Why avoid antibiotics unless there is significant suspicion of a bacterial pathogen?

Why Avoid Antibiotics Unless There Is Significant Suspicion of a Bacterial Pathogen

Antibiotics should be avoided unless there is significant suspicion of a bacterial pathogen because prescribing them in the absence of proven or strongly suspected bacterial infection provides no benefit to the patient while directly increasing the risk of developing drug-resistant bacteria, promoting antimicrobial resistance, and causing preventable adverse effects. 1, 2

Primary Rationale: Development of Drug-Resistant Bacteria

• Prescribing antibiotics without proven or strongly suspected bacterial infection is unlikely to provide benefit and increases the risk of drug-resistant bacteria development. 1, 2
• Antibiotic use promotes overgrowth of resistant microorganisms, which can precipitate secondary infections that are more difficult to treat. 3
• Resistant organisms spread to other patients and the environment, contributing to increasing antimicrobial resistance worldwide. 3
• Organisms exposed to antibiotics undergo molecular changes that may enhance virulence, particularly affecting patients if the organism becomes multiply resistant. 3

Evidence from COVID-19 Experience

• Bacterial co-infection occurs infrequently in viral respiratory infections—systematic reviews show less than 10% of COVID-19 patients isolate a bacterial pathogen. 4
• The European Respiratory Society recommends against offering azithromycin to hospitalized COVID-19 patients in the absence of bacterial infection. 4
• WHO recommends against empiric antibiotics in mild COVID-19, and for moderate COVID-19, antibiotics should only be considered when there is clinical concern for bacterial pneumonia. 4
• NICE guidelines state antibiotics should not be prescribed if COVID-19 is the likely cause of respiratory illness unless there is suspicion for bacterial infection. 4
• The NIH states there are insufficient data to recommend empiric broad-spectrum antibiotics in COVID-19 patients, even those with severe or critical illness, without a clear indication. 4

Additional Harms Beyond Resistance

• Long-term concerns include antimicrobial resistance and Clostridioides difficile-associated diarrhea (CDAD), which has been reported with nearly all antibacterial agents and may range from mild diarrhea to fatal colitis. 4, 1
• Treatment with antibacterial agents alters normal colonic flora, leading to C. difficile overgrowth. 1
• Adverse effects include hypersensitivity reactions, severe cutaneous adverse reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis, DRESS, AGEP), and organ-specific toxicities. 1
• The less obvious results of antimicrobial consumption, including environmental effects and selection pressure for resistance, probably go unrecognized in routine clinical care. 3

When Antibiotics ARE Appropriate

• Antibiotics should be initiated promptly when there is proven or strongly suspected bacterial infection, particularly in septic shock or bacterial meningitis where delays increase mortality. 5, 6
• For patients with clinical features of sepsis, prompt empiric broad-spectrum antimicrobial therapy should be given after appropriate cultures are collected. 5
• Empiric antibiotics are warranted for COVID-19 patients with shock as part of standard sepsis management. 5
• All clinically infected diabetic foot wounds should receive antibiotic therapy, but uninfected wounds should not be treated with antibiotics. 5

Best Practices to Avoid Inappropriate Use

• Obtain appropriate microbiological samples before antibiotic administration—in the absence of clinical signs of infection, colonization rarely requires antimicrobial treatment. 7
• Avoid using antibiotics to "treat" fever; use them to treat infections, and investigate the root cause of fever prior to starting treatment. 7
• For less severe infectious syndromes without septic shock or bacterial meningitis, withholding antibiotic therapy until diagnostic results are available (e.g., by 4-8 hours) seems acceptable in most cases. 6
• Stop unnecessarily prescribed antibiotics once the absence of infection is likely. 7

Common Pitfalls to Avoid

• Do not prescribe antibiotics for viral respiratory infections based solely on fever or respiratory symptoms without evidence of bacterial superinfection. 4
• Do not use procalcitonin elevation alone to justify antibiotics, as 21% of COVID-19 patients without bacterial pneumonia had elevated procalcitonin levels. 4
• Avoid empiric coverage for atypical pathogens in hospitalized patients with suspected viral infections unless specific clinical indicators are present. 4
• Do not continue empiric antibiotics when representative cultures taken before antibiotic initiation show no bacterial pathogens after 48 hours of incubation. 4