Patients with S. aureus Bacteremia Benefit From Formal Infectious Disease Consultation

ABSTRACT & COMMENTARY

Source: Fowler VG Jr, et al. Outcome of Staphylococcus aureus bacteremia according to compliance with recommendations of infectious disease specialists: Experience with 244 patients. Clin Infect Dis 1998;227:478-486.

Fowler and colleagues at duke university prospectively evaluated 244 hospitalized patients with Staphylococcus aureus bacteremia and made recommendations for management based upon a consensus developed prior to the start of the study. In this consensus, the recommendation for treatment of patients with "simple" bacteremia, who had a negative trans-esophageal echocardiogram (TEE), negative "surveillance" blood cultures obtained after 2-4 days of therapy, a removable focus of infection, clinical resolution of signs and symptoms within 72 hours of the onset of therapy, and absence of any indwelling prosthetic devices, was seven days of IV antibiotic therapy. Patients with "uncomplicated" bacteremia, defined by the presence of a negative (for vegetations) TEE but a preexisting valve abnormality, and/or a positive "surveillance" blood culture, and/or a superficial but nonremovable focus of infection, and/or persistent signs of infection more than 72 hours after the start of therapy, were to receive IV antibiotics for 14 days. Patients with endocarditis or a deep extracardiac site of infection, such as mediastinitis of osteomyelitis, were to receive 4-8 weeks of IV antibiotics, as well as, in some cases, surgery.

In each case, a treating physician for the bacteremic patient was contacted, management recommendations discussed, and an official consultation offered. All patients were subsequently assessed to determine outcome and whether the recommendations were followed.

The consultants' recommendations were followed by the physicians of only 112 (45.9%) of the patients, while consultation was declined and verbal advice completely or partially ignored by the remainder. The physicians of the two groups of patients did not differ by specialty. However, physicians for patients with the following characteristics were more likely to follow the advice: those with metastatic infection, those with more prolonged duration of symptoms, and those with hospital-acquired infection. Those with hemodialysis-dependent patients were less likely to follow the recommendations of the consultant.

Despite their apparent greater severity of infection, patients whose physicians followed the infectious disease consultants' recommendations were more likely to be cured of bacteremia (79.5% vs 64.4%, respectively; P = 0.01). They were also less likely to relapse (6.3% vs 18.2%; P < 0.01). The most important risk factor for failure was failure to remove an intravascular device; patients whose device was not removed were 6.5 times more likely to relapse or die from their infection than were those whose device was removed (P < 0.01).

COMMENT BY STAN DERESINSKI, MD, FACP

This study provides information concerning the value of informal ("curbside") consultation vis à vis formal consultation. The outcome of patients provided formal infectious disease consultation with recommendations followed by their physician was better than that of patients whose physician received only informal consultation with recommendations. This is the strongest prospective evidence of which I am aware indicating the inadequacy of informal consultation, a practice which is distressingly common.

Furthermore, this study demonstrates the benefit of infectious disease consultation in a clearly defined patient population. As pointed out by Fowler et al, although the management recommendations were based on a set of consensus guidelines, their implementation "required individual assessment (as to the likely source of infection), interpretation of clinical and laboratory findings, and judgment." Thus, such guidelines alone cannot supplant the skills, knowledge, and experience represented by a competent infectious disease consultant.