title: Intermedilysin release by Streptococcus intermedius: effects of various antibacterial drugs at sub-MIC levels.
abstract: Intermedilysin is a cytolytic toxin produced by Streptococcus intermedius, a pathogen of humans. In vitro studies showed that exposure of S. intermedius to sub-minimum inhibitory concentration (MIC) levels (1/2 MIC) of protein-inhibiting antibiotics and nucleic acid-inhibiting antibiotics decreased intermedilysin release by S. intermedius. The most potent antibiotic was clindamycin. On the other hand, exposure to cell wall-inhibiting antibiotics generally showed insignificant changes in intermedilysin release at sub-MIC concentrations. Investigations into possible mechanisms underlying this sub-MIC effect with clindamycin showed that there was selective decrease in biosynthesis and release of toxin after exposure to 1/2 MIC condition. However, no significant differences in the mRNA levels of the intermedilysin gene were observed.
authors.affiliation: Department of Microbiology, National University of Singapore, Blk MD4, 5 Science Drive 2, Singapore 117597, Singapore. micmbt@nus.edu.sg
authors.forename: Mark B
authors.initials: MB
authors.lastname: Taylor
authors.forename: Janice H L
authors.initials: JH
authors.lastname: Oh
authors.forename: K L
authors.initials: KL
authors.lastname: Kang
authors.forename: Vincent T K
authors.initials: VT
authors.lastname: Chow
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism; D001430:Bacteriocins; D002981:Clindamycin / Q000494:pharmacology; D006801:Humans; D008826:Microbial Sensitivity Tests; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034367:Streptococcus intermedius / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D001430:Bacteriocins; D012333:RNA, Messenger; C403910:intermedilysin protein, Streptococcus intermedius; D002981:Clindamycin