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Early studies on in-vitro and experimental activity of spiramycin: a review
1National Reference Center for Antibiotics, Institut Pasteur, Paris, France.
Abstract:
This review of spiramycin activity in vitro is based mainly on early studies. The MICs of spiramycin for common pathogenic bacteria such as staphylococci, streptococci and pneumococci are higher than those of erythromycin. Conversely, in experimental models, the activity of spiramycin is equal to or greater than that of erythromycin. In addition, the activity of spiramycin on Neisseria, Legionella, Mycoplasma, Chlamydia, and Toxoplasma spp. completes its antimicrobial spectrum and shows that spiramycin covers the majority of agents responsible for respiratory tract infections. The 'spiramycin paradox'-the discrepancy between the relatively modest activity of spiramycin in vitro and its excellent activity in vivo will be explained by other papers. Its high tissue and intracellular concentrations, and the slow recovery of bacteria submitted to spiramycin are of great importance to account for its activity in vivo.
Insights
Spiramycin shows modest in vitro activity but excellent in vivo efficacy against respiratory pathogens. Its high tissue concentrations and slow bacterial recovery explain this
Area of Science:
- Microbiology
- Pharmacology
- Infectious Diseases
Background:
- Early studies on spiramycin activity are reviewed.
- Spiramycin's in vitro minimum inhibitory concentrations (MICs) for common bacteria like staphylococci, streptococci, and pneumococci are higher than erythromycin's.
- Spiramycin exhibits activity against Neisseria, Legionella, Mycoplasma, Chlamydia, and Toxoplasma species.
Purpose of the Study:
- To review the in vitro and in vivo activity of spiramycin.
- To highlight the discrepancy between in vitro and in vivo spiramycin activity (the 'spiramycin paradox').
- To identify factors contributing to spiramycin's effectiveness in vivo.
Main Methods:
- Review of early in vitro studies.
- Comparison of spiramycin and erythromycin MICs.
- Evaluation of spiramycin activity in experimental models.
- Assessment of spiramycin's spectrum of activity against various pathogens.
Main Results:
- Spiramycin's in vitro MICs are generally higher than erythromycin's for common respiratory pathogens.
- In experimental models, spiramycin's activity is comparable to or exceeds that of erythromycin.
- Spiramycin demonstrates activity against a broad range of pathogens, including those causing respiratory tract infections.
- The 'spiramycin paradox' is noted, with a discrepancy between in vitro and in vivo activity.
Conclusions:
- Spiramycin possesses a broad antimicrobial spectrum relevant to respiratory tract infections.
- The 'spiramycin paradox' suggests factors beyond simple in vitro activity influence its clinical efficacy.
- High tissue and intracellular concentrations, along with slow bacterial recovery, are key to understanding spiramycin's potent in vivo performance.