FUNG-TOMC J, GRADELSKI E, BONNER D; Interscience Conference on Antimicrobial Agents and Chemotherapy.

Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 1999 Sep 26-29; 39: 288 (abstract no. 2329).

Bristol-Myers Squibb Co., Wallingford, CT.

Quinolones are bactericidal agents that exhibit concentration-dependent killing. Maximal bactericidal concentrations of quinolones generally occur close to 10x their MICs. Determination of the killing rates by fluoroquinolones (FQs) led to the observation that their rate of killing may be organism group-dependent. In this study, the rate of killing by gatifloxacin (GAT) and/or trovafloxacin (TVA), at 10x their MICs were determined vs. E. coli (2 strains), methicillin-resistant S. aureus (MRSA, 2 strains), S. pneumoniae (9 strains), S. pyogenes (1 strain), S. agalactiae (1 strain), S. mitis (1 strain), S. sanguis (1 strain), and E. faecalis (5 strains). Time-kill studies were done using Mueller-Hinton broth (MHB), except vs. S. pneumoniae and the viridans streptococci (MHB + 7% lysed horse blood), and beta-hemolytic streptococci (Brain Heart Infusion broth). Viable cell counts were determined at 0, 2, 4, 6, and except for pneumococci, also at 24h of incubation. Since a 3 log[10] decrease in viable count is an accepted index of bactericidal activity, the time required to achieve this level of kill was used for data analysis. Both FQs achieved a 3 log[10] kill within /=6h of incubation to obtain a 3 log[10] kill of pneumococci, E. faecalis (except strain A26830, 3h by GAT), the viridans streptococci and S. agalactiae. Both FQs decreased the S. pyogenes count by 3 log[10] at 3h of incubation. Thus, a 3 log[10] kill was achieved by the FQs in /=6h was needed to attain similar reduction for GAT, in 16 of the 18 (and for TVA, in 8 of the 9) streptococci and related organisms.

Publication Types:

• Meeting Abstracts

Keywords:

• Fluoroquinolones
• Microbial Sensitivity Tests
• Naphthyridines
• Quinolones
• Staphylococcal Infections
• Staphylococcus aureus
• Streptococcus
• Streptococcus pneumoniae
• Viridans Streptococci
• gatifloxacin
• trovafloxacin

Other ID:

• GWAIDS0007901

UI: 102245398

From Meeting Abstracts