In this article, we will discuss Antibiotic Therapy in Acute Bacterial Meningitis (Nontubercular). So, let’s get started.
Acute bacterial meningitis is a grave medical emergency, needs early diagnosis and early institution of antibiotic therapy to prevent significant mortality and morbidity associated with the disease. Any patient with suspected meningitis needs hospitalization.
1. Antibiotic therapy: Empirical antibiotic therapy should be started soon after the diagnosis is suspected or confirmed with characteristic CSF findings without waiting for the isolation or identification of the causative pathogen.
A. Empirical therapy: The choice of antibiotic depends on the age, underlying health status of the patient and its penetration into the CSF. In most patients, vancomycin 10-15 mg/kg I.V. every 12 hourly and third generation cephalosporins (cefotaxime or ceftriaxone 2 gm I.V. every 12 hourly) or fourth generation cephalosporin (cefepime) are recommended. In elderly patients (>50 years), a combination of third generation cephalosporin with broad spectrum penicillin (ampicillin) and vancomycin are recommended. Patients with head trauma and immunocompromised hosts need broader antibiotic coverage such as a combination of cefepime plus vancomycin and ampicillin. Merepenem may be added to sterilise CSF in neurosurgical conditions. Metronidazole may be added to empirical regime to cover anaerobic infection as cause of meningitis following otitis media and mastoiditis. The antibiotic therapy should be modified as soon as the result of CSF culture and antibiotic-sensitivity report becomes available.
B. Duration of antibiotic therapy: The antibiotic therapy for bacterial meningitis is variable depending on the organism isolated and antibiotic sensitivity. The duration of antibiotic therapy for the three common pathogens (S. penumoniae, N. meningitidis and H. influenzae) is 1-2 weeks; and for L. monocytogenes and gram-negative bacilli, it is 2-3 weeks. It is essential that antibiotic therapy is continued in full dosage throughout this period because the penetration of these antibiotics is better with meninges inflammed, declines with improvement.
C. Response to treatment: In responsive patient, the CSF becomes sterile 1 to 3 days after antibiotic therapy. The fever disappears within few days but may persist for several weeks. Dead bacteria may be seenon Gram’s staining of CSF for several days. Repeat CSF should not be done if clinical recovery is satisfactory. It is warranted only in meningitis caused by gram-negative bacilli or when therapeutic response is inadequate or when complications arise.