Can E. coli (Escherichia coli) cause meningitis?

Can E. coli Cause Meningitis?

Yes, Escherichia coli is a well-established cause of bacterial meningitis, particularly in neonates where it accounts for approximately 21% of all neonatal meningitis cases and is the second most common pathogen after Group B Streptococcus. 1

Epidemiology by Age Group

Neonatal Meningitis (0-6 weeks)

• E. coli causes 21% of all neonatal meningitis cases across multiple European surveillance studies 1
• E. coli is the leading cause of meningitis in premature infants, accounting for 42% of cases in preterm neonates and 53% in very preterm infants (gestational age <33 weeks) 2
• In term infants, Group B Streptococcus predominates, but E. coli still causes 13% of early-onset and 28% of late-onset meningitis 2
• Transmission occurs through vertical transmission (mother to child) in early neonatal meningitis or horizontal/nosocomial transmission in late neonatal meningitis 1

Adults

• E. coli is recognized as a cause of gram-negative bacillary meningitis in adults, though less common than in neonates 1
• Gram stain detects gram-negative bacilli in approximately 50% of cases when present 1
• Adult cases typically occur in patients with specific risk factors including immunocompromised states, recent neurosurgery, or CNS anatomical abnormalities 1

Clinical Significance and Outcomes

Mortality and Morbidity

• Mortality rates range from 11-18%, with higher rates in premature infants (15%) compared to term infants 3, 2
• Neurological sequelae occur in 20-50% of survivors, including neurosensorial deficits (14-17%) and neurodevelopmental impairments (10-17%) 3, 2
• E. coli meningitis has a high degree of bacteremia and requires specific virulence factors for blood-brain barrier invasion 4, 5

Complications

• Early complications include cerebral abscesses, ventriculitis, and ischemic-hemorrhagic cerebral lesions 3
• Risk factors for poor outcomes include hemodynamic failure, apnea, seizures, hypoglycorrhachia, and abnormal EEG 3

Pathogenic Mechanisms

• E. coli K1 capsular serotype is the predominant strain causing neonatal meningitis 5
• Successful CNS invasion requires high-grade bacteremia and specific bacterial virulence factors (K1 capsule, Sfa, Ibe proteins, CNF1) that facilitate blood-brain barrier penetration 5
• The organism commonly colonizes the gastrointestinal tract and travels hematogenously to the central nervous system 4

Treatment Considerations

• Third-generation cephalosporins (cefotaxime) are first-line therapy, often combined with aminoglycosides and ciprofloxacin in neonates 3, 2
• CSF sterilization typically occurs within 2-4 days in 84% of cases with appropriate therapy 2
• Emerging concern: Extended-spectrum beta-lactamase (ESBL)-producing E. coli strains are reported, though still uncommon (3% in one series), necessitating consideration of meropenem in confirmed resistant cases 3
• Delayed or inadequate antibiotic treatment is associated with excess complications 3

Key Clinical Pitfall

The prevalence of third-generation cephalosporin-resistant E. coli in vaginal flora of pregnant women reaches 5% in some French hospitals, which may necessitate reconsideration of empiric therapy in high-risk settings 3. However, ESBL strains remain relatively uncommon in most surveillance data 2.