Is amoxicillin (amoxicillin) effective in patients with COVID-19 (Coronavirus disease 2019) who develop co-bacterial infections?

Amoxicillin for Co-Bacterial Infections in COVID-19 Patients

Amoxicillin is recommended for mild to moderate bacterial co-infections in COVID-19 patients following local/national community-acquired pneumonia (CAP) guidelines, but should be used restrictively as bacterial co-infections are uncommon in COVID-19 patients. 1

Prevalence of Bacterial Co-Infections in COVID-19

• Bacterial co-infections are relatively uncommon in COVID-19 patients, with studies showing rates of only 1-8% at hospital admission 1
• Secondary bacterial infections may develop in up to 15% of hospitalized patients, with higher rates (up to 50%) in non-survivors 1
• Bacterial co-infections are more common in critically ill patients requiring ICU admission or mechanical ventilation 2

When to Consider Antibiotics in COVID-19 Patients

• Generally, restrictive use of antibiotics is recommended for patients with COVID-19, especially those with mild to moderate illness 1
• Exceptions for antibiotic use include:
  • Patients with radiological findings and/or inflammatory markers compatible with bacterial co-infection 1
  • Severely ill or immunocompromised patients 1
  • Critically ill patients admitted to ICU 1

Diagnostic Approach Before Starting Antibiotics

• Maximum efforts should be made to obtain sputum and blood cultures before starting empirical antibiotic therapy 1
• Pneumococcal urinary antigen testing is recommended in all patients 1
• Legionella urinary antigen testing should be performed according to local/national guidelines 1
• Laboratory findings suggesting bacterial co-infection include elevated white blood cell count, elevated C-reactive protein, and procalcitonin level >0.5 ng/mL 3

Antibiotic Selection for Bacterial Co-Infections

• For mild to moderately severe CAP in COVID-19 patients, amoxicillin is recommended as first-line therapy 1
• For patients with severe CAP at the general ward, a second or third generation cephalosporin is recommended 1
• Empirical antibiotic regimens should follow local and national guidelines for CAP 1
• Routine empirical treatment covering atypical pathogens is not recommended for COVID-19 patients hospitalized at the general ward 1

Duration and De-escalation of Antibiotic Therapy

• Stop antibiotics when cultures and urinary antigen tests show no bacterial pathogens after 48 hours of incubation 1
• For confirmed bacterial infections, a 5-day course is suggested upon improvement of signs, symptoms, and inflammatory markers 1

Common Bacterial Pathogens in COVID-19

• Bacterial pathogens in COVID-19 co-infections are similar to those in regular bacterial CAP 1
• Common pathogens include Streptococcus pneumoniae, Staphylococcus aureus (including MRSA), and Haemophilus influenzae 2
• In some settings, gram-negative bacteria like Klebsiella species may be common 4

Pitfalls to Avoid

• Overuse of antibiotics in COVID-19 patients without evidence of bacterial co-infection can increase antimicrobial resistance 5
• Empirical antibiotic use was not associated with prevention of deterioration or mortality in COVID-19 pneumonia patients 6
• Not all radiographic abnormalities in COVID-19 patients indicate bacterial co-infection; they may be due to the viral infection alone 2
• Serum biomarkers alone should not determine when to start antibiotics, especially in non-critically ill patients 3

In conclusion, amoxicillin can be effective for treating bacterial co-infections in COVID-19 patients, but should be used judiciously given the low prevalence of bacterial co-infections, particularly in mild to moderate cases. Diagnostic testing before antibiotic initiation and early de-escalation when bacterial infection is not confirmed are essential strategies to prevent antimicrobial resistance.