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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 | |
| 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: | |
| Staphylococcus aureus | methicillin-sensitive methicillin-resistant Coagulase-negative AND OxacillinMIC ≤0.25 OR OxacillinMIC>0.25 |
Oxacillin Vancomycin Oxacillin Vancomycin |
Vancomycin Vancomycin |