Inclusion Criteria (for each episode):
- patient with cancer aged 18 years or below,
- absolute neutrophil count below 0.5x10⁹/L with expected duration of neutropenia for more than 7 days, and
- a single temperature of at least 38.5°C, or a temperature above 38.0°C sustained over a 1-hour period (auricular, oral or rectal).
Exclusion Criteria (for each episode):
- known etiology of fever, defined by a clinically significant positive culture (blood, urine, tracheal) collected during the feverish episode or a clinically documented focal infection despite negative cultures (e.g. pneumonia and cellulitis),
- obvious non-infectious causes of fever (e.g. drug and transfusion related),
- children requiring prophylactic antibacterial antibiotics according to protocol besides co-trimoxazole for Pneumocystis jirovecii after the febrile episode.