# Hospital-onset methicillin-resistant Staphylococcus aureus bloodstream infections within tertiary and community hospitals and implications for prevention

## TL;DR

This study examines hospital-onset MRSA bloodstream infections in New York City hospitals to identify patterns and prevention strategies.

## Contribution

The study provides updated epidemiological data on HO-MRSA BSI in both tertiary and community hospitals in NYC.

## Key findings

- HO-MRSA BSI rates remained stable with SIRs of 0.815 overall from 2020–2023.
- Pneumonia was the most common source of HO-MRSA BSI, followed by skin infections and central line infections.
- Mortality from HO-MRSA BSI was 35%, highlighting the severity of these infections.

## Abstract

An improved understanding of the epidemiology of hospital-onset methicillin-resistant Staphylococcus aureus bloodstream infection (HO-MRSA BSI) could inform future prevention strategies for HO-MRSA BSI.

We performed a retrospective cohort study of HO-MRSA BSI reported to NHSN from 2020–2023 at a system of 9 acute care hospitals located in New York City. The primary outcome was to describe the demographic and clinical characteristics of patients with HO-MRSA BSI. Secondary outcomes included comparisons of tertiary (TH) and community (CH) hospitals, standardized infection ratio (SIR) and rates per 10,000 patient-discharges, presumptive potential infectious sources, and mortality.

Between 2020 and 2023, 222 patients had HO-MRSA BSI. Their median age was 65 years, 139 (63%) were male, 92 (41%) had central lines, 89 (40%) were in ICUs, and 63 (28%) were on a ventilator. These characteristics were similar across the 176 (79%) patients in TH and the 46 (21%) patients in CH. SIRs were similar across each year of the study (with cumulative SIRs of 0.815 overall, 1.412 [CH] and 0.732 [TH]). Overall HO-MRSA BSI rates ranged from 2.58–3.53 per 10,000 patient-discharges. The most common sources of HO-MRSA BSI were pneumonia (41%), SSTIs (17%), CLABSIs (13%), and PIV catheter-related issues (9%). The all-cause mortality rate was 35%.

The unchanged HO-MRSA BSI SIRs in this study support the need for additional interventions that focus on prevention of the primary sources of MRSA infections. Ongoing systematic surveillance of the primary sources of HO-MRSA BSI should be implemented to inform and monitor best practices for prevention.