Stomatococcus mucilaginosus septicemia in leukemic patients

OBJECTIVE: To report an unexpectedly high number of cases of septicemia with Stomatococcus mucilaginosus, and try to identify predisposing factors. METHODS: All blood cultures obtained during 1991--93 from patients treated at the hematologic ward were bacteriologically identified. The medical records of patients with S. mucilaginosus-positive blood cultures were retrospectively reviewed and evaluated. The antibiotic susceptibility pattern and restriction fragment length polymorphism (RFLP) of S. mucilaginosus were tested. RESULTS: S. mucilaginosus blood isolates from patients with hematologic malignancies were found to be as common as isolates of Staphylococcus aureus. Eleven patients with myelogenous leukemia and isolation of S. mucilaginosus from the blood are reported on. One patient had concomitant meningitis. All patients were neutropenic and most had oral mucositis and had been given ciprofloxacin prophylaxis. S. mucilaginosus isolates from these patients were resistant to ciprofloxacin in contrast to isolates from patients who had received other prophylactic regimens and seven isolates found in healthy individuals not recently treated with antibiotics. The resistant S. mucilaginosus were found to be of diverse genetic origin as determined by RFLP. CONCLUSIONS: The appearance of resistant strains during ciprofloxacin prophylaxis may be a predisposing factor for S. mucilaginosus septicemia. There was no evidence of a nosocomial spread of S. mucilaginosus strains.