Preoperative carriage of Staphylococcus aureus, especially in the nose, is associated with increased risk of S aureus surgical-site and postoperative bloodstream infections (SA SSI/BSI), researchers reported yesterday in Open Forum Infectious Diseases.
Higher bacterial load in the nose and S aureus colonization at other body sites further increased the risk, researchers with the ASPIRE-SSI study group found. ASPIRE-SSI was a prospective observational cohort study that followed adult surgical patients at 33 European hospitals for up to 90 days after surgery to assess the occurrence of and risk factors for postoperative S aureus infections.
S aureus is known to colonize 20% to 30% of the human population at different body sites, particularly the nose but also the throat, axilla, and perineal region, and previous studies have shown that it causes approximately 30% of SSIs. This study aimed to determine the effects of S aureus nasal carriage alone, carriage at multiple sites, and bacterial load on the risk of developing SA SSI/BSI.
Findings support decolonization strategies
Of the 5,004 patients included in the study cohort, 3,369 (67.3%) were S aureus carriers. Of the 100 SA SSI/BSIs that occurred, 86 occurred in S aureus carriers. Both S aureus nasal carriage (adjusted hazard ratio [aHR], 4.2; 95% confidence interval [CI], 2.0 to 8.6) and S aureus carriage at any body site (aHR, 4.6; 95% CI, 2.1 to 10.0) were independently associated with an increased risk of developing SA SSI/BSI within 90 days of surgery.
The risk increased as the number of preoperatively colonized bodily sites increased (aHR, 3.5 to 8.5) as the number of colonized sites increased from one to three) and as the S aureus bacterial load in the nose increased (aHR, 1.8 to 3.4). But extranasal carriage only was not independently associated with increased SA SSI/BSI risk.
The study authors say the findings are in line with previous studies and provide further evidence in support of S aureus decolonization strategies.
“Such interventions have been shown to be efficacious, effective, and cost-effective,” they wrote.
