Streptococcus salivarius meningitis

Abstract

A 7 1 -year-old man was admitted to the emergency room because of fever, progressive malaise, headache, and vomiting. His previous history was uneventful, and until the evening before admission, he had no complaints. His level of consciousness was decreased (Glasgow coma scale, 9/15). He had a stiff neck and a cluster of petechiae on the right chest. He had fever (temperature, 38°C) with blood pressure, 2 1 O/l 10 mmHg. Laboratory results showed an elevated leukocyte count of 11.6 x 109/1 (normal range, 3.5 to 9.8) with a neutrophilia of 90.4% (normal range, 37.9 to 70.2). The C-reactive protein (CRP) was slightly elevated at 1.6 mg/dl (normal range, < 1 mg/dl). Two blood cultures were obtained, and a lumbar puncture was performed. The cerebrospinal fluid (CSF) analysis revealed 5,820 leukocytes/mm3 (99% were polymorphonuclear cells) and 2,120 erythrocytes/mm3. A Gramstained smear revealed no organisms. Bacterial meningitis was suspected, and empirical antibiotic treatment was initiated with ceftriaxone, 2 x 2 g IV/d, and ampicillin, 4 x 2g IV/d. The next day, the patient was afebrile and alert but retained retrograde amnesia. The leukocyte count rose to 16.4 x 109/1 and CRP rose to 7.9 mg/dl. The CSF was cultured onto Columbia sheep blood agar (Becton Dickinson, Meylan Cedex, France) and chocolate agar with hemoglobin and IsoVitaleX (Becton Dickinson). After 15 h incubation at 35°C in 8% COZ, the chocolate agar showed poor growth of gram-positive cocci. The blood cultures obtained on admission were processed with the BacT/Alert 3D system (Organon Technika Corp., Durham, NC). After 36 h, three of four bottles were flagged positive. Gram-stained smears showed gram-positive cocci in chains. Overnight incubation of subcultures revealed small, non+-hemolytic colonies on sheep blood agar. A presumptive identification of Streptococcus salivarius was made based on the biochemical characteristics of the isolate (Table 1). The organism did not react with Streptococcus grouping antisera (Streptex kit; Murex Biotech Ltd., Dartford, England). It was not possible to identify the Streptococcus to the species level by using the API 20 Strep system (bio-Mtrieux, Marcy l’Etoile, France). Genetic analysis was performed with the MicroSeq 500 16s Ribosomal DNA bacterial sequencing kit (Applied Biosystems, Foster City, CA), and the obtained fragments were analyzed by the ABI PRISM 3 10 DNA sequencer (Applied Biosystems). The MicroSeq search resulted in a similarity of almost 99% with the S. salivarius sequence. Phenotypic methods and genetic analysis identified thejsolated strain in the CSF and blood as 5. salivarius. Antibiotic susceptibility testing was done by Etest (AB Biodisk, Solna, Sweden) and revealed susceptibility to ceftriaxone (MIC, 0.032 yg/ml), ampicillin (MIC, 0.094 pg/ml), and penicillin (MIC, 0.064 pg/ml). A transesophageal echocardiography was performed and showed no vegetations. Treatment with ampiciIlin was stopped on day 3. The patient improved clinically. Two weeks after admission, the intravenous ceftriaxone was stopped and the patient was discharged from the hospital in good condition.