Antimicrobial activity and spectrum of the new glycylcycline, GAR-936 tested against 1,203 recent clinical bacterial isolates

The in vitro activity of GAR-936, a new semisynthetic glycylcycline, was ev aluated in comparison with two tetracyclines and several other antimicrobia l agents. A total of 1, 203 recent clinical isolates were tested by referen ce broth or agar dilution methods. Among the members of the family Enteroba cteriaceae, GAR-936 was generally two- to four-fold more active than minocy cline, and two- to 16-fold more active than tetracycline. All enteric bacil li MIC90 results were less than or equal to 4 mu g/mL; the exception being Proteus mirabilis and indole-positive Proteae (greater than or equal to 8 m u g/mL). GAR-936 demonstrated excellent activity against all Gram-positive cocci with 90% of the penicillin-resistant Streptococcus pneumoniae isolate s inhibited at 0.03 mu g/ml, while the same isolates had a MIC90 of 8 and > 8 mu g/mL for minocycline and tetracycline, respectively. All Enterococcus spp., including vancomycin-resistant isolates, were inhibited at 0.25 mu g /mL of GAR-936 (MIC90, 0.12 or 0.25 mu g/mL). Although GAR-936 (MIC50, 0.25 mu g/mL) was two-fold less active than minocycline (MIC50, 0.12 mu g/mL) a gainst oxacillin-resistant Staphylococcus aureus, all isolates were inhibit ed at less than or equal to 0.25 mu g/mL. GAR-936 demonstrated good activit y against nonfermentative bacteria such as Acinetobacter spp. (MIC90, mu g/ ml) and Stenotrophomonas maltophilia (MIC90, 4 mu g/mL), but the compound e xhibited only modest activity against Pseudomonas aeruginosa (MIC50, 8 mu g /mL). Haemophilus influenzae (MIC90, 1-2 mu g/mL), Moraxella catarrhalis (M IC90, 0.12 mu g/mL), and various Neisseria spp. (MIC90, 0.12-0.5 mu g/mL) w ere susceptible to GAR-936. These results indicate that GAR-936 has potent in vitro activity against a wide range of clinically important pathogenic b acteria, and that several Gram-positive and -negative isolates resistant to older tetracyclines and other drug classes remain susceptible to GAR-936, the newest glycylcycline candidate for clinical use. (C) 2000 Elsevier Scie nce Inc. All rights reserved.