Can E. coli (Escherichia coli) cause myocarditis?

E. coli as a Cause of Myocarditis

Yes, Escherichia coli can cause myocarditis, though it is a rare cause compared to viral etiologies. Multiple case reports document E. coli-induced myocarditis, particularly in the context of bacteremia or urosepsis 1, 2, 3.

Pathophysiology of Bacterial Myocarditis

Bacterial myocarditis occurs through several mechanisms:

1. Direct bacterial invasion: Bacteria can directly invade the myocardium
2. Toxin-mediated damage: Bacterial endotoxins (particularly from gram-negative organisms like E. coli) can trigger inflammatory reactions in the myocardium 2
3. Immune-mediated injury: The host immune response to bacterial infection can cause collateral damage to cardiac tissue

E. coli Myocarditis: Clinical Evidence

The American Heart Association guidelines recognize that while gram-negative bacilli like E. coli frequently cause catheter-related bacteremias in intensive care settings, they rarely cause infective endocarditis or myocarditis 4. This rarity is attributed to poor adhesion of gram-negative bacilli to cardiac valves 4.

However, several documented cases demonstrate that E. coli can indeed cause myocarditis:

• A case report from 2019 described a 77-year-old woman with E. coli bacteremia who developed myocarditis complicated by permanent complete atrioventricular block 1
• Another report documented peri-myocarditis during a urinary tract infection caused by E. coli without sepsis 2
• A 25-year-old woman with E. coli urosepsis developed acute myocarditis that mimicked acute myocardial infarction 3

Clinical Presentation and Diagnosis

E. coli myocarditis may present with:

• Chest pain
• Electrocardiographic changes (ST-segment elevation, conduction abnormalities)
• Elevated cardiac biomarkers
• Arrhythmias (including complete heart block)
• Heart failure symptoms

Diagnosis typically requires:

• Evidence of bacteremia (positive blood cultures)
• Cardiac imaging (echocardiography, cardiac MRI)
• Exclusion of coronary artery disease
• In some cases, endomyocardial biopsy

Treatment Approach

For E. coli-induced myocarditis, treatment should focus on:

1. Targeted antimicrobial therapy: Based on susceptibility testing of the E. coli isolate

   • For susceptible strains, an extended-spectrum penicillin (e.g., piperacillin/tazobactam) or an extended-spectrum cephalosporin (e.g., ceftazidime, ceftriaxone) together with an aminoglycoside is recommended 4
   • Treatment duration is typically 6 weeks 4

2. Supportive care:

   • Management of heart failure if present
   • Treatment of arrhythmias
   • In cases of complete heart block, pacemaker implantation may be necessary 1

3. Monitoring for complications:

   • Serial echocardiography to assess ventricular function
   • ECG monitoring for arrhythmias

Prognosis

The prognosis of E. coli myocarditis varies:

• Some patients recover completely with appropriate antibiotic therapy 2
• Others may develop permanent sequelae such as conduction abnormalities requiring pacemaker implantation 1
• In severe cases, particularly with delayed diagnosis or treatment, ventricular rupture and death can occur (as documented with other bacterial myocarditis) 5

Important Considerations

• E. coli myocarditis can mimic acute myocardial infarction, making diagnosis challenging 1, 3
• Early recognition and prompt initiation of appropriate antibiotics are crucial for favorable outcomes
• Cardiac magnetic resonance imaging is particularly valuable for detecting myocardial inflammatory lesions that might otherwise remain undiagnosed 2

While E. coli is not among the common causes of myocarditis, clinicians should maintain a high index of suspicion in patients with E. coli bacteremia who develop cardiac symptoms or abnormalities.