The impact of an intervention to increase follow-up blood cultures for patients with Staphylococcus aureus bacteriuria.

Background: Staphylococcus aureus bacteriuria (SABU) may represent bacteremia in a subset of patients. We describe the impact of a microbiology alert recommending follow-up blood cultures (FUBC) for patients with SABU in a large integrated health system.

Methods: We conducted a quasi-experimental implementation study in adult ambulatory patients with documented SABU. We excluded patients with confirmed SAB up to 14 days prior to index SABU culture and with blood cultures obtained on the day of SABU. The primary outcome was rate of FUBC (collected between 1 and 5 days of SABU) among all cases of SABU. Secondary outcomes included percentage of patients with early SAB (collected between 1 and 5 days of SABU). We used interrupted time series analysis to compare rates of FUBC pre vs postintervention.

Results: A total of 2 540 patients were identified; 1 213 (48%) were male. By the end of the postintervention period, the rate of FUBC (20.6%) had increased by 6.3 percentage points (P = .005) compared to the counterfactual (14.2%) had no intervention taken place (44.5% relative increase). Early SAB detection due to FUBC increased from .6% preintervention to 2.0% postintervention (P = .004).

Conclusion: The microbiology alert initiative increased FUBC in patients with SABU by 44%, but the overall rate of FUBC remained low. The intervention increased early SAB detection. Risk-targeted strategies are needed to optimize FUBC collection in patients with SABU.