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Fratoni AJ, Berry AV, Liu X, Chen X, Wu Y, Nicolau DP, Abdelraouf K. Imipenem/funobactam (formerly XNW4107) in vivo pharmacodynamics against serine carbapenemase-producing Gram-negative bacteria: a novel modelling approach for time-dependent killing. J Antimicrob Chemother 2023; 78:2343-2353. [PMID: 37667103 PMCID: PMC10477119 DOI: 10.1093/jac/dkad242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 07/15/2023] [Indexed: 09/06/2023] Open
Abstract
BACKGROUND Imipenem/funobactam (formerly XNW4107) is a novel β-lactam/β-lactamase inhibitor with activity against MDR Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacterales strains. Using a neutropenic murine thigh infection model, we aimed to determine the pharmacokinetic/pharmacodynamic (PK/PD) index, relative to funobactam exposure, that correlated most closely with the in vivo efficacy of imipenem/funobactam combination and the magnitude of index required for efficacy against serine carbapenemase-producing clinical strains. METHODS Dose-fractionation was conducted against three strains. Imipenem human-simulated regimen (HSR, 500 mg q6h 1 h infusion) efficacy in combination with escalating funobactam exposures against seven A. baumannii, four P. aeruginosa and four Klebsiella pneumoniae (imipenem/funobactam MICs 0.25-16 mg/L) was assessed as 24 h change in log10cfu/thigh. RESULTS Increased funobactam fractionation enhanced efficacy, indicating time-dependent killing. Changes in log10cfu/thigh versus %fT > MIC were poorly predictive of efficacy; bactericidal activity was observed at %fT > MIC = 0%. Across different threshold plasma funobactam concentrations (CTs), %fT > CT(1 mg/L) had the highest correlation with efficacy. Normalizing the %fT > CT = 1 mg/L index to the respective isolate imipenem/funobactam MIC ([%fT > CT]/MIC) allowed integration of the isolate's susceptibility, which further enhanced the correlation. Median (%fT > CT[1 mg/L])/MIC values associated with 1-log reductions were 9.82 and 9.90 for A. baumannii and P. aeruginosa, respectively. Median (%fT > CT[1 mg/L])/MIC associated with stasis was 55.73 for K. pneumoniae. Imipenem/funobactam 500/250 mg q6h 1 h infusion HSR produced >1-log kill against 6/7 A. baumannii, 4/4 P. aeruginosa and stasis against 4/4 K. pneumoniae. CONCLUSIONS Imipenem/funobactam showed potent in vivo efficacy against serine carbapenemase-producers. The novel PK/PD index (%fT > CT)/MIC appeared to best describe in vivo activity.
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Affiliation(s)
- Andrew J Fratoni
- Center for Anti-Infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, CT 06102, USA
| | - Angela V Berry
- Center for Anti-Infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, CT 06102, USA
| | - Xiao Liu
- Department of Research and Development, Evopoint Biosciences Co., Ltd, Beijing, China
| | - Xi Chen
- Department of Research and Development, Evopoint Biosciences Co., Ltd, Beijing, China
| | - Yuchuan Wu
- Department of Research and Development, Evopoint Biosciences Co., Ltd, Beijing, China
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, CT 06102, USA
- Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, CT 06102, USA
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Abdelraouf K, Nicolau DP. In vivo pharmacokinetic/pharmacodynamic evaluation of cefepime/taniborbactam combination against cefepime-non-susceptible Enterobacterales and Pseudomonas aeruginosa in a murine pneumonia model. J Antimicrob Chemother 2023; 78:692-702. [PMID: 36640133 PMCID: PMC9978589 DOI: 10.1093/jac/dkac446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 12/19/2022] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Cefepime/taniborbactam is a cephalosporin/bicyclic boronate β-lactamase inhibitor combination in clinical development for nosocomial pneumonia due to MDR Gram-negative bacteria. A murine pneumonia model was used to characterize cefepime/taniborbactam in vivo pharmacodynamics against Enterobacterales and Pseudomonas aeruginosa strains. METHODS Clinical cefepime-non-susceptible Enterobacterales and P. aeruginosa strains expressing serine carbapenemases and/or other cefepime-hydrolysing β-lactamases with cefepime/taniborbactam combination MICs of 0.12-16 mg/L were used. Cefepime and taniborbactam human-simulated regimens equivalent to clinical doses (i.e. 2/0.5 g q8h) were established in the pneumonia model. The in vivo activity of the cefepime human-simulated regimen given alone or concomitantly with escalating taniborbactam exposures against eight Enterobacterales and four P. aeruginosa strains was assessed. Taniborbactam pharmacokinetics were evaluated to determine systemic exposures of regimens used; taniborbactam fAUC0-24/MIC values required for efficacy were estimated using the Hill equation. In addition, the in vivo activity of the cefepime/taniborbactam combination human-simulated regimen was assessed against 18 strains. RESULTS Among Enterobacterales, median taniborbactam fAUC0-24/MIC values associated with stasis and 1 log kill were 0.96 and 4.03, respectively, while for P. aeruginosa, requirements were 1.35 and 3.02 for stasis and 1 log kill, respectively. The cefepime/taniborbactam human-simulated regimen produced >2 log kill in 14/18 strains and >1 log kill in 18/18 strains. CONCLUSIONS Cefepime/taniborbactam produced marked in vivo bactericidal activity against cefepime-non-susceptible Enterobacterales and P. aeruginosa isolates with cefepime/taniborbactam MICs up to and including 16 mg/L in the pneumonia model. Assessments of the probability of clinical attainment of the identified targets should be undertaken to support the selected cefepime/taniborbactam dose for treatment of nosocomial pneumonia.
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Affiliation(s)
- Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
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Fratoni AJ, Berry A, Yuan H, Liu X, Chen X, Wu Y, Nicolau DP, Abdelraouf K. 1722. In vivo Activity of Imipenem/XNW4107 Human-Simulated Regimen against Serine Carbapenemase-Producing Acinetobacter baumannii and Pseudomonas aeruginosa in the Neutropenic Murine Thigh Infection Model. Open Forum Infect Dis 2022. [PMCID: PMC9752493 DOI: 10.1093/ofid/ofac492.1352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Background Imipenem (IPM)/XNW4107 is a novel β-lactam/β-lactamase inhibitor with in vitro activity against serine carbapenemase-producing Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacterales. Herein, we evaluated the in vivo activity of an IPM/XNW4107 human-simulated regimen (HSR) against clinical OXA-23- and OXA-24-producing A. baumannii as well as KPC- and GES-producing P. aeruginosa using a neutropenic murine thigh infection model. Methods Seven A. baumannii and 4 P. aeruginosa isolates were included. IPM and IPM/XNW4107 MICs (XNW4107 fixed at 8 mg/L) were tested in triplicate by broth microdilution. One thigh of neutropenic ICR mice (6 mice per group) was inoculated with ∼107 CFU/mL bacterial suspensions. HSR that mimicked the clinical exposures of IPM 500 mg q6h alone or in combination with XNW4107 250 mg q6h each as 1 h infusion were developed in the murine model. In efficacy studies, two hours after inoculation, placebo, IPM 500 mg q6h 1 h infusion HSR, or IPM/XNW4107 500/250 mg q6h 1 h infusion HSR were administered subcutaneously. Efficacy was measured as the change in log10CFU/thigh at 24 h compared with 0 h controls. Results Isolates were IPM resistant (MICs 16 - > 64 mg/L). IPM/XNW4107 A. baumannii and P. aeruginosa MIC ranges were 1-16 and 1- 8 mg/L, respectively. Across all examined isolates, 0 h mean ± SD bacterial burden was 5.86 ± 0.32 log10 CFU/thigh. The 24 h increase in bacterial burden was 2.68 ± 0.91 log10 CFU/thigh in the sham controls. IPM HSR monotherapy groups showed mean increase in bacterial burden of 2.34 ± 0.95 log10 CFU/thigh. Bacterial kill with IPM/XNW4107 500/250 mg q6h 1 h infusion HSR ranged from -0.46 ± 1.69 to -3.77 ± 0.15 and -2.33 ± 0.25 to -3.76 ± 0.57 among A. baumannii and P. aeruginosa isolates, respectively. IPM/XNW4107 500/250 mg q6h 1 h infusion HSR produced > 1-log kill against 6/7 examined A. baumannii with the exception of A. baumannii 160 (IPM/XNW4107 MIC 16 mg/L) and 4/4 P. aeruginosa as well as > 2-log kill against 4/7 A. baumannii and 4/4 P. aeruginosa. Conclusion IPM/XNW4107 500/250 mg q6h 1 h infusion HSR showed potent in vivo activity against serine carbapenemase-producing A. baumannii and P. aeruginosa. These data support the consideration of IPM/XNW4107 for the treatment of serious infections due to these organisms in clinical trials. Disclosures Haitao Yuan, PhD, Evopoint Biosciences Co., Ltd: Stocks/Bonds Xiao Liu, PhD, Evopoint Biosciences Co., Ltd: Stocks/Bonds Xi Chen, PhD, Evopoint Biosciences Co., Ltd: Stocks/Bonds Yuchuan Wu, PhD, Evopoint Biosciences Co., Ltd: Stocks/Bonds David P. Nicolau, PharmD, Shionogi: Grant/Research Support Kamilia Abdelraouf, PhD, Evopoint Biosciences Co., Ltd: Grant/Research Support|Venatorx Pharmaceuticals, Inc.: Grant/Research Support.
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Affiliation(s)
| | | | - Haitao Yuan
- Evopoint Biosciences Co., Ltd, Beijing, Beijing, China
| | - Xiao Liu
- Evopoint Biosciences Co., Ltd, Beijing, Beijing, China
| | - Xi Chen
- Evopoint Biosciences Co., Ltd, Beijing, Beijing, China
| | - Yuchuan Wu
- Evopoint Biosciences Co., Ltd, Beijing, Beijing, China
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Abdelraouf K, Gill CM, Gethers M, Tiseo G, Falcone M, Menichetti F, Nicolau DP. 1650. Efficacy of β-Lactam Therapy against Infections Caused by Metallo-β-lactamase (MBL)-Producing Enterobacterales: Bridging the Susceptibility Testing Gap. Open Forum Infect Dis 2022. [PMCID: PMC9751858 DOI: 10.1093/ofid/ofac492.116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Background In vitro-in vivo discordance in the activity of β-lactams against MBL-producing Enterobacterales has been described. This discordance is likely attributed to the supra-physiologic zinc level in the in vitro testing media, which facilitates the bicyclic β-lactam ring hydrolysis. In this study, we compared the outcome of empirical non-MBL-active β-lactam therapy (carbapenems and ceftazidime/avibactam) and MBL-active β-lactam therapy (ceftazidime/avibactam plus aztreonam) among patients with bloodstream infections due to NDM-producing Klebsiella pneumoniae. Validation of the efficacy of carbapenem in a murine septicemia model was conducted. In vitro susceptibility testing conditions were altered to better predict the in vivo outcome. Methods A retrospective observational study of patients admitted to hospitals in Italy. The primary outcome was 14-day all-cause mortality. Cox regression analysis was performed to evaluate primary outcome. Kaplan Meier survival and log-rank test were used to compare 14-day mortality between patient’s cohorts. Septicemia was induced in mice via intraperitoneal inoculation with the isolates retrieved from the patients then clinical exposure of meropenem (MEM; 2 g q8h 3h infusion) was given for 2 days. Survival was recorded for 4 days and compared with sham controls. Unbound zinc levels were measured in human and infected mice plasma. MEM MICs were determined in Mueller Hinton Broth (MHB) and MHB adjusted to the physiologic zinc levels. Results Of the patients identified, 29 received empirical non-MBL-active β-lactams for median duration 4 days while 29 received MBL-active β-lactams. The 14-day mortality rate was 21% in the non-MBL-active group vs 14% in the MBL-active group (P = 0.73) and survival patterns were not significantly different (Fig. 1). Cox regression showed that use of non-MBL-active therapy was not associated with significantly increased 14-day mortality (hazard ratio = 1.45; P = 0.57). MEM treatment resulted in protection from mortality in mice (Fig. 2). MEM MICs in zinc-adjusted MHB were 1- to > 16-fold lowered relative to MICs in MHB ( ≥ 64 mg/L). Conclusion Our data provide foundational support to help establish PK/PD relationships using MICs derived in physiologic zinc levels which may better predict β-lactam therapy outcome. Disclosures Kamilia Abdelraouf, PhD, Evopoint Biosciences Co., Ltd: Grant/Research Support|Venatorx Pharmaceuticals, Inc.: Grant/Research Support Christian M. Gill, PharmD, Everest Medicines, Shionogi, Cepheid: Grant/Research Support Matthew Gethers, PhD, Thermo Fisher: Employee Marco Falcone, MD, PhD, GILEAD: Grant/Research Support|GSK: Honoraria|MENARINI: Advisor/Consultant|MENARINI: Grant/Research Support|MSD: Honoraria|PFIZER: Honoraria|SHIONOGI: Grant/Research Support Francesco Menichetti, n/a, Aneglini: Advisor/Consultant|Aneglini: Board Member|Aneglini: Grant/Research Support|Aneglini: Honoraria|Astellas: Advisor/Consultant|Astellas: Honoraria|Becton: Advisor/Consultant|Becton: Honoraria|bioMérieux: Advisor/Consultant|bioMérieux: Honoraria|Biotest: Advisor/Consultant|Biotest: Board Member|Biotest: Honoraria|Bristol-Myers Squibb: Advisor/Consultant|Bristol-Myers Squibb: Honoraria|Correvio: Advisor/Consultant|Correvio: Speaker honoraria|Dickinson: Advisor/Consultant|Dickinson: Honoraria|Gilead: Advisor/Consultant|Gilead: Grant/Research Support|Janssen: Advisor/Consultant|Janssen: Honoraria|MSD: Advisor/Consultant|MSD: Speaker honoraria|Nordic pharma: Board Member|Nordic pharma: Honoraria|Pfizer: Advisor/Consultant|Pfizer: Honoraria|Shionogi: Advisor/Consultant|Shionogi: Honoraria|ViiV: Advisor/Consultant|ViiV: Honoraria David P. Nicolau, PharmD, Shionogi: Grant/Research Support.
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Affiliation(s)
| | | | | | - Giusy Tiseo
- Infectious Diseases Unit/University of Pisa, Pisa, Toscana, Italy
| | - Marco Falcone
- Infectious Diseases Unit/University of Pisa, Pisa, Toscana, Italy
| | - Francesco Menichetti
- Department of Clinical and Experimental Medicine, Infectious Diseases Unit, University of Pisa, Pisa, Italy, Pisa, Toscana, Italy
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Abouelhassan Y, Kuti JL, Nicolau DP, Abdelraouf K. 1652. Sulbactam against Acinetobacter baumannii Pneumonia: Pharmacokinetic/Pharmacodynamic Appraisal of Current Dosing Recommendations. Open Forum Infect Dis 2022. [DOI: 10.1093/ofid/ofac492.118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Abstract
Background
Sulbactam (SUL), available in the USA as ampicillin-sulbactam, is a first line treatment for Acinetobacter baumannii infections. SUL is bactericidal against A. baumannii through affinity to penicillin-binding proteins with no synergy upon ampicillin addition. Despite its wide use, SUL dosing has not been standardized for management of A. baumannii infections. Herein, we examined SUL pharmacokinetic/pharmacodynamic (PK/PD) targets against A. baumannii in a neutropenic murine pneumonia model followed by estimation of the probability of target attainment (PTA) across a range of clinical SUL doses.
Methods
Eight clinical A. baumannii isolates (SUL MICs 1–16 mg/L) were tested. Mice were inoculated intranasally with 107 colony forming units (CFU)/mL bacterial suspensions. Two hours post inoculation, escalating SUL doses (1–200 mg/kg) were administered q8h for 24 h as ampicillin-sulbactam, while control mice received saline. Efficacy was measured as the change in log10 CFU/ lungs at 24 h compared with 0 h controls. PK and ex vivo protein binding of SUL were assessed in infected mice to determine the free systemic exposures of the regimens utilized. The percentages of dosing interval in which the free plasma concentration exceeded the SUL MIC (%fT > MIC) required to achieve 1- and 2-log kill against each isolate were estimated using Hill-equation. Monte Carlo simulations were performed to determine PTA for these endpoints with various clinically-utilized SUL dosing regimens. Mean and standard deviation values for SUL PK parameters were derived from patients with nosocomial pneumonia due to A. baumannii.
Results
Median (Interquartile range, IQR) %fT > MIC needed for 1-log and 2-log kill at 24 h were 27.36 (19.94 – 35.11) and 48.36 (38.18 – 58.01), respectively. The corresponding PTA following the maximum FDA-approved SUL dose for pneumonia (1g q6h, 0.5 h infusion) and three off-label doses are reported in the table.
Conclusion
Currently approved dose of SUL for pneumonia (1g q6h, 0.5 h infusion) provides effective exposure against A. baumannii at the current FDA/CLSI susceptibility breakpoint (SUL MIC ≤ 4 mg/L). Higher and/or more frequent SUL dosing provides additional coverage with 3 g q8h extended infusion further enhancing the PK/PD exposure against isolates with SUL MICs up to 16 mg/L.
Disclosures
Yasmeen Abouelhassan, PhD, Pfizer: spouse salary Joseph L. Kuti, PharmD, Abbvie: Honoraria|bioMeriuex: Advisor/Consultant|bioMeriuex: Grant/Research Support|Contrafect: Grant/Research Support|Entasis: Grant/Research Support|Merck and Co: Grant/Research Support|Roche Diagnostics: Grant/Research Support|Shionogi: Advisor/Consultant|Shionogi: Grant/Research Support|Shionogi: Honoraria|Summit: Grant/Research Support David P. Nicolau, PharmD, Shionogi: Grant/Research Support Kamilia Abdelraouf, PhD, Evopoint Biosciences Co., Ltd: Grant/Research Support|Venatorx Pharmaceuticals, Inc.: Grant/Research Support.
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Gill CM, Abdelraouf K, Oota M, Nakamura R, Kuroiwa M, Ishioka Y, Takemura M, Yamano Y, Nicolau DP. Assessment of sustained efficacy and resistance emergence under human-simulated exposure of cefiderocol against Acinetobacter baumannii using in vitro chemostat and in vivo murine infection models. JAC Antimicrob Resist 2022; 4:dlac047. [PMID: 35529054 PMCID: PMC9070809 DOI: 10.1093/jacamr/dlac047] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 04/02/2022] [Indexed: 12/03/2022] Open
Abstract
Objectives This study evaluated the sustained kill and potential for resistance development of Acinetobacter baumannii exposed to human-simulated exposure of cefiderocol over 72 h in in vitro and in vivo infection models. Methods Seven A. baumannii isolates with cefiderocol MICs of 0.12-2 mg/L were tested. The sustained bactericidal activity compared with the initial inoculum and the resistance appearance over 72 h treatment were evaluated in both an in vitro chemostat and an in vivo murine thigh infection model under the human-simulated exposure of cefiderocol (2 g every 8 h as 3 h infusion). Results In the in vitro model, regrowth was observed against all seven tested isolates and resistance emergence (>2 dilution MIC increase) was observed in five test isolates. Conversely, sustained killing over 72 h and no resistance emergence were observed in six of seven tested isolates in vivo. The mechanism of one resistant isolate that appeared only in the in vitro chemostat studies was a mutation in the tonB-exbB-exbD region, which contributes to the energy transduction on the iron transporters. The resistance acquisition mechanisms of other isolates have not been identified. Conclusions The discrepancy in the sustained efficacy and resistance emergence between in vitro and in vivo models was observed for A. baumannii. Although the resistance mechanisms in vitro have not been fully identified, sustained efficacy without resistance emergence was observed in vivo for six of seven isolates. These studies reveal the in vivo bactericidal activity and the low potential for development of resistance among A. baumannii evaluated under human-simulated exposures.
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Affiliation(s)
- Christian M. Gill
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Merime Oota
- Shionogi TechnoAdvance Research & Co. Ltd, Osaka, Japan
| | - Rio Nakamura
- Shionogi TechnoAdvance Research & Co. Ltd, Osaka, Japan
| | - Miho Kuroiwa
- Laboratory for Innovative Therapy Research, Shionogi & Co. Ltd, Osaka, Japan
| | - Yoshino Ishioka
- Laboratory for Innovative Therapy Research, Shionogi & Co. Ltd, Osaka, Japan
| | - Miki Takemura
- Laboratory for Drug Discovery and Disease Research, Shionogi & Co. Ltd, Osaka, Japan
| | | | - David P. Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
- Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA
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Leopold SR, Abdelraouf K, Nicolau DP, Agresta H, Johnson J, Teter K, Dunne WM, Broadwell D, van Belkum A, Schechter LM, Sodergren EJ, Weinstock GM. Murine Model for Measuring Effects of Humanized-Dosing of Antibiotics on the Gut Microbiome. Front Microbiol 2022; 13:813849. [PMID: 35250930 PMCID: PMC8892246 DOI: 10.3389/fmicb.2022.813849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/13/2022] [Indexed: 11/29/2022] Open
Abstract
There is a current need for enhancing our insight in the effects of antimicrobial treatment on the composition of human microbiota. Also, the spontaneous restoration of the microbiota after antimicrobial treatment requires better understanding. This is best addressed in well-defined animal models. We here present a model in which immune-competent or neutropenic mice were administered piperacillin-tazobactam (TZP) according to human treatment schedules. Before, during and after the TZP treatment, fecal specimens were longitudinally collected at established intervals over several weeks. Gut microbial taxonomic distribution and abundance were assessed through culture and molecular means during all periods. Non-targeted metabolomics analyses of stool samples using Quadrupole Time of Flight mass spectrometry (QTOF MS) were also applied to determine if a metabolic fingerprint correlated with antibiotic use, immune status, and microbial abundance. TZP treatment led to a 5–10-fold decrease in bacterial fecal viability counts which were not fully restored during post-antibiotic follow up. Two distinct, relatively uniform and reproducible restoration scenarios of microbiota changes were seen in post TZP-treatment mice. Post-antibiotic flora could consist of predominantly Firmicutes or, alternatively, a more diverse mix of taxa. In general, the pre-treatment microbial communities were not fully restored within the screening periods applied. A new species, closely related to Eubacterium siraeum, Mageeibacillus indolicus, and Saccharofermentans acetigenes, became predominant post-treatment in a significant proportion of mice, identified by 16S rRNA gene sequencing. Principal component analysis of QTOF MS of mouse feces successfully distinguished treated from non-treated mice as well as immunocompetent from neutropenic mice. We observe dynamic but distinct and reproducible responses in the mouse gut microbiota during and after TZP treatment and propose the current murine model as a useful tool for defining the more general post-antibiotic effects in the gastro-intestinal ecosystem where humanized antibiotic dosing may ultimately facilitate extrapolation to humans.
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Affiliation(s)
- Shana R. Leopold
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, United States
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, United States
| | - David P. Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, United States
| | - Hanako Agresta
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, United States
| | - Jethro Johnson
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, United States
| | - Kathleen Teter
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, United States
| | | | | | - Alex van Belkum
- BioMérieux SA, Clinical Unit, Grenoble, France
- *Correspondence: Alex van Belkum,
| | | | - Erica J. Sodergren
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, United States
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Abstract
Objectives Ertapenem has proven to be an effective antimicrobial; however, increasing enzyme-mediated resistance has been noted. Combination with zidebactam, a β-lactam enhancer, is restorative. Human-simulated regimens (HSRs) of ertapenem and zidebactam alone and in combination (WCK 6777; 2 g/2 g q24h) were assessed for efficacy against carbapenemase-producing Klebsiella pneumoniae (CP-KP) in the pneumonia model. Methods Infected ICR mice were rendered neutropenic and exposed to various doses of ertapenem and zidebactam alone and in combination to develop the HSRs that were subsequently confirmed in additional pharmacokinetic studies. Twenty-one CP-KP (KPC or OXA-48-like producers) with WCK 6777 MICs of 1–8 mg/L were utilized. Mice were treated for 24 h with saline or HSRs of ertapenem, zidebactam and WCK 6777. Efficacy was defined as change in mean lung bacterial density relative to 0 h. Results Confirmatory pharmacokinetic analysis showed agreement between predicted human exposures (%fT>MIC) and those achieved in vivo for all three HSRs. The 0 h bacterial density across all isolates was 6.69 ± 0.31 log10 cfu/lungs. At 24 h, densities increased by 2.57 ± 0.50, 2.2 ± 0.60 and 2.05 ± 0.71 log10 cfu/lungs in the 24 h control, ertapenem HSR and zidebactam HSR groups, respectively. Overall, 18/21 of the isolates exposed to the WCK 6777 HSR displayed a killing profile that exceeded the translational benchmark for efficacy of a 1 log10 cfu reduction. Among the remaining three isolates, two displayed ∼0.5 log10 kill and stasis was observed in the third. Conclusions Human-simulated exposures of WCK 6777 demonstrated potent in vivo activity against CP-KP, including those with WCK 6777 MICs up to 8 mg/L.
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Affiliation(s)
- Matthew Gethers
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Iris Chen
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
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Gill CM, Abdelraouf K, Oota M, Nakamura R, Kuroiwa M, Gahara Y, Takemura M, Yamano Y, Nicolau DP. Discrepancy in sustained efficacy and resistance emergence under human-simulated exposure of cefiderocol against Stenotrophomonas maltophilia between in vitro chemostat and in vivo murine infection models. J Antimicrob Chemother 2021; 76:2615-2621. [PMID: 34212183 DOI: 10.1093/jac/dkab221] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/02/2021] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES The present study evaluated the sustained kill and the potential for resistance development of Stenotrophomonas maltophilia exposed to a human-simulated exposure of cefiderocol over 72 h in in vitro and in vivo infection models. METHODS A total of seven S. maltophilia isolates with cefiderocol MICs of 0.03-0.5 mg/L were utilized. The sustained bactericidal activity compared with the initial inoculum and the appearance of resistance after the 72 h treatment were evaluated in both an in vitro chemostat model (four strains) and an in vivo murine thigh infection model (six strains) under the human-simulated exposure of cefiderocol (2 g every 8 h as a 3 h infusion). RESULTS In the in vitro model, regrowth was observed for three of four tested isolates and resistance emergence (>2-dilution MIC increase) was observed for all of the four test isolates. Conversely, sustained killing over 72 h and no resistance emergence were observed for all of the six tested isolates in the in vivo models. The mechanism of all resistant isolates that appeared only in the in vitro chemostat studies was a mutation in the tonB-exbB-exbD region, which contributes to the energy transduction on the iron transporters. CONCLUSIONS The discrepancy in the sustained efficacy and resistance emergence between in vivo and in vitro models appears to be due to the resistance acquisition mechanism caused by mutation in the tonB-exbB-exbD region developing in the enriched media utilized in vitro. These studies reveal the in vivo bactericidal activity and the low potential for development of resistance among Stenotrophomonas evaluated under human-simulated exposures.
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Affiliation(s)
- Christian M Gill
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Merime Oota
- Shionogi TechnoAdvance Research & Co., Ltd, Osaka, Japan
| | - Rio Nakamura
- Shionogi TechnoAdvance Research & Co., Ltd, Osaka, Japan
| | - Miho Kuroiwa
- Laboratory for Innovative Therapy Research, Shionogi & Co., Ltd, Osaka, Japan
| | - Yoshinari Gahara
- Laboratory for Innovative Therapy Research, Shionogi & Co., Ltd, Osaka, Japan
| | - Miki Takemura
- Laboratory for Drug Discovery and Disease Research, Shionogi & Co., Ltd, Osaka, Japan
| | | | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
- Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA
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10
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Gill CM, Abdelraouf K, Nicolau DP. In vivo activity of WCK 4282 (high-dose cefepime/tazobactam) against serine β-lactamase-producing Enterobacterales and Pseudomonas aeruginosa in the neutropenic murine thigh infection model. J Antimicrob Chemother 2021; 76:993-1000. [PMID: 33438033 DOI: 10.1093/jac/dkaa551] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 12/08/2020] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES WCK 4282, high-dose cefepime/tazobactam, possesses potent in vitro activity against Gram-negative organisms including ESBL- and cephalosporinase-harbouring strains. The purpose of this evaluation was to investigate the in vivo activity of human-simulated exposures of WCK 4282 against serine-β-lactamase-harbouring Enterobacterales and Pseudomonas aeruginosa. METHODS Nineteen clinical isolates were evaluated (ESBL/cephalosporinase producers, n = 8 Escherichia coli, n = 4 P. aeruginosa; KPC producers, n = 3 Klebsiella pneumoniae, n = 1 Klebsiella aerogenes; OXA-48/181 producers, n = 2 K. pneumoniae, n = 1 E. coli). WCK 4282 MICs ranged from 4 to 32 mg/L compared with 16 to >128 mg/L for cefepime. Thigh-infected neutropenic mice received cefepime, WCK 4282 or sham control over 24 h prior to harvest. Cefepime and tazobactam dosing regimens produced plasma profiles of fAUC, fT>MIC and fCmax similar to human exposure after WCK 4282 2/2 g every 8 h (1.5 h infusion). RESULTS Bacterial burdens (log10 cfu/thigh) were 5.81 ± 0.36 at 0 h and 9.29 ± 0.88 at 24 h in untreated controls. WCK 4282 produced potent activity against ESBL/cephalosporinase-producing strains with WCK 4282 MIC ≤16 mg/L; mean changes in log10 cfu/thigh from 0 h were -1.70 ± 0.77 and +1.86 ± 2.03 log10 cfu/thigh for WCK 4282 and cefepime human-simulated regimens, respectively. WCK 4282 produced variable activity against serine-carbapenemase-harbouring isolates. For the KPC-harbouring strains, WCK 4282 produced bacteriostasis with a mean -0.1 ± 0.61 log10 cfu/thigh. Against OXA-48/181-harbouring isolates, WCK 4282 produced a range of change in bacterial burden of -1.23 ± 0.33 to +1.04 ± 0.7 log10 cfu/thigh. CONCLUSIONS Human-simulated exposures of WCK 4282 produced in vivo efficacy against ESBL/cephalosporinase-producing, piperacillin/tazobactam- and ceftolozane/tazobactam-non-susceptible Enterobacterales and P. aeruginosa. These findings support further development of this combination as a carbapenem-sparing agent.
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Affiliation(s)
- Christian M Gill
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA.,Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA
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11
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Abdelraouf K, Reyes S, Nicolau DP. The paradoxical in vivo activity of β-lactams against metallo-β-lactamase-producing Enterobacterales is not restricted to carbapenems. J Antimicrob Chemother 2021; 76:684-691. [PMID: 33179050 DOI: 10.1093/jac/dkaa467] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 10/16/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Using murine models of infection, we previously reported the potent in vivo activity of carbapenems against MBL-producing Enterobacterales despite the observed resistance in vitro. In the current study, we examined the in vivo activity of a cefepime human-simulated regimen against MBL-producing Enterobacterales in a murine thigh infection model. METHODS A population of clinical isolates and isogenic engineered MBL-producing Enterobacterales transformants expressing MBLs but no detectable cefepime-hydrolysing serine β-lactamases were utilized. KPC-producing isolates were included as positive controls. Cefepime, piperacillin/tazobactam and meropenem MICs were determined using broth microdilution in conventional CAMHB and EDTA-supplemented (zinc-limited) broth. In vivo efficacy of a cefepime human-simulated regimen (2 g q8h as a 2 h infusion) was determined in the neutropenic murine thigh infection model against the test strains. Efficacy was measured as the change in log10 cfu/thigh at 24 h compared with 0 h controls. RESULTS MBL-producing Enterobacterales strains were found to be cefepime, piperacillin/tazobactam and meropenem non-susceptible in conventional broth. Supplementation with EDTA at a concentration of 300 mg/L resulted in multi-fold reduction in the MICs and restoration of susceptibility. In accordance with the MICs generated in zinc-limited broth, administration of a cefepime human-simulated regimen was associated with substantial bacterial reductions among mice infected with MBL-producing Enterobacterales. Absence of MIC reduction in zinc-limited broth and lack of efficacy among mice infected with KPC-producing isolates were observed. CONCLUSIONS For MBL-producing Enterobacterales, susceptibility testing with Mueller-Hinton broth, a zinc-rich testing medium, is flawed since it does not recapitulate the host environment, in which zinc concentrations are low.
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Affiliation(s)
- Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Sergio Reyes
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA.,Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA
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12
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Nicolau DP, Bhagwat SS, Abdelraouf K. Comment on: An update on cefepime and its future role in combination with novel β-lactamase inhibitors for MDR Enterobacterales and Pseudomonas aeruginosa. J Antimicrob Chemother 2021; 76:3326-3327. [PMID: 34179957 DOI: 10.1093/jac/dkab229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/07/2021] [Indexed: 12/27/2022] Open
Affiliation(s)
- David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA.,Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA
| | - Sachin S Bhagwat
- Wockhardt Research Centre, D4-MIDC, Chikalthana, Aurangabad, India
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
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13
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Abdelraouf K, Almarzoky Abuhussain S, Nicolau DP. In vivo pharmacodynamics of new-generation β-lactamase inhibitor taniborbactam (formerly VNRX-5133) in combination with cefepime against serine-β-lactamase-producing Gram-negative bacteria. J Antimicrob Chemother 2021; 75:3601-3610. [PMID: 32862218 DOI: 10.1093/jac/dkaa373] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 08/03/2020] [Indexed: 01/21/2023] Open
Abstract
OBJECTIVES Cefepime/taniborbactam is a cephalosporin/cyclic boronate β-lactamase inhibitor combination under development for the treatment of infections due to MDR Enterobacterales and Pseudomonas aeruginosa. Using a neutropenic murine thigh infection model, we aimed to determine the pharmacokinetic/pharmacodynamic index, relative to taniborbactam exposure, that correlated most closely with the efficacy of the cefepime/taniborbactam combination and the magnitude of index required for efficacy against serine-β-lactamase-producing strains. METHODS Twenty-six clinical Enterobacterales (expressing ESBLs, plasmid-mediated AmpC and/or carbapenemases of classes A or D; cefepime/taniborbactam combination MICs 0.06-16 mg/L) and 11 clinical P. aeruginosa (AmpC overproducing or KPC expressing; cefepime/taniborbactam combination MICs 1-16 mg/L) were evaluated. A cefepime human-simulated regimen (HSR) equivalent to a clinical dose of 2 g q8h as a 2 h infusion was given in combination with taniborbactam for 24 h. For a subset of P. aeruginosa isolates, a sub-therapeutic cefepime exposure was utilized. RESULTS Dose-fractionation studies revealed that dosing frequency had no impact on taniborbactam potentiation of cefepime activity. Relative to the initial bacterial burden, the median taniborbactam fAUC0-24/MIC associated with 1 log kill in combination with the cefepime HSR for Enterobacterales and P. aeruginosa isolates was 2.62 and 0.46, respectively. In combination with sub-therapeutic cefepime, the median taniborbactam fAUC0-24/MIC associated with 1 and 2 log kill against AmpC-overproducing P. aeruginosa was 2.00 and 3.30, respectively, relative to the bacterial burden in the cefepime-treated groups. The taniborbactam HSR (equivalent to 0.5 g q8h as a 2 h infusion) was adequate to attain ≥1 log reduction against all test isolates. CONCLUSIONS Our data show that the cefepime/taniborbactam combination (2 g/0.5 g q8h as a 2 h infusion) exerts potent in vivo activity against cefepime-resistant isolates, including serine-carbapenemase producers.
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Affiliation(s)
- Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Safa Almarzoky Abuhussain
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA.,Umm Al-Qura University, Makkah, Saudi Arabia
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA.,Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA
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14
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Reyes S, Abdelraouf K, Nicolau DP. In vivo activity of human-simulated regimens of imipenem alone and in combination with relebactam against Pseudomonas aeruginosa in the murine thigh infection model. J Antimicrob Chemother 2021; 75:2197-2205. [PMID: 32386408 DOI: 10.1093/jac/dkaa145] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/20/2020] [Accepted: 03/23/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Imipenem/relebactam is a carbapenem/β-lactamase inhibitor combination with in vitro activity against Pseudomonas aeruginosa and Enterobacterales, including KPC producers. OBJECTIVES To provide translational data to support the clinical utility of the imipenem/relebactam 500/250 mg q6h regimen using a human-simulated regimen (HSR) of imipenem/relebactam, compared with imipenem alone, against a phenotypically and genotypically diverse population of P. aeruginosa. METHODS Twenty-nine P. aeruginosa isolates, including KPC (n = 6), PDC (n = 9), PAO (n = 4), GES (n = 5) and VIM (n = 1) producers, were used for the in vivo efficacy studies. Neutropenic mice were thigh-inoculated and randomized to receive HSRs of either imipenem 500 mg q6h, imipenem 1 g q8h, imipenem/relebactam 500/250 mg q6h or saline. RESULTS Twenty-seven of the 29 isolates examined were imipenem resistant, with 24/29 isolates showing imipenem MICs of ≥32 mg/L. The addition of relebactam decreased the MICs up to 64-fold; imipenem/relebactam MICs ranged from 0.25 to >32 mg/L. Efficacies of the imipenem monotherapies and the imipenem/relebactam therapy were comparable for the two imipenem-susceptible organisms. Among the imipenem-resistant isolates, an increased mean growth was observed in the imipenem 500 mg q6h HSR and 1 g q8h HSR treatment groups of 1.31 ± 1.01 and 0.18 ± 1.67 log10 cfu/thigh, respectively. In contrast, a ≥2 log reduction in bacterial density was observed in 27/29 (93%) of the imipenem-resistant isolates subjected to imipenem/relebactam 500/250 mg q6h HSR. CONCLUSIONS The imipenem/relebactam 500/250 mg q6h HSR demonstrated superior in vivo activity compared with the conventionally employed imipenem regimens against MDR P. aeruginosa over a wide range of imipenem/relebactam MICs.
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Affiliation(s)
- Sergio Reyes
- Center for Anti-infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA
| | - Kamilia Abdelraouf
- Center for Anti-infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA
| | - David P Nicolau
- Center for Anti-infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA.,Division of Infectious Diseases, Hartford Hospital, Hartford, Connecticut, USA
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15
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Asempa TE, Abdelraouf K, Nicolau DP. Metallo-β-lactamase resistance in Enterobacteriaceae is an artefact of currently utilized antimicrobial susceptibility testing methods. J Antimicrob Chemother 2021; 75:997-1005. [PMID: 31930305 DOI: 10.1093/jac/dkz532] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 11/26/2019] [Accepted: 11/30/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND MBLs are a major contributor to β-lactam resistance when tested using CAMHB. Despite in vitro resistance, positive outcomes have been reported in MBL-infected patients following carbapenem treatment. The impact of physiological zinc concentrations on this in vitro-in vivo MBL discordance warrants investigation. OBJECTIVES To evaluate meropenem in vitro activity against MBL-producing Enterobacteriaceae in zinc-depleted broth (Chelex-CAMHB, EDTA-CAMHB) and assess meropenem efficacy in murine infection models. METHODS Neutropenic mice received a meropenem human-simulated regimen of 2 g q8h or levofloxacin 750 mg q24h (for model validation). Zinc concentrations were determined in conventional CAMHB, zinc-depleted CAMHB and epithelial lining fluid (ELF) of lung-infected mice. RESULTS All MBL-producing isolates (NDM, n = 25; VIM, n = 3; IMP, n = 2) examined were meropenem resistant in CAMHB and susceptible in zinc-depleted CAMHB (5- to 11-fold reduction), with zinc depletion having no impact on levofloxacin MICs. Zinc concentrations (mean ± SD) in CAMHB were 0.959 ± 0.038 mg/L and in both zinc-depleted CAMHB and ELF were <0.002 mg/L. In vivo, levofloxacin displayed predictable efficacy consistent with its phenotypic profile, while meropenem produced >1 log unit bacterial killing despite in vitro resistance in conventional CAMHB. CONCLUSIONS Results indicate that meropenem in vivo efficacy is best represented by the pharmacodynamic profile generated using MICs determined in zinc-depleted media for MBL-producing Enterobacteriaceae. These translational data suggest that the use of conventional CAMHB for MBL susceptibility testing is inappropriate in distinguishing meaningful in vivo resistance given that zinc concentrations are supraphysiological in conventional CAMHB and negligible at infection sites.
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Affiliation(s)
- Tomefa E Asempa
- Center for Anti-Infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, CT, USA
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, CT, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, CT, USA.,Division of Infectious Diseases, Hartford Hospital, 80 Seymour Street, Hartford, CT, USA
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16
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Lasko MJ, Abdelraouf K, Nicolau DP. Comparative in vivo activity of human-simulated plasma and epithelial lining fluid exposures of WCK 5222 (cefepime/zidebactam) against KPC- and OXA-48-like-producing Klebsiella pneumoniae in the neutropenic murine pneumonia model. J Antimicrob Chemother 2021; 76:2310-2316. [PMID: 34096601 DOI: 10.1093/jac/dkab183] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 05/04/2021] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVES This was a comparative assessment of WCK 5222 (cefepime/zidebactam 2/1 g as a 1 h infusion every 8 h) efficacy using human-simulated plasma and ELF exposures against serine-carbapenemase-producing Klebsiella pneumoniae in the neutropenic murine pneumonia model. METHODS Ten clinical isolates were utilized: eight were serine-carbapenemase-producing (KPC, n = 4; OXA-48-like, n = 4) Enterobacterales with WCK 5222 MICs (1:1) ranging from 1 to 4 mg/L; and two were previously studied MDR isolates serving as quality controls. Lungs of mice were inoculated with 50 μL of 107 cfu/mL. Treatment mice received human-simulated regimens of cefepime, zidebactam or WCK 5222 derived from plasma or epithelial lining fluid (ELF) profiles obtained from healthy subjects. Lung bacterial densities resulting from the humanized exposures in plasma and ELF were compared. RESULTS Initial lung bacterial densities ranged from 6.06 to 6.87 log10 cfu/lungs, with a mean bacterial burden increase to 9.06 ± 0.42 after 24 h. Human-simulated plasma and ELF exposures of cefepime and zidebactam monotherapy had no activity. Human-simulated WCK 5222 plasma exposures resulted in a >1 log10 cfu/lungs reduction in bacterial burden for all isolates. Humanized WCK 5222 ELF exposures achieved a >1 log10 cfu/lungs reduction for all isolates. While statistically significant differences in bacterial burden reduction were observed between the plasma and ELF exposures for WCK 5222 in 5/8 isolates, all treatments achieved the translational kill target of a >1 log10 cfu reduction. CONCLUSIONS Clinically achievable WCK 5222 plasma and ELF exposures produced in vivo killing of carbapenem-resistant Enterobacterales in the neutropenic murine pneumonia model that is predictive of efficacy in humans.
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Affiliation(s)
- Maxwell J Lasko
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA.,Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA
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17
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Kidd JM, Abdelraouf K, Nicolau DP. Efficacy of human-simulated bronchopulmonary exposures of cefepime, zidebactam and the combination (WCK 5222) against MDR Pseudomonas aeruginosa in a neutropenic murine pneumonia model. J Antimicrob Chemother 2021; 75:149-155. [PMID: 31641765 DOI: 10.1093/jac/dkz414] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/03/2019] [Accepted: 09/04/2019] [Indexed: 02/01/2023] Open
Abstract
OBJECTIVES WCK 5222 combines cefepime with zidebactam, a β-lactam enhancer that binds PBP2 and inhibits class A and C β-lactamases. The efficacy of human-simulated bronchopulmonary exposures of WCK 5222 against MDR Pseudomonas aeruginosa was investigated in a neutropenic murine pneumonia model. METHODS Nineteen MDR isolates of P. aeruginosa (cefepime MICs ≥64 mg/L) were studied. MICs of zidebactam and WCK 5222 ranged from 4 to 512 mg/L and from 4 to 32 mg/L, respectively. Dosing regimens of cefepime and zidebactam alone and in combination that achieved epithelial lining fluid (ELF) exposures in mice approximating human ELF exposures after doses of 2 g of cefepime/1 g of zidebactam every 8 h (1 h infusion) were utilized; controls were vehicle-dosed. Lungs were intranasally inoculated with 107-108 cfu/mL bacterial suspensions. Mice were dosed subcutaneously 2 h after inoculation for 24 h, then lungs were harvested. RESULTS In vitro MIC was predictive of in vivo response to WCK 5222 treatment. Mean±SD changes in bacterial density at 24 h compared with 0 h controls (6.72±0.50 log10 cfu/lungs) for 13 isolates with WCK 5222 MICs ≤16 mg/L were 1.17±1.00, -0.99±1.45 and -2.21±0.79 log10 cfu/lungs for cefepime, zidebactam and WCK 5222, respectively. Against these isolates, zidebactam yielded >1 log10 cfu/lungs reductions in 8/13, while activity was enhanced with WCK 5222, producing >2 log10 cfu/lungs reductions in 10/13 and >1 log10 cfu/lungs reductions in 12/13. Among isolates with WCK 5222 MICs of 32 mg/L, five out of six showed a bacteriostatic response. CONCLUSIONS Human-simulated bronchopulmonary exposure of WCK 5222 is effective against MDR P. aeruginosa at MIC ≤16 mg/L in a murine pneumonia model. These data support the clinical development of WCK 5222 for pseudomonal lung infections.
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Affiliation(s)
- James M Kidd
- Center for Anti-Infective Research and Development, Hartford Hospital, Harford, CT, USA
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Harford, CT, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Harford, CT, USA
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18
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Abdelraouf K, Reyes S, Nicolau DP. 1299. In Vitro- In Vivo Discordance with β-lactams against Metallo-β-lactamase-Producing Enterobacterales: Implications for Susceptibility Testing. Open Forum Infect Dis 2020. [PMCID: PMC7777513 DOI: 10.1093/ofid/ofaa439.1482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background Using murine models of thigh and lung infection, we previously reported the potent in vivo activity of carbapenem human-simulated regimens against metallo-β-lactamase-producing Enterobacterales despite the observed resistance in vitro (JAC 2020 Apr 1;75(4):997-1005, AAC 2014;58(3):1671-7). In the current study, we examined the in vivo activity of cefepime human-simulated regimen against metallo-β-lactamase-producing Enterobacterales in a murine thigh infection model. Methods A population of clinical (n=21) and isogenic engineered (n=5) metallo-β-lactamase-producing Enterobacterales isolates expressing VIM, IMP or NDM but not co-expressing ESBLs or serine carbapenemases were utilized. KPC-producing strains (n=3) were included as positive controls. MICs of cefepime, piperacillin-tazobactam and meropenem were determined using broth microdilution in conventional cation-adjusted Muller Hinton and EDTA-supplemented broth at EDTA concentration of 300 mg/L (zinc-limited). The in vivo efficacy of a cefepime human-simulated regimen (2 g q8h as 2 h infusion) was determined in the neutropenic murine thigh infection model against the test isolates. Efficacy was measured as the change in log10cfu/thigh at 24 h compared with 0 h controls. Results Metallo-β-lactamase-producing Enterobacterales were found to be cefepime, piperacillin-tazobactam and meropenem non-susceptible in conventional broth. Supplementation with EDTA resulted in multi-fold reduction in the MICs and restoration of susceptibility. In accordance with the MICs generated in the zinc-limited broth, the administration of cefepime human-simulated regimen was associated with substantial bacterial reductions among mice infected with the clinical as well as the isogenic engineered metallo-β-lactamase-producing isolates. As anticipated with serine-based resistance, absence of MIC reduction in zinc-limited broth and lack of in vivo activity against KPC-producers were observed. Conclusion For metallo-β-lactamase-producing Enterobacterales, in vitro susceptibility testing to β-lactams with conventional media such as cation-adjusted Muller Hinton broth, a zinc-rich testing medium, is flawed since it does not recapitulate the host environment in which zinc concentrations are low. Disclosures David P. Nicolau, PharmD, Cepheid (Other Financial or Material Support, Consultant, speaker bureau member or has received research support.)Merck & Co., Inc. (Consultant, Grant/Research Support, Speaker’s Bureau)Wockhardt (Grant/Research Support)
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Affiliation(s)
| | - Sergio Reyes
- St. Vincent’s Medical Center, Bridgeport, Connecticut
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Lasko MJ, Abdelraouf K, Nicolau DP. 1245. In Vivo Efficacy of WCK 4282 (High Dose Cefepime [FEP]-Tazobactam [TZB]) Against β-Lactamase-Producing (BLP) Gram-Negative Bacteria in a Neutropenic Murine Pneumonia Model. Open Forum Infect Dis 2020. [PMCID: PMC7776658 DOI: 10.1093/ofid/ofaa439.1430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Carbapenems are often used for Extended-Spectrum β-lactamase (ESBL)- and cephalosporinase (AmpC or CMY)-producing infections. Their increased use resulted in the emergence of carbapenem resistance among Gram-negatives, promoting the need of an effective carbapenem-sparing option. WCK 4282 (FEP 2g-TZB 2g) maximizes systemic exposure of TZB and restores FEP activity against piperacillin-tazobactam (TZP) resistant isolates in vitro. Herein we describe the efficacy of WCK 4282 clinical exposures against BLP Enterobacterales (EB) and Pseudomonas aeruginosa (PA) in a murine pneumonia model.
Methods
Clinical isolates (14 EB and 2 PA) with in vitro resistance to FEP, ceftolozane-tazobactam, and TZP (EB isolates) were used. Isolates expressed ESBLs, AmpC/CMY, and/or serine carbapenemases (KPC, OXA-48-like). WCK 4282 MICs were 4-16 and 8-32 mg/L for non-carbapenemase and carbapenemase-producers, respectively. Human-simulated regimens (HSR) of FEP (mimicking human plasma exposure of 2g q8h as a 1.5 h infusion) alone and in combination with TZB (equivalent to 2g q8h as a 1.5 h infusion) were developed in a neutropenic pneumonia model. Treatment mice received FEP or FEP-TZB (WCK 4282) HSR. Control mice were vehicle-dosed. Efficacy was assessed as change in log10CFU/lung at 24 h compared with 0 h controls.
Results
Mean 0 h bacterial density across all isolates was 6.66 ± 0.29 log10CFU/lung and increased at 24 h by 2.48 ± 0.6 and 1.71 ± 1.13 among controls and FEP-treated groups, respectively. Potent WCK 4282 activity was observed against ESBL- and AmpC-harboring EB as well as ESBL- and AmpC-overexpressing PA with WCK 4282 MICs up to 16 mg/L (n=9); mean bacterial reductions were -2.70 ± 0.63 and -2.04 ± 0.18 log10CFU/lung, respectively. WCK 4282 showed variable activity against OXA-48-producing EB (n=3); log10CFU/lung change ranged from -1.2 to 0.28. Against KPC-producers (n=4), WCK 4282 groups grew to 0.53 ± 1.07 log10CFU/lung, ~1.2 log10CFU lower than FEP.
Conclusion
WCK 4282 produced potent in vivo activity against ESBL- and AmpC-harboring Gram-negative isolates and limited activity among serine carbapenamase-producers in a pneumonia model at clinically achievable exposures. Further studies are warranted to delineate WCK 4282’s spectrum of activity and susceptibility breakpoint.
Disclosures
David P. Nicolau, PharmD, Cepheid (Other Financial or Material Support, Consultant, speaker bureau member or has received research support.)Merck & Co., Inc. (Consultant, Grant/Research Support, Speaker’s Bureau)Wockhardt (Grant/Research Support)
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Affiliation(s)
- Maxwell J Lasko
- Center for Anti Infective Research and Development, Hartford, Connecticut
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Abdelraouf K, Nicolau DP. 1312. Metallo-β-lactamase-Producing Enterobacterales (MBL-EB): Is it Time to Rethink Our Assessment Tools? Open Forum Infect Dis 2020. [PMCID: PMC7777439 DOI: 10.1093/ofid/ofaa439.1494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background We previously reported the potent in vivo activity of ceftazidime/avibactam human-simulated regimen (HSR) against MBL-EB despite the observed resistance in vitro and the lack of avibactam MBL-inhibitory activity (AAC 2014 Nov;58(11):7007-9). Similar to avibactam, relebactam (REL) is a diazabicyclooctane that inhibits serine β-lactamases belonging to Classes A - C but not MBLs. In the current study, we examined the in vivo activity of cefepime (FEP)/REL combination HSR against MBL-EB in a murine thigh infection model. Methods Six clinical MBL-EB isolates expressing VIM, IMP or NDM and co-expressing at least one β-lactamase of Classes A - C (KPC, CTX-M, TEM, SHV, ACT, CMY) were utilized. MICs of FEP and FEP/REL combination (at fixed REL concentration of 4 mg/L) were determined using broth microdilution. FEP HSR (2 g q12h as 0.5 h infusion) alone and in combination with REL HSR (250 mg q6h as 0.5 h infusion) were established in the infection model. Thighs of neutropenic ICR mice were inoculated with bacterial suspensions of 107 CFU/ml. Two hours later, mice were administered the FEP HSR or the FEP/REL HSR. Efficacy was measured as the change in log10CFU/thigh at 24 h compared with 0 h controls. Results All isolates were FEP resistant (MIC ≥ 32 mg/L). Addition of REL had no impact on the MIC of the isolates. In in vivo studies, the average bacterial burden at 0 h was 5.84 ± 0.41 log10CFU/thigh. In accordance with the in vitro susceptibility, administration of FEP HSR was associated with net bacterial growth among all isolates ranging from 0.46 ± 0.60 to 2.97 ± 0.53 log10CFU/thigh. In contrast, FEP/REL combination HSR resulted in substantial bacterial reductions among all isolates ranging from -0.73 ± 0.13 to -1.72 ± 0.14 log10CFU/thigh, indicating that REL enhanced the FEP activity in vivo. Conclusion Despite the powerful β-lactam hydrolytic capability of MBLs in vitro, FEP inactivation in the murine model was attributed predominantly to the expression of the serine β-lactamases. The in vitro/in vivo discordance in β-lactam/β-lactamase activity against MBL-EB reveals a potential flaw in the currently utilized in vitro susceptibility testing methodologies and highlights a challenge encountered during the development of new agents against these isolates. Disclosures David P. Nicolau, PharmD, Cepheid (Other Financial or Material Support, Consultant, speaker bureau member or has received research support.)Merck & Co., Inc. (Consultant, Grant/Research Support, Speaker’s Bureau)Wockhardt (Grant/Research Support)
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Gill CM, Abdelraouf K, Nicolau DP. 1244. Assessment of the In Vivo Activity of Human-Simulated Exposure of WCK 4282 (High Dose Cefepime [FEP]-Tazobactam [TZB]) against Enterobacterales (EB) and Pseudomonas aeruginosa (PA) in the Neutropenic Murine Thigh Infection Model. Open Forum Infect Dis 2020. [PMCID: PMC7776753 DOI: 10.1093/ofid/ofaa439.1429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background Carbapenems are often used for infections due to extended-spectrum-β-lactamase (ESBL) and cephalosporinase (CSase)-producers. As increased carbapenem utilization is associated with the development of carbapenem resistance, antimicrobial stewardship has targeted non-carbapenem options. WCK 4282 (FEP 2 g-TZB 2 g) offers pharmacodynamically optimized TZB exposure and demonstrated potent activity in vitro against ESBL-phenotype isolates. We describe the pharmacodynamics of a WCK 4282 human-simulated regimen (HSR) in the neutropenic murine thigh model. Methods 19 clinical strains harboring ESBLs or CSase (EB; n=8 and PA; n=4) or serine-carbapenemases (EB; KPC n=4 or OXA-48-like n=3) were tested in vivo. Per CLSI, 19, 18, and 17 isolates were cefepime, ceftolozane/tazobactam, and piperacillin/tazobactam (TZP) non-susceptible, respectively. Thighs of neutropenic, female, CD-1 mice (3 per group) were inoculated with ~107 CFU/mL of bacterial suspension 2 h prior to dosing. Mice received WCK 4282 HSR, FEP HSR, or saline (controls) for 24 h. WCK 4282 HSR and FEP HSR provided plasma exposures in mice that were similar in f%T > MIC and fAUC to FEP-TZB 2 g-2 g and FEP 2 g, respectively, as IV infusions over 1.5 h q8h in humans. Bacterial densities and their changes at 24 h relative to 0 h controls were determined to assess efficacy and reported as mean±SD log10 CFU/thigh. Results Bacterial burdens were 5.81±0.36 at 0 h and 9.29±0.88 at 24 h in untreated controls. WCK 4282 produced potent activity against ESBL/CSase producing EB and PA with WCK 4282 MIC ≤ 16 mg/L; mean change in log10 CFU from 0 h was -1.70±0.77, while growth was observed with FEP alone. WCK 4282 produced variable activity against OXA-48-like harboring EB. Against KPC-harboring EB, WCK 4282 produced stasis to growth. Mean Log10 CFU changes are reported in Table 1 and Figure 1. Table 1. Comparative efficacy of FEP HSR and WCK 4282 HSR by genotypic β-lactamase ![]()
Figure 1. Mean Change in log10CFU/thigh for 24 h controls, FEP HSR, and WCK 4282 HSR across the tested MIC distribution. ![]()
Conclusion WCK 4282, a novel TZB containing regimen, resulted in enhance in vitro potency against ESBL/CSase and OXA-48-like producers. Humanized exposures of WCK 4282 produced substantial kill in vivo against ESBL/CSase producers with MICs ≤ 16 mg/L including FEP resistant/TZP non-susceptible PA. These data support further evaluations of WCK 4282 as a carbapenem-sparing regimen for ESBL/cephalosporinase harboring strains. Disclosures David P. Nicolau, PharmD, Cepheid (Other Financial or Material Support, Consultant, speaker bureau member or has received research support.)Merck & Co., Inc. (Consultant, Grant/Research Support, Speaker’s Bureau)Wockhardt (Grant/Research Support)
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Affiliation(s)
- Christian M Gill
- Center for Anti-Infective Research & Development, Hartford Hospital, Hartford, Connecticut
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22
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Righi E, Scudeller L, Chiamenti M, Abdelraouf K, Lodise T, Carrara E, Savoldi A, Menghin D, Pellizzari G, Ellis S, Franceschi F, Piddock L, Rebuffi C, Sanguinetti M, Tacconelli E. In vivo studies on antibiotic combination for the treatment of carbapenem-resistant Gram-negative bacteria: a systematic review and meta-analysis protocol. BMJ Open Science 2020; 4:e100055. [PMID: 35047691 PMCID: PMC8647577 DOI: 10.1136/bmjos-2019-100055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/04/2020] [Accepted: 03/16/2020] [Indexed: 12/16/2022] Open
Abstract
Objective There is poor evidence to determine the superiority of combination regimens versus monotherapy against infections due to carbapenem-resistant (CR) Gram-negative bacteria. In vivo models can simulate the pathophysiology of infections in humans and assess antibiotic efficacy. We aim to investigate in vivo effects of antibiotic combination on mortality and disease burden for infections due to CR Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacteriaceae and provide an unbiased overview of existing knowledge. The results of the study can help prioritising future research on the most promising therapies against CR bacteria. Methods and analysis This protocol was formulated using the Systematic Review Protocol for Animal Intervention Studies (SYRCLE) Checklist. Publications will be collected from PubMed, Scopus, Embase and Web of Science. Quality checklists adapted by Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies and SYRCLE’s risk of bias tool will be used. If the meta-analysis seems feasible, the ES and the 95% CI will be analysed. The heterogeneity between studies will be assessed by I2 test. Subgroup meta-analysis will be performed when possible to assess the impact of the studies on efficacy of the treatments. Funnel plotting will be used to evaluate the risk of publication bias. Dissemination This systematic review and meta-analysis is part of a wider research collaboration project, the COmbination tHErapy to treat sepsis due to carbapenem-Resistant bacteria in adult and paediatric population: EvideNCE and common practice (COHERENCE) study that includes also the analyses of in vitro and human studies. Data will be presented at international conferences and the results will be published in peer-reviewed journals. PROSPERO registration number CRD42019128104(available at: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42019128104).
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Affiliation(s)
- Elda Righi
- Infectious Diseases, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Luigia Scudeller
- Clinical Epidemiology and Biostatistics, IRCCS Ca’ Granda Ospedale Maggiore Policlinico di Milano Foundation, Milan, Italy
| | - Margherita Chiamenti
- Infectious Diseases, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA
| | - Thomas Lodise
- Albany College of Pharmacy and Health Sciences, Albany, New York, USA
| | - Elena Carrara
- Infectious Diseases, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Alessia Savoldi
- Infectious Diseases, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Dario Menghin
- Infectious Diseases, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Gloria Pellizzari
- Infectious Diseases, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Sally Ellis
- Global Antibiotic Research & Development Partnership (GARDP), Geneva, Switzerland
| | - Francois Franceschi
- Global Antibiotic Research & Development Partnership (GARDP), Geneva, Switzerland
| | - Laura Piddock
- Global Antibiotic Research & Development Partnership (GARDP), Geneva, Switzerland
| | | | - Maurizio Sanguinetti
- Microbiology, A. Gemelli Hospital, Catholic University of the Sacred Heart, Rome, Italy
| | - Evelina Tacconelli
- Infectious Diseases, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
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Kidd JM, Abdelraouf K, Nicolau DP. Efficacy of Humanized Cefiderocol Exposure Is Unaltered by Host Iron Overload in the Thigh Infection Model. Antimicrob Agents Chemother 2019; 64:e01767-19. [PMID: 31658966 PMCID: PMC7187581 DOI: 10.1128/aac.01767-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 10/11/2019] [Indexed: 01/10/2023] Open
Abstract
Cefiderocol is a siderophore-cephalosporin conjugate with greater in vitro potency under iron-depleted conditions. During infection, iron is scarce in host tissue; however, it is not known whether iron overload in the host, such as in cases of hereditary hemochromatosis, alters the efficacy of cefiderocol. We compared cefiderocol efficacy between iron-overloaded and standard murine thigh infection models. Female CD-1 mice rendered neutropenic received 2 weeks of iron dextran at 100 mg/kg of body weight/day intraperitoneally (iron-overloaded model) or no injections (standard model). Mice were inoculated (107 CFU/ml) with Enterobacterales, Acinetobacter baumannii, and Pseudomonas aeruginosa with previously determined cefiderocol MICs from 0.25 to 64 mg/liter. Human-simulated regimens of cefiderocol or meropenem (2 g every 8 h [q8h], 3-h infusion) were administered for 24 h (31 strains) or 72 h (15 strains; cefiderocol only). Procedures were simultaneously performed in standard and iron-overloaded models. Mean bacterial burdens (log10 CFU/thigh) at baseline were 5.75 ± 0.47 versus 5.81 ± 0.51 in standard versus iron-overloaded models, respectively. At 24 h, mean burdens in standard versus iron-overloaded models decreased by -0.8 ± 1.9 versus -1.2 ± 2.0 (P = 0.25) in meropenem-treated mice and by -1.5 ± 1.4 versus -1.6 ± 1.5 (P = 0.54) in cefiderocol-treated mice. At 72 h, mean burdens in cefiderocol-treated mice decreased by -2.5 ± 1.5 versus -2.5 ± 1.4. No overall differences in efficacy between the models were observed for meropenem or cefiderocol. Human-simulated exposure of cefiderocol is equally efficacious in iron-overloaded and normal hosts. The potential clinical use of cefiderocol to treat Gram-negative infections in patients with iron overload is supported.
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Affiliation(s)
- James M Kidd
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA
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Kidd JM, Abdelraouf K, Nicolau DP. Development of Neutropenic Murine Models of Iron Overload and Depletion To Study the Efficacy of Siderophore-Antibiotic Conjugates. Antimicrob Agents Chemother 2019; 64:e01961-19. [PMID: 31658967 PMCID: PMC7187605 DOI: 10.1128/aac.01961-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 10/20/2019] [Indexed: 02/07/2023] Open
Abstract
Siderophore-antibiotic conjugates have increased in vitro activity in low-iron environments where bacteria express siderophores and associated transporters. The host immune hypoferremic response reduces iron availability to bacteria; however, patients with iron overload or deficiency may have altered ability to restrict iron, which may affect the efficacy of siderophore-antibiotic conjugates. In vivo models of infection with iron overload and deficiency are needed to perform this assessment. The standard neutropenic murine thigh infection model was supplemented with iron-altering treatments: iron dextran at 100 mg/kg of body weight daily for 14 days to load iron or deferoxamine at 100 mg/kg daily plus a low-iron diet for up to 30 days to deplete iron. Human-simulated regimens of cefiderocol and meropenem were administered in both models to assess any impact of iron alteration on plasma pharmacokinetics. Median iron in overloaded mice was significantly higher than that of controls in plasma (1,657 versus 336 μg/dl; P < 0.001), liver (2,133 versus 11 μg/g; P < 0.001), and spleen (473 versus 144 μg/g; P < 0.001). At 30 days, depleted mice had significantly lower iron than controls in liver (2.4 versus 6.5 μg/g; P < 0.001) and spleen (72 versus 133 μg/g; P = 0.029) but not plasma (351 versus 324 μg/dl; P = 0.95). Cefiderocol and meropenem plasma concentrations were similar in iron overloaded and control mice but varied in iron-depleted mice. The iron-overloaded murine thigh infection model was established, and human-simulated regimens of cefiderocol and meropenem were validated therein. While deferoxamine successfully reduced liver and splenic iron, this depleting treatment altered the pharmacokinetics of both antimicrobials.
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Affiliation(s)
- James M Kidd
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA
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Asempa TE, Motos A, Abdelraouf K, Bissantz C, Zampaloni C, Nicolau DP. Meropenem-nacubactam activity against AmpC-overproducing and KPC-expressing Pseudomonas aeruginosa in a neutropenic murine lung infection model. Int J Antimicrob Agents 2019; 55:105838. [PMID: 31705960 DOI: 10.1016/j.ijantimicag.2019.10.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 10/22/2019] [Accepted: 10/27/2019] [Indexed: 10/25/2022]
Abstract
Nacubactam is a novel non-β-lactam diazabicyclooctane β-lactamase inhibitor under development for the treatment of serious Gram-negative infections. This study assessed the efficacy of human-simulated epithelial lining fluid (ELF) exposure of nacubactam in combination with meropenem against AmpC-overproducing (n=4) and Klebsiella pneumoniae carbapenemase (KPC)-expressing (n=3) Pseudomonas aeruginosa isolates in the neutropenic murine lung infection model. Meropenem, nacubactam and meropenem-nacubactam (1:1 concentration ratio) minimum inhibitory concentrations (MICs) were determined in triplicate using broth microdilution. Regimens that provided ELF profiles mimicking those observed in humans given nacubactam 2 g q8h (1.5-h infusion) alone and in combination with a subtherapeutic ELF exposure of meropenem were administered 2 h after inoculation. Efficacy was assessed as the change in log10 colony-forming units (CFU)/lung at 24 h compared with 24-h meropenem monotherapy. Meropenem, nacubactam and meropenem-nacubactam MICs were 8->64, 128->256 and 2-16 mg/L, respectively. Meropenem and nacubactam monotherapy groups demonstrated bacterial growth over 24 h for each isolate. Against AmpC-overproducing and KPC-expressing P. aeruginosa isolates, meropenem-nacubactam resulted in -2.73±0.93 and -4.35±1.90 log10CFU/lung reduction, respectively, relative to meropenem monotherapy. Meropenem-nacubactam showed promising in-vivo activity against meropenem-resistant P. aeruginosa, indicative of a potential role for the treatment of infections caused by these challenging pathogens.
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Affiliation(s)
- Tomefa E Asempa
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Ana Motos
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Caterina Bissantz
- Roche Pharma Research and Early Development Pharmaceutical Science, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Claudia Zampaloni
- Roche Pharma Research and Early Development, Immunology, Inflammation and Infectious Diseases, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA; Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA.
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Kidd JM, Abdelraouf K, Nicolau DP. 1544. Efficacy of Human-Simulated Cefiderocol Exposure Against Gram-Negative Bacteria in an Iron-Overloaded Murine Thigh Infection Model. Open Forum Infect Dis 2019. [PMCID: PMC6809466 DOI: 10.1093/ofid/ofz360.1408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background Cefiderocol (CFDC) is a siderophore-cephalosporin conjugate which exploits bacterial iron scavenging in reaction to the hypoferremic response of host immunity and achieves potent in vivo activity against various Gram-negative bacteria (GNB). In patients with hereditary or iatrogenic hemochromatosis, the hypoferremic response may be altered by iron overload, which could hypothetically suppress the bacterial iron scavenging that bolsters CFDC efficacy. We compared CFDC efficacy between iron-overloaded (Fe+) and normal iron (NFe) murine thigh infection models. Methods Female CD-1 mice received iron dextran 100 mg/kg/d for 14 d to induce iron overload (Fe+) (ASM Microbe 2019 abstract HMB-373); an equal number of same-age mice were not dosed (NFe). On day 15, both thighs of mice rendered neutropenic were inoculated with GNB suspensions of 107 CFU/mL. Twenty CFDC-susceptible isolates with previously determined CFDC MIC from 0.25 to 4 mg/L, including Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacteriales, were used. Two hours after inoculation, treatment mice were dosed with a CFDC regimen simulating the human plasma PK profile after doses of 2g q8h (3 h infusion), while control mice were sacrificed (0 h) or dosed with saline placebo on the same schedule as the CFDC regimen (24 h). All procedures were simultaneously performed in Fe+ and NFe mice. Efficacy was defined as a change in log10 CFU/thigh at 24 h vs. 0 h and was compared between Fe+ and NFe mice for individual isolates using Student’s t-test. Results Mean (SD) bacterial burdens at 0 h in Fe+ and NFe control mice were 5.77 (0.52) and 5.76 (0.52) and log10 CFU/thigh, respectively, and, at 24 h, increased by 3.49 (0.73) and 3.42 (0.96) log10 CFU/thigh, respectively. Mean (SD) efficacies of CFDC in Fe+ and NFe mice were -1.98 (0.83) and -1.98 (0.72) log10 CFU/thigh, respectively. For 17 of 20 individual isolates, no significant differences in efficacy between Fe+ and NFe mice were observed (P > 0.05); 2 of the 3 isolates with a difference had greater efficacy in Fe+ mice. Conclusion Human-simulated exposure of CFDC is equally efficacious in iron-overloaded and normal hosts against a variety of GNB susceptible to CFDC. The potential clinical use of CFDC to treat GNB infections in patients with iron overload is supported. Disclosures All authors: No reported disclosures.
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Asempa TE, Abdelraouf K, Nicolau DP. 1533. Is Cation-Adjusted Mueller–Hinton Broth (CAMHB) Appropriate for Metallo-β-lactamase (MBL) Susceptibility Testing? Novel Insights in In Vitro–In Vivo Discordance Among MBL-Producing Enterobacteriaceae. Open Forum Infect Dis 2019. [PMCID: PMC6810773 DOI: 10.1093/ofid/ofz360.1397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Background MBLs, which require Zn for catalytic activity, are a major contributor to high-level β-lactam resistance when tested using conventional CAMHB. We have previously reported marked reductions in meropenem (MEM) MICs in Zn-depleted media (Chelex-CAMHB and EDTA-CAMHB; Zn [C] <0.002 mg/L) compared with conventional CAMHB (Zn [C] 0.959 mg/L) against a variety of MBL-producing isolates, whereas Zn-depletion had no impact on levofloxacin (LVX) MICs (ASM Microbe 2019, San Francisco. Abstract P508). To explore in vivo implications, we evaluated the efficacy of MEM human simulated regimen (HSR) against MBL-producing isolates in a murine pneumonia model. In addition, LVX HSR was examined for model validation. Methods Nine MBL-producing isolates (NDM, n = 5; VIM, n = 2; IMP, n = 2) were utilized. CAMHB, Chelex-CAMHB, and EDTA-CAMHB MEM MICs ranged from 16 to > 64, ≤0.0625 to 0.5, and ≤ 0.0625 to 0.5 mg/L, respectively. LVX MICs ranged from ≤ 0.0625 – > 64 mg/L. Neutropenic lung-infected ICR mice received a MEM HSR of 2g q8h [1.5 hours infusion], 2 lower MEM exposures or LVX 750 mg q24h HSR. Zn [C] were determined in the epithelial lining fluid (ELF) of infected mice. Results LVX displayed predictable in vivo efficacy consistent with its phenotypic profile irrespective of the media utilized for MIC testing (figure). Despite attaining zero %T> MIC using values generated in CAMHB, MEM HSR produced marked bacterial reductions against all MBL-producing isolates (figure). Reductions in MEM exposures produced bacterial killing concordant with its pharmacodynamic profile using Zn-depleted CAMHB MIC values. Zn [C] in infected murine ELF were undetectable, i.e., <0.002 mg/L. Conclusion Our results indicate that MEM in vivo efficacy is best represented by the pharmacodynamic profile generated using MICs determined in Zn-depleted media for MBL-producing Enterobacteriaceae. These observations are consistent with the case reports describing positive outcomes in MBL-infected patients following treatment with carbapenems (Infection 2018;46:1–13). Our translational data suggest that the use of conventional CAMHB for MBL susceptibility testing is inappropriate in distinguishing meaningful in vivo resistance given that Zn [C] are supraphysiologic in conventional CAMHB and negligible at infection sites. ![]()
Disclosures All authors: No reported disclosures.
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Kidd JM, Abdelraouf K, Nicolau DP. 1553. Human-Simulated Pharmacokinetic Profiles of Cefiderocol and Meropenem Are Conserved in Murine Models of Thigh Infection With or Without Iron Overload. Open Forum Infect Dis 2019. [PMCID: PMC6810048 DOI: 10.1093/ofid/ofz360.1417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
A translational murine model of thigh infection with comorbid iron overload was previously developed to study the efficacy of iron-dependent siderophore-antibiotic conjugates under conditions where the hypoferremic response of innate immunity may be compromised. Given the potential for functional organ damage from excessive tissue iron, which could alter the pharmacokinetic (PK) profiles of antibiotics being compared for efficacy using this model, the effects of iron overload on a siderophore-β-lactam conjugate, cefiderocol (CFDC), and a non-siderophore β-lactam, meropenem (MEM), were studied.
Methods
Female CD-1 mice received iron dextran (Fe-D) 100 mg/kg intraperitoneally for 14 days as previously shown to produce vastly supranormal iron concentrations in serum, liver, and spleen (ASM Microbe 2019 abstract HMB-373). Age-matched control mice were not dosed with Fe-D. Mice were rendered neutropenic. On day 15, both thighs of iron-overloaded and control mice were inoculated intramuscularly with Acinetobacter baumannii suspensions of 107 CFU/mL. Two hours after inoculation, mice in each model were dosed with previously developed human-simulated regimens (HSR) of CFDC or MEM simulating human PK profiles after doses of 2g q8h (3 hours infusion) for both drugs. At 4 time points per regimen, 6 mice per model were sacrificed for blood collection. Plasma total MEM and CFDC concentrations were measured with HPLC and LC-MS-MS, respectively. Free concentrations were calculated with murine protein binding. At each time point, mean free concentrations in both models were compared using Student’s t-test.
Results
Observed murine-free plasma concentrations ± 95% CI of CFDC and MEM are overlaid with simulated human and murine profiles in the figure. In both models, these regimens approximated human exposures after clinical doses. For all time points and both drugs, concentrations were not significantly different (P > 0.05) between models with or without iron overload.
Conclusion
Iron overload did not significantly alter PK profiles of a siderophore-β-lactam conjugate, CFDC, or a non-siderophore β-lactam, MEM. These data support the use of CFDC and MEM HSR for pharmacodynamic studies utilizing both iron-overloaded and standard murine thigh infection models.
Disclosures
All authors: No reported disclosures.
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Kidd JM, Abdelraouf K, Nicolau DP. 675. Efficacy of Human-Simulated Bronchopulmonary Exposures of Cefepime and Zidebactam (WCK 5222) Against Multidrug-Resistant (MDR) Pseudomonas aeruginosa (PSA) in a Neutropenic Murine Pneumonia Model. Open Forum Infect Dis 2019. [PMCID: PMC6810914 DOI: 10.1093/ofid/ofz360.743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Background WCK 5222 combines cefepime (FEP) with zidebactam (ZID), a bicycloacyl hydrazide β-lactam enhancer which binds PBP2 in PSA and inhibits class A and C β-lactamases. The in vivo efficacy of human-simulated bronchopulmonary exposures of WCK 5222 against MDR PSA, a recalcitrant pneumonia-causing pathogen with few treatment options, was investigated in a neutropenic murine pneumonia model. Methods Thirteen clinical isolates of MDR PSA with FEP MIC ≥64 mg/L were studied in neutropenic CD-1 mice. FEP, ZID, and WCK 5222 MICs were measured by broth microdilution in triplicate. For in vivo experiments, lungs were intranasally inoculated with 107–108 CFU/mL bacterial suspensions. Human-simulated regimens (HSR) of FEP and ZID alone and in combination which achieved epithelial lining fluid (ELF) exposures in mice approximating human ELF exposures after doses of 2 g FEP/1 g ZID as a 1 hour infusion at steady state were developed. For each regimen, groups of 6 mice were dosed subcutaneously 2 hours after inoculation for 24 hours, then sacrificed. Vehicle-dosed control mice were sacrificed at the start (0 hour) and end (24 hours) of the dosing period. Lungs were aseptically harvested and bacterial CFU/lungs were determined. Results FEP MIC was >64 mg/L for all isolates, while ZID and WCK 5222 MICs ranged from 4–512 and 4–32 mg/L, respectively. Mean bacterial growth for all isolates at 0 hour was 6.68 log10 CFU/lungs. Mean changes ± SD in bacterial density at 24 hours compared with 0 hour controls for 12 isolates with WCK5222 MIC ≤16 mg/L were 2.08 ± 1.09, 1.09 ± 0.98, −0.92 ± 1.45, and −2.13 ± 0.75, for control, FEP, ZID, and WCK5222, respectively. Against these isolates, ZID yielded >1 log10 CFU/lungs reduction in 7/12, while activity was enhanced with WCK5222, producing >1 log10 CFU/lungs reduction in 11/12 and >2 log10 CFU/lungs reduction in 9/12. All isolates showed growth or stasis on FEP. Conclusion Human-simulated bronchopulmonary exposures of WCK5222 is effective against MDR PSA at MIC up to 16 mg/L in a neutropenic murine model. These data support the clinical development of WCK5222 for the treatment of pseudomonal lung infections, but further studies of PSA with high WCK5222 MIC are necessary to delineate the susceptibility breakpoint. Disclosures All authors: No reported disclosures.
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Avery LM, Abdelraouf K, Nicolau DP. 682. In Vivo Pharmacodynamics of VNRX-7145 in the Neutropenic Murine Thigh Infection Model When Administered in Combination with Humanized Exposures of Twice Daily Ceftibuten (CTB) Against Serine β-Lactamase-Producing Enterobacteriaceae (SBL-EB). Open Forum Infect Dis 2019. [PMCID: PMC6811277 DOI: 10.1093/ofid/ofz360.750] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Background There is a pressing need for development of oral antibiotics with activity against SBL-EB, particularly carbapenemase-producers, for use in the community or as step-down therapy for complicated urinary tract infection. VNRX-7145 is a novel boronic acid-based SBL inhibitor with no intrinsic activity that was designed as an orally bioavailable prodrug. The active moiety (VNRX-5236) is known to restore in vitro susceptibility to (CTB), an oral cephalosporin, among CTB-resistant SBL-EB. Methods CTB-resistant SBL-EB (N = 21) with CTB MICs ≥32 µg/mL and CTB/VNRX-5236 MIC range 0.12–2 µg/mL (VNRX-5236 fixed at 4 µg/mL) were evaluated. Carbapenemases were produced by 9 strains (4 OXA, 5 KPC). Bacterial suspensions (~107 CFU/mL) were used to inoculate the thighs of neutropenic mice. A human-simulated regimen of ceftibuten (CTB HSR) equivalent to a 400 mg q12h dosage was developed in infected mice. In dose ranging studies, groups of 3 animals each received the CTB HSR as monotherapy or combined with escalating VNRX-5236 exposures (CTB:VNRX-5236 dose ratios ranging from 10:1 to 1:4). Efficacy was assessed as the change in log10 CFU/thigh at 24 hours from 0 hour burden. With previous in vivo dose fractionation studies indicating the free area under the VNRX-5236 concentration–time curve to MIC ratio (fAUC0-24/MIC) as the PK/PD driver of efficacy, the Hill equation was used to estimate the magnitude required to achieve a static endpoint. Results Compared with 0 hour controls (mean log10 CFU/thigh, 5.7 ± 0.3), the bacterial burden for all isolates increased in saline-dosed controls and CTB HSR groups by 3.1 ± 0.8 and 2.5 ± 0.8 log10 CFU/thigh, respectively. The addition of VNRX-5236 resulted in bacterial stasis in 20/21 strains; the mean reduction in bacterial burden with the 1:1 CTB:VNRX-5236 dose ratio was −0.2 ± 0.7 log10 CFU/thigh. A composite assessment of exposure-responses indicated a fAUC0-24/MIC of 9.0 (R2 = 0.70) was associated with stasis. Conclusion Against CTB-resistant SBL-EB, inclusive of OXA-48- and KPC-producing strains, VNRX-5236 potentiated the in vivo activity of the CTB human-simulated exposure. The identified fAUC0-24/MIC target associated with bacterial stasis should be considered when selecting VNRX-7145 doses for clinical studies. Disclosures All authors: No reported disclosures.
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Ghahramani P, Chiu J, Asempa TE, Abdelraouf K, Nicolau DP, Abdel Hady W, Xiong Y, Bayer A, Carabeo T, Cassino C, Schuch R, Lehoux D. 1550. PK-PD Relationship and PK Driver of Efficacy of the Novel Antibacterial Lysin Exebacase (CF-301) in Pre-Clinical Models. Open Forum Infect Dis 2019. [PMCID: PMC6810366 DOI: 10.1093/ofid/ofz360.1414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Background Exebacase (CF-301) is a novel lysin with rapid bacteriolytic and anti-biofilm activity against S. aureus, pronounced synergy with antibiotics and low propensity for resistance. Exebacase has undergone Phase 1–2 trials. This work was to develop pharmacokinetic (PK) model in animal and determine the relationship between exebacase exposure and efficacy in animals. Methods PK data in 592 animals (4 species) included in population PK model. A range of linear and nonlinear mammillary models with allometric scaling fitted to the PK data using NONMEM and the most parsimonious model was selected by improvement in objective function value (P < 0.01). To evaluate efficacy, 349 animals with 177 mice (neutropenic thigh infection) and 172 rabbits (aortic valve infective endocarditis were treated with exebacase in addition to suboptimal doses of daptomycin (DAP). Full PK profiles were simulated for individual animals. Fifty-nine dosing regimens of exebacase in mice (0–90 mg/kg) and 18 regimens in rabbits (0–1.4 mg/kg) with q24h, q12h and q8h frequencies. Relationship between AUC/MIC, Cmax/MIC, T> MIC, and log-CFU was examined using a range of functions by comparing residual standard error (RSE). Results 3-compartment model with allometric scaling best described the PK data and was validated by bootstrap and Goodness of Fit. Maximum drop in log10CFU/g in target tissues was at AUC/MIC< 0.2 for exebacase when added to DAP that was associated with CF reduction of -5 logs in rabbits (Figure (a)) with similar magnitudes in cardiac vegetations, kidney and spleen, and -4 logs in mice (Figure (b)). Treatment with DAP alone had log10CFU reduction of -1 in mice; and -2 in rabbits. AUC/MIC was an appropriate predictor of CFU reductions. Conclusion PK model adequately described the data for 4 animal species. Exebacase addition to DAP has a synergistic effect on efficacy measured by CFU reductions in target tissues in the animal models. Results support previously presented determinations of AUC/MIC as predictor of efficacy. Maximum reductions in CFU in rabbits and mice were observed at AUC/MIC ratios <0.2. These results further indicate that rabbit is the most appropriate efficacy model with MICs and antibacterial activity reflective of previously reported observations in human serum. ![]()
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Disclosures All authors: No reported disclosures.
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Affiliation(s)
| | | | | | | | | | | | - Yan Xiong
- Los Angeles Biomedical Research Institute, Torrance, California
| | - Arnold Bayer
- LABioMed at Harbor-UCLA Medical Center, Torrance, California
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Asempa TE, Motos A, Abdelraouf K, Bissantz C, Zampaloni C, Nicolau DP. Efficacy of Human-Simulated Epithelial Lining Fluid Exposure of Meropenem-Nacubactam Combination against Class A Serine β-Lactamase-Producing Enterobacteriaceae in the Neutropenic Murine Lung Infection Model. Antimicrob Agents Chemother 2019; 63:e02382-18. [PMID: 30670411 PMCID: PMC6437545 DOI: 10.1128/aac.02382-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 01/16/2019] [Indexed: 12/22/2022] Open
Abstract
Nacubactam is a novel, broad-spectrum, β-lactamase inhibitor that is currently under development as combination therapy with meropenem. This study evaluated the efficacy of human-simulated epithelial lining fluid (ELF) exposures of meropenem, nacubactam, and the combination of meropenem and nacubactam against class A serine carbapenemase-producing Enterobacteriaceae isolates in the neutropenic murine lung infection model. Twelve clinical meropenem-resistant Klebsiella pneumoniae, Escherichia coli, and Enterobacter cloacae isolates, all harboring KPC or IMI-type β-lactamases, were utilized in the study. Meropenem, nacubactam, and meropenem-nacubactam (1:1) combination MICs were determined in triplicate via broth microdilution. At 2 h after intranasal inoculation, neutropenic mice were dosed with regimens that provided ELF profiles mimicking those observed in humans given meropenem at 2 g every 8 h and/or nacubactam at 2 g every 8 h (1.5-h infusions), alone or in combination. Efficacy was assessed as the change in bacterial growth at 24 h, compared with 0-h controls. Meropenem, nacubactam, and meropenem-nacubactam MICs were 8 to >64 μg/ml, 2 to >256 μg/ml, and 0.5 to 4 μg/ml, respectively. The average bacterial density at 0 h across all isolates was 6.31 ± 0.26 log10 CFU/lung. Relative to the 0-h control, the mean values of bacterial growth at 24 h in the untreated control, meropenem human-simulated regimen treatment, and nacubactam human-simulated regimen treatment groups were 2.91 ± 0.27, 2.68 ± 0.42, and 1.73 ± 0.75 log10 CFU/lung, respectively. The meropenem-nacubactam combination human-simulated regimen resulted in reductions of -1.50 ± 0.59 log10 CFU/lung. Meropenem-nacubactam human-simulated ELF exposure produced enhanced efficacy against all class A serine carbapenemase-producing Enterobacteriaceae isolates tested in the neutropenic murine lung infection model.
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Affiliation(s)
- Tomefa E Asempa
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA
| | - Ana Motos
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA
| | - Caterina Bissantz
- Roche Pharma Research and Early Development Pharmaceutical Science, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Claudia Zampaloni
- Roche Pharma Research and Early Development, Immunology, Inflammation, and Infectious Diseases, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA
- Division of Infectious Diseases, Hartford Hospital, Hartford, Connecticut, USA
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Kidd JM, Abdelraouf K, Nicolau DP. Comparative efficacy of human-simulated epithelial lining fluid exposures of tedizolid, linezolid and vancomycin in neutropenic and immunocompetent murine models of staphylococcal pneumonia. J Antimicrob Chemother 2018; 74:970-977. [DOI: 10.1093/jac/dky513] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 11/05/2018] [Accepted: 11/13/2018] [Indexed: 02/04/2023] Open
Affiliation(s)
- James M Kidd
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
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Abuhussain SA, Avery L, Abdelraouf K, Nicolau DP. 1336. Assessment of the In Vivo Efficacy of WCK 5222 (Cefepime-Zidebactam) Against Carbapenems-Resistant Acinetobacter baumannii (CR-ACBN) in the Neutropenic Murine Thigh Infection Model. Open Forum Infect Dis 2018. [PMCID: PMC6253952 DOI: 10.1093/ofid/ofy210.1168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background Methods Results Conclusion Disclosures
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Affiliation(s)
| | - Lindsay Avery
- Center of Anti-Infective Researchand Development, Hartford Hospital, Hartford, Connecticut
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut
| | - David P Nicolau
- Division of Infectious Diseases, Hartford Hospital, Hartford, Connecticut
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Asempa TE, Motos A, Abdelraouf K, Bissantz C, Zampaloni C, Nicolau DP. 1368. Assessment of the In Vivo Efficacy of Human-Simulated Epithelial Lining Fluid (ELF) Exposure of Meropenem/Nacubactam (MEM/NAC) Combination Against β-Lactamase-Producing Enterobacteriaceae in Neutropenic Lung Infection Model. Open Forum Infect Dis 2018. [PMCID: PMC6253160 DOI: 10.1093/ofid/ofy210.1199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
NAC is a novel dual action β-lactamase inhibitor with in vitro activity against class A, class C, and some class D β-lactamases and antibacterial activity against Enterobactaeriaceae. NAC is being developed as a combination therapy with MEM for the treatment of serious Gram-negative bacterial infections. This study evaluated the efficacy of the human-simulated ELF exposure of MEM/NAC, compared with those of MEM or NAC alone against β-lactamase-producing Enterobacteriaceae isolates in the neutropenic murine lung infection model.
Methods
Eight clinical MEM-resistant Enterobacteriaceae isolates harboring various β-lactamases (IMI, KPC, OXA, TEM, SHV, and AmpC) were utilized in the study. MEM and MEM:NAC (1:1) combination MICs were determined in triplicate via broth microdilution. ICR mice were rendered transiently neutropenic, and lungs were inoculated with 50 µL bacterial suspensions of 107 CFU/mL. Regimens in mice that simulated the human ELF exposures following doses of MEM 2g q8h and NAC 2g q8h (1.5 hours infusions) as monotherapies and in combination were established. Treatment mice received MEM human-simulated regimen (HSR), NAC HSR, or MEM/NAC HSR and control mice were vehicle-dosed. Treatment was started 2 hours after inoculation and continued for 24 hours. Efficacy was assessed as the change in log10CFU/lung at 24 hours compared with 0 hours controls.
Results
MEM and MEM/NAC MICs were 8–512 and 0.5–8 mg/L, respectively. The average log10CFU/lung at 0 hours across all isolates was 6.26 ± 0.26. Relative to 0 hours control, the mean bacterial growth at 24 hours in the untreated control mice, MEM HSR, and NAC HSR treatment groups were 2.93 ± 0.29, 2.72 ± 0.42, and 1.75 ± 0.80 log10CFU/lung, respectively. MEM/NAC HSR resulted in up to 2-log bacterial reduction in isolates with MEM/NAC MIC ≤4 mg/L.
Conclusion
MEM/NAC human-simulated ELF exposure produced enhanced efficacy against MEM-resistant β-lactamase-producing Enterobacteriaceae isolates with MEM/NAC MIC ≤4 mg/L. These data support a potential role for MEM/NAC for treatment of lung infections due to β-lactamase-producing Enterobacteriaceae and warrant further studies.
This project has been funded in part under HHS BARDA Contract HHSO100201600038C.
Disclosures
C. Bissantz, F Hoffmann La Roche Ltd.: Employee, Salary. C. Zampaloni, F. Hoffmann-La Roche Ltd.: Employee, Salary. D. P. Nicolau, Hoffmann-La Roche Ltd.: Grant Investigator, Grant recipient.
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Affiliation(s)
- Tomefa E Asempa
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut
| | - Ana Motos
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut
| | - Caterina Bissantz
- Roche Pharma Research and Early Development Pharmaceutical Science, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Claudia Zampaloni
- Roche Pharma Research and Early Development, Immunology, Inflammation and Infectious Diseases, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut
- Division of Infectious Diseases, Hartford Hospital, Hartford, Connecticut
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Kidd JM, Abdelraouf K, Nicolau DP. 1397. Comparative Efficacy of Human-Simulated Epithelial Lining Fluid (ELF) Exposures of Tedizolid (TZD) Against Methicillin-resistant Staphylococcus Aureus (MRSA) in Neutropenic (I−) vs. Immunocompetent (I+) Murine Models of Pneumonia. Open Forum Infect Dis 2018. [PMCID: PMC6252954 DOI: 10.1093/ofid/ofy210.1228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Background TZD is an oxazolidinone with potent in vitro activity against Gram-positive pathogens, including MRSA. Limited data currently exist on the efficacy of TZD in the presence of neutropenia. Herein, we investigate the comparative efficacy of human-simulated ELF exposures of TZD against MRSA in I− and I+ murine models of pneumonia. Methods Four MRSA isolates with TZD broth microdilution MICs of 0.5 mg/L were studied. BALB/c mice in I− groups were made neutropenic with cyclophosphamide. Lungs of I− mice were inoculated intranasally with bacterial suspensions of 107 CFU/mL; a higher inoculum of 109 CFU/mL was required to induce infection in I+ mice. Single daily doses of TZD simulating human ELF exposures after doses of 200 mg q24h were determined in both I+ (40 mg/kg) and I− (32 mg/kg) models. Three hours after inoculation, human-simulated doses of TZD were administered q24h for up to 72 hours while control mice were vehicle dosed. A group of control and another of treatment (n = 6) per isolate were sacrificed at 24, 48, or 72 hours for lung harvest. Bacterial densities were determined by quantitative culture and averaged across all isolates. Mice that succumbed to infection before the scheduled time of sacrifice were included in the next group due for sacrifice. Changes in log10 CFU/lungs at 24 hours were compared with 0 hour controls. Results The average bacterial burdens at 0 hour were 5.86 ± 0.21 and 8.10 ± 0.24 log10 CFU/lungs among I− and I+ mice, respectively. At 24 hours, average burdens in control mice were comparable among I− and I+ mice at 7.91 ± 0.62 and 9.01 ± 0.69 log10CFU/lungs, respectively. Mean changes in bacterial density are reported in the table. No I+ control mice survived past 48 hours. Conclusion Human-simulated ELF exposures of TZD demonstrated substantial and sustained efficacy in both I− and I+ murine models of pneumonia. These preclinical data utilizing clinically achievable bronchopulmonary exposures suggest that the efficacy of TZD for treatment of MRSA lung infections is not compromised by neutropenic status of the host. Further validation of these findings in patients is warranted. Disclosures D. P. Nicolau, Merck: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Speaker honorarium.
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Affiliation(s)
- James M Kidd
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut
| | - Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut
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Abdelraouf K, Abuhussain SA, Nicolau DP. 1405. Efficacy of the Human-Simulated Regimen (HSR) of Cefepime (FEP)/VNRX-5133 Combination Against Serine β-Lactamase-Producing Gram-negative Bacteria in the Neutropenic Murine Thigh Infection Model. Open Forum Infect Dis 2018. [PMCID: PMC6253331 DOI: 10.1093/ofid/ofy210.1236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Background VNRX-5133 is a new-generation β-lactamase inhibitor with potent activity against serine and metallo-β-lactamases. FEP/VNRX-5133 combination shows remarkable in vitro activity against multi-drug-resistant Gram-negative bacteria. The objective of this study was to assess the in vivo efficacy of HSR of the combination against a range of Enterobacteriaceae and Pseudomonas aeruginosa isolates expressing serine β-lactamases in the murine thigh infection model. Methods Twenty-four Enterobacteriaceae and P. aeruginosa clinical isolates producing KPC and extended-spectrum β-lactamases as well as P. aeruginosa with AmpC overexpression were utilized for in vivo studies. FEP and FEP/VNRX-5133 MIC ranges were 256 to >512 and 0.125––16 mg/L, respectively. ICR mice were rendered transiently neutropenic, and the thighs were inoculated with bacterial suspensions of 107 CFU/mL. HSR of FEP and VNRX-5133 equivalent to clinical doses of 2 g and 500 mg, respectively, each given q8h as 2 hours infusion were developed in the murine model. Treatment mice were administered either FEP HSR alone, FEP HSR + VNRX-5133 HSR combination, or FEP HSR + 1/8th the doses of VNRX-5133 HSR. Control mice were vehicle-dosed. Efficacy was assessed as the change in log10CFU/thigh at 24 hours compared with 0 hour. Results The average log10CFU/thigh at 0 hour across all isolates was 5.74 ± 0.53. At 24 hours, the bacterial burden increased by an average of 3.27 ± 0.53 log10 CFU/thigh in the untreated control mice. Treatment with FEP alone was associated with average net growth of 2.76 ± 0.75 log10CFU/thigh. The co-administration of VNRX-5133 HSR was adequate to attain ≥ 2-log reduction in initial bacterial burdens at 24 hours in seven out of 24 isolates and ≥ 1-log reduction in the remaining 17 isolates. Furthermore, FEP HSR + 1/8th VNRX-5133 HSR resulted in ≥1-log reduction in the initial bacterial burden in 16 out of 24 isolates. Conclusion FEP/VNRX-5133 combination showed potent in vivo efficacy against serine β-lactamase-producing Gram-negative isolates. The extent of bacterial killing achieved with 1/8th VNRX-5133 HSR attested to the robustness of the inhibitor activity. These data support the consideration of FEP/VNRX-5133 combination for the treatment of serious infections due to these organisms in clinical trials. Disclosures D. P. Nicolau, VenatoRx Pharmaceuticals, Inc.: Grant Investigator, Research grant
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Affiliation(s)
- Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut
| | | | - David P Nicolau
- Division of Infectious Diseases, Hartford Hospital, Hartford, Connecticut
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Abdelraouf K, Linder KE, Nailor MD, Nicolau DP. Predicting and preventing antimicrobial resistance utilizing pharmacodynamics: part II Gram-negative bacteria. Expert Opin Drug Metab Toxicol 2017; 13:705-714. [PMID: 28486001 DOI: 10.1080/17425255.2017.1329417] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Antimicrobial resistance is a serious health threat worldwide. Better understanding of exposure targets that could suppress resistance amplification is necessary to guide the dosing of currently available agents as well as new therapies in the drug development process. Areas covered: This review will discuss studies that focused on predicting development of resistance using the pharmacokinetic-pharmacodynamic approach and how to design dosing regimens that can successfully suppress resistance emergence in Gram-negative bacteria. Expert opinion: Pharmacokinetic-pharmacodynamic targets could provide useful insights to guide antimicrobial dosing to prevent resistance emergence. Exposure targets required for resistance suppression are higher than those for efficacy and might not be clinically feasible. Combination therapy is a possible approach to improve the efficacy and minimize the resistance emergence for difficult-to-treat infections.
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Affiliation(s)
- Kamilia Abdelraouf
- a Center for Anti-Infective Research and Development , Hartford Hospital , Hartford , CT , USA
| | - Kristin E Linder
- b Department of Pharmacy , Hartford Hospital , Hartford , CT , USA
| | - Michael D Nailor
- b Department of Pharmacy , Hartford Hospital , Hartford , CT , USA.,c Department of Pharmacy Practice , University of Connecticut School of Pharmacy , Storrs , CT , USA
| | - David P Nicolau
- a Center for Anti-Infective Research and Development , Hartford Hospital , Hartford , CT , USA.,d Division of Infectious Diseases , Hartford Hospital , Hartford , CT , USA
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Abdelraouf K, Nicolau DP. Comparative In Vivo Efficacy of Human-Simulated Exposures of Tedizolid (TZD) in Neutropenic (I-) versus Immunocompetent (I+) Murine Streptococcus pneumoniae Lung Infection Model. Open Forum Infect Dis 2016. [DOI: 10.1093/ofid/ofw172.1509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Kamilia Abdelraouf
- Center for Anti-Infective Research & Development at Hartford Hospital, Hartford, Connecticut
| | - David P. Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut
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Abdelraouf K, Nicolau DP. Human-Simulated Exposure and Pharmacodynamic (PD) Assessment of Tedizolid (TZD) Against Streptococcus pneumoniae in an Immunocompetent Murine Lung Infection Model. Open Forum Infect Dis 2016. [DOI: 10.1093/ofid/ofw172.1494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Kamilia Abdelraouf
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut
| | - David P. Nicolau
- Center for Anti-Infective Research and Development at Hartford Hospital, Hartford, Connecticut
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Nounou MI, ElAmrawy F, Ahmed N, Abdelraouf K, Goda S, Syed-Sha-Qhattal H. Breast Cancer: Conventional Diagnosis and Treatment Modalities and Recent Patents and Technologies. Breast Cancer (Auckl) 2015; 9:17-34. [PMID: 26462242 PMCID: PMC4589089 DOI: 10.4137/bcbcr.s29420] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 09/08/2015] [Accepted: 09/09/2015] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Breast cancer is the most prevalent cancer among women worldwide. However, increased survival is due to the dramatic advances in the screening methods, early diagnosis, and breakthroughs in treatments. Over the course of the last decade, many acquisitions have taken place in this critical field of research in the pharmaceutical industry. Advances in molecular biology and pharmacology aided in better understanding of breast cancer, enabling the design of smarter therapeutics able to target cancer and respond to its microenvironment efficiently. Patents and research papers investigating diagnosis and treatment strategies for breast cancer using novel technologies have been surveyed for the past 15 years. Various nanocarriers have been introduced to improve the therapeutic efficacy of anticancer drugs, including liposomes, polymeric micelles, quantum dots, nanoparticles, and dendrimers. This review provides an overview of breast cancer, conventional therapy, novel technologies in the management of breast cancer, and rational approaches for targeting breast cancer. HIGHLIGHTS Breast cancer is the most common cancer in women worldwide. However, survival rates vary widely, optimistically heading toward a positive trend. Increased survival is due to the drastic shift in the screening methods, early diagnosis, and breakthroughs in treatments.Different strategies of breast cancer classification and staging have evolved over the years. Intrinsic (molecular) subtyping is essential in clinical trials and well understanding of the disease.Many novel technologies are being developed to detect distant metastases and recurrent disease as well as to assess response to breast cancer management.Intensive research efforts are actively ongoing to take novel breast cancer therapeutics to potential clinical application.Most of the recent research papers and patents discuss one of the following strategies: the development of new drug entities that specifically target the breast tumor cells; tailor designing a novel carrier system that can multitask and multifunction as a drug carrier, targeting vehicle and even as a diagnostic tool, direct conjugation of a therapeutic drug moiety with a targeting moiety, diagnostic moiety or pharmacokinetics altering moiety; or the use of innovative nontraditional approaches such as genetic engineering, stem cells, or vaccinations.
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Affiliation(s)
- Mohamed I. Nounou
- Department of Pharmaceutics, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Fatema ElAmrawy
- Department of Pharmaceutics, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Nada Ahmed
- Department of Pharmaceutics, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Kamilia Abdelraouf
- Department of Pharmaceutics, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
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Abdelraouf K, Chang KT, Yin T, Hu M, Tam VH. Uptake of polymyxin B into renal cells. Antimicrob Agents Chemother 2014; 58:4200-2. [PMID: 24733472 PMCID: PMC4068554 DOI: 10.1128/aac.02557-14] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 04/10/2014] [Indexed: 11/20/2022] Open
Abstract
Polymyxin B is increasingly used as a treatment of last resort against multidrug-resistant Gram-negative infections. Using a mammalian kidney cell line, we demonstrated that polymyxin B uptake into proximal tubular epithelial cells was saturable and occurred primarily through the apical membrane, suggesting the involvement of transporters in the renal uptake of polymyxin B. Megalin might play a role in the uptake and accumulation of polymyxin B into renal cells.
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Affiliation(s)
- Kamilia Abdelraouf
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, Texas, USA
| | - Kai-Tai Chang
- Department of Clinical Sciences and Administration, University of Houston College of Pharmacy, Houston, Texas, USA
| | - Taijun Yin
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, Texas, USA
| | - Ming Hu
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, Texas, USA
| | - Vincent H Tam
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, Texas, USA Department of Clinical Sciences and Administration, University of Houston College of Pharmacy, Houston, Texas, USA
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He J, Abdelraouf K, Ledesma KR, Chow DSL, Tam VH. Pharmacokinetics and efficacy of liposomal polymyxin B in a murine pneumonia model. Int J Antimicrob Agents 2013; 42:559-64. [PMID: 24016799 DOI: 10.1016/j.ijantimicag.2013.07.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 07/10/2013] [Accepted: 07/14/2013] [Indexed: 11/25/2022]
Abstract
Polymyxin B (PB) is increasingly used as the last treatment for multidrug-resistant (MDR) Gram-negative bacterial infections. In this study, serum and epithelial lining fluid (ELF) pharmacokinetics and the efficacy of a PB liposomal formulation were investigated. Two groups of 24 Swiss Webster mice were intravenously administered PB liposomes or PB aqueous solution at ca. 3 mg/kg. Serum and ELF samples were collected for up to 6 h to quantify major PB components. Three groups of neutropenic mice (n = 6/group) were infected with a clinical MDR Pseudomonas aeruginosa strain followed by intravenous administration of PB liposomes or PB aqueous solution at 3 mg/kg every 6 h or sham (drug-free) liposomes every 6 h. Bacterial burden in animal lung tissues was quantified after 24 h of therapy and was compared using one-way ANOVA. Survival of infected animals over time (n = 10/group) was evaluated by Kaplan-Meier analysis and log-rank test. In the pharmacokinetic study, the AUC ratio in ELF between liposome and aqueous solution groups ranged from 4.6 to 11.1 for various major PB components. In the efficacy study, for strain PA 9019 a significantly lower bacterial burden was seen in the liposomal group (3.8 ± 0.7 vs. 7.9 ± 0.8 log(10)CFU/g in the aqueous solution group), which subsequently prolonged survival of infected animals. In this study, treatment with a PB liposomal formulation yielded higher drug penetration into pulmonary ELF, which resulted in superior efficacy. However, further investigations on the clinical utility of the PB liposomal formulation are warranted.
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Affiliation(s)
- Jie He
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, 1441 Moursund Street, Houston, TX, USA
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Guo B, Abdelraouf K, Ledesma KR, Nikolaou M, Tam VH. Predicting bacterial fitness cost associated with drug resistance. J Antimicrob Chemother 2012; 67:928-32. [DOI: 10.1093/jac/dkr560] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Affiliation(s)
| | - Kamilia Abdelraouf
- Department of Clinical Sciences and Administration, University of Houston College of Pharmacy, Houston, Texas
| | - Jenny G. H. Low
- Department of Infectious Diseases, Singapore General Hospital, Singapore; and
| | - Vincent H. Tam
- Department of Clinical Sciences and Administration, University of Houston College of Pharmacy, Houston, Texas
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Abdelraouf K, Kabbara S, Ledesma KR, Poole K, Tam VH. Effect of multidrug resistance-conferring mutations on the fitness and virulence of Pseudomonas aeruginosa. J Antimicrob Chemother 2011; 66:1311-7. [DOI: 10.1093/jac/dkr105] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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