Streptococcus agalactiae Meningitis in a Diabetic Middle-Aged Woman: A Case Report and Literature Review.

Streptococcus agalactiae (S. agalactiae) (Group B Streptococcus, GBS) is a well-established cause of neonatal meningitis but rarely causes meningitis in adults, accounting for only 1.3% of culture-positive cases. We report the case of a 57-year-old woman with diabetes mellitus and hypertension who presented with altered mental status, fever, and hyperosmolar hyperglycemic state. Initial investigations revealed leukocytosis, acute kidney injury, and metabolic acidosis. Cerebrospinal fluid (CSF) analysis showed lymphocytic pleocytosis, elevated protein, and low glucose. CSF culture was negative, but a multiplex polymerase chain reaction (PCR) panel detected S. agalactiae. The patient responded to appropriate antimicrobial therapy and supportive measures and was eventually discharged. This case highlights the potential severity of adult GBS meningitis, particularly in patients with underlying medical comorbidities. Prompt diagnosis using molecular methods is crucial for achieving favorable outcomes. A literature review is included to compare the clinical features, complications, and management strategies of adult GBS meningitis.