scholarly journals In vitro activity of HSR-903, a new quinolone.

1997 ◽  
Vol 41 (6) ◽  
pp. 1326-1330 ◽  
Author(s):  
Y Takahashi ◽  
N Masuda ◽  
M Otsuki ◽  
M Miki ◽  
T Nishino
Keyword(s):  
Topoisomerase Ii ◽  
Inoculum Size ◽  
The Other ◽  
Vitro Activity ◽  
Penicillin G ◽  
In Vitro Activity ◽  
Postantibiotic Effect ◽  
The Family ◽  
Acidic Conditions

The in vitro activity of the new fluoroquinolone HSR-903 was compared with those of ciprofloxacin, lomefloxacin, sparfloxacin, and levofloxacin. HSR-903 inhibited 90% of methicillin-susceptible and -resistant Staphylococcus aureus (MRSA) clinical isolates at 0.78 and 1.56 microg/ml, respectively, and its activity against MRSA was 16-fold higher than those of sparfloxacin and levofloxacin and 64-fold higher than that of ciprofloxacin. The MICs at which 90% of the isolates are inhibited (MIC90s) of HSR-903 for Streptococcus pyogenes and penicillin G-susceptible and -resistant Streptococcus pneumoniae (PRSP) were 0.10, 0.05, and 0.05 microg/ml, respectively. Against PRSP, the activity of HSR-903 was 4-fold higher than that of sparfloxacin and 32- to 256-fold higher than those of the other quinolones. The MIC90 of HSR-903 for Enterococcus faecalis was 0.20 microg/ml, and HSR-903 was more active than the other quinolones against enterococci. The activity of HSR-903 against members of the family Enterobacteriaceae and Pseudomonas aeruginosa was roughly similar to that of ciprofloxacin and greater than those of the other quinolones. Against Haemophilus influenzae, Moraxella catarrhalis, and Helicobacter pylori, HSR-903 was the most potent of the quinolones tested. The activity of HSR-903 was not affected by the medium, the inoculum size, or the addition of serum, but decreased under acidic conditions, as did those of the other quinolones tested. HSR-903 exhibited rapid bactericidal action and had a good postantibiotic effect on S. aureus and P. aeruginosa. HSR-903 inhibited supercoiling by DNA gyrase from Escherichia coli, but it was much less active against human topoisomerase II.

scholarly journals In Vitro and In Vivo Antibacterial Activities of DW-224a, a New Fluoronaphthyridone

2006 ◽  
Vol 50 (6) ◽  
pp. 2261-2264 ◽  
Author(s):  
Hee-Soo Park ◽  
Hyun-Joo Kim ◽  
Min-Jung Seol ◽  
Dong-Rack Choi ◽  
Eung-Chil Choi ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
The Other ◽  
Vitro Activity ◽  
Gram Negative Bacteria ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

ABSTRACT DW-224a showed the most potent in vitro activity among the quinolone compounds tested against clinical isolates of gram-positive bacteria. Against gram-negative bacteria, DW-224a was slightly less active than the other fluoroquinolones. The in vivo activities of DW-224a against gram-positive bacteria were more potent than those of other quinolones.

scholarly journals In vitro activity of A-86719.1, a novel 2-pyridone antimicrobial agent.

1995 ◽  
Vol 39 (4) ◽  
pp. 850-853 ◽  
Author(s):  
G M Eliopoulos ◽  
C B Wennersten ◽  
G Cole ◽  
D Chu ◽  
D Pizzuti ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Agent ◽  
Vitro Activity ◽  
Pseudomonas Cepacia ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Xanthomonas Maltophilia ◽  
Gram Positive Bacteria ◽  
The Family

This study evaluated the in vitro activity of A-86719.1, a novel 2-pyridone antimicrobial agent. The drug inhibited all tested members of the family Enterobacteriaceae at < or = 0.5 microgram/ml and all tested Pseudomonas aeruginosa, Burkholderia (Pseudomonas) cepacia, and Xanthomonas maltophilia strains at < or = 2 micrograms/ml. All but two strains of gram-positive bacteria were inhibited by < or = 1 microgram of the new drug per ml, including isolates highly resistant to ciprofloxacin.

scholarly journals Antipneumococcal Activity of ABT-773 Compared to Those of 10 Other Agents

2000 ◽  
Vol 44 (7) ◽  
pp. 1894-1899 ◽  
Author(s):  
Todd A. Davies ◽  
Lois M. Ednie ◽  
Dianne M. Hoellman ◽  
Glenn A. Pankuch ◽  
Michael R. Jacobs ◽  
...  
Keyword(s):  
Ribosomal Protein ◽  
Vitro Activity ◽  
Penicillin Resistance ◽  
Penicillin G ◽  
23S Rrna ◽  
In Vitro Activity ◽  
Resistant Strains ◽  
Domain V ◽  
Kinetics Of

ABSTRACT MICs, time-kills, and postantibiotic effects (PAEs) of ABT-773 (a new ketolide) and 10 other agents were determined against 226 pneumococci. Against 78 ermB- and 44mefE-containing strains, ABT-773 MICs at which 50% of the isolates tested were inhibited (MIC50s) and MIC90s were 0.016 to 0.03 and 0.125 μg/ml, respectively. Clindamycin was active only against macrolide-resistant strains containing mefE (MIC50, 0.06 μg/ml; MIC90, 0.125 μg/ml). Activities of pristinamycin (MIC90, 0.5 μg/ml) and vancomycin (MIC90, 0.25 μg/ml) were unaffected by macrolide or penicillin resistance, while β-lactam MICs rose with those of penicillin G. Against 19 strains with L4 ribosomal protein mutations and two strains with mutations in domain V of 23S rRNA, ABT-773 MICs were 0.03 to 0.25 μg/ml, while macrolide and azalide MICs were all ≥16.0 μg/ml. ABT-773 was bactericidal at twice the MIC after 24 h for 8 of 12 strains (including three strains with erythromycin MICs greater than or equal to 64.0 μg/ml). Kill kinetics of erythromycin, azithromycin, clarithromycin, and roxithromycin against macrolide-susceptible strains were slower than those of ABT-773. ABT-773 had longer PAEs than macrolides, azithromycin, clindamycin, or β-lactams, including against ermB-containing strains. ABT-773, therefore, shows promising in vitro activity against macrolide-susceptible as well as -resistant pneumococci.

scholarly journals In Vitro Activity of DC-159a, a New Broad-Spectrum Fluoroquinolone, Compared with That of Other Agents against Drug-Susceptible and -Resistant Pneumococci

2007 ◽  
Vol 52 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Catherine Clark ◽  
Kathy Smith ◽  
Lois Ednie ◽  
Tatiana Bogdanovich ◽  
Bonifacio Dewasse ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
The Other ◽  
Quinolone Resistance ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Resistance Selection ◽  
Resistant Strains

ABSTRACT DC-159a yielded MICs of ≤1 μg/ml against 316 strains of both quinolone-susceptible and -resistant pneumococci (resistance was defined as a levofloxacin MIC ≥4 μg/ml). Although the MICs for DC-159a against quinolone-susceptible pneumococci were a few dilutions higher than those of gemifloxacin, the MICs of these two compounds against 28 quinolone-resistant pneumococci were identical. The DC-159a MICs against quinolone-resistant strains did not appear to depend on the number or the type of mutations in the quinolone resistance-determining region. DC-159a, as well as the other quinolones tested, was bactericidal after 24 h at 2× MIC against 11 of 12 strains tested. Two of the strains were additionally tested at 1 and 2 h, and DC-159a at 4× MIC showed significant killing as early as 2 h. Multistep resistance selection studies showed that even after 50 consecutive subcultures of 10 strains in the presence of sub-MICs, DC-159a produced only two mutants with maximum MICs of 1 μg/ml.

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