Meningitis empirical antimicrobial therapy

Empiric antimicrobial therapy should be instituted as soon as possible to eradicate the causative organism (Table 36-2). Antimicrobial therapy should last at least 48 to 72 hours or until the diagnosis of bacterial meningitis can be ruled out. Continued therapy should be based on the assessment of clinical improvement, cultures, and susceptibility testing results. Once a pathogen is identified, antibiotic therapy should be tailored to the specific pathogen. 

Initial selection of antimicrobial therapy is nearly always empirical, which is the initiation of antimicrobials sometimes prior to documentation of the presence of infection and before the offending organism is identified. Infectious diseases generally are acute, and a delay in antimicrobial therapy may result in serious morbidity or even mortality. An example is the rapidly lethal nature of various forms of meningitis. Thus empirical antimicrobial therapy selection is... 

The principal justification for empiric, antimicrobial therapy is that the infection is best treated early to avoid serious morbidity or death. Suspected bacterial meningitis is a classic example... 

High-dose penicillin G traditionally has been the drug of choice for the treatment of pneumococcal meningitis. However, due to increases in pneumococcal resistance, the preferred empirical treatment now includes a third-generation cephalosporin in combination with vancomycin.13 All CSF isolates should be tested for penicillin and cephalosporin resistance by methods endorsed by the CLSI. Once in vitro sensitivity results are known, therapy may be tailored (Table 67-3). Patients with a history of type I penicillin allergy or cephalosporin allergy may be treated with vancomycin. Treatment should be continued for 10 to 14 days, after which no further maintenance therapy is required. Antimicrobial prophylaxis is not indicated for close contacts. 

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