What are the recommended antibiotic choices for a 2-month-old infant with sepsis?

From the Guidelines

For a 2-month-old infant with suspected sepsis, the recommended empiric antibiotic regimen is ampicillin (150 mg/kg per day divided every 8 hours) and either ceftazidime (150 mg/kg per day divided every 8 hours) or gentamicin (4 mg/kg per dose every 24 hours) 1. This combination provides coverage against common neonatal pathogens including Group B Streptococcus, Escherichia coli, Listeria monocytogenes, and other gram-negative bacteria.

• Ampicillin covers gram-positive organisms and Listeria,
• while gentamicin or ceftazidime targets gram-negative bacteria. Some key points to consider in the management of sepsis in a 2-month-old infant include:
• Blood cultures should be obtained before starting antibiotics,
• and lumbar puncture should be considered to rule out meningitis. Treatment duration typically ranges from 7-10 days for bacteremia without a focus,
• but may extend to 14-21 days for meningitis or other focal infections. Antibiotic therapy should be narrowed based on culture results and clinical response.
• Gentamicin levels should be monitored if therapy continues beyond 48 hours to prevent ototoxicity and nephrotoxicity. Reassessment at 48 hours is crucial to determine whether antibiotics should be continued or modified based on clinical improvement and culture results 1. It's also important to note that the use of a local antibiogram, if available, can guide choices 1. In the absence of a focus of infection, the recommended regimen can be used, but if a focus of infection such as pneumonia, cellulitis, gastroenteritis, or musculoskeletal infection is identified, different regimens that cover typical microbial pathogens for the site of infection should be administered 1.

From the FDA Drug Label

Gentamicin Injection, USP is indicated in the treatment of serious infections caused by susceptible strains of the following microorganisms: Pseudomonas aeruginosa, Proteus species (indole-positive and indole-negative), Escherichia coli, Klebsiella-Enterobacter-Serratia species, Citrobacter species and Staphylococcus species (coagulase-positive and coagulase-negative) Clinical studies have shown gentamicin injection to be effective in bacterial neonatal sepsis; bacterial septicemia and serious bacterial infections of the central nervous system (meningitis), urinary tract, respiratory tract, gastrointestinal tract (including peritonitis), skin, bone and soft tissue (including burns) In the neonate with suspected bacterial sepsis or staphylococcal pneumonia, a penicillin-type drug is also usually indicated as concomitant therapy with gentamicin.

The recommended antibiotic choice for a 2-month-old infant with sepsis is gentamicin in combination with a penicillin-type drug, as it has been shown to be effective in bacterial neonatal sepsis 2.

• Gentamicin is indicated for the treatment of serious infections caused by susceptible strains of various microorganisms.
• A penicillin-type drug should also be considered as concomitant therapy with gentamicin in neonates with suspected bacterial sepsis or staphylococcal pneumonia.

From the Research

Recommended Antibiotic Choices for 2-Month-Old Infants with Sepsis

The choice of antibiotics for a 2-month-old infant with sepsis depends on various factors, including the suspected or confirmed pathogen, the severity of the infection, and the presence of any underlying medical conditions.

• According to a study published in 2023 3, ampicillin plus gentamicin remains the recommended antibiotic regimen for early onset neonatal sepsis, despite the emergence of resistance and concerns about long-term safety.
• Another study from 2009 4 found that the combination of ampicillin and gentamicin is still appropriate for both term and preterm newborns, with low rates of resistance to this combination.
• A 2022 study 5 reported that the vast majority of contemporary early-onset sepsis pathogens are susceptible to the combination of ampicillin and gentamicin, and clinicians may consider the addition of broader-spectrum therapy among newborns at highest risk of early-onset sepsis.

Considerations for Antibiotic Resistance

• A review of WHO guidelines for antibiotic use in sepsis in neonates and children, published in 2018 6, found that current recommendations supporting the use of gentamicin and penicillin for hospital-based patients or gentamicin and amoxicillin when referral to a hospital is not possible are in accordance with currently available evidence.
• A 2021 study 7 found significant resistance to current first-line antibiotics and cephalosporins, and identified low birthweight and late-onset sepsis as risk factors for antibiotic-resistant infections.

Summary of Antibiotic Options

• Ampicillin and gentamicin are commonly recommended for early-onset neonatal sepsis 3, 4, 5.
• Gentamicin and penicillin are recommended for hospital-based patients, or gentamicin and amoxicillin when referral to a hospital is not possible 6.
• Alternative antibiotics, such as amikacin and piperacillin-tazobactam, may be considered in cases of resistance or allergy to first-line antibiotics 7.