What is the preferred antibiotic choice and treatment course for Bacterial Upper Respiratory Infection (URI)?

From the Guidelines

For bacterial upper respiratory infections (URIs), first-line antibiotic treatment is typically amoxicillin-clavulanate 875/125 mg twice daily for 5-7 days in adults, as recommended by the American College of Physicians and the Centers for Disease Control and Prevention 1. When considering antibiotic treatment for bacterial URIs, it's essential to note that most URIs are viral and don't require antibiotics. Bacterial URIs typically present with symptoms lasting more than 10 days, high fever, purulent nasal discharge, or worsening symptoms after initial improvement.

• The 2016 guidelines from the American College of Physicians and the Centers for Disease Control and Prevention recommend using clinical signs and symptoms to differentiate bacterial from viral causes 1.
• The American Academy of Otolaryngology-Head and Neck Surgery emphasizes watchful waiting as initial management for all patients with uncomplicated ABRS, regardless of severity 1.
• For patients with penicillin allergy, alternatives include azithromycin 500 mg on day 1 followed by 250 mg daily for 4 more days, or doxycycline 100 mg twice daily for 5-7 days, as suggested by the 2004 guidelines for antimicrobial treatment of acute bacterial rhinosinusitis 1.
• In areas with high prevalence of penicillin-resistant Streptococcus pneumoniae, amoxicillin-clavulanate 875/125 mg twice daily for 5-7 days may be preferred, as it has been shown to have a high clinical efficacy of 90-91% and bacteriologic efficacy of 97-99% 1.
• For patients with risk factors such as recent antibiotic use, immunocompromise, or healthcare exposure, broader coverage with levofloxacin 750 mg daily for 5 days can be considered, as it has been shown to have a high clinical efficacy of 92% and bacteriologic efficacy of 100% 1. It's crucial to note that antibiotics should be taken with food to minimize gastrointestinal side effects, and patients should complete the full course even if symptoms improve. These recommendations target common respiratory pathogens including Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, which are the predominant bacterial causes of sinusitis, pharyngitis, and other upper respiratory infections.

From the FDA Drug Label

To reduce the development of drug-resistant bacteria and maintain the effectiveness of amoxicillin and other antibacterial drugs, amoxicillin should be used only to treat infections that are proven or strongly suspected to be caused by bacteria Treatment should be continued for a minimum of 48 to 72 hours beyond the time that the patient becomes asymptomatic, or evidence of bacterial eradication has been obtained Amoxicillin for oral suspension is indicated in the treatment of infections due to susceptible (ONLY β-lactamase–negative) isolates of Streptococcusspecies. (α-and β-hemolytic isolates only), Streptococcus pneumoniae, Staphylococcusspp., or Haemophilus influenzae.

Bacterial URI Antibiotic Choice and Course:

• The antibiotic of choice is amoxicillin for bacterial URI caused by susceptible (β-lactamase–negative) isolates of Streptococcus species, Streptococcus pneumoniae, Staphylococcus species, or Haemophilus influenzae.
• The treatment course should be continued for a minimum of 48 to 72 hours beyond the time the patient becomes asymptomatic or evidence of bacterial eradication has been obtained 2.
• Levofloxacin may be considered for patients with bacterial URI caused by multi-drug resistant Streptococcus pneumoniae (MDRSP) or other susceptible pathogens, with a treatment course of 5 to 14 days 3.

From the Research

Bacterial URI Antibiotic Choice

• The treatment of choice for streptococcal infection is penicillin V given in two daily doses 4.
• Amoxicillin is equally effective as penicillin and more palatable 5.
• For children who fail amoxicillin therapy, amoxicillin/clavulanate provides better coverage against beta-lactamase producing H. influenzae and M. catarrhalis 4.
• Cephalosporins and macrolides may be used as alternative treatments, but the evidence is uncertain regarding their effectiveness compared to penicillin 6.

Antibiotic Course

• The traditional course of antibiotic treatment for streptococcal pharyngitis is 10 days of oral therapy or one injection of intramuscular benzathine penicillin 5.
• Short-course antibiotic treatment (≤5 days) may be as effective as long-course antibiotic treatment (≥7 days) for early clinical cure and early bacterial eradication 7.
• However, short-course penicillin was less effective for early clinical cure and bacteriological eradication compared to long-course penicillin 7.
• The optimal duration of antibiotic treatment may depend on the specific antibiotic used and the individual patient's response to treatment 7, 6.

Specific Antibiotics

• Penicillin is the first-line antibiotic for the management of patients with streptococcal pharyngitis due to its cost, narrow spectrum of activity, and effectiveness 5, 7.
• Amoxicillin is a suitable alternative to penicillin, especially in children 4, 5.
• Cephalosporins and macrolides may be used as alternative treatments, but their effectiveness compared to penicillin is uncertain 6.
• Azithromycin may be effective in a single dose for the treatment of streptococcal pharyngitis in children, but the evidence is limited 6.