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Staphylococcus aureus bacteremia in patients with hematologic disorders
H Funada1, H Yoneyama, T Machi
1Protected Environment Unit, Kanazawa University, Japan.
Abstract:
During the 20-year period, 1972-1991, 27 episodes of Staphylococcus aureus bacteremia, including 10 with methicillin-resistant strains (MRSA), were documented in 26 patients with hematologic disorders, mainly acute leukemia and malignant lymphoma, representing 6% of all 433 episodes of bacteremia in a hematology unit. MRSA replaced methicillin-sensitive strains (MSSA) in the last four years. The skin and upper respiratory tract were the two most common primary foci. Most episodes occurred during neutropenia. Pharyngeal colonization often preceded the development of bacteremia. Antibiotic therapy predisposed to MRSA acquisition during hospitalization, whereas MSSA was mostly detected in admission cultures. Among 22 patients with monomicrobial bacteremia, 19 (86%) survived longer than one week, including all four with MRSA bacteremia who received vancomycin. The survival rate did not differ materially between MRSA and MSSA bacteremias. Secondary foci, chiefly located in the lung, were found in 30% of all patients with S. aureus bacteremia. Prolonged antibiotic therapy, therefore, seems warranted in patients with evident metastatic lesions, although abbreviated therapy is proposed in neutropenic cancer patients.
Insights
Staphylococcus aureus bacteremia, including MRSA, occurred in hematology patients, often during neutropenia. Survival rates were similar for MRSA and MSSA, with vancomycin showing promise.
Area of Science:
- Infectious Diseases
- Hematology
- Clinical Microbiology
Background:
- Staphylococcus aureus bacteremia is a significant concern in patients with hematologic disorders.
- Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a prevalent pathogen, replacing methicillin-sensitive strains (MSSA) in recent years.
- Understanding the epidemiology and outcomes of S. aureus bacteremia in this vulnerable population is crucial.
Purpose of the Study:
- To analyze the incidence, sources, risk factors, and outcomes of Staphylococcus aureus bacteremia in patients with hematologic disorders over a 20-year period.
- To compare the clinical characteristics and survival rates between MRSA and MSSA bacteremia.
- To identify factors influencing MRSA acquisition and treatment efficacy.
Main Methods:
- Retrospective analysis of 27 S. aureus bacteremia episodes in 26 patients with hematologic disorders (1972-1991).
- Data collection included patient demographics, underlying hematologic conditions, primary and secondary foci, neutropenia status, colonization, and antibiotic exposure.
- Survival analysis was performed comparing MRSA and MSSA bacteremia outcomes.
Main Results:
- S. aureus bacteremia accounted for 6% of all bacteremia episodes in the hematology unit.
- MRSA became predominant over MSSA in the last four years of the study period.
- Common primary foci included skin and respiratory tract; most episodes occurred during neutropenia, with pharyngeal colonization preceding bacteremia. Antibiotic therapy predisposed to MRSA acquisition.
- Survival rates were comparable between MRSA and MSSA bacteremia, with all four MRSA patients receiving vancomycin surviving beyond one week. Secondary foci, mainly pulmonary, were observed in 30% of patients.
Conclusions:
- Staphylococcus aureus bacteremia, including MRSA, poses a significant risk in hematology patients, particularly during neutropenia.
- Vancomycin demonstrated effectiveness in treating MRSA bacteremia in this cohort.
- Prolonged antibiotic therapy may be warranted for patients with metastatic lesions, while abbreviated courses could be considered for neutropenic cancer patients.