Vital Signs

Trends in Staphylococcus Aureus Infections in Veterans Affairs Medical Centers — United States, 2005–2017

Makoto Jones, MD; John A. Jernigan, MD; Martin E. Evans, MD; Gary A. Roselle, MD; Kelly M. Hatfield, MSPH; Matthew H. Samore, MD

Disclosures

Morbidity and Mortality Weekly Report. 2019;68(9):220-224. 

In This Article

Results

The analysis included 130 VA hospitals. The overall rate of S. aureus infections decreased by 43% during 2005–2017 (4.7% annually, p<0.001) (Table). The reductions were driven primarily by decreases in MRSA infections, which declined by 55% (7.3% annual rate of decrease, p<0.001); MSSA infection rates decreased much more slowly, by 12% (1.2% annually, p = 0.003) (Figure 1). Hospital-onset MRSA infections decreased by 66% (p<0.001), and hospital-onset MSSA infections decreased 19% (p = 0.02); similar reductions were observed in both bloodstream and nonbloodstream infections (Figure 2).

Figure 1.

Rate* of Staphylococcus aureus infections among hospitalized patients, by methicillin resistance status — 130 Veterans Affairs medical centers, United States, 2005–2017
Abbreviations: MRSA = methicillin-resistant Staphylococcus aureus; MSSA = methicillin-susceptible Staphylococcus aureus.
* Unadjusted.

Figure 2.

Hospital-onset Staphylococcus aureus bloodstream and nonbloodstream infection rates,* by methicillin resistance status — 130 Veterans Affairs medical centers, United States, 2005–2017
Abbreviations: MRSA = methicillin-resistant Staphylococcus aureus; MSSA = methicillin-susceptible Staphylococcus aureus.
* Unadjusted

Among community-onset infections, overall MRSA infection rates decreased by 41% (p<0.001), and community-onset MSSA infection rates declined by 0.4% (p = 0.93) (Table) (Figure 3). The decreases in community-onset MRSA bloodstream and nonbloodstream infections were greatest among infections occurring within 30 days of hospital discharge (Table). Decreases in community-onset infections played a substantial role in overall S. aureus trends: reduction in community-onset MRSA infections accounted for 48% of the overall MRSA rate decreases, and 40% of decreases in overall S. aureus infection rates.

Figure 3.

Community-onset Staphylococcus aureus infection rates,* by methicillin resistance status — 130 Veterans Affairs medical centers, United States, 2005–2017
Abbreviations: MRSA = methicillin-resistant Staphylococcus aureus; MSSA = methicillin-susceptible Staphylococcus aureus.
* Unadjusted

The rate of hospital-acquired MRSA colonization decreased 78% during the study period 6.8 per 1,000 patient-days at risk (2008) to 1.5 per 1,000 patient-days at risk (2017) (16.7% annually, p<0.001). When hospital-onset MRSA infection rates were stratified according to results of admission nasal surveillance tests, MRSA infection rates among patients whose admission screening tests were negative declined by 58% (9.7% annually, p<0.001). In contrast, the reduction among patients with positive admission screening tests was significantly less; MRSA infections decreased 31% (4.2% annually, p<0.001) (p<0.05 compared with patients with a negative admission test). Fluoroquinolone use did not change significantly between 2005 and 2008, but between 2009 and 2017, fluoroquinolone use rates decreased by 44% (annual decrease = 4.8% p<0.001).

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