GAR-936 (9-t-butylglycylamido-minocycline) susceptibility test development for streptococci, Haemophilus influenzae and Neisseria gonorrhoeae: preliminary guidelines and interpretive criteria

Int J Antimicrob Agents. 2001 Jul;18(1):29-35. doi: 10.1016/s0924-8579(01)00355-7.


GAR-936, a new semisynthetic derivative of minocycline, has earlier shown promising activity against tetracycline-resistant pathogens, including Streptococcus pneumoniae. In this study, the activity of GAR-936 was tested against a total of 514 tetracycline-susceptible and -resistant strains of S. pneumoniae, beta-haemolytic streptococci, viridans group streptococci, Haemophilus influenzae and Neisseria gonorrhoeae. All strains of H. influenzae, were inhibited by < or =2 mg/l of GAR-936, with MIC(90)s for all streptococci and gonococci of < or =0.5 mg/l. Scattergrams of GAR-936 comparing MICs by broth microdilution testing and zone diameters using 30 microg disks, confirmed the proposed susceptibility criteria of < or 2 mg/l or > or =20 mm zone diameter. Clinical trial results should be correlated with these preliminary in vitro results to confirm and/or adjust these susceptibility interpretive criteria for GAR-936 when testing fastidious streptococci, H. influenzae and N. gonorrhoeae.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Haemophilus influenzae / drug effects*
  • Microbial Sensitivity Tests*
  • Minocycline / analogs & derivatives
  • Minocycline / pharmacology*
  • Neisseria gonorrhoeae / drug effects*
  • Penicillin Resistance
  • Streptococcus / drug effects*
  • Tetracycline / pharmacology
  • Tetracycline Resistance
  • Tigecycline


  • Anti-Bacterial Agents
  • Tigecycline
  • Tetracycline
  • Minocycline