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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
Immuno-compromised	Streptococcus pneumoniae , 'Neisseria meningitidis, Haemophilus influenzae, Listeria	Vancomycin PLUS Cefepime PLUS Ampicillin	Vancomycin PLUS TMP/SMX PLUS Ciprofloxacin

^† 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
Haemophilus influenzae		Pen. allergic: chloramphenicol 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
Neisseria meningitidis	Pen. MIC <0.1 mcg per mL	Penicillin OR Ceftriaxone	Chloramphenicol* OR Ciprofloxacin
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.
S. pneumoniae	Penicillin G MIC ____<0.1 mcg/mL ____0.1—1 mcg/mL ____≥2 mcg/mL Ceftriaxone MIC ____ ≥1 mcg/mL ____ >2 mcg/mL	Penicillin G 4 million units IV q4h OR Ampicillin 2 gm IV q4h Ceftriaxone 2 gm IV q12h OR Cefotaxime 2 gm IV q4—6h Vancomycin 500—750 mg IV q6h PLUS Ceftriaxone OR Cefotaxime as above Vancomycin 500—750 mg IV q6h PLUS Ceftriaxone OR Cefotaxime as above Vancomycin 500—750 mg IV q6h PLUS Ceftriaxone OR Cefotaxime as above	Ceftriaxone 2 gm IV q12h OR Chloramphenicol 1 gm IV q6h Cefepime 2 gm IV q8h OR Meropenem 2 gm IV q8h Moxifloxacin 400 mg IV q24h Moxifloxacin 400 mg IV q24h Moxifloxacin 400 mg IV q24h PLUS Rifampin 600 mg 1x/day
Pseudomonas aeruginosa		Cefepime OR Meropenem	Any 2 of the following: Ciprofloxacin, Tobramycin‡,Aztreonam
Staphylococcus aureus	methicillin-sensitive methicillin-resistant Coagulase-negative AND OxacillinMIC ≤0.25 OR OxacillinMIC>0.25	Oxacillin Vancomycin Oxacillin Vancomycin	Vancomycin Vancomycin

References

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