JAC Advance Access published online on September 14, 2007
Journal of Antimicrobial Chemotherapy, doi:10.1093/jac/dkm346
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Comparative activity of pradofloxacin against anaerobic bacteria isolated from dogs and cats
1 MB Consult Limited, Lymington, SO41 3TQ, UK 2 Department of Biomedical Sciences, University of Bradford, Bradford, UK 3 Bayer HealthCare AG, Leverkusen, D-51368, Germany 4 Don Whitley Scientific Ltd, Shipley, West Yorkshire, BD17 7SE, UK
* Corresponding author. Tel: +44-1590-678700; Fax: +44-1590-678751; E-mail: p-s{at}mbconsult.co.uk
Received 10 July 2007; returned 25 July 2007; revised 9 August 2007; accepted 10 August 2007
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and methodsResults and discussionTransparency declarationsSupplementary dataFundingReferences |
|---|
Objectives: To compare the intrinsic activity of pradofloxacin, a new fluoroquinolone developed for use in veterinary medicine, with other fluoroquinolones, against anaerobic bacteria isolated from dogs and cats.
Methods: One hundred and forty-one anaerobes were isolated from dogs and cats and comparative MICs of pradofloxacin, marbofloxacin, enrofloxacin, difloxacin and ibafloxacin were determined according to standardized agar dilution methodology.
Results: Pradofloxacin exerted the greatest antibacterial activity followed by marbofloxacin, enrofloxacin, difloxacin and ibafloxacin. Based on the distinctly lower MIC50, MIC90 and mode MIC values, pradofloxacin exhibited a higher in vitro activity than any of the comparator fluoroquinolones.
Conclusions: Pradofloxacin, a novel third-generation fluoroquinolone, has broad-spectrum anti-anaerobe activity and offers utility as single-drug therapy for mixed aerobic/anaerobic infections.
Key Words: fluoroquinolones , anaerobes , companion animals
|
Introduction |
|---|
|
TopAbstractIntroductionMaterials and methodsResults and discussionTransparency declarationsSupplementary dataFundingReferences |
|---|
Quinolones were first described in the early 1960s,1 with limited in vitro activity against Gram-negative species. Modifications to nalidixic acid in the 1970s gave rise to compounds that were generally used for oral treatment of urinary tract infections. Improvements in activity against Gram-negative and -positive pathogens followed the introduction of piperazine substitution at position 7 of the naphthyridine core and fluorination at position 6 of the molecule, this group being commonly referred to as the fluoroquinolones. Norfloxacin was the first member of this class. Substitution of a carbon atom for nitrogen resulted in ciprofloxacin, a 1-cyclopropanyl, and ofloxacin and levofloxacin, both 1,8-cyclo compounds; all three of these latter mentioned compounds have been classified as second-generation fluoroquinolones.2 The next development included compounds such as moxifloxacin, resulting from a 7-azabicyclo modification that enhanced antibacterial activity and pharmacokinetic properties, consequently referred to as a third-generation fluoroquinolone.2 While the spectrum of activity of the first-generation fluoroquinolones was essentially against Enterobacteriaceae, the second-generation fluoroquinolones have a wider spectrum including activity against many Gram-negative species (bacilli and cocci), some Gram-positive species, intracellular organisms (Rickettsia spp. and Mycobacterium spp.) and Mycoplasma spp.3–6 Third-generation fluoroquinolones such as moxifloxacin have enhanced activity against Gram-positive bacteria relative to first- and second-generation compounds and good activity against anaerobes.7 Fluoroquinolones substituted at position C-8 by a methoxy group such as moxifloxacin have been shown to have greatly improved bactericidal activity.8,9 Pradofloxacin is being exclusively developed for use in veterinary medicine. It is a third-generation fluoroquinolone structurally similar to moxifloxacin2,7 and can therefore be expected to show enhanced activity against Gram-positive organisms and anaerobes; this will differentiate pradofloxacin from earlier generation fluoroquinolone compounds used in veterinary medicine. It is structurally distinguished from enrofloxacin, the first veterinary fluoroquinolone,10 by two elements: a bicyclic amine, S,S-pyrrolidino-piperidine, replacing the ethyl-piperazine moiety located at position C-7 of enrofloxacin, and a cyano group that is attached to the C atom at position 8 (Figure 1). The increased potency of pradofloxacin is mainly attributed to the S,S-pyrrolidino-piperidine moiety at C-7, but the cyano group at C-8 extends activity to first- and second-step fluoroquinolone-resistant strains. Pradofloxacin has been shown to be highly active in vitro against aerobic clinical isolates from dogs and cats. Typical MIC90 values for pradofloxacin against organisms such as Pasteurella multocida, Escherichia coli, Staphylococcus intermedius and Streptococcus spp. have been shown to be in the range 0.016–0.25 mg/L.11 Low mutant prevention concentrations (MPCs) have been reported for pradofloxacin against E. coli and Staphylococcus spp.12 Low MPC has recently been reported also for one strain of the anaerobic bacterium Porphyromonas gingivalis.13 Therefore, pradofloxacin should possess an exceptional potential in eliminating not only large populations of wild-type but also selected first-step resistant clones.12
|
In order to evaluate its potential for use against anaerobes from cats and dogs, we studied the comparative activity of pradofloxacin relative to other fluoroquinolones used in companion animals against 141 anaerobic strains isolated in the period 2000–2002.
|
Materials and methods |
|---|
|
TopAbstractIntroductionMaterials and methodsResults and discussionTransparency declarationsSupplementary dataFundingReferences |
|---|
Bacterial strains
Anaerobic bacteria were isolated from oral infections, abscesses and wound infections and also from faecal flora of dogs and cats. A total of 141 strains were isolated from dogs (94) and cats (47) in the period 2000–2002, all of which were from the UK and obtained from animals that had not received antimicrobial agents for at least 3 months prior to sampling. Individual species were isolated from separate animals and thus all bacterial species can be considered as unrelated. Identification was to species level using the BiologTM system (Hayward, CA, USA) and isolates were stored at –80°C prior to testing. The strains identified to species level were: Actinomyces [A. bovis (n = 2), A. israelii (1)]; Bacteroides [B. capillosus (3), B. cellulosolvens (1), B. eggerthii (1), B. forsythus (2), B. fragilis (3), B. helcogenes (4), B. putredinis (1), B. stercoris (1), B. suis (3), B. uniformis (1), B. ureolyticus (1), B. vulgatus (6)]; Clostridium [C. absonum (4), C. carnis (2), C. cellobioparum (3), C. glycolicum (1), C. hydroxybenzoicum (3), C. irregularis (1), C. oroticum (1), C. perfringens (4), C. ramosum (2), C. rectum (1), C. sporosphaeroides (1), C. subterminale (1), C. tetanomorphum (1)]; Desulfomonile tiedjei (1); Eubacterium [E. biforme (1), E. cylindroides (1), E. plautii (1)]; Fusobacterium [F. naviforme (1), F. necrogenes (5), F. necrophorum (1), F. nucleatum (9), F. russii (1), F. ulcerans (1), F. varium (2)]; Hallella seregrens (1); Macrococcus bovicus (1), Megamonas hypermegale (2); Peptostreptococcus anaerobius (3); Porphyromonas [P. gingivalis (5), P. macacae (1)], Prevotella [P. buccae (1), P. corporis (2), P. dentalis (2), P. denticola (3), P. disiens (1), P. heparinolytica (1), P. oralis (7), P. oris (1), P. zoogleoformans (2)]; Propionibacterium [P. acnes (3), P. granulosum (1) P. propionicum (1)]; Rhodococcus fascians (1); Ruminococcus torques (2); Sebaldella termitidis (1); Selenomonas sputigena (2); Sporomusa [S. acidovorans (3), S. sphaeroides (3)]. There were a number of isolates for which species names could not be defined: Clostridum spp. (7), Bacteroides spp. (1), Bifidobacterium spp. (1), Fusobacterium spp. (2), Megasphaera spp. (1). Isolates were sub-cultured on Fastidious Anaerobe Agar (LabM, LAB103, Bury, UK) prior to susceptibility testing.
The test compounds, pradofloxacin, marbofloxacin, enrofloxacin, ibafloxacin and difloxacin were all supplied with a certificate of analysis detailing purity. MICs of each of the test compounds against 141 anaerobic bacteria were determined using agar dilution methodology as described by the CLSI (formerly NCCLS) in complete accordance with the procedures detailed in M11-A5, Methods for Antimicrobial Susceptibility Testing of Anaerobic Bacteria, using Brucella blood agar (Difco, D0964-17) supplemented with haemin (5 mg/L) and vitamin K1 (1 mg/L) and incubating for up to 48 h.14 B. fragilis ATCC 25285 and Eubacterium lentum ATCC 43055 were used as quality control organisms. All susceptibility testing was carried out under strict anaerobic conditions using an anaerobic workstation (Don Whitley Scientific Limited, Shipley, UK).
|
Results and discussion |
|---|
|
TopAbstractIntroductionMaterials and methodsResults and discussionTransparency declarationsSupplementary dataFundingReferences |
|---|
The MIC data for pradofloxacin and the other veterinary fluoroquinolones are summarized in Table 1 for all genera where n was
5, i.e. Clostridium, Bacteroides, Fusobacterium, Prevotella, Porphyromonas, Sporomusa and Propionibacterium. Comparative MIC data were also generated for species where n was between 2 and 4, namely Actinomyces where n = 3 (pradofloxacin, 0.125–0.25; marbofloxacin, 0.5–1; enrofloxacin, 0.25–1; difloxacin, 1; ibafloxacin, 0.5–2), Eubacterium, n = 3 (pradofloxacin, 0.25–0.5; marbofloxacin, 0.5–2; enrofloxacin, 0.25–4; difloxacin, 1–2; ibafloxacin, 4), P. anaerobius, n = 3 (pradofloxacin, 0.25; marbofloxacin, 1; enrofloxacin, 1–2; difloxacin, 2; ibafloxacin, 4), M. hypermegale, n = 2 (pradofloxacin, 1–2; marbofloxacin, 2–16; enrofloxacin, 16–32; difloxacin, 4–16; ibafloxacin, 2–8), R. torques, n = 2 (pradofloxacin, 0.062–0.5; marbofloxacin, 1–4; enrofloxacin, 0.5–8; difloxacin, 0.25–16; ibafloxacin, 0.5–2) and S. sputigena, n = 2 (pradofloxacin, 0.25–1; marbofloxacin, 1–8; enrofloxacin, 2–16; difloxacin, 2–16; ibafloxacin, 4–32). Additionally, MICs for single species were Bifidobacterium spp. (pradofloxacin, 0.125; marbofloxacin, 0.5; enrofloxacin, 0.5; difloxacin, 1; ibafloxacin, 2), D. tiedjei (pradofloxacin, 0.25; marbofloxacin, 0.125; enrofloxacin, 0.5; difloxacin, 0.5; ibafloxacin, 0.5), H. seregens (pradofloxacin, 0.25; marbofloxacin, 0.5; enrofloxacin, 2; difloxacin, 8; ibafloxacin, 4), M. bovicus (pradofloxacin, 0.5; marbofloxacin, 1; enrofloxacin, 0.5; difloxacin, 0.5; ibafloxacin, 4), Megasphaera spp. (pradofloxacin, 0.031; marbofloxacin, 0.062; enrofloxacin, 0.125; difloxacin, 0.125; ibafloxacin, 0.25), R. fascians (pradofloxacin, 0.031; marbofloxacin, 0.062; enrofloxacin, 0.031; difloxacin, 0.062; ibafloxacin, 0.062) and S. termitidis (pradofloxacin, 0.062; marbofloxacin, 1; enrofloxacin, 2; difloxacin, 1; ibafloxacin, 2). All individual strain MIC values are provided in Table S1, available as Supplementary data at JAC Online (http://jac.oxfordjournals.org/).
|
Pradofloxacin demonstrates enhanced activity relative to the other tested compounds, consistent with what would be expected from a third-generation fluoroquinolone.15–17 This is best expressed in Figure 2 where the total data set is presented as susceptibility distributions for the respective antimicrobial agents from which it can be seen that the mode MIC for pradofloxacin was 0.25 mg/L compared with 1 mg/L for marbofloxacin, 2 mg/L for enrofloxacin and difloxacin and 4 mg/L for ibafloxacin. Figure 2 also shows that all isolates were susceptible to pradofloxacin at 2 mg/L, whereas the MIC range extended to 32 mg/L for difloxacin and 64 mg/L for marbofloxacin, enrofloxacin and ibafloxacin.
|
Goldstein18 emphasized that due to increasing development of resistance of anaerobic bacteria to all antimicrobial agents there is a need to find new agents active against anaerobes. Additionally, the point was made that it would be useful to have oral antimicrobial agents with broad-spectrum activity against both aerobes and anaerobes. Currently available fluoroquinolones in veterinary medicine only have modest activity against anaerobes, as evident from the data in Table 1. It is clear that pradofloxacin has enhanced anaerobic activity and further provides broad-spectrum coverage against aerobic organisms.11 While data supporting the activity of third-generation fluoroquinolones against human isolates are available, such data have not previously been reported for animal isolates. Indeed, there has been contrasting data reported, suggesting that animal isolates may not be equally susceptible. In this context, Wexler et al.19 reported that 96% of 557 anaerobes tested were susceptible to trovafloxacin at
2 mg/L; Goldstein et al.20 showed trovafloxacin to be active against anaerobic pathogens isolated from human and animal bite-wounds, all were susceptible at 2 mg/L with the exception of Fusobacterium spp., which were susceptible at 4 mg/L. The authors commented on this small one dilution difference in susceptibility of Fusobacterium spp. with the Wexler study19 and pointed out that the same methods were used and the reason for the disparity was unclear except that they studied veterinary isolates recovered from human infections, whereas Wexler et al.19 used human isolates from other sources. The data from our study suggest that animal isolates exhibit similar susceptibility as human isolates. Moxifloxacin is probably the most relevant example of how third-generation fluoroquinolones demonstrate enhanced anti-anaerobe activity because it is structurally similar to pradofloxacin. Indeed, the reported MIC data for pradofloxacin are consistent with MIC data reported for moxifloxacin.21–23 This study provides the first comparative MIC data for veterinary fluoroquinolones against anaerobes isolated from dogs and cats and reveals a high level of anti-anaerobe activity for pradofloxacin. It is clear that third-generation fluoroquinolones, such as pradofloxacin, may have important utility in veterinary medicine as single-drug therapy for infections caused by mixed aerobic/anaerobic infections15,24 and in this context they could also be used to treat bacteria associated with dental infections as has been demonstrated in a large pan-European study investigating the in vitro activity of a range of anti-anaerobe antimicrobials against Gram-negative bacilli.25
|
Transparency declarations |
|---|
|
TopAbstractIntroductionMaterials and methodsResults and discussionTransparency declarationsSupplementary dataFundingReferences |
|---|
P. S. has received funds for speaking at symposia organized on behalf of Bayer HealthCare AG and also acts as a consultant to Bayer HealthCare AG. B. S. and H. A. G. are Bayer employees. A. P.: none to declare.
|
Supplementary data |
|---|
|
TopAbstractIntroductionMaterials and methodsResults and discussionTransparency declarationsSupplementary dataFundingReferences |
|---|
Table S1 is available as Supplementary data at JAC Online (http://jac.oxfordjournals.org/).
|
Funding |
|---|
|
TopAbstractIntroductionMaterials and methodsResults and discussionTransparency declarationsSupplementary dataFundingReferences |
|---|
This study was funded by Bayer HealthCare AG.
|
References |
|---|
|
TopAbstractIntroductionMaterials and methodsResults and discussionTransparency declarationsSupplementary dataFundingReferences |
|---|
1 . Lesher GY, Froelich EJ, Gruett MD, et al. 1, 8-Naphthyridine derivatives: a new class of chemotherapeutic agents. J Med Pharm Chem (1962) 5:1063–5.[CrossRef][Web of Science]
2 . Blondeau JM. A review of the comparative in-vitro activities of 12 antimicrobial agents, with a focus on five new ‘respiratory quinolones’. J Antimicrob Chemother (1999) 43(Suppl B):1–11.[Abstract]
3
.
Cambau E, Bordon F, Collatz E, et al. Novel gyrA point mutation in a strain of Escherichia coli resistant to fluoroquinolones but not to nalidixic acid. Antimicrob Agents Chemother (1993) 37:1247–52.
4 . Gautier-Bouchardon AV, Reinhardt AK, Kobisch M, et al. In vitro development of resistance to enrofloxacin, erythromycin, tylosin, tiamulin and oxytetracycline in Mycoplasma gallisepticum, Mycoplasma iowae and Mycoplasma synoviae. Vet Microbiol (2002) 88:47–58.[CrossRef][Web of Science][Medline]
5 . Hannan PCT, Windsor GD, Jong de A, et al. Comparative susceptibilities of various animal-pathogenic mycoplasmas to fluoroquinolones. Antimicrob Agents Chemother (1997) 41:2037–40.[Abstract]
6
.
Rolain J-M, Stuhl L, Maurin M, et al. Evaluation of antibiotic susceptibilities of three rickettsial species including Rickettsia felis by a quantitative PCR DNA assay. Antimicrob Agents Chemother (2002) 46:2747–51.
7 . Hawkey PM. Mechanisms of quinolone action and microbial response. J Antimicrob Chemother (2003) 51(Suppl S1):29–35.[Abstract]
8 . Drlica K, Malik M. Fluoroquinolones: action and resistance. Curr Top Med Chem (2003) 3:249–82.[CrossRef][Web of Science][Medline]
9
.
Lu T, Zhao X, Li X, et al. Enhancement of fluoroquinolone activity by C-8 halogen and methoxy moieties: action against a gyrase resistance mutant of Mycobacterium smegmatis and a gyrase-topoisomerase IV double mutant of Staphylococcus aureus. Antimicrob Agents Chemother (2001) 45:2703–9.
10 . Greene CE, Budsberg SC. Veterinary use of quinolones. In: Quinolone Antimicrobial Agents—Hooper DC, Wolfson JS, eds. (1993) 2nd edn. Washington, DC: American Society for Microbiology Press. 473–88.
11 . Stephan B, Friederichs S, Pridmore A, et al. Novel fluoroquinolone pradofloxacin: clinical efficacy and safety in the treatment of feline wound infections. J Vet Pharmacol Therap (2006) 29(Suppl 1):77–8.[CrossRef][Web of Science]
12
.
Wetzstein H-G. Comparative mutant prevention concentrations of pradofloxacin and other veterinary fluoroquinolones indicate differing potentials in preventing selection of resistance. Antimicrob Agents Chemother (2005) 49:4166–73.
13 . Stephan B, Greife HA, Pridmore A, et al. Mutant prevention concentration of pradofloxacin against Porphyromonas gingivalis. Vet Microbiol (2007) 121:194–5.[CrossRef][Web of Science][Medline]
14 . National Committee for Clinical Laboratory Standards. Methods for Antimicrobial Susceptibility Testing of Anaerobic Bacteria–Fifth Edition: Approved Standard M11-A5 (2001) Wayne, PA, USA: NCCLS.
15 . Appelbaum PC. Quinolone activity against anaerobes. Drugs (1999) 58(Suppl 2):60–4.[CrossRef][Web of Science][Medline]
16
.
Ednie LM, Jacobs MR, Appelbaum PC. Activities of gatifloxacin compared to those of seven other agents against anaerobic organisms. Antimicrob Agents Chemother (1998) 42:2459–62.
17
.
Goldstein EJC, Citron DM, Warren YA, et al. In vitro activity of moxifloxacin against 923 anaerobes isolated from human intra-abdominal infections. Antimicrob Agents Chemother (2006) 50:148–52.
18 . Goldstein EJC. Possible role for the new fluoroquinolones (levofloxacin, grepafloxacin, trovafloxacin, clinafloxacin, sparfloxacin, and DU-6859a) in the treatment of anaerobic infections: review of current information on efficacy and safety. Clin Infect Dis (1996) 23:S25–30.[Web of Science][Medline]
19 . Wexler HM, Molitoris E, Molitoris D, et al. In vitro activities of trovafloxacin against 557 strains of anaerobic bacteria. Antimicrob Agents Chemother (1996) 40:2232–5.[Abstract]
20
.
Goldstein EJC, Citron DM, Hudspeth M, et al. Trovafloxacin compared with levofloxacin, ofloxacin, ciprofloxacin, azithromycin and clarithromycin against unusual aerobic and anaerobic human and animal bite-wound pathogens. J Antimicrob Chemother (1998) 41:391–6.
21 . Aldridge KE, Ashcraft DS. Comparison of the in vitro activities of BAY 12-8039, a new quinolone, and other antimicrobials against clinically important anaerobes. Antimicrob Agents Chemother (1997) 41:709–11.[Abstract]
22 . Ackermann G, Schaumann R, Pless B, et al. Comparative activity of moxifloxacin in vitro against obligately anaerobic bacteria. Eur J Clin Microbiol Infect Dis (2000) 19:228–32.[CrossRef][Web of Science][Medline]
23 . Milazzo I, Blandino G, Musumeci R, et al. Antibacterial activity of moxifloxacin against periodontal anaerobic pathogens involved in systemic infections. Int J Antimicrob Agents (2002) 20:451–6.[CrossRef][Web of Science][Medline]
24 . Goldstein EJC. Review of the in vitro activity of gemifloxacin against Gram-positive and Gram-negative anaerobic pathogens. J Antimicrob Chemother (2000) 45(Suppl 1):55–65.[Abstract]
25 . King A, Downes J, Nord C-E, et al. Antimicrobial susceptibility of non-Bacteroides fragilis group anaerobic Gram-negative bacilli in Europe. Clin Microbiol Infect (1999) 5:404–16.[Medline]
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  B. Stephan, H. A. Greife, A. Pridmore, and P. Silley Activity of Pradofloxacin against Porphyromonas and Prevotella spp. Implicated in Periodontal Disease in Dogs: Susceptibility Test Data from a European Multicenter Study Antimicrob. Agents Chemother., June 1, 2008; 52(6): 2149 - 2155. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||