary catheter. 12% with MSSA bacteriuria had concurrent MSSA bacteremia. In bacteremic patients vs. non-bacteremic patients: fever in 58% vs. 26% (P < 0.025), antibiotics administered in 92% vs. 60% (P < 0.04), and death by 28th post-discharge day 58% vs. 9% (P < 0.001). Conclusions: MSSA bacteriuria is rare, equally frequent in both genders, occurs in younger patients than previously described, and may occur even without a urinary catheter. Hospital-acquired bacteriuria and bacteremia are risk factors for mortality.