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Chen H, Li L, Liu Y, Wu M, Xu S, Zhang G, Qi C, Du Y, Wang M, Li J, Huang X. In vitro activity and post-antibiotic effects of linezolid in combination with fosfomycin against clinical isolates of Staphylococcus aureus. Infect Drug Resist 2018; 11:2107-2115. [PMID: 30464553 PMCID: PMC6219420 DOI: 10.2147/idr.s175978] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Objectives Linezolid combination therapy is recommended for the treatment of Staphylococcus aureus (S. aureus) infections. However, the optimal regimen of the combination therapy for S. aureus is unknown. The objective of this study was to investigate the antibacterial activity, post-antibiotic effect (PAE), and post-antibiotic subminimum inhibitory concentration (MIC) effect (PA-SME) of linezolid alone and in combination with fosfomycin against eleven clinical isolates of S. aureus. Methods The synergistic effects and antibacterial activity of linezolid and fosfomycin were assessed by checkerboard and time-kill assays. To determine the PAE and PA-SME, S. aureus strains in the logarithmic phase of growth were exposed for 1, 2, and 3 hours to the antibiotics, alone and in combination. Recovery periods of test strains were evaluated using viable counting after dilution. Results Synergistic effects were observed for eight strains and no antagonism was found with any combination. Moreover, linezolid combined with fosfomycin at 4x MIC showed the best synergistic antibacterial effect, and this effect was retained after 24 hours. In addition, both the antibiotics alone and in combination showed increased PAE and PA-SME values in a concentration- and time-dependent manner. Conclusion Linezolid combined with fosfomycin exerted a good antibacterial effect against S. aureus, and the combinations have significant PAE and PA-SME.
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Affiliation(s)
- Hao Chen
- Department of Pharmacy, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.,Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China, .,Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China,
| | - Lan Li
- Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China, .,Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China,
| | - Yanyan Liu
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China,
| | - Maomao Wu
- Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China, .,Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China,
| | - Shuangli Xu
- Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China, .,Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China,
| | - Guijun Zhang
- Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China, .,Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China,
| | - Caifen Qi
- Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China, .,Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China,
| | - Yan Du
- Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China, .,Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China,
| | - Mingli Wang
- Department of Microbiology, Anhui Medical University, Hefei, Anhui, China
| | - Jiabin Li
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China,
| | - Xiaohui Huang
- Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China, .,Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, Anhui, China,
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Population pharmacokinetic/pharmacodynamic analysis of the bactericidal activities of sutezolid (PNU-100480) and its major metabolite against intracellular Mycobacterium tuberculosis in ex vivo whole-blood cultures of patients with pulmonary tuberculosis. Antimicrob Agents Chemother 2014; 58:3306-11. [PMID: 24687496 DOI: 10.1128/aac.01920-13] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sutezolid (PNU-100480 [U-480]) is an oxazolidinone antimicrobial being developed for the treatment of tuberculosis. An active sulfoxide metabolite (PNU-101603 [U-603]), which reaches concentrations in plasma several times those of the parent, has been reported to drive the killing of extracellular Mycobacterium tuberculosis by sutezolid in hollow-fiber culture. However, the relative contributions of the parent and metabolite against intracellular M. tuberculosis in vivo are not fully understood. The relationships between the plasma concentrations of U-480 and U-603 and intracellular whole-blood bactericidal activity (WBA) in ex vivo cultures were examined using a direct competitive population pharmacokinetic (PK)/pharmacodynamic 4-parameter sigmoid model. The data set included 690 PK determinations and 345 WBA determinations from 50 tuberculosis patients enrolled in a phase 2a sutezolid trial. The model parameters were solved iteratively. The median U-603/U-480 concentration ratio was 7.1 (range, 1 to 28). The apparent 50% inhibitory concentration of U-603 for intracellular M. tuberculosis was 17-fold greater than that of U-480 (90% confidence interval [CI], 9.9- to 53-fold). Model parameters were used to simulate in vivo activity after oral dosing with sutezolid at 600 mg twice a day (BID) and 1,200 mg once a day (QD). Divided dosing resulted in greater cumulative activity (-0.269 log10 per day; 90% CI, -0.237 to -0.293 log10 per day) than single daily dosing (-0.186 log10 per day; 90% CI, -0.160 to -0.208 log10 per day). U-480 accounted for 84% and 78% of the activity for BID and QD dosing, respectively, despite the higher concentrations of U-603. Killing of intracellular M. tuberculosis by orally administered sutezolid is mainly due to the activity of the parent compound. Taken together with the findings of other studies in the hollow-fiber model, these findings suggest that sutezolid and its metabolite act on different mycobacterial subpopulations.
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Biomarker-assisted dose selection for safety and efficacy in early development of PNU-100480 for tuberculosis. Antimicrob Agents Chemother 2010; 55:567-74. [PMID: 21078950 DOI: 10.1128/aac.01179-10] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Tuberculosis is a serious global health threat for which new treatments are urgently needed. This study examined the safety, tolerability, pharmacokinetics, and pharmacodynamics of multiple ascending doses of the oxazolidinone PNU-100480 in healthy volunteers, using biomarkers for safety and efficacy. Subjects were randomly assigned to PNU-100480 or placebo (4:1) at schedules of 100, 300, or 600 mg twice daily or 1,200 mg daily for 14 days or a schedule of 600 mg twice daily for 28 days to which pyrazinamide was added on days 27 and 28. A sixth cohort was given linezolid at 300 mg daily for 4 days. Signs, symptoms, and routine safety tests were monitored. Bactericidal activity against Mycobacterium tuberculosis was measured in ex vivo whole-blood culture. Plasma drug and metabolite concentrations were compared to the levels required for inhibition of M. tuberculosis growth and 50% inhibition of mitochondrial protein synthesis. All doses were safe and well tolerated. There were no hematologic or other safety signals during 28 days of dosing at 600 mg twice daily. Plasma concentrations of PNU-100480 and metabolites at this dose remained below those required for 50% inhibition of mitochondrial protein synthesis. Cumulative whole-blood bactericidal activity of PNU-100480 at this dose (-0.316 ± 0.04 log) was superior to the activities of all other doses tested (P < 0.001) and was significantly augmented by pyrazinamide (-0.420 ± 0.06 log) (P = 0.002). In conclusion, PNU-100480 was safe and well tolerated at all tested doses. Further studies in patients with tuberculosis are warranted. Biomarkers can accelerate early development of new tuberculosis treatments.
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Alffenaar JWC, van Altena R, Harmelink IM, Filguera P, Molenaar E, Wessels AMA, van Soolingen D, Kosterink JGW, Uges DRA, van der Werf TS. Comparison of the pharmacokinetics of two dosage regimens of linezolid in multidrug-resistant and extensively drug-resistant tuberculosis patients. Clin Pharmacokinet 2010; 49:559-65. [PMID: 20608757 DOI: 10.2165/11532080-000000000-00000] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
BACKGROUND AND OBJECTIVES For the treatment of multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB), potent new drugs are urgently needed. Linezolid is a promising drug, but its use is limited by adverse effects with prolonged administration of 600 mg twice daily. In order to reduce its adverse effects and maintain efficacy, we investigated whether linezolid in a reduced dosage resulted in drug serum concentrations exceeding a ratio of the in vitro minimum inhibitory concentration (MIC) to the area under the serum concentration-time curve (AUC) over 24 hours (AUC(24)) [AUC(24)/MIC] of >100. PATIENTS AND METHODS This open-label, prospective pharmacokinetic study evaluated two doses (300 and 600 mg) of linezolid in MDR-TB patients, who received linezolid as part of their treatment. They received linezolid 300 mg twice daily for 3 days, followed by 600 mg twice daily. Blood samples taken at predefined intervals for measuring serum linezolid concentrations were processed by a validated liquid chromatography-tandem mass spectrometry procedure. The AUC(24)/MIC ratio was used as a predictive model of efficacy. Adverse effects of linezolid, including peripheral neuropathy, were evaluated by clinical and laboratory assessments. RESULTS Eight patients were included in this study. The median duration of linezolid treatment was 56 days (interquartile range [IQR 44-82] days), with a median cumulative dose of 51,000 mg (IQR 33,850-60,450 mg). The median linezolid AUC over 12 hours (AUC(12)) values were 57.6 mg x h/L (IQR 38.5-64.2 mg x h/L) with the 300 mg dose and 145.8 mg x h/L (IQR 101.2-160.9 mg x h/L) with the 600 mg dose. The AUC(24)/MIC ratios were 452 (IQR 343-513) with the 300 mg dose and 1151 (IQR 656-1500) with the 600 mg dose. Linezolid was well tolerated. CONCLUSION Seemingly effective serum concentrations were reached after 3 days of administration of linezolid 300 mg twice daily, i.e. the AUC(24)/MIC ratio was at least 100 in 7 of 8 patients. Larger numbers of patients should be studied to confirm the efficacy of the linezolid 300 mg twice-daily dosage in MDR-TB or XDR-TB treatment.
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Affiliation(s)
- Jan-Willem C Alffenaar
- Department of Hospital and Clinical Pharmacy and Toxicology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
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