Infantile meningitis caused by Streptococcus infantarius subspecies coli (formerly S. lutetiensis)

Streptococcus infantarius subspecies coli (formerly S. lutetiensis), a member of the S. bovis/S. equinus complex (SBSEC), is a rare cause of neonatal and infantile infection. In contrast to more common pathogens seen in this age group (ie, S. agalactiae (group B Streptococcus)), SBSEC organisms are infrequently implicated in neonatal and infantile meningitis. A previously healthy infant male presented with fever, irritability and poor feeding. Lumbar puncture revealed cloudy cerebrospinal fluid with elevated white cells, high protein and low glucose. Gram stain showed polymorphonuclear leucocytes without visible organisms; culture later grew S. infantarius subspecies coli at 48 hours of incubation. MRI findings were consistent with leptomeningitis (figure 1) and early ventriculitis (figure 2). The patient was treated with ceftriaxone for 21 days, with full clinical recovery. S. infantarius subspecies coli differs from S. gallolyticus in epidemiology and reported incidence. Accurate species identification is essential for proper management, prognosis and epidemiologic understanding. Increased clinical awareness and molecular diagnostics are key to uncovering the true burden of this rare pathogen.