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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 |
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. |