Is Streptococcus (a Gram-positive coccus in chains) susceptible to Ceftriaxone (Ceftriaxone)?

From the Guidelines

Yes, gram-positive cocci in chains (typically Streptococcus species) generally respond well to ceftriaxone. Ceftriaxone is a third-generation cephalosporin that effectively targets the cell wall synthesis of gram-positive cocci, particularly streptococci including Streptococcus pneumoniae and beta-hemolytic streptococci. The typical dosing for serious streptococcal infections is 1-2 grams IV every 24 hours, with treatment duration varying based on the specific infection type (typically 7-14 days) 1. Ceftriaxone works by binding to penicillin-binding proteins in the bacterial cell wall, disrupting peptidoglycan synthesis and causing cell lysis. It has good tissue penetration and a long half-life allowing for once-daily dosing. However, it's essential to note that some strains, particularly certain viridans group streptococci, may show reduced susceptibility, and methicillin-resistant Staphylococcus aureus (MRSA) is resistant to ceftriaxone despite being gram-positive cocci that sometimes appear in chains. For severe infections, susceptibility testing is recommended to confirm effectiveness 1.

Some key points to consider:

• Ceftriaxone is effective against penicillin-susceptible streptococci, with a cure rate of >95% 1.
• For penicillin-resistant strains, ceftriaxone may still be effective, but the dose and duration of treatment may need to be adjusted 1.
• Ceftriaxone can be used in combination with other antibiotics, such as gentamicin, for the treatment of streptococcal endocarditis 1.
• The treatment of streptococcal infections with ceftriaxone should be guided by susceptibility testing and clinical judgment, taking into account the severity of the infection and the patient's underlying health status 1.

In summary, ceftriaxone is a effective treatment option for gram-positive cocci in chains, but its use should be guided by susceptibility testing and clinical judgment.

From the FDA Drug Label

Ceftriaxone for Injection is indicated for the treatment of the following infections when caused by susceptible organisms: SKIN AND SKIN STRUCTURE INFECTIONS Caused by Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Viridans group streptococci

The bacteria described, Gram positive cocci in chains, is likely Streptococcus pyogenes or another species of Streptococcus.

• Ceftriaxone may be effective against this type of bacteria, as it is indicated for the treatment of skin and skin structure infections caused by Streptococcus pyogenes and other Streptococcus species 2.
• However, the susceptibility of the specific bacteria should be determined through susceptibility testing, as the effectiveness of ceftriaxone can vary depending on the specific strain and local epidemiology 2.
• Key points to consider:
  • Ceftriaxone has in vitro activity against Streptococcus pyogenes and other Streptococcus species.
  • The clinical efficacy of ceftriaxone in treating infections caused by Gram positive cocci in chains has not been explicitly stated in the provided drug labels.
  • Susceptibility testing is recommended to determine the effectiveness of ceftriaxone against the specific bacteria.

From the Research

Gram Positive Cocci in Chains Response to Ceftriaxone

• Gram positive cocci in chains are typically Streptococcus species, such as Streptococcus pneumoniae or Streptococcus pyogenes 3, 4, 5.
• Ceftriaxone has been shown to be effective against Streptococcus pneumoniae, with low resistance rates (5.0-5.1%) 3.
• Ceftriaxone also has activity against other Streptococcus species, including Streptococcus pyogenes and viridans group streptococci 3, 4.
• However, the effectiveness of ceftriaxone against Gram positive cocci in chains can depend on the specific species and strain, as well as the presence of resistance mechanisms 6, 7.
• In cases of cephalosporin-resistant Streptococcus pneumoniae, combination therapy with vancomycin and/or rifampicin may be effective 6, 7.

Specific Studies

• A study published in 2002 found that ceftriaxone had low resistance rates against Streptococcus pneumoniae (5.0-5.1%) 3.
• Another study published in 2005 found that combination therapy with ceftriaxone, vancomycin, and rifampicin was effective against highly cephalosporin-resistant Streptococcus pneumoniae 7.
• A review of ceftriaxone's activity against Gram-positive and Gram-negative pathogens found that it retained its potent activity against the most commonly encountered pathogens despite widespread use 3.