[Treatment of cancer and counter-measures for MRSA infections]

Patients with malignancy, especially those with hematological malignancy, are well known to be very susceptible to infection in general, because of bone marrow suppression induced by anticancer chemotherapy in addition to the nature of the disease itself. Accordingly, the risk of MRSA infection is very high in these patients, and the infection is often fatal. In an attempt to establish effective measures to prevent MRSA infection, we investigated the nosocomial spread of strains of MRSA and studied the characteristics of patients from the clinical standpoint. We found that strict isolation of patients with MRSA infection is an urgent necessity to prevent the intrahospital spread of MRSA strains and that disinfection of the hands of medical staff and sterilization of the environment are extremely important. In addition, due care must be taken to select an adequate antimicrobial agent and to determine the optimal dose and period for treatment of the infection in patients with malignancy to avoid selecting MRSA strains or inducing resistance in mecA positive strains of S. aureus. For treatment of MRSA infections in patients with malignancy, a combination chemotherapy with vancomycin (VCM), or arbekacin (ABK) plus beta-lactam antibiotic is recommended, and granulocyte colony stimulating factor (G-CSF) is clinically useful when the granulocytopenia was induced by chemotherapy.