F. mortiferum Bacteremia in a Pediatric Patient with B-cell Acute Lymphoblastic Leukemia; A Rare Case from Pakistan

INTRODUCTION: Fusobacterium species infect individuals who are immunocompromised, often due to chronic disease and chemotherapy, and have been rarely associated with bloodstream infections (BSI). Among the species of the genus, F. mortiferum has been rarely reported in the literature. Herein, we report a rare case of F. mortiferum bacteremia in a pediatric patient with B-cell Acute Lymphoblastic Leukemia (B-ALL). METHODS: A four-year-old-female patient known case of B-ALL and on chemotherapy, presented with complaints of fever without rigors and chills, sore throat and dry cough since five days and nasal bleeding since two days. On examination, patient was lethargic with a temperature of 103oF. Throat was hyperemic on oral examination. Two sets of blood cultures were sent to the microbiology laboratory for evaluation of bacteremia. RESULTS: Blood cultures revealed bacterial growth after 72 hours on anaerobic incubation. Gram stain from the blood culture broth showed pleomorphic gram-negative rods. Subculture on 5% Sheep Blood Agar grew pin-pointed, grey, convex, translucent and non-hemolytic colonies. The isolate was identified as F. mortiferum on VITEK-2 automated system (BioMérieux) and was sensitive to clindamycin, metronidazole, amoxicillin/clavulanate, piperacillin/tazobactam, imipenem and meropenem via Disk Diffusion method. CONCLUSION: We reported a rare case of F. mortiferum BSI in a pediatric patient B-ALL, which according to the best of our knowledge is the first case of F. mortiferum infection from Pakistan. The patient was successfully treated with metronidazole with complete resolution of symptoms after three weeks of therapy. In this regard, it is crucial to report similar cases as prompt reporting and antibiotic therapy are essential for the appropriate management of such patients.