In-vitro effects of penicillin and clindamycin on the expression of Streptococcus pneumoniae capsule

• Published in: Journal of medical microbiology Vol. 45; no. 6; pp. 505 - 506
• Main Authors: Brook, I, Gober, A. E
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01-12-1996; Society for General Microbiology
• Subjects: Anti-Bacterial Agents - pharmacology; Antibacterial agents; Antibiotics. Antiinfectious agents. Antiparasitic agents; Bacterial Capsules - biosynthesis; Bacterial Capsules - drug effects; Biological and medical sciences; Child; Clindamycin - pharmacology; Humans; Medical sciences; Penicillin Resistance; Penicillins - pharmacology; Pharmacology. Drug treatments; Streptococcus pneumoniae; Streptococcus pneumoniae - drug effects; Streptococcus pneumoniae - pathogenicity; Streptococcus pneumoniae - ultrastructure; Virulence - drug effects; Microorganism capsule; Streptococcaceae; Antibiotic; Sensitivity resistance; Clindamycin; Penicillin; Bacteria; Micrococcales; Antibacterial agent; In vitro; Biological activity; Streptococcus pneumoniae
• ISSN: 0022-2615; 1473-5644
• DOI: 10.1099/00222615-45-6-505

Department of Pediatrics, Georgetown University and George Washington University Schools of Medicine, Washington, DC, USA
5 Corresponding author: Professor I. Brook, PO Box 70412, Chevy Chase, MD 20814-0412, USA.
Received January 5, 1996
Revision received April 24, 1996.
The effects of subinhibitory concentrations of penicillin or clindamycin were evaluated in 20 isolates of Streptococcus pneumoniae that were fully susceptible to penicillin and in 20 isolates that were of intermediate resistance. All isolates were capsulate and susceptible to clindamycin. After incubation in one-half of the MIC of clindamycin, 17.5% of isolates retained a capsule, compared to 87.5% after incubation with one-half of the MIC of penicillin. Clindamycin appears to be superior to penicillin in reducing the expression of the capsule by S. pneumoniae .