282. Epidemiological Evaluation of Methicillin-Resistant Staphylococcus aureus (MRSA) and Methicillin-Susceptible Staphylococcus aureus (MSSA) Bacteremia: A Comprehensive Cancer Center’s 10-Year Experience

Abstract

BackgroundCoagulase-positive Staphylococcus aureus bacteremia among cancer patients carries significant morbidity and mortality. This study aims to compare the risk factors and clinical outcomes among cancer patients diagnosed with bloodstream infection (BSI) with methicillin-sensitive S. aureus (MSSA) or methicillin-resistant S. aureus (MRSA).MethodsWe performed a retrospective cohort study on all patients diagnosed with an active solid tumor or hematologic cancer with positive blood culture for S. aureus from January 2009 to May 2019. We collected data on demographics, comorbidities, malignancy type, venous access, neutropenia status, echocardiogram results, treatment (tx) duration, antibiotics usage pre/post culture, hospital LOS, infection severity, and 7-day and 30-day mortality. We used the Chi-square test to analyze categorical variables, t-test to analyze continuous variables, and the Kaplan-Meier survival curve and multivariate regression to analyze mortality.ResultsTwo hundred eighty-three cases with malignancies and S. aureus BSIs were reviewed, and 168 were identified with BSIs for MRSA or MSSA during the ten years. The mean age for MRSA cases was 73.1 (±13.7) and 70.1 (± 14.6) for MSSA; male patients were most of the sex (P < 0.01). MRSA and MSSA bacteremia presented equally in hematologic malignancies, while MSSA was observed more in skin cancer than MRSA. Cancers that obstruct GU tracts may be associated with MRSA and MSSA from urine source as both were overrepresented in patients with bladder and rectal cancer. In most patients, the CVC was promptly removed and appropriate antibiotics were given promptly within 1 hour of the positive blood culture. For patients who underwent echocardiogram, most had a negative result in both groups. There was no significant difference for seven and 30-day mortality between the two groups. The mean hospital LOS was longer for MRSA cases (10.5 ± 13.5) versus MSSA cases (4.88 ± 9.1), (P < 0.01). Figures 1 & 2. Kaplan-Meier Survival Curve Comparing 7 and 30-day Mortality of Cancer Patients with MRSA vs MSSA BSI Figure 3 & 4. Distribution of Cancer Types for MRSA (n=84) and MSSA (n=84) BSI ConclusionEndocarditis with either MRSA or MSSA BSI is not a prominent finding among cancer patients at our institution. Given the extensive usage of CVCs and devices in patients with malignancies, prompt removal and antibiotic administration are essential to reduce morbidity; even then, the LOS for MRSA BSI remains longer than MSSA BSI.Disclosures All Authors: No reported disclosures