207. High Severity and Mortality Due to Methicillin-Susceptible Staphylococcus aureus Infections in a Colombian Hospital

BACKGROUND: Methicillin-susceptible Staphylococcus aureus (MSSA) infections are considered less severe than those caused by methicillin-resistant S. aureus. However, we have observed an important increase in severe cases of invasive MSSA infections in a hospital in Pereira, Colombia. Here, we characterize the clinical outcomes and epidemiology of these infections. METHODS: We included adult and pediatric patients hospitalized between February 2018 and April 2019 presenting with invasive infections caused by MSSA. All isolates were sent to a central laboratory to confirm identification. We determined cefazolin MICs at standard (10(5) CFU/mL) and high inoculum (10(7) CFU/mL) by broth microdilution and a rapid test to detect cefazolin inoculum effect (CIE). The CIE was defined as an increase of MIC to ≥16 µg/mL when tested at high inoculum. Clinical data (demographics, intensive care unit (ICU) admission, therapy and mortality) were obtained from medical records. RESULTS: A total of 60 patients were included in the study and 41.6% were women. Most (63.3%) infections were hospital-associated. Bacteremia was the most frequent type of infection (71.6%). The mean duration of hospital stay was 24.5 days (IQR, 14–44). 61.6% of patients were admitted to the ICU with a mean length of stay of 14 days (IQR, 7–30). Mortality at 30 days was 28.3% (17 out of 60 patients) and was slightly higher (30.2%) in patients with bacteremia. Early mortality (48 h) was 10% (n = 6). Most patients (75%) received β-lactams (28.8% cefazolin and 84% oxacillin). 18 patients (33%) had isolates that exhibited the CIE but most (n = 11) received oxacillin. Among 17 patients who died, 35% had received antibiotics other than β-lactams (5 vancomycin, 1 ampicillin-sulbactam) and two did not received any therapy due to rapid death. The mean duration of antibiotic therapy was 11 days. Source control was deemed appropriate in 65% of the cases. CONCLUSION: An increase in severe invasive infections caused by MSSA was observed in our hospital with a high proportion of patients requiring ICU care. A significant proportion of patients received inappropriate treatment. Due to the aggressive nature of invasive MSSA infections, efforts to optimize appropriate therapy for these infections are urgently needed in Colombia. DISCLOSURES: All authors: No reported disclosures.