title: Comparison of the effects of macrolides, amoxicillin, ceftriaxone, doxycycline, tobramycin and fluoroquinolones, on the production of pneumolysin by Streptococcus pneumoniae in vitro.
abstract: OBJECTIVE
  To compare the effects of subinhibitory concentrations of amoxicillin, ceftriaxone, azithromycin, clarithromycin, erythromycin, telithromycin, clindamycin, ciprofloxacin, moxifloxacin, tobramycin and doxycycline on pneumolysin production by a macrolide-susceptible strain and two macrolide-resistant strains [erm(B) or mef(A)] of Streptococcus pneumoniae.
  
  
  METHODS
  Pneumolysin was assayed using a functional procedure based on the influx of Ca(2+) into human neutrophils.
  
  
  RESULTS
  Only the macrolides/macrolide-like agents caused significant attenuation of the production of pneumolysin, which was evident with all three strains of the pneumococcus.
  
  
  CONCLUSIONS
  Macrolides, at sub-MICs, but not other classes of antibiotic, subvert the production of pneumolysin, even in the presence of (and irrespective of the mechanism of) macrolide resistance in S. pneumoniae.
authors.affiliation: Medical Research Council (MRC) Unit for Inflammation and Immunity, Department of Immunology, Faculty of Health Sciences, University of Pretoria, and Tshwane Academic Division of the National Health Laboratory Service, South Africa. ronald.anderson@up.ac.za
authors.forename: R
authors.initials: R
authors.lastname: Anderson
authors.forename: H C
authors.initials: HC
authors.lastname: Steel
authors.forename: R
authors.initials: R
authors.lastname: Cockeran
authors.forename: A
authors.initials: A
authors.lastname: von Gottberg
authors.forename: L
authors.initials: L
authors.lastname: de Gouveia
authors.forename: K P
authors.initials: KP
authors.lastname: Klugman
authors.forename: T J
authors.initials: TJ
authors.lastname: Mitchell
authors.forename: C
authors.initials: C
authors.lastname: Feldman
mesh_terms: D000658:Amoxicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000096:biosynthesis; D002443:Ceftriaxone / Q000494:pharmacology; D004318:Doxycycline / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D024841:Fluoroquinolones / Q000494:pharmacology; D018942:Macrolides / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000378:metabolism*; D013301:Streptolysins / Q000096:biosynthesis*; D014031:Tobramycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D024841:Fluoroquinolones; D018942:Macrolides; D013301:Streptolysins; C032290:plY protein, Streptococcus pneumoniae; D002443:Ceftriaxone; D000658:Amoxicillin; D004318:Doxycycline; D014031:Tobramycin