This patient requires immediate parenteral administration of a broad-spectrum antibiotic such as piperacillin-tazobactam while blood and urine cultures are pending. Neutropenia is defined as an absolute neutrophil count less than 1000/µL (1.0 × 109/L). Monotherapy with a β-lactam agent with broad coverage of gram-positive and gram-negative organisms with antipseudomonal activity has been shown to be effective in treating neutropenic fever and is the most commonly used approach. Although combination antibiotic therapy is often used (such as the addition of an aminoglycoside for additional antipseudomonal coverage), no specific regimen has been shown to be superior to broad-spectrum monotherapy. It is also reasonable to further broaden directed antimicrobial therapy if a specific source is suspected, such as adding gram-positive coverage (for example, vancomycin) if a central catheter infection is considered likely. Antifungal agents are usually considered only for patients with mucosal barrier inflammation and prolonged neutropenia (>1 week), and antiviral agents are used only in patients whose disease or therapy is associated with immunosuppression. Antimicrobial therapy should be narrowed if a specific organism or organisms are identified on culture.
Because of resistance, fluoroquinolones are not frequently used as initial monotherapy for patients with neutropenic fever. However, they may have a role in selected low-risk patients with stable vital signs and an unremarkable physical examination who might be eligible for outpatient oral therapy at experienced centers with close monitoring capability. They may also be used as add-on therapy for specific infections or for directed therapy based on culture results.
Hematopoietic growth factors, including granulocyte-macrophage colony-stimulating factors, are effective in preventing neutropenia and allowing for continued full-dose chemotherapy when appropriate. These agents also may reduce the duration of neutropenia and the length of hospitalization for patients admitted if fever develops in the setting of neutropenia. However, hematopoietic growth factors are not a replacement for immediate antimicrobial therapy in patients with fever and neutropenia and do not have a clear role in treatment.
Waiting for culture results before administering antimicrobial agents in patients with neutropenia and fever is never appropriate. If patients do not receive parenteral antimicrobials immediately after cultures are taken, their condition can rapidly deteriorate over 12 to 24 hours, and they can experience sepsis, shock, and death.
Although gram-positive organisms are the most commonly identified cause of neutropenic fever, initial monotherapy with vancomycin is not appropriate because of the potential virulence of gram-negative organisms. Vancomycin is usually not a routine component of empiric broad-spectrum antibiotic therapy for neutropenic fever without a specific indication.