Bacterial infections in low-risk, febrile neutropenic patients.

Background: Accurate identification of low-risk, febrile neutropenic patients has become possible only recently. Many such patients are treated with oral antibiotics without hospitalization. To the authors' knowledge, data concerning the spectrum of bacterial infections in these patients are scarce, and collecting such data may have an impact on the choice of empiric oral regimen(s).

Methods: Using the same risk-prediction and eligibility criteria, four studies of empiric therapy in low-risk, febrile neutropenic patients were conducted at the authors' institution. Based on that experience, patients also were entered on clinical pathways for outpatient therapy. For the current study, microbiologic data were pooled from those trials and clinical pathways (757 episodes) to describe the nature and spectrum of infections seen in this setting.

Results: Unexplained fever occurred most often (58% of episodes), and both clinically documented and microbiologically documented infections were seen with equal frequency (21% of episodes, respectively). The most common clinical sites of infection were the upper respiratory tract, skin, and skin structure. Among microbiologically documented infections, monomicrobial, gram-positive infections accounted for 49% (with coagulase-negative staphylococci the most frequent); monomicrobial, gram-negative infections accounted for 36% (with Escherichia coli the most frequent); and 15% of infections were polymicrobial.

Conclusions: In this description of the spectrum of infections in the largest cohort of low-risk febrile neutropenic patients to date, episodes of unexplained fever were predominant, but gram-positive, gram-negative, and polymicrobial infections also were documented. Although these patients were at low risk for complications, they required broad-spectrum antibiotic therapy when they developed neutropenic fever.