You are seeing a 5-month-old infant who has been irritable with fever of 24 hours. Mom states that the infant refuses her formula, has not been active, and cries whenever she is moved. On physical examination, you note a bulging anterior fontanel. Laboratory results show a WBC of 30 × 103/μL (30 × 109/L) with 20% immature forms. Evaluation of the cerebrospinal fluid shows a glucose level of 15 mg/dL, protein concentration of 130 mg/dL, WBC of 500/μL, and a Gram stain positive for Gram-positive diplococci. Appropriate antibiotic management for this patient should include:
This infant has bacterial meningitis. The most common bacterial causes in infants between 0 and 3 months of age are group B Streptococcus, E coli, Listeria, Enterococcus and other Gram-negative enteric bacilli. In patients from 3 months to 21 years, N. meningitidis and S. pneumoniae predominate. In the first month of life, the treatment is amipicillin with gentamicin or a third-generation cephalosporin. After the first month of life, treatment is vancomycin and a third-generation parenteral cephalosporin such as cefotaxime or ceftriaxone until the organism is identified. Third-generation cephalosporins are active against gram-negative enteric bacteria, H. influenzae, M. catarrhalis, S. pneumoniae, Neisseria meningitidis, and group A streptococci, all of which are serious causes of meningitis in infants and children. Ceftazidime has excellent activity against Pseudomonas aeruginosa but is less active with S. pneumonia, Group A Streptococcus, and Staphylococcus aureus. Oral antibiotics are not indicated for bacterial meningitis.