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Bacterial Meningitis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Diagnosis

• Bacterial meningitis is the infection of meninges by bacteria.

Empiric Therapy

Negative CSF Gram Stain

Group	Etiology	Preferred Regimen	Alternative Regimen
Preterm—1 mo	Streptococcus agalactiae (49%) Escherichia coli (18%) misc. Gram-positive (10%) misc. Gram-negative (10%) Listeria (7%)	Ampicillin PLUS Cefotaxime (for dosage see footnote)	Ampicillin PLUS Gentamicin (for dosage see footnote)
1 mo—50 yrs	Streptococcus pneumoniae Neisseria meningitidis Haemophilus influenzae†	Adult dosage: Cefotaxime 2 gm IV q4—6h OR Ceftriaxone 2 gm IV q12h PLUS Vancomycin 500—750 mg IV q6h‡ PLUS Dexamethasone 'Peds'dosage:'Cefotaxime 200 mg/kg per day IV div.q6–8h; Ceftriaxone 100 mg/kg per day IV div. q12h; Vancomycin 15 mg/kg IV q6h.	Meropenem2 gm IV q8h PLUS Vancomycin PLUS IV Dexamethasone
1.>50 yrs 2.alcoholism 3.debilitating assoc diseases 4.impaired cellular immunity	Streptococcus pneumoniae listeria Gram-negative bacilli	Ampicillin 2 gm IV q4h PLUS 'Ceftriaxone 2 gm IV q12h OR Cefotaxime 2 gm IV q6h PLUS Vancomycin PLUS IV Dexamethasone	Meropenem 2 gm IV q8h PLUS Vancomycin PLUS IV Dexamethasone
Post-neurosurgery, post-head trauma, or post-cochlear implant	Streptococcus pneumoniae most common, esp. if CSF leak. Other: Staphylococcus aureus, coliforms, Pseudomonas aeruginosa	Vancomycin (until known not MRSA) 500–750 mg IV q6h2' PLUS Cefepime or Ceftazidime 2 gm IV q8h	Meropenem 2 gm IV q8h PLUS Vancomycin1 gm IV q6–12h
Ventriculitis/meningitis due to infected ventriculo-peritoneal (atrial) shunt	Staphylococcus epidermidis,Staphylococcus aureus,coliforms,diphtheroids (rare),'Propionibacterium acnes	Vancomycin 500–750 mg IV q6h PLUS Cefepime or Ceftazidime 2 gm IV q8h	Vancomycin 500–750 mg IV q6h PLUS Meropenem 2 gm IV q8h

^† H. influenzae now very rare, listeria unlikely if young & immuno-competent (add ampicillin if suspect listeria: 2 gm IV q4h)

^‡ Children’s dosage 15 mg/kg IV q6h (2x standard adult dose). In adults, max dose of 2-3 gm/day is suggested: 500–750 mg IV q6h.

Postive CSF Gram Stain

Group	Etiology	Preferred Regimen	Alternative Regimen
Gram-positive diplococci	S.pneumoniae	Ceftriaxone 2 gm IV q12h OR Cefotaxime 2 gm IV q4–6h PLUS Vancomycin 500–750 mg IV q6h PLUS timed Dexamethasone 0.15 mg/kg q6h IV x 2–4 days	Meropenem 2 gm IV q8h OR Moxifloxacin 400 mg IV q24h
Gram-negative diplococci	N. meningitidis	Cefotaxime 2 gm IV q4–6h OR Ceftriaxone 2 gm IV q12h	Penicillin G 4 mill. units IV q4h OR Ampicillin 2 gm q4h OR Moxifloxacin 400 mg IV q24h OR Chloro 1 gm IV q6h
1.>50 yrs 2.alcoholism 3.debilitating assoc diseases 4.impaired cellular immunity	Streptococcus pneumoniae listeriaGram-negative bacilli	Ampicillin 2 gm IV q4h PLUS 'Ceftriaxone 2 gm IV q12h OR Cefotaxime 2 gm IV q6h PLUS Vancomycin PLUS IV Dexamethasone	Meropenem 2 gm IV q8h PLUS Vancomycin PLUS IV Dexamethasone
Post-neurosurgery, post-head trauma, or post-cochlear implant	Streptococcus pneumoniae most common, esp. if CSF leak. Other:Staphylococcus aureus, coliforms, Pseudomonas aeruginosa	Vancomycin (until known not MRSA) 500–750 mg IV q6h2' PLUS Cefepime or Ceftazidime 2 gm IV q8h	Meropenem 2 gm IV q8h PLUS Vancomycin1 gm IV q6–12h
Ventriculitis/meningitis due to infected ventriculo-peritoneal (atrial) shunt	Staphylococcus epidermidis,Staphylococcus aureus,coliforms,diphtheroids (rare),'Propionibacterium acnes	Vancomycin 500–750 mg IV q6h PLUS cefepime or ceftazidime 2 gm IV q8h	Vancomycin 500–750 mg IV q6h PLUS Meropenem 2 gm IV q8h

Pathogen-Specific Therapy

Bacteria	Specific Lab Findings	Preferred Regimen	Alternative Regimen
Haemophilus influenzae	ȕ-lactamase positive	Ceftriaxone (peds): 50 mg/kg IV q12h	Pen. allergic: Chlorine 12.5 mg/kg IV q6h (max. 4 gm/day.)
Listeria monocytogenes		Ampicillin 2 gm IV q4h PLUS OR NOT Gentamicin 2 mg/kg loading dose, then 1.7 mg/kg q8h	If pen-allergic, use TMP-SMX 20 mg/kg per day div. q6–12h Alternative: 1. Meropenem2 gm IV q8h 2. linezolid PLUS Rifampin
Neisseria meningitidis	Pen. MIC 0.1–1 mcg per mL	Ceftriaxone 2 gm IV q12h x 7 days ; if ȕ-lactam allergic, Chlorine 12.5 mg/kg (up to 1 gm) IV q6h	Meropenem 2 gm IV q8h OR moxifloxacin 400 mg q24h
S. pneumoniae	1. Pen G MIC <0.1 mcg/mL 2. 0.1–1 mcg/mL' 3. ≥2 mcg/mL 4. CeftriaxoneMIC ≥ 1 mcg/mL,	1.Pen G 4 million units IV q4h OR Ampicillin 2 gm IV q4h 2. Ceftriaxone 2 gm IV q12h OR Cefotaxime 2 gm IV q4–6h 3.vancomycin 500–750 mg IV q6h PLUS ceftriaxone OR''cefotaxime as above) 4. vancomycin 500–750 mg IV q6h' PLUS ceftriaxone OR''cefotaxime as above)	1. Ceftriaxone 2 gm IV q12h, Chlorine 1 gm IV q6h; 2. Cefepime 2 gm IV q8h OR Meropenem 2 gm IV q8h 3.Moxifloxacin 400 mg IV q24h 4.Moxifloxacin 400 mg IV q24h .If MIC to Ceftriaxone >2 mcg/mL, add Rifampin 600 mg 1x/day.
E. coli, other coliforms, or Pseudomonas aeruginosa		Ceftazidime OR Cefepime 2 gm IV q8h PLUS OR NOT''Gentamicin	Ciprofloxacin 400 mg IV q8–12h; Meropenem 2 gm IV q8h.

References

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