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

GAR-936, a new semisynthetic derivative of minocycline, has earlier shown p romising activity against tetracycline-resistant pathogens, including Strep tococcus pneumoniae. In this study, the activity of GAR-936 was tested agai nst a total of 514 tetracycline-susceptible and -resistant strains of S. pt icumoniae, beta -haemolytic streptococci, viridans group streptococci, Haem ophilus influenzae and Neisseria gonorrhoeae. All strains,of H. influenzae, were inhibited by less than or equal to 2 mg/l of GAR-936, with MIC(90)s f or all streptococci and gonococci of less than or equal to0.5 mg/l. Scatter grams of GAR-936 comparing MICs by broth microdilution testing and zone dia meters using 30 mug disks, confirmed the proposed susceptibility criteria o f less than or equal to 2 mg/l or greater than or equal to 20 mm zone diame ter. Clinical trial results should be correlated with these preliminary in vitro results to confirm and/or adjust these susceptibility interpretive cr iteria for GAR-936 when testing fastidious streptococci, H. influenzae and N. gonorrhoeae. (C) 2001 Elsevier Science B.V. and International Society of Chemotherapy. All rights reserved.