From the FDA Drug Label
Adults: Parenteral (IM or IV Administration): Serious infections due to aerobic gram-positive cocci and the more susceptible anaerobes (NOT generally including Bacteroides fragilis, Peptococcus species and Clostridium species other than Clostridium perfringens): 600 mg to 1,200 mg per day in 2,3 or 4 equal doses
The following in vitro data are available, but their clinical significance is unknown Vancomycin exhibits in vitro MIC's of 1 mcg/mL or less against most (≥90%) strains of streptococci listed below and MIC's of 4 mcg/mL or less against most (≥90%) strains of other listed microorganisms; however, the safety and effectiveness of vancomycin in treating clinical infections due to these microorganisms have not been established in adequate and well-controlled clinical trials Aerobic gram-positive microorganisms Streptococcus agalactiae
The clindamycin and vancomycin drug labels provide some information about treating infections caused by gram-positive cocci, including Streptococcus agalactiae, which is also known as Group B strep.
- Clindamycin may be used to treat serious infections due to aerobic gram-positive cocci, but the label does not specifically mention Group B strep osteomyelitis.
- Vancomycin has been shown to be active against Streptococcus agalactiae in vitro, but the label does not provide specific dosage recommendations for Group B strep osteomyelitis. There is no information in the penicillin G drug label that directly supports its use for Group B strep osteomyelitis. Therefore, based on the available information, clindamycin or vancomycin may be considered for the treatment of Group B strep osteomyelitis, but the dosage and treatment duration should be determined by a healthcare professional based on the individual patient's needs and the severity of the infection 1, 2.
From the Research
For group B streptococcal (GBS) osteomyelitis, penicillin G is the first-line antibiotic treatment, typically administered intravenously at 3-4 million units every 4 hours for adults or 200,000-300,000 units/kg/day divided every 4-6 hours for children, as GBS remains highly susceptible to beta-lactam antibiotics, with penicillin being the most effective due to its excellent bone penetration and bactericidal activity against the organism 3. The treatment usually begins with 2-4 weeks of IV therapy followed by oral amoxicillin (500-875 mg three times daily for adults or 40-50 mg/kg/day divided three times daily for children) to complete a total 4-6 week course. Some key points to consider in the treatment of GBS osteomyelitis include:
- The importance of accurate diagnosis and identification of the offending organism
- The need for surgical debridement in cases with abscess formation or sequestered bone
- The use of alternative antibiotics, such as clindamycin or vancomycin, in patients who are allergic to penicillin
- The monitoring of treatment response through clinical improvement, normalization of inflammatory markers, and follow-up imaging studies It is also important to note that while GBS is still recognized as being universally susceptible to beta-lactam antibiotics, there have been reports of reduced susceptibility to beta-lactams, including penicillin, in some countries 3. Additionally, resistance to second-line antibiotics, such as erythromycin and clindamycin, remains high amongst GBS, and resistance to other antibiotic classes, such as fluoroquinolones and aminoglycosides, also continues to rise 3. Therefore, it is essential to stay up-to-date with the latest resistance patterns and to use antibiotic susceptibility testing to guide treatment decisions. In cases where patients are allergic to penicillin and second-line antibiotics are ineffective, vancomycin may be administered, although there have been two documented cases of vancomycin resistance in GBS 3.