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Munn R, Whittem T. Moxidectin is a candidate for use as an in vivo internal standard in pharmacokinetic studies, as demonstrated with use in simultaneous tissue cage and ultrafiltration fluid collection. Front Vet Sci 2024; 11:1332974. [PMID: 38292465 PMCID: PMC10824831 DOI: 10.3389/fvets.2024.1332974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 01/04/2024] [Indexed: 02/01/2024] Open
Abstract
In vivo ultrafiltration has been used in veterinary pharmacokinetics since the early 2000's as an improvement on the tissue cage model which enables sampling of fluids from extra-circulatory compartments. Variability in analyte recovery from ultrafiltration samples, due to membrane fouling or tissue inflammation, has been a concern for this technique. Internal standards may be used to scale or verify the unknown result, such as is common in analytical extractions and in vivo microdialysis. Eight merino sheep were implanted with subcutaneous tissue cages and 2 weeks prior to the initiation of the study the sheep were injected with 0.2 mg/kg moxidectin subcutaneously. On the day of the study ultrafiltration probes were inserted subcutaneously. At time zero 4 mg/kg of carprofen was injected intravenously. Plasma, tissue cage, and ultrafiltration samples were taken 30 min before and 0.5, 1, 2, 3, 4, 5, 7, 24, 36, 48, 72 h after dosing. Carprofen and moxidectin concentrations were measured by LC-MS/MS. Pharmacokinetic parameters were estimated using Monolix for both the carprofen concentrations and the moxidectin corrected carprofen concentrations. The ultrafiltration probes failed to consistently produce enough sample volume to analyse. Moxidectin concentrations in the plasma and tissue cage fluid were stable throughout the 72 h sampling window. Moxidectin proved to be suitable as an in vivo internal standard for pharmacokinetic research using, tissue cages, plasma sampling and ultrafiltration probes, but the application of ultrafiltration techniques requires refinement.
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Affiliation(s)
- Richard Munn
- Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, VIC, Australia
- Cognosco, Anexa Veterinary Services, Morrinsville, New Zealand
| | - Ted Whittem
- Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, VIC, Australia
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
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2
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Azzariti S, Mead A, Toutain PL, Bond R, Pelligand L. Time-Kill Analysis of Canine Skin Pathogens: A Comparison of Pradofloxacin and Marbofloxacin. Antibiotics (Basel) 2023; 12:1548. [PMID: 37887249 PMCID: PMC10603860 DOI: 10.3390/antibiotics12101548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/10/2023] [Accepted: 10/13/2023] [Indexed: 10/28/2023] Open
Abstract
Time-kill curves (TKCs) are more informative compared with the use of minimum inhibitory concentration (MIC) as they allow the capture of bacterial growth and the development of drug killing rates over time, which allows to compute key pharmacodynamic (PD) parameters. Our study aimed, using a semi-mechanistic mathematical model, to estimate the best pharmacokinetic/pharmacodynamic (PK/PD) indices (ƒAUC/MIC or %ƒT > MIC) for the prediction of clinical efficacy of veterinary FQs in Staphylococcus pseudintermedius, Staphylococcus aureus, and Escherichia coli collected from canine pyoderma cases with a focus on the comparison between marbofloxacin and pradofloxacin. Eight TCKs for each bacterial species (4 susceptible and 4 resistant) were analysed in duplicate. The best PK/PD index was ƒAUC24h/MIC in both staphylococci and E. coli. For staphylococci, values of 25-40 h were necessary to achieve a bactericidal effect, whereas the calculated values (25-35 h) for E. coli were lower than those predicting a positive clinical outcome (100-120 h) in murine models. Pradofloxacin showed a higher potency (lower EC50) in comparison with marbofloxacin. However, no difference in terms of a maximal possible pharmacological killing rate (Emax) was observed. Taking into account in vivo exposure at the recommended dosage regimen (3 and 2 mg/kg for pradofloxacin and marbofloxacin, respectively), the overall killing rates (Kdrug) computed were also similar in most instances.
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Affiliation(s)
- Stefano Azzariti
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, UK; (S.A.); (A.M.); (P.-L.T.)
| | - Andrew Mead
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, UK; (S.A.); (A.M.); (P.-L.T.)
| | - Pierre-Louis Toutain
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, UK; (S.A.); (A.M.); (P.-L.T.)
- INTHERES, Université de Toulouse, INRAE, Ecole Nationale Vétérinaire de Toulouse, 23 chemin des Capelles-BP 87614, CEDEX 03, 31076 Toulouse, France
| | - Ross Bond
- Department of Clinical Sciences and Services, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, UK;
| | - Ludovic Pelligand
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, UK; (S.A.); (A.M.); (P.-L.T.)
- Department of Clinical Sciences and Services, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, UK;
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Caneschi A, Bardhi A, Barbarossa A, Zaghini A. The Use of Antibiotics and Antimicrobial Resistance in Veterinary Medicine, a Complex Phenomenon: A Narrative Review. Antibiotics (Basel) 2023; 12:antibiotics12030487. [PMID: 36978354 PMCID: PMC10044628 DOI: 10.3390/antibiotics12030487] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/25/2023] [Accepted: 02/27/2023] [Indexed: 03/05/2023] Open
Abstract
As warned by Sir Alexander Fleming in his Nobel Prize address: “the use of antimicrobials can, and will, lead to resistance”. Antimicrobial resistance (AMR) has recently increased due to the overuse and misuse of antibiotics, and their use in animals (food-producing and companion) has also resulted in the selection and transmission of resistant bacteria. The epidemiology of resistance is complex, and factors other than the overall quantity of antibiotics consumed may influence it. Nowadays, AMR has a serious impact on society, both economically and in terms of healthcare. This narrative review aimed to provide a scenario of the state of the AMR phenomenon in veterinary medicine related to the use of antibiotics in different animal species; the impact that it can have on animals, as well as humans and the environment, was considered. Providing some particular instances, the authors tried to explain the vastness of the phenomenon of AMR in veterinary medicine due to many and diverse aspects that cannot always be controlled. The veterinarian is the main reference point here and has a high responsibility towards the human–animal–environment triad. Sharing such a burden with human medicine and cooperating together for the same purpose (fighting and containing AMR) represents an effective example of the application of the One Health approach.
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Affiliation(s)
| | - Anisa Bardhi
- Correspondence: (A.B.); (A.B.); Tel.: +39-051-2097-500 (Andrea Barbarossa)
| | - Andrea Barbarossa
- Correspondence: (A.B.); (A.B.); Tel.: +39-051-2097-500 (Andrea Barbarossa)
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Hertzsch R, Richter A. Systematic Review of the Pharmacological Evidence for the Selection of Antimicrobials in Bacterial Infections of the Central Nervous System in Dogs and Cats. Front Vet Sci 2022; 8:769588. [PMID: 35118150 PMCID: PMC8803749 DOI: 10.3389/fvets.2021.769588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 12/24/2021] [Indexed: 11/13/2022] Open
Abstract
Bacterial meningitis in dogs and cats is a rare disease associated with a high lethality rate. The spectrum of causative bacteria includes a diverse set of gram positive, gram negative and anaerobic species. Currently, no veterinary medicinal product is approved for this indication in these species in Europe. The objective of this review was to collect the available pharmacokinetic data for antibiotics approved in dogs and cats to enable a preliminary analysis of their potential effectiveness for the treatment of bacterial meningitis. This analysis yielded data for 13 different antibiotics in dogs and two in cats. Additionally, data about frequently recommended cephalosporines not approved in dogs and cats were included. The collected data was used to assess the potential of the respective antibiotics to attain certain simple pharmacokinetic-pharmacodynamic (PK-PD) indexes in the cerebrospinal fluid (CSF). A more sophisticated investigation using modern methods was not possible due to the limited data available. For this purpose, data about the sensitivity of four bacterial species commonly associated with meningitis in dogs and cats to these antibiotics were included. The analysis provided evidence for the potential effectiveness of ampicillin, doxycycline, enrofloxacin, ceftriaxone and cefoxitin against bacteria frequently detected in bacterial meningitis in dogs. Data were not available or insufficient for the assessment of several antibiotics, including frequently recommended substances like metronidazole and trimethoprim-sulphonamide. Little evidence is available for the use of antibiotics in cats afflicted with this disease, highlighting the need for further research to obtain data for evidence based therapeutic recommendations.
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Xie S, Trott DJ, Saputra S, Ebrahimie E, Dehcheshmeh MM, Page C, Woodward N, Griffiths N, Kimble B, Govendir M. Pharmacokinetic profile and effect on the faecal microbiome of a single dose of pradofloxacin oral suspension in the rabbit (Oryctolagus cuniculus). J Vet Pharmacol Ther 2021; 45:203-212. [PMID: 34897751 DOI: 10.1111/jvp.13038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 12/02/2021] [Accepted: 12/06/2021] [Indexed: 11/30/2022]
Abstract
Fluoroquinolones are often administered to pet rabbits given their perceived safety and limited effects on anaerobic gut microbiota. However, the pharmacokinetics and relative safety of pradofloxacin, a third-generation veterinary fluoroquinolone with a much broader spectrum of activity, have not been reported in this species. Here, we determined the pharmacokinetic profile of a single dose of oral pradofloxacin in rabbits and evaluated effects on the faecal microbiome. Four mature female rabbits were administered pradofloxacin (25 mg/ml oral suspension), at a dose of 7.5 mg/kg. The pradofloxacin median (range) Tmax was 4.50 (2.00-5.00) h, Cmax 600.66 (395.85-886.72) ng/ml and t½ was 1.27 (0.12-1.39) h. These results indicated that oral absorption of pradofloxacin was slower, and elimination faster compared with other fluoroquinolones in healthy rabbits, as well as relative to cats and dogs. Following treatment with pradofloxacin, faecal microbiota profiling showed some compositional differences between treated and control animals. This was the result of a significant decrease in the abundance of Proteobacteria, in particular bacteria belonging to the Pseudomonas, Atopostipes and Parabacteroides genera. The pharmacokinetic profile of pradofloxacin in rabbits should be further studied by increasing the sample size and using multiple-dose protocols (i.e. 7 days) to confirm safety. Further information on the effects of protein binding, higher dosages and disease on pradofloxacin pharmacokinetics in rabbits are needed before an accurate dosing regimen can be recommended.
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Affiliation(s)
- Shangzhe Xie
- Mandai Wildlife Group, Singapore, Singapore.,Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy Campus, Roseworthy, SA, Australia
| | - Darren J Trott
- Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy Campus, Roseworthy, SA, Australia
| | - Sugiyono Saputra
- Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy Campus, Roseworthy, SA, Australia
| | - Esmaeil Ebrahimie
- Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy Campus, Roseworthy, SA, Australia.,La Trobe Genomics Research Platform, School of Life Sciences, College of Science, Health and Engineering, La Trobe University, Melbourne, Vic., Australia
| | - Manijeh Mohammadi Dehcheshmeh
- Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy Campus, Roseworthy, SA, Australia
| | - Caitlyn Page
- Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy Campus, Roseworthy, SA, Australia
| | - Nicola Woodward
- Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy Campus, Roseworthy, SA, Australia
| | - Neil Griffiths
- Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy Campus, Roseworthy, SA, Australia
| | - Benjamin Kimble
- Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Merran Govendir
- Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
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Toutain PL, Pelligand L, Lees P, Bousquet-Mélou A, Ferran AA, Turnidge JD. The pharmacokinetic/pharmacodynamic paradigm for antimicrobial drugs in veterinary medicine: Recent advances and critical appraisal. J Vet Pharmacol Ther 2020; 44:172-200. [PMID: 33089523 DOI: 10.1111/jvp.12917] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 08/16/2020] [Accepted: 09/22/2020] [Indexed: 12/12/2022]
Abstract
Pharmacokinetic/pharmacodynamic (PK/PD) modelling is the initial step in the semi-mechanistic approach for optimizing dosage regimens for systemically acting antimicrobial drugs (AMDs). Numerical values of PK/PD indices are used to predict dose and dosing interval on a rational basis followed by confirmation in clinical trials. The value of PK/PD indices lies in their universal applicability amongst animal species. Two PK/PD indices are routinely used in veterinary medicine, the ratio of the area under the curve of the free drug plasma concentration to the minimum inhibitory concentration (MIC) (fAUC/MIC) and the time that free plasma concentration exceeds the MIC over the dosing interval (fT > MIC). The basic concepts of PK/PD modelling of AMDs were established some 20 years ago. Earlier studies have been reviewed previously and are not reconsidered in this review. This review describes and provides a critical appraisal of more recent, advanced PK/PD approaches, with particular reference to their application in veterinary medicine. Also discussed are some hypotheses and new areas for future developments.First, a brief overview of PK/PD principles is presented as the basis for then reviewing more advanced mechanistic considerations on the precise nature of selected indices. Then, several new approaches to selecting PK/PD indices and establishing their numerical values are reviewed, including (a) the modelling of time-kill curves and (b) the use of population PK investigations. PK/PD indices can be used for dose determination, and they are required to establish clinical breakpoints for antimicrobial susceptibility testing. A particular consideration is given to the precise nature of MIC, because it is pivotal in establishing PK/PD indices, explaining that it is not a "pharmacodynamic parameter" in the usual sense of this term.
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Affiliation(s)
- Pierre-Louis Toutain
- INTHERES, INRA, ENVT, Université de Toulouse, Toulouse, France.,Royal Veterinary College, University of London, London, UK
| | | | - Peter Lees
- Royal Veterinary College, University of London, London, UK
| | | | - Aude A Ferran
- INTHERES, INRA, ENVT, Université de Toulouse, Toulouse, France
| | - John D Turnidge
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
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Boothe DM, Bush KM, Boothe HW, Davis HA. Pharmacokinetics and pharmacodynamics of oral pradofloxacin administration in dogs. Am J Vet Res 2019; 79:1268-1276. [PMID: 30457901 DOI: 10.2460/ajvr.79.12.1268] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine whether target values for pharmacokinetic-pharmacodynamic (PK-PD) indices against selected canine pathogens were achievable for pradofloxacin in various canine fluids and leukocytes. ANIMALS 8 healthy adult hounds (experiments 1 and 2) and 6 healthy adult dogs (experiment 3). PROCEDURES In 3 experiments, pradofloxacin (3, 6, or 12 mg/kg) and enrofloxacin (5 or 10 mg/kg) were orally administered once a day for 5 days, and blood, interstitial fluid (ISF), and other fluid samples were collected at various points. Sample drug concentrations were measured, and noncompartmental pharmacokinetic analysis was performed; then, PK-PD indices (ratios between maximum observed concentration [Cmax] and minimum inhibitory or mutant prevention concentrations) were determined for 7 bacterial species. RESULTS PK-PD values for pradofloxacin at 3 mg/kg were approximately 5 times as high in leukocyte versus plasma and were lowest in CSF, synovial fluid, and aqueous humor. No significant differences were noted between serum and ISF. Value ratios for serum versus other body fluids were numerically higher for pradofloxacin (vs enrofloxacin) for all fluid types except CSF and aqueous humor. Target PK-PD values were exceeded for pradofloxacin against all 7 bacterial species in leukocytes and against all species except Bacteroides spp in serum and ISF. Enrofloxacin achieved the target Cmax-to-minimum inhibitory concentration ratio against Pasteurella multocida in serum, ISF, and leukocytes and for Staphylococcus pseudintermedius in serum and leukocytes. A Cmax-to-mutant prevention concentration ratio ≥ 1 against Eschericha coli was achieved for pradofloxacin at 6 mg/kg. CONCLUSIONS AND CLINICAL RELEVANCE These findings supported once-daily oral administration of pradofloxacin to dogs at the currently recommended dose (7.5 mg/kg).
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Ito Y, Inagaki Y, Kobuchi S, Takada K, Sakaeda T. Therapeutic Drug Monitoring of Vancomycin in Dermal Interstitial Fluid Using Dissolving Microneedles. Int J Med Sci 2016; 13:271-6. [PMID: 27076783 PMCID: PMC4829539 DOI: 10.7150/ijms.13601] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 02/24/2016] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVE To design an alternative painless method for vancomycin (VCM) monitoring by withdrawing interstitial fluid (ISF) the skin using dissolving microneedles (DMNs) and possibly replace the conventional clinical blood sampling method. METHODS Male Wistar rats were anesthetized with 50 mg/kg sodium pentobarbital. Vancomycin at 5 mg/mL in saline was intravenously administered via the jugular vein. ISF was collected from a formed pore at 15, 30, 45, 60, 75, 90, and 120 min after the DMNs was removed from the skin. In addition, 0.3 mL blood samples were collected from the left femoral vein. RESULTS The correlation between the plasma and ISF VCM concentrations was significantly strong (r = 0.676, p < 0.05). Microscopic observation of the skin after application of the DMNs demonstrated their safety as a device for sampling ISF. CONCLUSION A novel monitoring method for VCM was developed to painlessly determine concentrations in the ISF as opposed to blood sampling.
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Affiliation(s)
- Yukako Ito
- 1. Department of Pharmacokinetics, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto, 607-8412, Japan
| | - Yuto Inagaki
- 1. Department of Pharmacokinetics, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto, 607-8412, Japan
| | - Shinji Kobuchi
- 1. Department of Pharmacokinetics, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto, 607-8412, Japan
| | - Kanji Takada
- 2. BioSerenTach Inc., Shimogyo-ku, Kyoto, 600-8040, Japan
| | - Toshiyuki Sakaeda
- 1. Department of Pharmacokinetics, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto, 607-8412, Japan
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Maaland MG, Guardabassi L, Papich MG. Minocycline pharmacokinetics and pharmacodynamics in dogs: dosage recommendations for treatment of meticillin-resistant Staphylococcus pseudintermedius infections. Vet Dermatol 2015; 25:182-e47. [PMID: 24840325 DOI: 10.1111/vde.12130] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND Although minocycline is not licensed for use in dogs, this tetracycline has therapeutic potential against meticillin-resistant Staphylococcus pseudintermedius. HYPOTHESIS/OBJECTIVES The aim of this study was to establish rational dosage recommendations for minocycline use in dogs. Specific objectives were to generate and analyse minocycline pharmacokinetic (PK) data on plasma and interstitial fluid (ISF) concentrations, plasma protein binding and pharmacodynamic (PD) data on antimicrobial activity against S. pseudintermedius. ANIMALS Six healthy dogs from a research colony were used in this study. METHODS Dogs were administered 5 mg/kg intravenously and 10 mg/kg orally (p.o.) of minocycline hydrochloride in separate crossover experiments. In vivo drug concentrations in plasma and in ISF collected by ultrafiltration were measured by high-performance liquid chromatography. Pharmacokinetic analysis was performed on plasma and ISF concentrations. PK/PD analysis was completed using in vitro data on plasma protein binding and minocycline susceptibility in 168 S. pseudintermedius isolates. RESULTS Minocycline distributed to the ISF to a higher degree than predicted by the protein-unbound fraction in plasma. A large volume of distribution after oral administration, with plasma and ISF elimination half-lives of 4.1 and 7.4 h, respectively, demonstrated that the ISF serves as a drug reservoir for sustained tissue concentrations. Monte Carlo simulation, used to assess target attainment at different drug dosages, indicated that p.o. administration of 5 mg/kg twice daily is sufficient to inhibit S. pseudintermedius strains with minimal inhibitory concentrations ≤0.25 μg/mL. CONCLUSIONS AND CLINICAL IMPORTANCE Besides dosage recommendations for therapy of meticillin-resistant Staphylococcus pseudintermedius infections in dogs, the study also provides PK/PD data necessary to consider species-specific clinical breakpoints for minocycline susceptibility testing.
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Affiliation(s)
- Marit G Maaland
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870, Frederiksberg C, Denmark
| | - Luca Guardabassi
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870, Frederiksberg C, Denmark
| | - Mark G Papich
- College of Veterinary Medicine, North Carolina State University, 1060 William Moore Drive, Raleigh, North Carolina, 27607, USA
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Mutant prevention concentrations of pradofloxacin for susceptible and mutant strains of Escherichia coli with reduced fluoroquinolone susceptibility. Int J Antimicrob Agents 2014; 44:354-7. [PMID: 25129317 DOI: 10.1016/j.ijantimicag.2014.06.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 05/23/2014] [Accepted: 06/10/2014] [Indexed: 11/23/2022]
Abstract
Pharmacodynamic and mutant prevention properties of the fluoroquinolone pradofloxacin (PRA) were measured against a set of 17 Escherichia coli strains carrying no, one or two known mutations conferring reduced fluoroquinolone susceptibility. The strains included susceptible wild-types, isogenic constructed mutants, isogenic selected mutants and clinical isolates. The effectiveness of PRA was determined with regard to preventing the selection of resistant mutants, using static and changing concentrations of drug. Ciprofloxacin was used as a reference drug. Minimum inhibitory concentrations (MICs) and mutant prevention concentrations (MPCs) of PRA for the susceptible wild-type strains were in the range 0.012-0.016mg/L and 0.2-0.3mg/L, respectively, giving a mean±standard deviation mutant prevention index (MPI=MPC/MIC) of 17.7±1.1. The mean MPI PRA of the 14 mutant strains was 19.2±12, and the mean MPI across all 17 strains was 18.9±10.8. In an in vitro kinetic model in which PRA was diluted with a half-life of 7h to mimic in vivo conditions, an initial concentration of PRA of 1.6-2.4mg/L (8-10× MPC), giving a PRA AUC/MPC ratio of 73-92, and a T>MPC of 21-23h was sufficient to prevent the selection of resistant mutants from the three susceptible wild-type strains. Dosing to reduce selection for antibiotic resistance in veterinary therapy has a role in reducing the reservoir of resistant mutants. We conclude that a level of dosing that prevents the selection of resistant mutants during therapy should be achievable in vivo.
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