ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, Feb. 1990, p. 189-195
Vol. 34, No. 2
0066-4804/90/020189-07$02.00/0 Copyright C) 1990, American Society for Microbiology
In Vitro Activity of Ro 23-9424, a Dual-Action Cephalosporin, Compared with Activities of Other Antibiotics JIAN-WEI GU' AND HAROLD C. NEUl12* Departments of Medicine' and Pharmacology,2 College of Physicians and Surgeons, Columbia University, New York, New York 10032 Received 8 August 1989/Accepted 25 October 1989
The in vitro activity of Ro 23-9424, which is desacetyl-cefotaxime linked to fleroxacin, was compared with the activities of cefotaxime, desacetyl-cefotaxime, fleroxacin, ofloxacin, and ciprofloxacin. It inhibited the majority of members of the family Enterobacteriaceae, except for some Serratia marcescens, Citrobacter freundii, and Enterobacter cloacae strains, at 16 ,ug/ml. Ro 23-9424 inhibited 90o of the Streptococcus pneumoniae isolates at 16 0.125->16 0.06-0.25 0.06-0.5 0.03-0.125
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin Ro 23-9424
Desacetyl-cefotaxime Cefotaxime
0.5 1 0.5 0.5 0.5 0.25
0.125 0.25 0.06 0.125 0.125 0.03
1 >16 >16 0.5 1 0.125
0.5 4 0.5 0.125 0.125 0.03
0.5 >16 >16 0.25 0.25 0.125
0.06-2 0.25->16 0.06->16 0.06-1 0.06-0.5 s0.008-1
0.25 1 0.125 0.125 0.125 0.03
1 >16 >016 0.25 0.5 0.125
0.125-0.5 0.125->16
0.25 0.25 0.06 0.03 0.03 s0.008
0.5 0.5 0.125 0.06 0.06 0.015
0.06-4 0.03-0.125 0.03-0.06
0.015-0.5 1->16 0.125-8 0.03-0.5
Ro 23-9424
s-0.008
0.125 0.5 0.25 0.125 0.06 s0.008
Ro 23-9424
Ciprofloxacin
0.25 0.125 0.06 0.125 0.125 0.03
90%o 0.5 2 0.25 0.25 0.06
0.015-0.5 0.03-2 s0.008-1 0.03-0.25 0.03-0.5 .0.008-0.06
0.008-0.015
Cefotaxime Fleroxacin Ofloxacin
Proteus mirabilisb (15)
0.125-1 0.06->16
Ciprofloxacin Desacetyl-cefotaxime
Serratia marcescensb,c (14)
0.125 0.5 0.06 0.125 0.06 s0.008
Ciprofloxacin
Enterobacter agglomeransb,c (11)
Hafnia alveib,c (14)
0.015-0.5 0.03-16 s0.03-0.5 0.03-0.25 0.03-0.125 0.008-0.015
s0.015-1 0.03->16 s0.03->16 0.03-1 0.015-2
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
Citrobacter diversusb (16)
50o
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Enterobacter cloacaeb c (15)
Enterobacter aerogenesb,c (15)
MIC (,ug/ml)a Range
0.5 2 0.5 0.25 0.5 0.06
0.125 8 0.5 0.125 0.06 s0.015
0.5 >16 1 0.5 0.25 0.06
0.5-1 0.5->16 0.125-16 0.125-0.5 0.25-2
0.5 4 0.5 0.25 0.5 s0.008
1 16 1 0.25 1 0.25
0.125-0.5 0.06-0.25
0.125 0.06 0.03
.0.015-0.25
s0.015-0.06
.0.008-0.25
.0.008-0.25
0.25 0.125 0.125
Continued on following page
192
GU AND NEU
ANTIMICROB. AGENTS CHEMOTHER.
TABLE 1-Continued Organism
(no. tested)
Antibiotic Fleroxacin Ofloxacin Ciprofloxacin
Morganella morganiib e (17)
Proteus vulgarisbeC (15)
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
Range
MIC (,mg/mj)a 50% 90.
0.06-0.25 0.06-0.25 .0.008-0.125
0.06 0.06 0.03
0.25 0.25 0.125
0.0154-.5 0.06-8 0.015-0.25 0.03-0.125
0.125 2 0.03 0.06 0.06 0.015
0.5 8 0.125 0.125 0.25 0.03
0.25 2 0.5 0.125 0.125 0.03
.0.008-0.25
.0.008-0.06
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
0.03-0.125 0.03-0.125 .0.008-0.03
0.25 0.25 0.125 0.125 0.06 0.015
Providencia rettgerib c (15)
Ro 23-9424 De sacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
0.06-2 0.03->16 0.015->16 0.03-2 0.125-1 32 >32 0.25 0.25 0.125
0.125 0.5 0.125 0.125 0.06
0.5 >16 16 2 0.25 0.06
Yersinia enterocoliticab,c (10)
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin Salmonella Spp.b (14)
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin Shigella Spp.b (15)
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime
Fleroxaci;n Ofloxacin Ciprofloxacin Aeromonas hydrophilab C (11)
Ro 23-9424
Desacetyl-cefotaxime
0.03-0.25 0.03-2
.0.08-16
0.25-2 1->32 0.125-232 0.06-1 0.03-2
.0.008-2 0.015-0.5 0.125->16 0.03-16 0.06-2
.0.015-0.25 .0.015-0.06 0.125-0.5 0.125-0.5 0.034 0.06-0.125 0.03-1
.0.008-0.25 0.06-0.5 0.125-0.5 0.015-0.125 0.03-0.125 0.060.25
.O.008-0.03
.0.015 0.25 0.25 0.06 0.06 0.125
C0.008 0.125 0.25
0.25 0.5
0.03 0.06 0.06 16 0.015->16
Cefotaxime Fleroxacin Ofloxacin
2 >16 >16 1 1 1
0.5 0.5
0.06 0.125 0.125 0.03 0.5 >16 >16
0.25 0.06 0.015
Continued on following page
VOL. 34, 1990
IN VITRO ACTIVITY OF Ro 23-9424
193
TABLE 1-Continued Organism
MIC (,Wg/ml)a
Antibiotic
(no. tested) (o A t
Acinetobacter Spp.b,c (15)
Range 90216 Ro 23-9424 0.5-16 1 16
Desacetyl-cefotaxime
Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin Pseudomonas aeruginosab,C (30)
2-16
8->16
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin
Haemophilus influenzaed (16)
Neisseria gonorrhoeaed (10)
Ro 23-9424
Staphylococcus epidermidis,b,c,e methicillin resistant (11)
2->16 4->16 2->16
2-8
0.06-0.125
Desacetyl-cefotaxime
0.06-0.5
>16
1-4
8 >16 >16 2 2 2
8 >16 >16 8 4 4
0.125 0.125
.0.008-0.25
0.125
.0.008-0.25
0.06
0.015-0.06
s0.008-0.06 0.06-0.5 .0.008-0.03
0.03 0.125 '0.008
_0.008
s0.008
2->16 >16 4->16 1-8 0.125-2 0.25-1 2-4 16->16 2->16
0.5-1 0.25-1
Ciprofloxacin
0.25-1
Ro 23-9424
0.06-2 0.06->16
Desacetyl-cefotaxime Cefotaxime Fleroxacin
2
>16 >16 >16 8 16 4
.0.008-0.008
0.015-0.5
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ro 23-9424
4 >16 16
0.06 0.008
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
8 >16 >16 4 4 0.5
0.03
Ciprofloxacin
Ro 23-9424
4 16 >16 1 1 0.125
0.06 0.03 '0.008
50.008-0.5
Desacetyl-cefotaxime
>16 >16 2 2 1
0.125 0.5 0.5
Cefotaxime Fleroxacin Ofloxacin
Ro 23-9424
16 8 0.5 0.5 0.25
0.5-8 0.25-16 0.06-4
Ro 23-9424
Ciprofloxacin Staphylococcus epidermidis,b e methicillin susceptible (13)
0.03-0.5
8->16 0.06-8 0.5-4
Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin Staphylococcus aureus,be methicillin susceptible (12)
>16 0.5-4 0.5-4
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin Staphylococcus aureus, b,c,e methicillin resistant (19)
0.015-1
Desacetyl-cefotaxime
Ciprofloxacin
Xanthomonas maltophiliab,c (16)
0.25-2
0.125-2
Ro 23-9424
Cefotaxime Fleroxacin Ofloxacin Pseudomonas cepaciabc (10)
1->16
1->16
0.06-8 0.06-1 0.125-1 0.25-0.5 0.125-4 0.06->16 0.06-8 0.125-8
0.5
0.25 0.25 0.06 0.5 0.03 '0.008
4 >16 >16 1 0.25 0.5
>16 >16 >16 8 2 1
4 >16 8 1 1
4 >16 >16 1 1
1
1
1
2 0.125
0.5 0.25 0.25 1 2 0.5 0.5
2 >16 8 1 1 0.5 2 >16 4
4
Continued on following page
194
ANTIMICROB. AGENTS CHEMOTHER.
GU AND NEU TABLE 1-Continued Organism (no. tested)
A
Ofloxacin Ciprofloxacin Streptococcus pneumoniae (14)
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin Streptococcus pyogenes (22)
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin Streptococcus agalactiae (10)
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
Group C and G streptococci (20)
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
Enterococcus faecalisc (22)
MIC (pg/ml)a
50Ai Range
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin
90
0.25-1 0.25-1
0.25 0.25
1 1
0.015-0.25 0.06-0.5 S0.008-0.06 2-16 1-2 1-2
0.06 0.125 0.015 8 2 1
0.25 0.25 0.06 8 2 2
0.015-0.5 0.015-1 '0.008-0.125 1-16 0.5-4 0.25-2
0.06 0.015 0.015 4 1 0.5
0.25 0.5 0.125 8 4 2
0.03-0.5 0.015-0.125 0.015-0.06 4-8 1-4 0.25-4
0.25 0.125 0.03 4 2 0.5
0.5 0.125 0.06 8 4 4
0.03 0.03 0.015 4 1 0.5
0.06 0.125 0.03 8 2 1
0.015-0.06 0.015-0.25 C0.008-0.03 1-8 0.25-4 0.125-1 2->16 2->16 1->16 2->16 1-4 0.5-4
4 >16 >16 4 2 1
>16 >16 >16 >16 4 4
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
0.015-4 0.03->16 '0.06-2 0.25->16 0.5-2 0.125-2
0.5 2 0.5 8 2 1
4 >16 2 >16 2 2
Listeria monocytogenesc (22)
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
4->16 8->16 16->16 2->16 1-2 0.25-1
8 >16 >16 2 2 0.5
16 >16 >16 >16 2 1
Bacteroides fragilisb c (15)
Ro 23-9424
0.5-32 2->32
8 16 32 8 2 4
32 >32 >32 16 8 8
Viridans group streptococci (13)
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin Clostridium perfringens (15)
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin a 509% and 90%, MIC for 50 and 90%o of isolates, respectively. b Strains were resistant to ampicillin. Strains were resistant to cefazolin. d Strains produced 50%o -lactamase. Strains were resistant to penicillin G.
1->32 1-16
2-8 4-8 1-2 2-32 0.25-8 0.5-4 0.25-0.5 0.25
1
8 2 1 0.5 0.25
2 32 8 4 0.5 0.25
VOL. 34, 1990
IN VITRO ACTIVITY OF Ro 23-9424
TABLE 2. In vitro activities of Ro 23-9424 and fleroxacin against cefotaxime-resistant members of the family Enterobacteriaceaea MIC
Organism and strain
(ILg/ml)
Cefotaxime
Ro 23-9424
Fleroxacin
Klebsiella pneumoniae 5561
>16
0.5
0.25
Klebsiella oxytoca 8492 124
>16 >16
0.25 1
0.5 0.5
Enterobacter cloacae 8879 10322
>16 >16
0.25 0.5
0.06 0.25
Enterobacter aerogenes 34 6305
>16 >16
0.5 1
0.25 0.25
Providencia rettgeri 8652 4302
>16 >16
0.25 1
0.06 2
Citrobacter freundii UI-82 8335 8686
> 16 >16 >16
1 0.5 1
0.25 0.125 0.25
3-lactamase-containing
a Of the isolates, Klebsiella pneumoniae contained TEM-3; Klebsiella oxytoca contained K-1; and Enterobacter cloacae, Providencia rettgeri, and Citrobacter freundii contained derepressed RichmondSykes type Ia.
were inhibited by c8 ,ug of Ro 23-9424 per ml. In comparison with quinolones such as fleroxacin, ofloxacin, and ciprofloxacin, Ro 23-9424 was more active against hemolytic streptococci. Ro 23-9424 was 8 to 16 times more active than ciprofloxacin against Streptococcus pneumoniae, Streptococcus pyogenes, and group G streptococci. Although it is theorized that a simultaneous attack on both the cell wall and DNA synthesis could actually hinder or prevent the development of bacterial resistance, development of high-level resistance was produced by serially TABLE 3. Development of resistance to Ro 23-9424 MIC (p.g/ml) on day: Organism 5 0 Escherichia coli 0.06 4 Klebsiella pneumoniae 0.25 4 Serratia marcescens 0.5 2 Enterobacter cloacae 0.5 16 Citrobacterfreundii 0.25 4 Pseudomonas aeruginosa 4 64 Staphylococcus aureus 1 8
14
32 64 32 128 16 128 16
195
passaging the isolates in Mueller-Hinton broth containing increasing concentrations of Ro 23-9424. The degree of development of resistance to Ro 23-9424 was similar to that produced against fleroxacin and other quinolones (1, 3). Overall, results of this study demonstrate that Ro 23-9424 has excellent in vitro activity against gram-negative and gram-positive bacteria, including Pseudomonas aeruginosa, Staphylococcus aureus, members of the family Enterobacteriaceae, and Clostridium species, especially streptococci and ,-lactamase-producing organisms. The compound has been shown to have excellent activity in experimental animal infections and to have typical cephalosporin pharmacokinetics in animals (2, 4). Ro 23-9424 seems to be a promising new agent in the category of dual-action antibiotics. It is not clear whether the ideal way to combine cephalosporins and fluoroquinolones is by use of the carboxyl group of the fluoroquinolones. It is postulated that the vicinal carboxyl and keto groups of the quinolone are important in facilitating the entry of fluoroquinolones by chelating cations that stabilize the outer membrane of gram-negative organisms. It may be possible to construct other dual-action agents which have a free carboxyl function. This would be possible by using quinolones that contain a methyl group at position N-4 or C-3 on the piperazinyl C-7 moiety or by using an amino or methyl group of a pyrrole attached at position C-7. Future research on the use of the combination of 1-lactams and fluoroquinolones is indicated since it offers a way of delivering two agents simultaneously. LITERATURE CITED 1. Barry, A. L., R. N. Jones, C. Thornsberry, L. W. Ayers, E. H. Gerlach, and H. M. Sommers. 1984. Antibacterial activities of ciprofloxacin, norfloxacin, oxolinic acid, cinoxacin, and nalidixic acid. Antimicrob. Agents Chemother. 25:533-537. 2. Beskid, G., V. Faliat, E. R. Lipschitz, D. H. McGarry, R. Cleeland, K. Chan, D. D. Keith, and J. Unowsky. 1989. In vitro activities of a dual-action antibacterial agent, Ro 23-9424, and comparative agents. Antimicrob. Agents Chemother. 33:10721077. 3. Chin, N.-X., D. C. Brittain, and H. C. Neu. 1986. In vitro activity of Ro 23-6240, a new fluorinated 4-quinolone. Antimicrob. Agents Chemother. 29:675-680. 4. Georgopadakou, N. H., A. Bertasso, K. K. Chan, J. S. Chapman, R. Cleeland, L. M. Cummings, B. A. Dix, and D. D. Keith. 1989. Mode of action of the dual-action cephalosporin Ro 23-9424. Antimicrob. Agents Chemother. 33:1067-1071. 5. Jones, R. N., A. L. Barry, and C. Thornsberry. 1989. Antimicrobial activity of Ro 23-9424, a novel ester-linked codrug of fleroxacin and desacetyl-cefotaxime. Antimicrob. Agents Chemother. 33:944-950. 6. National Committee for Clinical Laboratory Standards. 1988. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically, 2nd ed. Standard M7-T2. National Committee for Clinical Laboratory Standards, Villanova, Pa. 7. O'Callaghan, C. H., R. B. Sykes, and S. E. Staniforth. 1976. A new cephalosporin with a dual mode of action. Antimicrob. Agents Chemother. 10:245-248.
Vol. 34, No. 2
0066-4804/90/020189-07$02.00/0 Copyright C) 1990, American Society for Microbiology
In Vitro Activity of Ro 23-9424, a Dual-Action Cephalosporin, Compared with Activities of Other Antibiotics JIAN-WEI GU' AND HAROLD C. NEUl12* Departments of Medicine' and Pharmacology,2 College of Physicians and Surgeons, Columbia University, New York, New York 10032 Received 8 August 1989/Accepted 25 October 1989
The in vitro activity of Ro 23-9424, which is desacetyl-cefotaxime linked to fleroxacin, was compared with the activities of cefotaxime, desacetyl-cefotaxime, fleroxacin, ofloxacin, and ciprofloxacin. It inhibited the majority of members of the family Enterobacteriaceae, except for some Serratia marcescens, Citrobacter freundii, and Enterobacter cloacae strains, at 16 ,ug/ml. Ro 23-9424 inhibited 90o of the Streptococcus pneumoniae isolates at 16 0.125->16 0.06-0.25 0.06-0.5 0.03-0.125
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin Ro 23-9424
Desacetyl-cefotaxime Cefotaxime
0.5 1 0.5 0.5 0.5 0.25
0.125 0.25 0.06 0.125 0.125 0.03
1 >16 >16 0.5 1 0.125
0.5 4 0.5 0.125 0.125 0.03
0.5 >16 >16 0.25 0.25 0.125
0.06-2 0.25->16 0.06->16 0.06-1 0.06-0.5 s0.008-1
0.25 1 0.125 0.125 0.125 0.03
1 >16 >016 0.25 0.5 0.125
0.125-0.5 0.125->16
0.25 0.25 0.06 0.03 0.03 s0.008
0.5 0.5 0.125 0.06 0.06 0.015
0.06-4 0.03-0.125 0.03-0.06
0.015-0.5 1->16 0.125-8 0.03-0.5
Ro 23-9424
s-0.008
0.125 0.5 0.25 0.125 0.06 s0.008
Ro 23-9424
Ciprofloxacin
0.25 0.125 0.06 0.125 0.125 0.03
90%o 0.5 2 0.25 0.25 0.06
0.015-0.5 0.03-2 s0.008-1 0.03-0.25 0.03-0.5 .0.008-0.06
0.008-0.015
Cefotaxime Fleroxacin Ofloxacin
Proteus mirabilisb (15)
0.125-1 0.06->16
Ciprofloxacin Desacetyl-cefotaxime
Serratia marcescensb,c (14)
0.125 0.5 0.06 0.125 0.06 s0.008
Ciprofloxacin
Enterobacter agglomeransb,c (11)
Hafnia alveib,c (14)
0.015-0.5 0.03-16 s0.03-0.5 0.03-0.25 0.03-0.125 0.008-0.015
s0.015-1 0.03->16 s0.03->16 0.03-1 0.015-2
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
Citrobacter diversusb (16)
50o
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Enterobacter cloacaeb c (15)
Enterobacter aerogenesb,c (15)
MIC (,ug/ml)a Range
0.5 2 0.5 0.25 0.5 0.06
0.125 8 0.5 0.125 0.06 s0.015
0.5 >16 1 0.5 0.25 0.06
0.5-1 0.5->16 0.125-16 0.125-0.5 0.25-2
0.5 4 0.5 0.25 0.5 s0.008
1 16 1 0.25 1 0.25
0.125-0.5 0.06-0.25
0.125 0.06 0.03
.0.015-0.25
s0.015-0.06
.0.008-0.25
.0.008-0.25
0.25 0.125 0.125
Continued on following page
192
GU AND NEU
ANTIMICROB. AGENTS CHEMOTHER.
TABLE 1-Continued Organism
(no. tested)
Antibiotic Fleroxacin Ofloxacin Ciprofloxacin
Morganella morganiib e (17)
Proteus vulgarisbeC (15)
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
Range
MIC (,mg/mj)a 50% 90.
0.06-0.25 0.06-0.25 .0.008-0.125
0.06 0.06 0.03
0.25 0.25 0.125
0.0154-.5 0.06-8 0.015-0.25 0.03-0.125
0.125 2 0.03 0.06 0.06 0.015
0.5 8 0.125 0.125 0.25 0.03
0.25 2 0.5 0.125 0.125 0.03
.0.008-0.25
.0.008-0.06
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
0.03-0.125 0.03-0.125 .0.008-0.03
0.25 0.25 0.125 0.125 0.06 0.015
Providencia rettgerib c (15)
Ro 23-9424 De sacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
0.06-2 0.03->16 0.015->16 0.03-2 0.125-1 32 >32 0.25 0.25 0.125
0.125 0.5 0.125 0.125 0.06
0.5 >16 16 2 0.25 0.06
Yersinia enterocoliticab,c (10)
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin Salmonella Spp.b (14)
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin Shigella Spp.b (15)
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime
Fleroxaci;n Ofloxacin Ciprofloxacin Aeromonas hydrophilab C (11)
Ro 23-9424
Desacetyl-cefotaxime
0.03-0.25 0.03-2
.0.08-16
0.25-2 1->32 0.125-232 0.06-1 0.03-2
.0.008-2 0.015-0.5 0.125->16 0.03-16 0.06-2
.0.015-0.25 .0.015-0.06 0.125-0.5 0.125-0.5 0.034 0.06-0.125 0.03-1
.0.008-0.25 0.06-0.5 0.125-0.5 0.015-0.125 0.03-0.125 0.060.25
.O.008-0.03
.0.015 0.25 0.25 0.06 0.06 0.125
C0.008 0.125 0.25
0.25 0.5
0.03 0.06 0.06 16 0.015->16
Cefotaxime Fleroxacin Ofloxacin
2 >16 >16 1 1 1
0.5 0.5
0.06 0.125 0.125 0.03 0.5 >16 >16
0.25 0.06 0.015
Continued on following page
VOL. 34, 1990
IN VITRO ACTIVITY OF Ro 23-9424
193
TABLE 1-Continued Organism
MIC (,Wg/ml)a
Antibiotic
(no. tested) (o A t
Acinetobacter Spp.b,c (15)
Range 90216 Ro 23-9424 0.5-16 1 16
Desacetyl-cefotaxime
Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin Pseudomonas aeruginosab,C (30)
2-16
8->16
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin
Haemophilus influenzaed (16)
Neisseria gonorrhoeaed (10)
Ro 23-9424
Staphylococcus epidermidis,b,c,e methicillin resistant (11)
2->16 4->16 2->16
2-8
0.06-0.125
Desacetyl-cefotaxime
0.06-0.5
>16
1-4
8 >16 >16 2 2 2
8 >16 >16 8 4 4
0.125 0.125
.0.008-0.25
0.125
.0.008-0.25
0.06
0.015-0.06
s0.008-0.06 0.06-0.5 .0.008-0.03
0.03 0.125 '0.008
_0.008
s0.008
2->16 >16 4->16 1-8 0.125-2 0.25-1 2-4 16->16 2->16
0.5-1 0.25-1
Ciprofloxacin
0.25-1
Ro 23-9424
0.06-2 0.06->16
Desacetyl-cefotaxime Cefotaxime Fleroxacin
2
>16 >16 >16 8 16 4
.0.008-0.008
0.015-0.5
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ro 23-9424
4 >16 16
0.06 0.008
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
8 >16 >16 4 4 0.5
0.03
Ciprofloxacin
Ro 23-9424
4 16 >16 1 1 0.125
0.06 0.03 '0.008
50.008-0.5
Desacetyl-cefotaxime
>16 >16 2 2 1
0.125 0.5 0.5
Cefotaxime Fleroxacin Ofloxacin
Ro 23-9424
16 8 0.5 0.5 0.25
0.5-8 0.25-16 0.06-4
Ro 23-9424
Ciprofloxacin Staphylococcus epidermidis,b e methicillin susceptible (13)
0.03-0.5
8->16 0.06-8 0.5-4
Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin Staphylococcus aureus,be methicillin susceptible (12)
>16 0.5-4 0.5-4
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin Staphylococcus aureus, b,c,e methicillin resistant (19)
0.015-1
Desacetyl-cefotaxime
Ciprofloxacin
Xanthomonas maltophiliab,c (16)
0.25-2
0.125-2
Ro 23-9424
Cefotaxime Fleroxacin Ofloxacin Pseudomonas cepaciabc (10)
1->16
1->16
0.06-8 0.06-1 0.125-1 0.25-0.5 0.125-4 0.06->16 0.06-8 0.125-8
0.5
0.25 0.25 0.06 0.5 0.03 '0.008
4 >16 >16 1 0.25 0.5
>16 >16 >16 8 2 1
4 >16 8 1 1
4 >16 >16 1 1
1
1
1
2 0.125
0.5 0.25 0.25 1 2 0.5 0.5
2 >16 8 1 1 0.5 2 >16 4
4
Continued on following page
194
ANTIMICROB. AGENTS CHEMOTHER.
GU AND NEU TABLE 1-Continued Organism (no. tested)
A
Ofloxacin Ciprofloxacin Streptococcus pneumoniae (14)
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin Streptococcus pyogenes (22)
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin Streptococcus agalactiae (10)
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
Group C and G streptococci (20)
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
Enterococcus faecalisc (22)
MIC (pg/ml)a
50Ai Range
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin
90
0.25-1 0.25-1
0.25 0.25
1 1
0.015-0.25 0.06-0.5 S0.008-0.06 2-16 1-2 1-2
0.06 0.125 0.015 8 2 1
0.25 0.25 0.06 8 2 2
0.015-0.5 0.015-1 '0.008-0.125 1-16 0.5-4 0.25-2
0.06 0.015 0.015 4 1 0.5
0.25 0.5 0.125 8 4 2
0.03-0.5 0.015-0.125 0.015-0.06 4-8 1-4 0.25-4
0.25 0.125 0.03 4 2 0.5
0.5 0.125 0.06 8 4 4
0.03 0.03 0.015 4 1 0.5
0.06 0.125 0.03 8 2 1
0.015-0.06 0.015-0.25 C0.008-0.03 1-8 0.25-4 0.125-1 2->16 2->16 1->16 2->16 1-4 0.5-4
4 >16 >16 4 2 1
>16 >16 >16 >16 4 4
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
0.015-4 0.03->16 '0.06-2 0.25->16 0.5-2 0.125-2
0.5 2 0.5 8 2 1
4 >16 2 >16 2 2
Listeria monocytogenesc (22)
Ro 23-9424 Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin
4->16 8->16 16->16 2->16 1-2 0.25-1
8 >16 >16 2 2 0.5
16 >16 >16 >16 2 1
Bacteroides fragilisb c (15)
Ro 23-9424
0.5-32 2->32
8 16 32 8 2 4
32 >32 >32 16 8 8
Viridans group streptococci (13)
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin
Ciprofloxacin Clostridium perfringens (15)
Ro 23-9424
Desacetyl-cefotaxime Cefotaxime Fleroxacin Ofloxacin Ciprofloxacin a 509% and 90%, MIC for 50 and 90%o of isolates, respectively. b Strains were resistant to ampicillin. Strains were resistant to cefazolin. d Strains produced 50%o -lactamase. Strains were resistant to penicillin G.
1->32 1-16
2-8 4-8 1-2 2-32 0.25-8 0.5-4 0.25-0.5 0.25
1
8 2 1 0.5 0.25
2 32 8 4 0.5 0.25
VOL. 34, 1990
IN VITRO ACTIVITY OF Ro 23-9424
TABLE 2. In vitro activities of Ro 23-9424 and fleroxacin against cefotaxime-resistant members of the family Enterobacteriaceaea MIC
Organism and strain
(ILg/ml)
Cefotaxime
Ro 23-9424
Fleroxacin
Klebsiella pneumoniae 5561
>16
0.5
0.25
Klebsiella oxytoca 8492 124
>16 >16
0.25 1
0.5 0.5
Enterobacter cloacae 8879 10322
>16 >16
0.25 0.5
0.06 0.25
Enterobacter aerogenes 34 6305
>16 >16
0.5 1
0.25 0.25
Providencia rettgeri 8652 4302
>16 >16
0.25 1
0.06 2
Citrobacter freundii UI-82 8335 8686
> 16 >16 >16
1 0.5 1
0.25 0.125 0.25
3-lactamase-containing
a Of the isolates, Klebsiella pneumoniae contained TEM-3; Klebsiella oxytoca contained K-1; and Enterobacter cloacae, Providencia rettgeri, and Citrobacter freundii contained derepressed RichmondSykes type Ia.
were inhibited by c8 ,ug of Ro 23-9424 per ml. In comparison with quinolones such as fleroxacin, ofloxacin, and ciprofloxacin, Ro 23-9424 was more active against hemolytic streptococci. Ro 23-9424 was 8 to 16 times more active than ciprofloxacin against Streptococcus pneumoniae, Streptococcus pyogenes, and group G streptococci. Although it is theorized that a simultaneous attack on both the cell wall and DNA synthesis could actually hinder or prevent the development of bacterial resistance, development of high-level resistance was produced by serially TABLE 3. Development of resistance to Ro 23-9424 MIC (p.g/ml) on day: Organism 5 0 Escherichia coli 0.06 4 Klebsiella pneumoniae 0.25 4 Serratia marcescens 0.5 2 Enterobacter cloacae 0.5 16 Citrobacterfreundii 0.25 4 Pseudomonas aeruginosa 4 64 Staphylococcus aureus 1 8
14
32 64 32 128 16 128 16
195
passaging the isolates in Mueller-Hinton broth containing increasing concentrations of Ro 23-9424. The degree of development of resistance to Ro 23-9424 was similar to that produced against fleroxacin and other quinolones (1, 3). Overall, results of this study demonstrate that Ro 23-9424 has excellent in vitro activity against gram-negative and gram-positive bacteria, including Pseudomonas aeruginosa, Staphylococcus aureus, members of the family Enterobacteriaceae, and Clostridium species, especially streptococci and ,-lactamase-producing organisms. The compound has been shown to have excellent activity in experimental animal infections and to have typical cephalosporin pharmacokinetics in animals (2, 4). Ro 23-9424 seems to be a promising new agent in the category of dual-action antibiotics. It is not clear whether the ideal way to combine cephalosporins and fluoroquinolones is by use of the carboxyl group of the fluoroquinolones. It is postulated that the vicinal carboxyl and keto groups of the quinolone are important in facilitating the entry of fluoroquinolones by chelating cations that stabilize the outer membrane of gram-negative organisms. It may be possible to construct other dual-action agents which have a free carboxyl function. This would be possible by using quinolones that contain a methyl group at position N-4 or C-3 on the piperazinyl C-7 moiety or by using an amino or methyl group of a pyrrole attached at position C-7. Future research on the use of the combination of 1-lactams and fluoroquinolones is indicated since it offers a way of delivering two agents simultaneously. LITERATURE CITED 1. Barry, A. L., R. N. Jones, C. Thornsberry, L. W. Ayers, E. H. Gerlach, and H. M. Sommers. 1984. Antibacterial activities of ciprofloxacin, norfloxacin, oxolinic acid, cinoxacin, and nalidixic acid. Antimicrob. Agents Chemother. 25:533-537. 2. Beskid, G., V. Faliat, E. R. Lipschitz, D. H. McGarry, R. Cleeland, K. Chan, D. D. Keith, and J. Unowsky. 1989. In vitro activities of a dual-action antibacterial agent, Ro 23-9424, and comparative agents. Antimicrob. Agents Chemother. 33:10721077. 3. Chin, N.-X., D. C. Brittain, and H. C. Neu. 1986. In vitro activity of Ro 23-6240, a new fluorinated 4-quinolone. Antimicrob. Agents Chemother. 29:675-680. 4. Georgopadakou, N. H., A. Bertasso, K. K. Chan, J. S. Chapman, R. Cleeland, L. M. Cummings, B. A. Dix, and D. D. Keith. 1989. Mode of action of the dual-action cephalosporin Ro 23-9424. Antimicrob. Agents Chemother. 33:1067-1071. 5. Jones, R. N., A. L. Barry, and C. Thornsberry. 1989. Antimicrobial activity of Ro 23-9424, a novel ester-linked codrug of fleroxacin and desacetyl-cefotaxime. Antimicrob. Agents Chemother. 33:944-950. 6. National Committee for Clinical Laboratory Standards. 1988. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically, 2nd ed. Standard M7-T2. National Committee for Clinical Laboratory Standards, Villanova, Pa. 7. O'Callaghan, C. H., R. B. Sykes, and S. E. Staniforth. 1976. A new cephalosporin with a dual mode of action. Antimicrob. Agents Chemother. 10:245-248.
