ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, OCt. 1992, p. 2293-2303
0066-4804/92/102293-11$02.00/0 Copyright © 1992, American Society for Microbiology
Vol. 36, No. 10
In Vitro Activity of T-3761, a New Fluoroquinolone TETSURO MURATANI,l* MATSUHISA INOUE,2 AND SUSUMU MITSUHASHI1 Episome Institute, Kogure, Fujimi-mura, Seta-gun, Gunma 371-01,1 and Department of Microbiology, School of Medicine, Kitasato University, Sagamihara, Kanagawa 228, 2 Japan Received 4 May 1992/Accepted 28 July 1992
The in vitro activity of T-3761, a new fluoroquinolone antimicrobial agent which has an oxazine ring structure with a cyclopropyl moiety at C-10, was compared with those of other agents against 2,854 clinical isolates. T-3761 had a broad spectrum of activity and had potent activity against gram-positive and -negative bacteria. The MICs of T-3761 against 90% of the methicillin-susceptible Staphylococcus aureus, methicillinsusceptible and -resistant Staphylococcus epidermidis, and Clostridium spp. tested were 0.39 to 6.25 ,g/m!. Its activity was comparable to those of ciprofloxacin and ofloxacin and four- to eightfold greater than those of norfloxacin and fleroxacin, but its activity was two- to eightfold less than that of tosufloxacin. Some isolates of ciprofloxacin-resistant S. aureus (MIC of ciprofloxacin, .3.13 ,ug/ml) were still susceptible to T-3761 (MIC of T-3761, .0.78 ,ug/ml). The MICs of T-3761 against 90%o of the streptococci and enterococci tested were 3.13 to 100 ,ug/ml. Its activity was equal to or 2- or 4-fold greater than those of norfloxacin and fleroxacin, equal to or 2- or 4-fold less than those of ofloxacin and ciprofloxacin, and 4- to 16-fold less than that of tosufloxacin. The activity of T-3761 against gram-negative bacteria was usually fourfold greater than those of norfloxacin, ofloxacin, and fleroxacin. Many isolates which were resistant to nonfluoroquinolone agents, such as minocycline- or imipenem-resistant S. aureus, ceftazidime-resistant members of the family Enterobacteriaceae, gentamicin- or imipenem-resistant Pseudomonas aeruginosa, and ampicillin-resistant Haemophilus influenzae and Neisseria gonorrhoeae, were susceptible to T-3761. The MBCs of T-3761 were either equal to or twofold greater than the MICs. The number of viable cells decreased rapidly during incubation with T-3761 at one to four times the MIC. At a concentration of four times the MIC, the frequencies of appearance of spontaneous mutants resistant to T-3761 against S. aureus, Escherichia coli, Serratia marcescens, and P. aeruginosa were 2.2 x 10-8 to 100 0.39-> 100 0.20-> 100 0.012-12.5 0.39-> 100 0.05->100 0.05-1.56 0.012-0.20 0.78-6.25
Methicillin-resistant Staphylococcus aureus (282)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Minocycline Imipenem Methicillin
0.10-100 0.20->100 0.78-> 100 0.20-> 100 0.012-25 0.39-> 100 0.10->100 0.05-100 0.025->100 12.5->100
0.39 1.56 25 3.13 0.10 3.13 50 0.20 50 >100
12.5 50 >100 100 6.25 >100 >100 6.25 100 >100
Methicillin-susceptible Staphylococcus epidermidis (84)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Methicillin
0.10-12.5 0.20-12.5 0.10-100 0.10-12.5 100 0.39-6.25
0.39 0.39 0.78 0.20 0.05 0.78 0.10 1.56
0.39 0.78 1.56 0.39 0.10 1.56 50 6.25
Methicillin-resistant Staphylococcus epidermidis (130)
T-3761 Ofloxacin Norfloxacin
0.10->100 0.20->100 0.39->100 0.10-100 0.025-12.5 0.39->100 0.05->100 12.5->100
0.39 0.39 0.78 0.20 0.05 0.78 25 100
6.25 12.5 50 6.25 3.13 25 100 >100
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Methicillin
0.20-3.13 0.20-6.25 0.39-50 0.20-12.5 0.025-3.13 0.39-25 0.025-100 1.56->100
0.39 0.78 0.78 0.39 0.05 1.56 0.10 6.25
0.39 1.56 6.25 0.78 0.20 3.13 25 >100
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime Ampicillin
3.13-100 1.56-50 6.25-100 0.39-50 0.10-12.5 6.25-> 100 6.25-12.5 25-100 0.10-100 .0.006-0.012 0.10-0.39 0.025-0.05
6.25 3.13 12.5 3.13 0.20 12.5 12.5 100 0.20
T-3761 Ofloxacin Norfloxacin
0.78-6.25 0.78-6.25 0.78-25
Ciprofloxacin
0.20-3.13 0.05-0.78
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Methicillin
Staphylococcus hominis (20)
Streptococcus pneumoniae (29)
Streptococcus pyogenes (80)
T-3761 Ofloxacin Norfloxacin
Tosufloxacin
0.20 0.39 1.56 0.39 0.025 0.78 0.39 0.10 0.025 3.13
.0.006 0.20 0.025 3.13 1.56 3.13 0.78 0.10
0.39 0.78 3.13 0.78 0.05 1.56 50 0.20 0.025 3.13
6.25 3.13 25 3.13 0.39 25 12.5 100 25 _0.006 0.39 0.05 3.13 1.56 3.13
0.78 0.20
Continued on following page
2296
MURATANI ET AL.
ANTIMICROB. AGENTS CHEMOTHER. TABLE 1-Continued
Organism (no. of isolates)
MIC (,ug/ml)a
Compound Range
Fleroxacin Gentamicin Amikacin
Minocycline Imipenem Ceftazidime
Ampicillin Enterococcus faecalis (97)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin
Tosufloxacin Fleroxacin Gentamicin Amikacin
Minocycline Imipenem Ceftazidime
Ampicillin Enterococcus faecium (54)
T-3761 Ofloxacin
Norfloxacin
Ciprofloxacin
Tosufloxacin Fleroxacin Gentamicin Amikacin
Minocycline Imipenem Ceftazidime
Escherichia coli (108)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime Citrobacter diversus (12)
T-3761 Ofloxacin
Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
Citrobacterfreundii (97)
T-3761
Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem
1.56-50 3.13-12.5 50-> 100 0.05-50 .0.006-0.10 0.10-3.13 0.012-0.78
50%
6.25 12.5 50 0.20
C0.006 0.10 0.012
90%
12.5 12.5 100 25 100 50-> 100 0.05-50 0.39-3.13 12.5-> 100 0.39-3.13
3.13 1.56 3.13 0.78 0.20 3.13 25 >100 12.5 0.78 >100 1.56
3.13 3.13 6.25 3.13 0.39 6.25 50 >100 25 0.78 >100 1.56
3.13-> 100 1.56-> 100 1.56-> 100 0.39-> 100 0.20->25 3.13-> 100 6.25-> 100 12.5-> 100 0.10-100 0.78-> 100 >100
6.25 6.25 6.25 3.13 1.56 12.5 25 100 12.5 100 >100
100 100 >100 100 25 >100 >100 >100 50 >100 >100
0.012-3.13 0.025-12.5 0.012-6.25 _0.006-1.56 0.05-25 0.20-> 100 0.78-12.5 0.78-> 100 0.05-0.78 0.025-0.78
0.025 0.05 0.05 0.012 0.025 0.10 0.78 1.56 3.13 0.10 0.10
0.05 0.10 0.10 0.025 0.05 0.20 0.78 3.13 50 0.20 0.20
0.012-0.025 0.025-0.10 0.025-0.20
0.025 0.05 0.05
.0.006-0.025
.0.006
0.012-0.05 0.05-0.10 0.20-0.78 0.78-3.13 0.78-12.5 0.10-0.20 0.025-0.20
0.012 0.10 0.39 1.56 1.56 0.10 0.05
0.025 0.05 0.05 0.012 0.05 0.10 0.39 3.13 3.13 0.20 0.10
0.012-25 0.025-100 0.025-50
0.05 0.20 0.10 0.025 0.05 0.39 0.78 1.56 3.13 0.20
.0.006-3.13
.0.006-12.5 0.012->25 0.05-> 100 0.20-100 0.78-100 0.78-> 100
.0.006-1.56
0.39 1.56 1.56 0.39 0.78 1.56 12.5 1.56 50 0.39
Continued on following page
ANTIBACTERIAL ACTIVITY OF T-3761
VOL. 36, 1992
2297
TABLE 1-Continued Organism (no. of isolates)
Compound
CeftaZ;dime Salmonella spp. (108)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin
Tosufloxacin Fleroxacin Gentamicin Amikacin
Minocycline Imipenem Ceftazidime
Shigella spp. (108)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin
Tosufloxacin Fleroxacin Gentamicin Amikacin
Minocycline Imipenem Ceftazidime
Kiebsiella pneumoniae (127)
T-3761 Ofloxacin
Norfloxacin
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin
Minocycline Imipenem Ceftazidime
Kiebsiella oxytoca (104)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin
Tosufloxacin Fleroxacin Gentamicin Amikacin
Minocycline Imipenem Ceftazidime Enterobacter aerogenes (10)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline
Imipenem Ceftazidime Enterobacter cloacae (105)
T-3761
MIC (>Lg/ml)f
Range
0.05-> 100
50% 0.39
90% 100
0.012-0.05 0.05-0.20 0.39-1.56 0.78-3.13 0.78-100 0.05-0.78 0.05-0.78
0.025 0.10 0.10 0.012 0.025 0.10 0.78 1.56 3.13 0.10 0.20
0.05 0.20 0.10 0.025 0.05 0.20 0.78 3.13 12.5 0.20 0.39
0.012-0.39 0.025-1.56 0.025-0.78 C0.006-0.39 .0.006-0.39 0.05-1.56 0.20-3.13 0.78-25 0.20-50 0.05-0.20 0.05-3.13
0.025 0.05 0.05 0.012 0.012 0.10 1.56 6.25 3.13 0.10 0.10
0.025 0.10 0.10 0.025 0.025 0.20 1.56 12.5 12.5 0.20 0.39
0.012-1.56 0.05-3.13 0.05-6.25 50.006-1.56 0.025-0.78 0.05-6.25 0.20-100 0.39-25 1.56->100 0.05-0.78 0.025-6.25
0.025 0.20 0.10 0.025 0.05 0.20 0.39 1.56 6.25 0.20 0.10
0.012-0.10 0.05-0.39 0.025-0.39 C0.006-0.05 .0.006-0.05 0.05-0.78 0.20-0.78 0.78-3.13 3.13-12.5 0.10-1.56 0.025-0.78
0.025 0.10 0.05 0.012 0.025 0.10 0.78 1.56 3.13 0.20 0.05
0.05 0.20 0.10 0.025 0.025 0.20 0.78 1.56 3.13 0.39 0.20
0.05 0.20 0.10 0.025 0.025 0.20 0.39 1.56 3.13 0.78 0.10
0.05 0.20 0.10 0.025 0.05 0.20 0.78 3.13 3.13 0.78 0.20
0.05 0.10 0.05 0.012 0.05
0.20 0.78 0.78 0.10 0.20
0.025-0.05 0.05-0.20 0.025-0.20
C0.006-0.025
0.025-0.05 0.10-0.20 0.10-0.20 0.025-0.025 0.025-0.05 0.20-0.20 0.39-0.78 1.56-3.13 1.56-3.13 0.39-1.56 0.10-25
Ofloxacin Norfloxacin Ciprofloxacin
0.012-6.25 0.025-12.5 0.025-25 C0.006-6.25
Tosufloxacin
'0.006-3.13
0.10 0.39 0.39 0.05 0.10 0.39 0.78 1.56 100 0.20 0.39
Continued on following page
2298
ANTIMICROB. AGENTS CHEMOTHER.
MURATANI ET AL. TABLE 1-Continued Organism (no. of isolates)
Compound
Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
Hafnia alvei (12)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
Serratia marcescens (111)
T-3761
MIC (p.g/ml)a Range
0.025-25 0.20-> 100 0.78-50 1.56-> 100 0.05-0.78 0.05-> 100
0.025-0.05 0.05-0.20 0.025-0.10 .0.006-0.05 0.025-0.10 0.05-0.10 0.20-1.56 1.56-6.25 0.78-25 0.20-1.56 0.05-6.25
50%
90%
0.10 0.39 1.56 6.25 0.20 0.39
0.78 6.25 1.56 100 0.39 50
0.025 0.10 0.05 0.025 0.05 0.10 0.39 1.56 3.13 0.39 0.10
0.05 0.10 0.10 0.05 0.05 0.10 0.78 3.13 25 1.56 3.13
Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
0.025-25 0.05->100 0.025-100 0.012-25 0.025->25 0.05-> 100 0.20->100 0.39-> 100 3.13-> 100 0.20-25 0.05-> 100
0.39 1.56 3.13 0.39 0.39 1.56 1.56 3.13 12.5 0.78 0.39
6.25 25 50 12.5 6.25 25 100 100 50 6.25 100
Proteus mirabilis (101)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
0.012-0.20 0.05-0.78 0.05-0.39 0.012-0.20 0.025-0.78 0.10-1.56 0.20-25 0.78-12.5 12.5-> 100 0.10-3.13 0.025-0.39
0.025 0.10 0.05 0.025 0.10 0.20 0.78 1.56 100 0.78 0.05
0.025 0.20 0.10 0.05 0.20 0.20 6.25 3.13 >100 3.13 0.10
Proteus vulgaris (95)
T-3761 Ofloxacin Norfloxacin
0.012-0.10 0.05-1.56 0.025-0.20 0.012-0.20 0.025-1.56 0.05-0.78 0.10-6.25 0.39-12.5 3.13-> 100 0.10-6.25 0.05-0.78
0.025 0.10 0.05 0.025 0.05 0.10 0.39 0.78 12.5 1.56 0.10
0.05 0.39 0.10 0.10 0.39 0.39 0.78 1.56 50 3.13 0.20
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
Morganella morganii (63)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
.0.006-1.56 0.05-12.5 0.025-6.25 s0.006-6.25 0.05-50 0.05-12.5 0.39-100 0.78-50 1.56-> 100 0.20-6.25 0.05-100
0.012 0.10 0.05 0.012 0.39 0.05 0.39 1.56 6.25 1.56 0.20
0.025 0.20 0.05 0.025 0.78 0.10 0.78 3.13
>100 3.13 12.5
Continued on following page
VOL. 36, 1992
ANTIBACTERIAL ACTIVITY OF T-3761
2299
TABLE 1-Continued Organism (no. of isolates)
MIC
Compound Range
Providencia rettgeri (49)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
C0.006-6.25
gWml)a 50%
90%
0.025-12.5 0.025-50 0.10-6.25 3.13-> 100 0.20-1.56 0.012-3.13
0.10 0.20 0.20 0.05 0.10 0.20 0.78 0.78 50 0.78 0.10
0.78 3.13 1.56 0.78 1.56 6.25 3.13 3.13 >100 1.56 0.39
0.025-25 0.025-12.5
C0.006-6.25 C0.006-1.56
Providencia stuartii (59)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
0.025-0.10 0.05-1.56 0.05-3.13 0.012-0.78 0.012-0.78 0.025-3.13 0.05-> 100 0.20-50 6.25-> 100 0.05-3.13 0.05-1.56
0.05 0.39 0.39 0.10 0.10 0.20 6.25 1.56 >100 0.78 0.20
0.10 0.78 1.56 0.20 0.20 0.39 >100 12.5 >100 1.56 0.39
Alcaligenes faecalis (54)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
0.20->100 0.20-> 100 1.56-> 100 0.10-> 100 0.05->25 0.39->100 0.39->100 3.13-> 100 0.10->100 0.05-100 0.39-> 100
1.56 3.13 25 3.13 3.13 3.13 12.5 50 3.13 0.39 3.13
25 50 >100 50 >25 50 >100 >100 25 1.56 50
Pseudomonas aeruginosa (158)
T-3761 Ofloxacin Norfloxacin
0.20->100 0.78->100 0.39-> 100 0.10-100 0.10->25 0.78->100 0.39->100 0.39->100 6.25-> 100 0.20-25 0.39-> 100
0.39 1.56 0.78 0.39 0.39 3.13 6.25 12.5 100 1.56 3.13
3.13 12.5 6.25 1.56 3.13 12.5 25 25 >100 6.25 50
0.78->100 3.13-> 100 6.25-> 100 0.78->100 0.39->25 3.13->100 0.20->100 6.25-> 100 1.56-> 100 0.78-6.25 0.20-12.5
3.13 12.5 25 6.25 6.25 6.25 100 >100 12.5 3.13 1.56
6.25 25 50 12.5 12.5 25 >100 >100 100 6.25 3.13
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime Pseudomonas cepacia (92)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime Pseudomonas fluorescens (11)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin Fleroxacin
0.20-25 0.20-50 0.20-25 0.025-6.25 0.025-12.5 0.78-> 100
0.39 3.13 0.78 6.25 0.78 3.13 0.10 0.78 0.20 1.56 1.56 25 Continued on following page
2300
ANTIMICROB. AGENTS CHEMOTHER.
MURATANI ET AL. TABLE 1-Continued
MIC
Organism (no. of isolates)
Pseudomonas putida (29)
Compound
Gentamicin Amikacin Minocycline Imipenem Ceftazidime
u.U5-> 1Wu
T-3761 Ofloxacin Norfloxacin
0.20-12.5 0.39-100 0.20-100 0.05-25 0.10-50
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
Xanthomonas maltophilia (39)
Acinetobacter calcoaceticus (35)
Haemophilus influenzae (95)
T-3761
Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime T-3761
Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime T-3761 Ofloxacin
Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime Ampicillin Neisseria gonorrhoeae (42)
Range
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime Ampicillin
0.20-50 0.05-> 100 0.05-6.25 1.56-100
0.78-25
0.05-> 100 0.20->100 1.56-> 100 0.20-3.13 0.39-100
0.78-12.5 0.78-12.5 6.25-100 0.78-12.5 0.10-3.13 1.56-12.5 3.13-> 100 6.25-> 100 0.20-1.56 50-> 100 3.13-> 100 0.20-3.13 0.10-3.13
0.78-25
0.05-3.13 0.012-0.20 0.39-3.13 0.10->100 0.39-50 0.05-0.78 0.05-0.39 3.13-25 100 100 >100 1.56 50
3.13 3.13 12.5 3.13 0.78 3.13 100 >100 0.78 >100 100
6.25 6.25 50 6.25 1.56 6.25 >100 >100 1.56 >100 >100
0.39 0.39 3.13 0.20 0.025 0.39 0.39 1.56 0.10 0.20 6.25
0.78 0.78 6.25 0.78 0.10 1.56 6.25 25 0.20 0.39 12.5
0.012 0.025 0.05 0.012 0.012 0.05 1.56 12.5 0.39 1.56 0.10 0.20
0.025 0.05 0.10 0.025 0.012 0.10 3.13 12.5 0.78 3.13 0.10 6.25
.0.006
0.10 0.05 0.39 0.025 0.012 0.20 3.13 12.5 3.13 0.10 0.05 100
0.012 0.025
.0.006 .0.006 0.025 1.56 6.25 0.78 0.05 0.012 0.20
Continued on following page
VOL. 36, 1992
ANTIBACTERIAL ACTIVITY OF T-3761
2301
TABLE 1-Continued Organism (no. of isolates)
MIC (1Lg/ml)'
Compound Range
Moraxella catarrhalis (42)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
Bacteroides fragilis (35)
0.025-0.20 0.05-0.39
0.10-0.78 0.012-0.10
.0.006-0.05 0.10-0.39 0.10-0.39 0.20-1.56
0.20-0.78 100 3.13->100 0.39-3.13 6.25-50 0.025-12.5 3.13->100
T-3761 Ofloxacin Norfloxacin
Clostridium perfringens (16)
6.25 12.5 25-50 6.25-12.5
90%
50%
0.05 0.10 0.20 0.025 0.025 0.20 0.20 0.78 0.20 0.05 0.05
0.39 0.10 0.05
6.25 3.13 100 12.5 0.78 6.25 0.10 50
12.5 25 >100 50 1.56 25 1.56 >100
6.25 12.5 50 12.5 1.56 25 6.25 100 0.39 1.56 1.56 0.78 0.20 1.56 0.20 0.10
Ciprofloxacin Tosufloxacin Fleroxacin Imipenem Ceftazidime
3.13-12.5 25-100
6.25 12.5 50 6.25 1.56 25 3.13 100
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Imipenem Ceftazidime
0.20-0.39 0.78-1.56 0.78-1.56 0.20-0.78 0.10-0.20 0.78-1.56 0.05-0.20 0.025-0.10
0.39 0.78 1.56 0.39 0.20 0.78 0.10 0.05
1.56-3.13 25
0.10 0.20 0.78 0.05 0.025 0.39 0.39 1.56
a 50% and 90%, MICs for 50 and 90% of isolates tested, respectively.
TABLE 2. Bactericidal activities of T-3761 and other fluoroquinolones against clinical isolates Organism S. aureus
Compound T-3761 Ofloxacin
Norfloxacin Ciprofloxacin Tosufloxacin E. coli
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin P. aeruginosa
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin
MIC
(tg/ml)a
MBC (pg/ml)b
Range
50%
90%
Range
50%
90%
0.20-0.39 0.39-0.78 0.78-12.5 0.39-3.13 0.025-0.10
0.39 0.39 1.56 0.78 0.05
0.39 0.78 3.13 1.56 0.05
0.39-0.78 0.39-1.56 1.56-12.5 0.39-3.13 0.025-0.10
0.78 0.78 3.13 0.78 0.05
0.78 0.78 6.25 1.56 0.10
0.012-0.20 0.025-0.20 0.025-0.39 0.006-0.05 0.012-0.10
0.05 0.10 0.10
0.012-0.20 0.05-0.20 0.025-0.39 0.006-0.05 0.025-0.10
0.05 0.10 0.10 0.025 0.05
0.20 0.20 0.20
0.025
0.10 0.20 0.20 0.05 0.05
0.78 3.13 1.56 0.78 0.78
3.13 12.5 3.13 0.78 1.56
0.39-12.5 3.13-50 0.78-12.5 0.20-12.5 0.39-6.25
0.78 6.25 3.13 0.78 1.56
3.13 12.5 6.25 3.13 3.13
0.39-6.25
1.56-25 0.78-12.5 0.10-3.13 0.39-3.13
0.012
a Broth dilution method, 5 x 105 to 2 x 106 CFU/ml. 50% and 90%, MICs for 50 and 90% of 20 clinical isolates of each organism tested, respectively. b The MBC was defined as .99.9% killing. 50% and 90%, MBCs for 50 and 90% of 20 clinical isolates of each organism tested, respectively.
0.05
0.05
2302
A
ANTIMICROB. AGENTs
MURATANI ET AL.
CHEMOTHER.
TABLE 3. Inhibition of supercoiling activity of DNA gyrase by T-3761 and other fluoroquinolonesa
T-31
(McCZ0p0mI)
Compound
MIC (4g/ml)
E. coli KL16
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin
0.025 0.05 0.05 0.006 0.012
ICso (4ig/ml)b 0.88 0.75 0.60 0.13 0.25
P. aeginsa PAQ1
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin
0.20 0.78 0.39 0.10 0.20
1.9 2.5 1.5 0.38 0.90
Organism
Tm (IN)
actnivties
aenigma
a The specific of DNA gyrases from E. coli and P. were 1.3 x 103 and 1.0 x 102 U/mg of protein, respectvely. One unit (the amount of enzyme that catalyzed the conversion of one-half of 0.1 ,ug of relaxed closed circular pBR322 DNA to the supercoiled form in 60 min at 37C) of gyrases was used in both experments. b 50% inhibitory concentration.
IC5c,
aeruginosa was compared with the activities of ofloxacin, norfloxacin, ciprofloxacin, and tosufloxacim (Table 2). The MBCs of T-3761 were either equal to or twofold greater than the MICs, as was observed for the other fluoroquinolones. The time-killing curves of T-3761, ofloxacin, and ciprofloxacin against S. aureus Smith, E. coli NIHJ JC-2, and P. aerzginosa GN11189 are shown in Fig. 2. The number of viable cells decreased rapidly during incubation with T-3761 at one- to fourfold the MIC. T-3761 reduced the viable cell count to undetectable levels at twice the MIC within 1 to 4 h. The regrowth of all organisms tested was observed at concentrations equal to or greater than the MICs after 24 h of in,cubation with the fluoroquinolones tested. The studies show that the bactericidal activity of T-3761 is similar to those of ofloxacin and ciprofloxacin against these type
T
E
strains.
a
'I
Tom
(hv)
FIG. 2. Bactericidal activities of T-3761, ofloxacin, and ciprofloxacin against S. aureus Smith (A), E. col NIHJ JC- (B), and P. aeruginosa (N11189 (C). The initial inoculum sizes (zero time) against S. aureus Smith, E. coli NIHJ JC-2, and P. aeruginosa GN11189 were 5.0 x 10', 8.2 x 10S, and 7.7 x 105 CFU/ml, respectively.
ceftazidime-resistant isolates of the family Enterobactenaceae (79%) were susceptible to T-3761. Sity-two of 158 P. aeruginosa isolates (39%) were resistant to gentamicin (MIC of gentamicin, t12.5 ,tg/ml), and 47 of 62 (76%) genta.micin-resistant P. aeruginosa isolates were susceptible to T-3761. Ten of 158 P. aeruginosa isolates (6.3%) were resistant to imipenem (MIC of imipenem, 212.5 p,g/ml), and 8 of 10 imipenem-resistantP. aenuginosa isolates (80%) were susceptible to T-3761. Thirteen of 137 N. gonorrhoeae and H. influ>enzae isolates (9.5%) were resistant to ampicillin (MIC of ampicillin, 212.5 ,g/ml), but there were no N. gonorrhoeae or H. influenzae isolates resistant to T-3761. 'Bactericidal activty. The bactericidal activity of T-3761 against 20 clinical isolates each of S. aureus, E. col, and P.
Frequency of spontaneous fluoroqulnolone resistance mutations. The frequencies of appearance of spontaneous mutants of S. aureus Smith, E. coli ML4707, S. marcescens GN7577, and P. aeruginosa GN11189 resistant to T-3761, ofloxacin, ciprofloxacin, and tosufloxacin were tested. No mutants resistant to any of the agents tested were detected at concentrations of eight times the MIC. At concentrations of four times the MIC, no mutants of S. aureus Smith resistant to T-3761 or ofloxacin were observed. At concentrations of two and four times the MIC, the frequencies of appearance of spontaneous mutants of the four organisms tested that were resistant to T-3761 ranged from 2.2 x 10-7 to 3.1 x 10-8 and 2.2 x 10-8 to
0066-4804/92/102293-11$02.00/0 Copyright © 1992, American Society for Microbiology
Vol. 36, No. 10
In Vitro Activity of T-3761, a New Fluoroquinolone TETSURO MURATANI,l* MATSUHISA INOUE,2 AND SUSUMU MITSUHASHI1 Episome Institute, Kogure, Fujimi-mura, Seta-gun, Gunma 371-01,1 and Department of Microbiology, School of Medicine, Kitasato University, Sagamihara, Kanagawa 228, 2 Japan Received 4 May 1992/Accepted 28 July 1992
The in vitro activity of T-3761, a new fluoroquinolone antimicrobial agent which has an oxazine ring structure with a cyclopropyl moiety at C-10, was compared with those of other agents against 2,854 clinical isolates. T-3761 had a broad spectrum of activity and had potent activity against gram-positive and -negative bacteria. The MICs of T-3761 against 90% of the methicillin-susceptible Staphylococcus aureus, methicillinsusceptible and -resistant Staphylococcus epidermidis, and Clostridium spp. tested were 0.39 to 6.25 ,g/m!. Its activity was comparable to those of ciprofloxacin and ofloxacin and four- to eightfold greater than those of norfloxacin and fleroxacin, but its activity was two- to eightfold less than that of tosufloxacin. Some isolates of ciprofloxacin-resistant S. aureus (MIC of ciprofloxacin, .3.13 ,ug/ml) were still susceptible to T-3761 (MIC of T-3761, .0.78 ,ug/ml). The MICs of T-3761 against 90%o of the streptococci and enterococci tested were 3.13 to 100 ,ug/ml. Its activity was equal to or 2- or 4-fold greater than those of norfloxacin and fleroxacin, equal to or 2- or 4-fold less than those of ofloxacin and ciprofloxacin, and 4- to 16-fold less than that of tosufloxacin. The activity of T-3761 against gram-negative bacteria was usually fourfold greater than those of norfloxacin, ofloxacin, and fleroxacin. Many isolates which were resistant to nonfluoroquinolone agents, such as minocycline- or imipenem-resistant S. aureus, ceftazidime-resistant members of the family Enterobacteriaceae, gentamicin- or imipenem-resistant Pseudomonas aeruginosa, and ampicillin-resistant Haemophilus influenzae and Neisseria gonorrhoeae, were susceptible to T-3761. The MBCs of T-3761 were either equal to or twofold greater than the MICs. The number of viable cells decreased rapidly during incubation with T-3761 at one to four times the MIC. At a concentration of four times the MIC, the frequencies of appearance of spontaneous mutants resistant to T-3761 against S. aureus, Escherichia coli, Serratia marcescens, and P. aeruginosa were 2.2 x 10-8 to 100 0.39-> 100 0.20-> 100 0.012-12.5 0.39-> 100 0.05->100 0.05-1.56 0.012-0.20 0.78-6.25
Methicillin-resistant Staphylococcus aureus (282)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Minocycline Imipenem Methicillin
0.10-100 0.20->100 0.78-> 100 0.20-> 100 0.012-25 0.39-> 100 0.10->100 0.05-100 0.025->100 12.5->100
0.39 1.56 25 3.13 0.10 3.13 50 0.20 50 >100
12.5 50 >100 100 6.25 >100 >100 6.25 100 >100
Methicillin-susceptible Staphylococcus epidermidis (84)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Methicillin
0.10-12.5 0.20-12.5 0.10-100 0.10-12.5 100 0.39-6.25
0.39 0.39 0.78 0.20 0.05 0.78 0.10 1.56
0.39 0.78 1.56 0.39 0.10 1.56 50 6.25
Methicillin-resistant Staphylococcus epidermidis (130)
T-3761 Ofloxacin Norfloxacin
0.10->100 0.20->100 0.39->100 0.10-100 0.025-12.5 0.39->100 0.05->100 12.5->100
0.39 0.39 0.78 0.20 0.05 0.78 25 100
6.25 12.5 50 6.25 3.13 25 100 >100
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Methicillin
0.20-3.13 0.20-6.25 0.39-50 0.20-12.5 0.025-3.13 0.39-25 0.025-100 1.56->100
0.39 0.78 0.78 0.39 0.05 1.56 0.10 6.25
0.39 1.56 6.25 0.78 0.20 3.13 25 >100
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime Ampicillin
3.13-100 1.56-50 6.25-100 0.39-50 0.10-12.5 6.25-> 100 6.25-12.5 25-100 0.10-100 .0.006-0.012 0.10-0.39 0.025-0.05
6.25 3.13 12.5 3.13 0.20 12.5 12.5 100 0.20
T-3761 Ofloxacin Norfloxacin
0.78-6.25 0.78-6.25 0.78-25
Ciprofloxacin
0.20-3.13 0.05-0.78
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Methicillin
Staphylococcus hominis (20)
Streptococcus pneumoniae (29)
Streptococcus pyogenes (80)
T-3761 Ofloxacin Norfloxacin
Tosufloxacin
0.20 0.39 1.56 0.39 0.025 0.78 0.39 0.10 0.025 3.13
.0.006 0.20 0.025 3.13 1.56 3.13 0.78 0.10
0.39 0.78 3.13 0.78 0.05 1.56 50 0.20 0.025 3.13
6.25 3.13 25 3.13 0.39 25 12.5 100 25 _0.006 0.39 0.05 3.13 1.56 3.13
0.78 0.20
Continued on following page
2296
MURATANI ET AL.
ANTIMICROB. AGENTS CHEMOTHER. TABLE 1-Continued
Organism (no. of isolates)
MIC (,ug/ml)a
Compound Range
Fleroxacin Gentamicin Amikacin
Minocycline Imipenem Ceftazidime
Ampicillin Enterococcus faecalis (97)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin
Tosufloxacin Fleroxacin Gentamicin Amikacin
Minocycline Imipenem Ceftazidime
Ampicillin Enterococcus faecium (54)
T-3761 Ofloxacin
Norfloxacin
Ciprofloxacin
Tosufloxacin Fleroxacin Gentamicin Amikacin
Minocycline Imipenem Ceftazidime
Escherichia coli (108)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime Citrobacter diversus (12)
T-3761 Ofloxacin
Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
Citrobacterfreundii (97)
T-3761
Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem
1.56-50 3.13-12.5 50-> 100 0.05-50 .0.006-0.10 0.10-3.13 0.012-0.78
50%
6.25 12.5 50 0.20
C0.006 0.10 0.012
90%
12.5 12.5 100 25 100 50-> 100 0.05-50 0.39-3.13 12.5-> 100 0.39-3.13
3.13 1.56 3.13 0.78 0.20 3.13 25 >100 12.5 0.78 >100 1.56
3.13 3.13 6.25 3.13 0.39 6.25 50 >100 25 0.78 >100 1.56
3.13-> 100 1.56-> 100 1.56-> 100 0.39-> 100 0.20->25 3.13-> 100 6.25-> 100 12.5-> 100 0.10-100 0.78-> 100 >100
6.25 6.25 6.25 3.13 1.56 12.5 25 100 12.5 100 >100
100 100 >100 100 25 >100 >100 >100 50 >100 >100
0.012-3.13 0.025-12.5 0.012-6.25 _0.006-1.56 0.05-25 0.20-> 100 0.78-12.5 0.78-> 100 0.05-0.78 0.025-0.78
0.025 0.05 0.05 0.012 0.025 0.10 0.78 1.56 3.13 0.10 0.10
0.05 0.10 0.10 0.025 0.05 0.20 0.78 3.13 50 0.20 0.20
0.012-0.025 0.025-0.10 0.025-0.20
0.025 0.05 0.05
.0.006-0.025
.0.006
0.012-0.05 0.05-0.10 0.20-0.78 0.78-3.13 0.78-12.5 0.10-0.20 0.025-0.20
0.012 0.10 0.39 1.56 1.56 0.10 0.05
0.025 0.05 0.05 0.012 0.05 0.10 0.39 3.13 3.13 0.20 0.10
0.012-25 0.025-100 0.025-50
0.05 0.20 0.10 0.025 0.05 0.39 0.78 1.56 3.13 0.20
.0.006-3.13
.0.006-12.5 0.012->25 0.05-> 100 0.20-100 0.78-100 0.78-> 100
.0.006-1.56
0.39 1.56 1.56 0.39 0.78 1.56 12.5 1.56 50 0.39
Continued on following page
ANTIBACTERIAL ACTIVITY OF T-3761
VOL. 36, 1992
2297
TABLE 1-Continued Organism (no. of isolates)
Compound
CeftaZ;dime Salmonella spp. (108)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin
Tosufloxacin Fleroxacin Gentamicin Amikacin
Minocycline Imipenem Ceftazidime
Shigella spp. (108)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin
Tosufloxacin Fleroxacin Gentamicin Amikacin
Minocycline Imipenem Ceftazidime
Kiebsiella pneumoniae (127)
T-3761 Ofloxacin
Norfloxacin
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin
Minocycline Imipenem Ceftazidime
Kiebsiella oxytoca (104)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin
Tosufloxacin Fleroxacin Gentamicin Amikacin
Minocycline Imipenem Ceftazidime Enterobacter aerogenes (10)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline
Imipenem Ceftazidime Enterobacter cloacae (105)
T-3761
MIC (>Lg/ml)f
Range
0.05-> 100
50% 0.39
90% 100
0.012-0.05 0.05-0.20 0.39-1.56 0.78-3.13 0.78-100 0.05-0.78 0.05-0.78
0.025 0.10 0.10 0.012 0.025 0.10 0.78 1.56 3.13 0.10 0.20
0.05 0.20 0.10 0.025 0.05 0.20 0.78 3.13 12.5 0.20 0.39
0.012-0.39 0.025-1.56 0.025-0.78 C0.006-0.39 .0.006-0.39 0.05-1.56 0.20-3.13 0.78-25 0.20-50 0.05-0.20 0.05-3.13
0.025 0.05 0.05 0.012 0.012 0.10 1.56 6.25 3.13 0.10 0.10
0.025 0.10 0.10 0.025 0.025 0.20 1.56 12.5 12.5 0.20 0.39
0.012-1.56 0.05-3.13 0.05-6.25 50.006-1.56 0.025-0.78 0.05-6.25 0.20-100 0.39-25 1.56->100 0.05-0.78 0.025-6.25
0.025 0.20 0.10 0.025 0.05 0.20 0.39 1.56 6.25 0.20 0.10
0.012-0.10 0.05-0.39 0.025-0.39 C0.006-0.05 .0.006-0.05 0.05-0.78 0.20-0.78 0.78-3.13 3.13-12.5 0.10-1.56 0.025-0.78
0.025 0.10 0.05 0.012 0.025 0.10 0.78 1.56 3.13 0.20 0.05
0.05 0.20 0.10 0.025 0.025 0.20 0.78 1.56 3.13 0.39 0.20
0.05 0.20 0.10 0.025 0.025 0.20 0.39 1.56 3.13 0.78 0.10
0.05 0.20 0.10 0.025 0.05 0.20 0.78 3.13 3.13 0.78 0.20
0.05 0.10 0.05 0.012 0.05
0.20 0.78 0.78 0.10 0.20
0.025-0.05 0.05-0.20 0.025-0.20
C0.006-0.025
0.025-0.05 0.10-0.20 0.10-0.20 0.025-0.025 0.025-0.05 0.20-0.20 0.39-0.78 1.56-3.13 1.56-3.13 0.39-1.56 0.10-25
Ofloxacin Norfloxacin Ciprofloxacin
0.012-6.25 0.025-12.5 0.025-25 C0.006-6.25
Tosufloxacin
'0.006-3.13
0.10 0.39 0.39 0.05 0.10 0.39 0.78 1.56 100 0.20 0.39
Continued on following page
2298
ANTIMICROB. AGENTS CHEMOTHER.
MURATANI ET AL. TABLE 1-Continued Organism (no. of isolates)
Compound
Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
Hafnia alvei (12)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
Serratia marcescens (111)
T-3761
MIC (p.g/ml)a Range
0.025-25 0.20-> 100 0.78-50 1.56-> 100 0.05-0.78 0.05-> 100
0.025-0.05 0.05-0.20 0.025-0.10 .0.006-0.05 0.025-0.10 0.05-0.10 0.20-1.56 1.56-6.25 0.78-25 0.20-1.56 0.05-6.25
50%
90%
0.10 0.39 1.56 6.25 0.20 0.39
0.78 6.25 1.56 100 0.39 50
0.025 0.10 0.05 0.025 0.05 0.10 0.39 1.56 3.13 0.39 0.10
0.05 0.10 0.10 0.05 0.05 0.10 0.78 3.13 25 1.56 3.13
Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
0.025-25 0.05->100 0.025-100 0.012-25 0.025->25 0.05-> 100 0.20->100 0.39-> 100 3.13-> 100 0.20-25 0.05-> 100
0.39 1.56 3.13 0.39 0.39 1.56 1.56 3.13 12.5 0.78 0.39
6.25 25 50 12.5 6.25 25 100 100 50 6.25 100
Proteus mirabilis (101)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
0.012-0.20 0.05-0.78 0.05-0.39 0.012-0.20 0.025-0.78 0.10-1.56 0.20-25 0.78-12.5 12.5-> 100 0.10-3.13 0.025-0.39
0.025 0.10 0.05 0.025 0.10 0.20 0.78 1.56 100 0.78 0.05
0.025 0.20 0.10 0.05 0.20 0.20 6.25 3.13 >100 3.13 0.10
Proteus vulgaris (95)
T-3761 Ofloxacin Norfloxacin
0.012-0.10 0.05-1.56 0.025-0.20 0.012-0.20 0.025-1.56 0.05-0.78 0.10-6.25 0.39-12.5 3.13-> 100 0.10-6.25 0.05-0.78
0.025 0.10 0.05 0.025 0.05 0.10 0.39 0.78 12.5 1.56 0.10
0.05 0.39 0.10 0.10 0.39 0.39 0.78 1.56 50 3.13 0.20
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
Morganella morganii (63)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
.0.006-1.56 0.05-12.5 0.025-6.25 s0.006-6.25 0.05-50 0.05-12.5 0.39-100 0.78-50 1.56-> 100 0.20-6.25 0.05-100
0.012 0.10 0.05 0.012 0.39 0.05 0.39 1.56 6.25 1.56 0.20
0.025 0.20 0.05 0.025 0.78 0.10 0.78 3.13
>100 3.13 12.5
Continued on following page
VOL. 36, 1992
ANTIBACTERIAL ACTIVITY OF T-3761
2299
TABLE 1-Continued Organism (no. of isolates)
MIC
Compound Range
Providencia rettgeri (49)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
C0.006-6.25
gWml)a 50%
90%
0.025-12.5 0.025-50 0.10-6.25 3.13-> 100 0.20-1.56 0.012-3.13
0.10 0.20 0.20 0.05 0.10 0.20 0.78 0.78 50 0.78 0.10
0.78 3.13 1.56 0.78 1.56 6.25 3.13 3.13 >100 1.56 0.39
0.025-25 0.025-12.5
C0.006-6.25 C0.006-1.56
Providencia stuartii (59)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
0.025-0.10 0.05-1.56 0.05-3.13 0.012-0.78 0.012-0.78 0.025-3.13 0.05-> 100 0.20-50 6.25-> 100 0.05-3.13 0.05-1.56
0.05 0.39 0.39 0.10 0.10 0.20 6.25 1.56 >100 0.78 0.20
0.10 0.78 1.56 0.20 0.20 0.39 >100 12.5 >100 1.56 0.39
Alcaligenes faecalis (54)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
0.20->100 0.20-> 100 1.56-> 100 0.10-> 100 0.05->25 0.39->100 0.39->100 3.13-> 100 0.10->100 0.05-100 0.39-> 100
1.56 3.13 25 3.13 3.13 3.13 12.5 50 3.13 0.39 3.13
25 50 >100 50 >25 50 >100 >100 25 1.56 50
Pseudomonas aeruginosa (158)
T-3761 Ofloxacin Norfloxacin
0.20->100 0.78->100 0.39-> 100 0.10-100 0.10->25 0.78->100 0.39->100 0.39->100 6.25-> 100 0.20-25 0.39-> 100
0.39 1.56 0.78 0.39 0.39 3.13 6.25 12.5 100 1.56 3.13
3.13 12.5 6.25 1.56 3.13 12.5 25 25 >100 6.25 50
0.78->100 3.13-> 100 6.25-> 100 0.78->100 0.39->25 3.13->100 0.20->100 6.25-> 100 1.56-> 100 0.78-6.25 0.20-12.5
3.13 12.5 25 6.25 6.25 6.25 100 >100 12.5 3.13 1.56
6.25 25 50 12.5 12.5 25 >100 >100 100 6.25 3.13
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime Pseudomonas cepacia (92)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime Pseudomonas fluorescens (11)
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin Fleroxacin
0.20-25 0.20-50 0.20-25 0.025-6.25 0.025-12.5 0.78-> 100
0.39 3.13 0.78 6.25 0.78 3.13 0.10 0.78 0.20 1.56 1.56 25 Continued on following page
2300
ANTIMICROB. AGENTS CHEMOTHER.
MURATANI ET AL. TABLE 1-Continued
MIC
Organism (no. of isolates)
Pseudomonas putida (29)
Compound
Gentamicin Amikacin Minocycline Imipenem Ceftazidime
u.U5-> 1Wu
T-3761 Ofloxacin Norfloxacin
0.20-12.5 0.39-100 0.20-100 0.05-25 0.10-50
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
Xanthomonas maltophilia (39)
Acinetobacter calcoaceticus (35)
Haemophilus influenzae (95)
T-3761
Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime T-3761
Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime T-3761 Ofloxacin
Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime Ampicillin Neisseria gonorrhoeae (42)
Range
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime Ampicillin
0.20-50 0.05-> 100 0.05-6.25 1.56-100
0.78-25
0.05-> 100 0.20->100 1.56-> 100 0.20-3.13 0.39-100
0.78-12.5 0.78-12.5 6.25-100 0.78-12.5 0.10-3.13 1.56-12.5 3.13-> 100 6.25-> 100 0.20-1.56 50-> 100 3.13-> 100 0.20-3.13 0.10-3.13
0.78-25
0.05-3.13 0.012-0.20 0.39-3.13 0.10->100 0.39-50 0.05-0.78 0.05-0.39 3.13-25 100 100 >100 1.56 50
3.13 3.13 12.5 3.13 0.78 3.13 100 >100 0.78 >100 100
6.25 6.25 50 6.25 1.56 6.25 >100 >100 1.56 >100 >100
0.39 0.39 3.13 0.20 0.025 0.39 0.39 1.56 0.10 0.20 6.25
0.78 0.78 6.25 0.78 0.10 1.56 6.25 25 0.20 0.39 12.5
0.012 0.025 0.05 0.012 0.012 0.05 1.56 12.5 0.39 1.56 0.10 0.20
0.025 0.05 0.10 0.025 0.012 0.10 3.13 12.5 0.78 3.13 0.10 6.25
.0.006
0.10 0.05 0.39 0.025 0.012 0.20 3.13 12.5 3.13 0.10 0.05 100
0.012 0.025
.0.006 .0.006 0.025 1.56 6.25 0.78 0.05 0.012 0.20
Continued on following page
VOL. 36, 1992
ANTIBACTERIAL ACTIVITY OF T-3761
2301
TABLE 1-Continued Organism (no. of isolates)
MIC (1Lg/ml)'
Compound Range
Moraxella catarrhalis (42)
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Gentamicin Amikacin Minocycline Imipenem Ceftazidime
Bacteroides fragilis (35)
0.025-0.20 0.05-0.39
0.10-0.78 0.012-0.10
.0.006-0.05 0.10-0.39 0.10-0.39 0.20-1.56
0.20-0.78 100 3.13->100 0.39-3.13 6.25-50 0.025-12.5 3.13->100
T-3761 Ofloxacin Norfloxacin
Clostridium perfringens (16)
6.25 12.5 25-50 6.25-12.5
90%
50%
0.05 0.10 0.20 0.025 0.025 0.20 0.20 0.78 0.20 0.05 0.05
0.39 0.10 0.05
6.25 3.13 100 12.5 0.78 6.25 0.10 50
12.5 25 >100 50 1.56 25 1.56 >100
6.25 12.5 50 12.5 1.56 25 6.25 100 0.39 1.56 1.56 0.78 0.20 1.56 0.20 0.10
Ciprofloxacin Tosufloxacin Fleroxacin Imipenem Ceftazidime
3.13-12.5 25-100
6.25 12.5 50 6.25 1.56 25 3.13 100
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin Fleroxacin Imipenem Ceftazidime
0.20-0.39 0.78-1.56 0.78-1.56 0.20-0.78 0.10-0.20 0.78-1.56 0.05-0.20 0.025-0.10
0.39 0.78 1.56 0.39 0.20 0.78 0.10 0.05
1.56-3.13 25
0.10 0.20 0.78 0.05 0.025 0.39 0.39 1.56
a 50% and 90%, MICs for 50 and 90% of isolates tested, respectively.
TABLE 2. Bactericidal activities of T-3761 and other fluoroquinolones against clinical isolates Organism S. aureus
Compound T-3761 Ofloxacin
Norfloxacin Ciprofloxacin Tosufloxacin E. coli
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin P. aeruginosa
T-3761 Ofloxacin Norfloxacin
Ciprofloxacin Tosufloxacin
MIC
(tg/ml)a
MBC (pg/ml)b
Range
50%
90%
Range
50%
90%
0.20-0.39 0.39-0.78 0.78-12.5 0.39-3.13 0.025-0.10
0.39 0.39 1.56 0.78 0.05
0.39 0.78 3.13 1.56 0.05
0.39-0.78 0.39-1.56 1.56-12.5 0.39-3.13 0.025-0.10
0.78 0.78 3.13 0.78 0.05
0.78 0.78 6.25 1.56 0.10
0.012-0.20 0.025-0.20 0.025-0.39 0.006-0.05 0.012-0.10
0.05 0.10 0.10
0.012-0.20 0.05-0.20 0.025-0.39 0.006-0.05 0.025-0.10
0.05 0.10 0.10 0.025 0.05
0.20 0.20 0.20
0.025
0.10 0.20 0.20 0.05 0.05
0.78 3.13 1.56 0.78 0.78
3.13 12.5 3.13 0.78 1.56
0.39-12.5 3.13-50 0.78-12.5 0.20-12.5 0.39-6.25
0.78 6.25 3.13 0.78 1.56
3.13 12.5 6.25 3.13 3.13
0.39-6.25
1.56-25 0.78-12.5 0.10-3.13 0.39-3.13
0.012
a Broth dilution method, 5 x 105 to 2 x 106 CFU/ml. 50% and 90%, MICs for 50 and 90% of 20 clinical isolates of each organism tested, respectively. b The MBC was defined as .99.9% killing. 50% and 90%, MBCs for 50 and 90% of 20 clinical isolates of each organism tested, respectively.
0.05
0.05
2302
A
ANTIMICROB. AGENTs
MURATANI ET AL.
CHEMOTHER.
TABLE 3. Inhibition of supercoiling activity of DNA gyrase by T-3761 and other fluoroquinolonesa
T-31
(McCZ0p0mI)
Compound
MIC (4g/ml)
E. coli KL16
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin
0.025 0.05 0.05 0.006 0.012
ICso (4ig/ml)b 0.88 0.75 0.60 0.13 0.25
P. aeginsa PAQ1
T-3761 Ofloxacin Norfloxacin Ciprofloxacin Tosufloxacin
0.20 0.78 0.39 0.10 0.20
1.9 2.5 1.5 0.38 0.90
Organism
Tm (IN)
actnivties
aenigma
a The specific of DNA gyrases from E. coli and P. were 1.3 x 103 and 1.0 x 102 U/mg of protein, respectvely. One unit (the amount of enzyme that catalyzed the conversion of one-half of 0.1 ,ug of relaxed closed circular pBR322 DNA to the supercoiled form in 60 min at 37C) of gyrases was used in both experments. b 50% inhibitory concentration.
IC5c,
aeruginosa was compared with the activities of ofloxacin, norfloxacin, ciprofloxacin, and tosufloxacim (Table 2). The MBCs of T-3761 were either equal to or twofold greater than the MICs, as was observed for the other fluoroquinolones. The time-killing curves of T-3761, ofloxacin, and ciprofloxacin against S. aureus Smith, E. coli NIHJ JC-2, and P. aerzginosa GN11189 are shown in Fig. 2. The number of viable cells decreased rapidly during incubation with T-3761 at one- to fourfold the MIC. T-3761 reduced the viable cell count to undetectable levels at twice the MIC within 1 to 4 h. The regrowth of all organisms tested was observed at concentrations equal to or greater than the MICs after 24 h of in,cubation with the fluoroquinolones tested. The studies show that the bactericidal activity of T-3761 is similar to those of ofloxacin and ciprofloxacin against these type
T
E
strains.
a
'I
Tom
(hv)
FIG. 2. Bactericidal activities of T-3761, ofloxacin, and ciprofloxacin against S. aureus Smith (A), E. col NIHJ JC- (B), and P. aeruginosa (N11189 (C). The initial inoculum sizes (zero time) against S. aureus Smith, E. coli NIHJ JC-2, and P. aeruginosa GN11189 were 5.0 x 10', 8.2 x 10S, and 7.7 x 105 CFU/ml, respectively.
ceftazidime-resistant isolates of the family Enterobactenaceae (79%) were susceptible to T-3761. Sity-two of 158 P. aeruginosa isolates (39%) were resistant to gentamicin (MIC of gentamicin, t12.5 ,tg/ml), and 47 of 62 (76%) genta.micin-resistant P. aeruginosa isolates were susceptible to T-3761. Ten of 158 P. aeruginosa isolates (6.3%) were resistant to imipenem (MIC of imipenem, 212.5 p,g/ml), and 8 of 10 imipenem-resistantP. aenuginosa isolates (80%) were susceptible to T-3761. Thirteen of 137 N. gonorrhoeae and H. influ>enzae isolates (9.5%) were resistant to ampicillin (MIC of ampicillin, 212.5 ,g/ml), but there were no N. gonorrhoeae or H. influenzae isolates resistant to T-3761. 'Bactericidal activty. The bactericidal activity of T-3761 against 20 clinical isolates each of S. aureus, E. col, and P.
Frequency of spontaneous fluoroqulnolone resistance mutations. The frequencies of appearance of spontaneous mutants of S. aureus Smith, E. coli ML4707, S. marcescens GN7577, and P. aeruginosa GN11189 resistant to T-3761, ofloxacin, ciprofloxacin, and tosufloxacin were tested. No mutants resistant to any of the agents tested were detected at concentrations of eight times the MIC. At concentrations of four times the MIC, no mutants of S. aureus Smith resistant to T-3761 or ofloxacin were observed. At concentrations of two and four times the MIC, the frequencies of appearance of spontaneous mutants of the four organisms tested that were resistant to T-3761 ranged from 2.2 x 10-7 to 3.1 x 10-8 and 2.2 x 10-8 to
