Treating staphylococcal bacteremia demands expertise

Some hospitals require an ID consult for all patients with staphylococcal bacteremia. While the necessity of mandatory consultation can be debated there's no disputing the fact that treatment requires a certain level of expertise beyond the scope of knowledge and experience of many practitioners.

What does the literature say?

In this retrospective cohort study:

Patients who received IDC had closer blood culture follow-up and better antibiotic selection, and were more likely to have pus or prosthetic material removed. Hospital mortality from SAB was lower in patients who received IDC than in those who did not (13.9% vs. 23.7%; p = 0.05). In multivariate survival analysis, IDC was associated with substantially lower hazard of hospital mortality during SAB (hazard 0.46; p = 0.03).

...In conclusion, IDC is associated with reduced mortality in patients with staphylococcal bacteremia.

In another recent study:

Factors significantly associated with in-hospital mortality in multivariate analysis were ICU admission (OR 5.8, CI 3.5–9.7), MRSA (OR 2.6, CI 1.4–4.9), age greater than or equal to 60 years (OR 2.4, CI 1.4–4.2), a diagnosis of endocarditis (OR 2.8, CI 1.4–5.7), a non-fatal underlying disease/comorbidity according to the McCabe classification (OR 0.2, CI 0.1–0.4), and infectious disease specialist consultation (OR 0.6, CI 0.4–1.0).

Conclusions
These data suggest that outcome of S. aureus bacteremia may be improved by an expert consultation service.

Another study from last year showed a non-statistically significant trend toward decreased treatment failures with ID consultation but an increased rate of detection of complicated infections and some process differences:

Echocardiography (57% vs. 73%; p = .01) and radiographic studies (81% vs. 91%; p = .04) were used more frequently during the period of routine consultation, and infective endocarditis or metastatic infections were diagnosed more frequently (33% vs. 46%; p = .04). All 4 standards of care (removal of intravascular foci of infection, obtaining follow-up blood culture samples, use of parenteral beta-lactam therapy when possible, and administration of greater than or equal to 28 days of therapy for complicated infections) were adhered to more frequently with routine consultation (40% vs. 74%; P less than .001).

So if ID consultation really is producing better outcomes what are the ID docs adding? From the descriptions above, better evaluation and management all the way around, it would appear. Based on the descriptions above, if ID consultation is not readily available at your hospital, be aware of the modalities often overlooked by non-specialists: knowing when vanco is not enough; getting follow up blood cultures; source control; treating long enough; appropriate use of imaging to diagnose endocarditis and other complications; switching to a beta lactam antibiotic if the organism turns out to be MSSA.