PC1211: A Rare Case of Bacterial Meningitis in an Infant with Milk-protein Allergy

Introduction: Streptococcus gallolyticus subspecies pasteurianus is considered a rare cause of meningitis and septicemia in the neonatal and infantile period. In a study conducted in 2003 by Grant, R et al., 28 cases of Group D Streptococcus were reported from 1977 – 2003, and sporadic cases have been reported. This case highlights the importance of identifying rare pathogens in cases of meningitis, especially in patients presenting with preceding gastrointestinal complaints and a history of milk protein allergy.

Case Description: A 2-month old male born at 37 weeks, with history of milk protein allergy, presented with a 12 hour history of non-bloody, nonbilious emesis, fever, and irritability. He also had a generalized tonic-clonic seizure which was aborted with lorazepam. Cerebrospinal fluid studies were significant for leukocytosis, pleocytosis, low glucose, and moderate gram-positive cocci. The patient was started on ceftriaxone, vancomycin, dexamethasone, and acyclovir, for suspected bacterial meningitis. Physical exam revealed a tense fontanelle, head lag, extreme irritability, tachypnea, tachycardia, and fever of 39.5 C. A head computed tomography (CT) scan showed extra-axial fluid but was negative for empyema, an abdominal ultrasound was negative for acute intra-abdominal process, and an echocardiogram was negative for cardiac valvular vegetations. Repeat labs revealed an elevated C-reactive protein of 111.3 and normal white blood cell count. Blood and cerebrospinal fluid cultures resulted on day 2 of admission showing Streptococcus gallolyticus subspecies pasteurianus, and was treated with ceftriaxone. The clinical course was complicated by unremitting fevers for 6 days, and focal neurological deficits that included poor tracking and upward gaze deviation. Magnetic resonance imaging done on day 4 of admission showed ventriculitis and pus within the subarachnoid space versus trace amount of subdural empyema. The fevers resolved on day 6 of admission, and his neurologic status gradually improved. Notably, the patient has a history of milk protein allergy and developed diarrhea on day 6 of admission which progressed to frank bloody stools on day 15. Diarrhea ultimately improved when the formula was changed to Neocate. The patient will complete a 6-week course of parenteral antibiotics.

Discussion: To our knowledge, only 3 cases of Streptococcus pasteurianus meningitis have been reported in the United States, most of them described in healthy neonates. It has been proven that milk protein allergy induces changes in fecal microbiota, which may lead to an ineffective immune response and mucosal changes in the colon. In view of this pathological process, S. pasteurianus infection may predispose to infection, leading to bacteremia, meningitis, and gastroenteritis.

Conclusion: Given that Streptococcus gallolyticus pasteurianus can become an enteric pathogen, it should be considered as a rare cause of bacterial meningitis, especially in infants with milk-protein allergy and preceding gastrointestinal symptoms.