Is ceftriaxone (a third-generation cephalosporin) a broad-spectrum antibiotic?

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Last updated: June 17, 2025View editorial policy

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From the Guidelines

Ceftriaxone is a broad-spectrum antibiotic, effective against a wide range of bacteria, including many gram-negative and some gram-positive organisms. As a third-generation cephalosporin, ceftriaxone works particularly well against Enterobacteriaceae (like E. coli, Klebsiella, and Proteus), Neisseria species (including N. gonorrhoeae and N. meningitidis), and some streptococci 1. Ceftriaxone exerts its antibacterial effect by binding to penicillin-binding proteins and inhibiting bacterial cell wall synthesis, ultimately causing cell death.

Its broad-spectrum activity makes it useful for treating various infections including pneumonia, meningitis, intra-abdominal infections, urinary tract infections, and gonorrhea. Ceftriaxone is typically administered parenterally (usually intravenously or intramuscularly) and has a long half-life allowing for once-daily dosing. However, it has limited activity against Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), enterococci, and anaerobes, which is important to consider when selecting appropriate antibiotic therapy 1.

Some key points to consider when using ceftriaxone include:

  • It is effective against a wide range of bacteria, but has limited activity against certain organisms such as Pseudomonas aeruginosa and MRSA
  • It is typically administered parenterally and has a long half-life, allowing for once-daily dosing
  • It is useful for treating various infections, including pneumonia, meningitis, and urinary tract infections
  • Antibiotic stewardship is important when using ceftriaxone, and coverage should be narrowed as soon as culture results are available and given for as short a time as possible 1.

Overall, ceftriaxone is a valuable antibiotic for treating a range of infections, but its use should be guided by careful consideration of the potential benefits and limitations, as well as the need for antibiotic stewardship.

From the FDA Drug Label

Ceftriaxone for Injection, USP is a sterile, semisynthetic, broad-spectrum cephalosporin antibiotic for intravenous or intramuscular administration.

  • Ceftriaxone is a broad-spectrum antibiotic, as directly stated in the drug label 2.
  • The drug label explicitly mentions that ceftriaxone has activity against a wide range of Gram-negative and Gram-positive bacteria, as well as some anaerobic bacteria.
  • This indicates that ceftriaxone has a broad spectrum of activity, making it effective against various types of infections.

From the Research

Ceftriaxone Spectrum of Activity

  • Ceftriaxone is a third-generation cephalosporin with a broad spectrum of activity against Gram-positive and Gram-negative aerobic, and some anaerobic, bacteria 3.
  • It has excellent activity against many gram-negative aerobic bacilli, including Escherichia coli, species of Proteus, Klebsiella, Morganella, Providencia, and Citrobacter, and Enterobacter agglomerans 4.
  • Ceftriaxone also has outstanding bactericidal action against pneumococci, group B streptococci, meningococci, gonococci, and Hemophilus influenzae 4.

Limitations of Ceftriaxone

  • Although ceftriaxone has some activity against Pseudomonas aeruginosa, it cannot be recommended as sole antibiotic therapy in pseudomonal infections 3, 5.
  • The sensitivity of ceftriaxone is progressively decreasing, with a higher resistance rate against Klebsiella pneumoniae (35%) compared to Escherichia coli (10%) 6.

Clinical Use of Ceftriaxone

  • Ceftriaxone has been effective in treating infections due to multidrug-resistant Enterobacteriaceae, and has been used to treat serious bacterial infections in neonates, infants, children, and adults 3, 4.
  • It has been used as single-dose chemoprophylaxis in coronary artery bypass, biliary tract, vaginal hysterectomy, and prostatic surgery, with efficacy and safety similar to multiple-dose cefazolin 4.
  • Ceftriaxone has also been used to treat bacteremia, with clinical failure rates not significantly differing between 1g and 2g doses 7.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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