What bacteria does Amoxicillin (amoxicillin) cover in a 3-year-old patient with fever, cough, shortness of breath, and retractions?

From the Guidelines

Amoxicillin is effective in covering Haemophilus influenzae, a common bacterial pathogen that can cause respiratory infections in children, and is often prescribed at a dose of 75-100 mg/kg/day in 3 doses for mild infections, as recommended by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America 1. For a 3-year-old with fever, cough, shortness of breath, and retractions, amoxicillin is a suitable choice, given its efficacy against common bacterial pathogens such as Haemophilus influenzae, as stated in the guidelines by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America 1. Some key points to consider when prescribing amoxicillin for this patient include:

• The dose of amoxicillin should be 75-100 mg/kg/day in 3 doses, as recommended for mild infections caused by Haemophilus influenzae 1.
• The presence of retractions suggests respiratory distress, which may indicate pneumonia requiring prompt medical evaluation, and amoxicillin may be an appropriate choice for treatment, as recommended by the guidelines 1.
• If the child has a penicillin allergy, alternative antibiotics like azithromycin or cefdinir may be needed, as stated in the guidelines by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America 1.
• Viral infections, which are common causes of respiratory symptoms in children, will not respond to amoxicillin, and the child should be reassessed if symptoms worsen despite antibiotic therapy, as they may need respiratory support, different antibiotics, or hospitalization, as recommended by the guidelines 1.

From the FDA Drug Label

Infections of the Lower Respiratory Tract:Amoxicillin for oral suspension is indicated in the treatment of infections due to susceptible (ONLY β-lactamase–negative) isolates of Streptococcusspp. (α-and β-hemolytic isolates only), S. pneumoniae, Staphylococcusspp., or H. influenzae.

Amoxicillin covers the following bacteria for a 3-year-old patient with fever, cough, shortness of breath, and retractions:

• Streptococcus species (α-and β-hemolytic isolates only)
• S. pneumoniae
• Staphylococcus species
• H. influenzae (only β-lactamase–negative isolates) 2

From the Research

Bacteria Covered by Amoxicillin

• Amoxicillin covers several bacteria, including:
  • Streptococcus pneumoniae: 55.2% to 91.6% susceptible to amoxicillin 3, 4
  • Haemophilus influenzae: 55% to 70.2% susceptible to amoxicillin 3, 4
  • Moraxella catarrhalis: 4.8% to 11.2% susceptible to amoxicillin 3, 4

Susceptibility of Bacteria to Amoxicillin

• The susceptibility of these bacteria to amoxicillin varies, with:
  • S. pneumoniae having a susceptibility rate of 91.6% to amoxicillin 4
  • H. influenzae having a susceptibility rate of 70.2% to amoxicillin 4
  • M. catarrhalis having a low susceptibility rate to amoxicillin, with 4.8% to 11.2% susceptible 3, 4

Importance of Judicious Use of Antibiotics

• The use of antibiotics should be judicious to maintain remaining activity and avoid the development of further resistance 4
• Antibiotics should be chosen carefully based on activity determined by pharmacokinetic/pharmacodynamic-based breakpoints to avoid the development of further resistance, particularly to fluoroquinolones 4