CASE 1
A 3 years old boy with high risk acute lymphoblastic leukemia (ALL), presented with 48 hours of fever without a source at emergency room. Three weeks earlier, he experienced febrile neutropenia and grade III mucositis (WHO scale) and persisted with profound neutropenia since then. Six days before admission, he received third consolidation cycle of chemotherapy. Laboratory tests revealed leucocytes count of 120 cells/μL (reference range, 5.5–14.5 × 103 cells/μL) with an absolute neutrophil count of 20 cells/μL. Hemoglobin level was 7.2 g/dL (reference range, 10.2–12.7 g/dL) and platelet count was 8 x 103 cells/μL (reference range, 150 – 450 x 103 cells/μL ). C-reactive protein (CRP) level was 88.32 mg/L (reference range, <5 mg/L). He was admitted to Pediatric Intensive Care Unit (PICU) and was commenced on vancomycin and piperacillin/tazobactam after blood cultures were drawn. Peripheral blood culture was positive at 14 hours. The quantitative central and peripheral blood cultures were positive for 8 and 32 colony forming units (CFU) respectively, each for Rothia mucilaginosa (Figure 1). Echocardiogram showed an image suggestive of vegetation in the right atrium (11.6 mm x 15.6 mm) in relation to the central venous catheter (CVC) tip in the interatrial septum (Figure 2). CVC was removed. CVC tip and peripheral concomitant blood cultures were negative. Susceptibility evaluation was performed in Mueller Hinton Blood (MHB) Broth medium and epsilometry. Rothia mucilaginosa was resistant to sulphamethoxazole/trimethoprim and susceptible to penicillin, ceftriaxone, vancomycin (MIC ≤ 0.5), erythromycin and clarithromycin. Piperacillin/tazobactam was replaced by ceftriaxone. On third day of hospitalization he was transferred to the Oncology Unit. As he persisted febrile until day eight of hospitalization a bone scintigram, abdominal ultrasound and a cerebral magnetic resonance image (MRI) were performed, all resulted normal. The patient completed 6 weeks of intravenous vancomycin plus ceftriaxone with no evidence of vegetation at 38 days of treatment.