Main source of S. aureus differed for community- and hospital-acquired infections
PHILADELPHIA — Data presented at IDWeek 2014 suggest soft tissue infections are the main source in community-acquired Staphylococcus aureus bloodstream infections, whereas central catheters are the main source of hospital-acquired cases.
Researchers from the University of Alberta Hospital in Edmonton, Canada examined the records of patients with a blood culture positive for S. aureus from 2010-2012 (n=342). The mean age of the patients was 60.6 years, and 69.3% were male. ICU admission was required for 43.5%, while 57.8% were admitted to medical services.
Fifty-four percent of S. aureus cases were community-acquired (CA). Other than a decline of hospital-acquired (HA) MRSA in 2012, bloodstream infection rates were consistent throughout the study period.
Thirty-day mortality rates were 24.2% for CA cases and 19.2% for HA cases. The CA group had a higher 120-day mortality rate: 32.3% vs. 26.2% among the HA group.
Infection source was identified in 89.1% of cases. For CA bloodstream infections, skin and soft tissue infections (12%), pneumonia or aspiration (9.5%) and endocarditis (8.5%) were the most common sources. For HA infections, central access (15.4%), post-operative infections (9.8%) and pneumonia or aspiration (6.6%).
Distributions of age and sex, mean duration of bacteremia and mean vancomycin inhibitory concentration were similar between CA and HA cases. Patients with HA bacteremia spent, on average, almost 1 day longer in the ICU (6.8 vs 5.9) and 1.6 days longer in the hospital (35.1 vs 33.5).
“To our knowledge very few studies have examined the differences in CA and HA S. aureus bloodstream infections,” the researchers wrote. “Our study suggests the geographical place of onset is not determined by age, sex or resistance pattern and does not affect mortality. The main difference between the two entities is the source of infection.”
For more information:
King A. Abstract 723. Presented at: IDWeek 2014; Oct. 8-12, 2014; Philadelphia.
Disclosure: The researchers report no relevant financial disclosures.