SAN DIEGO (FRONTLINE MEDICAL NEWS) – Thirty-day mortality associated with Staphylococcus aureus bacteremia is reduced if there is guidance from either an antimicrobial stewardship team (AST) or an infectious disease consultant (IDC), according to a multivariate experience at Yale New Haven Hospital presented at an annual scientific meeting on infectious diseases.

“This has been a hot area, because there have been a lot of recent studies suggesting that expert infectious disease advice improves care, but not every study has associated expert advice with a mortality benefit,” said Jacqueline Sherbuk, MD, a fellow in the division of infectious diseases and international health at the University of Virginia, Charlottesville. She was a resident at Yale University when this study was conducted.

In this study, the impact of an IDC on outcome in patients with S. aureus bacteremia was evaluated relative to no expert advice. By itself, an IDC was associated with improved adherence to standards of care for S. aureus bacteremia management, but the reduction in mortality was not statistically significant for those who received IDC guidance relative to those who did not.

“Given that patient care may be guided by consultations from the AST independent of IDC, we looked at the overall impact of expert opinion versus no expert involvement, and this achieved significance on multivariate analysis,” Dr. Sherbuk reported.

For adherence to guidelines, IDC guidance was better than no expert advice on multiple measures, including proportion obtaining an echocardiogram (89% vs. 67%; P less than .001), appropriate definitive antibiotics (98% vs. 80%; P less than .001), and appropriate treatment duration (92% vs. 35%; P less than .001). However, the advantage for 30-day mortality rates was only a trend (11% vs. 21%, P = .07). It was only when patients who received IDC guidance or a consultation from the AST were combined that the difference climbed to significance (11% vs. 23%; P = .04).

“On multivariate analysis, the OR [odds ratio] was substantial, predicting a 60% reduction [OR 0.40; P = .03) in 30-day mortality for expert advice vs. no expert advice,” Dr. Sherbuk reported.

In this retrospective observational study, 261 unique cases of S. aureus bacteremia cases in adult patients established with positive blood cultures were evaluated. The cases were collected over a 1-year period at Yale New Haven Hospital. After exclusion of those who died within 3 days of the initial positive culture or who were transferred to other facilities, 236 were included in this analysis.

IDC guidance, which is not required for S. aureus bacteremia at Yale New Haven Hospital, was provided for 74.5% of the patients. Another 4% of patients received guidance from the AST, which is an independent service often provided prior to IDC guidance, according to Dr. Sherbuk.

When those who received expert advice were compared with those who were not, there were no differences in age, sex, clinical diagnosis, or rate of methicillin-resistant S. aureus. While the IDC group had a lower rate of immunosuppressed patients relative to the non–expert advice group, it had a higher proportion of patients with orthopedic prostheses.

Relapse (3% vs. 5%) and reinfection (6% vs. 4%) rates were low in both those who did and did not receive expert advice, respectively. These rates were not significantly different. On multivariate analysis, the two factors associated with increased 30-day mortality were patient age greater than 60 years and sepsis based on sequential organ failure assessment.

Several previous studies have associated IDC advice with improved outcomes in S. aureus bacteremia, according to Dr. Sherbuk, but this study suggests that the AST “can be a meaningful adjunct” to IDC guidance to improve outcomes. She noted that several other sets of data presented at this year’s ID Week also associated AST with improved infection management.