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Eales BM, Smith JE, Pouya N, Teran NS, Miller WR, Tam VH. Alternative iron-depleted media for cefiderocol susceptibility testing. Int J Antimicrob Agents 2024:107193. [PMID: 38723696 DOI: 10.1016/j.ijantimicag.2024.107193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 04/17/2024] [Accepted: 05/03/2024] [Indexed: 05/19/2024]
Affiliation(s)
- Brianna M Eales
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas
| | - James E Smith
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas
| | - Nazanin Pouya
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas
| | - Nicholas S Teran
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas
| | - William R Miller
- Center for Infectious Diseases Research, Houston Methodist Research Institute, Houston, Texas
| | - Vincent H Tam
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas.
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Hudson CS, Smith JE, Eales BM, Kajiji S, Liu X, Truong LD, Tam VH. Zileuton ameliorates aminoglycoside and polymyxin-associated acute kidney injury in an animal model. J Antimicrob Chemother 2023; 78:2435-2441. [PMID: 37563789 DOI: 10.1093/jac/dkad246] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 07/15/2023] [Indexed: 08/12/2023] Open
Abstract
OBJECTIVES Aminoglycosides and polymyxins are antibiotics with in vitro activity against MDR Gram-negative bacteria. However, their clinical use is hindered by dose-limiting nephrotoxicity. The objective of this project was to determine if zileuton can reduce nephrotoxicity associated with amikacin and polymyxin B in a rat model of acute kidney injury. METHODS Sprague Dawley rats (n = 10, both genders) were administered either amikacin (300 mg/kg) or polymyxin B (20 mg/kg) daily for 10 days. Zileuton (4 and 10 mg/kg) was delivered intraperitoneally 15 min before antibiotic administration. Blood samples were collected at baseline and daily to determine serum creatinine concentration. Nephrotoxicity was defined as a ≥2× elevation of baseline serum creatinine. Time-to-event analysis and log rank test were used to compare the onset of nephrotoxicity in different cohorts. Histopathological analysis was also conducted to characterize the extent of kidney injury. RESULTS Animals receiving amikacin or polymyxin B alone had nephrotoxicity rates of 90% and 100%, respectively. The overall rate was reduced to 30% in animals receiving adjuvant zileuton. The onset of nephrotoxicity associated with amikacin and polymyxin B was also significantly delayed by zileuton at 4 and 10 mg/kg, respectively. Histopathology confirmed reduced kidney injury in animals receiving amikacin concomitant with zileuton. CONCLUSIONS Our pilot data suggest that zileuton has the potential to attenuate nephrotoxicity associated with last-line antibiotics. This would allow these antibiotics to treat MDR Gram-negative bacterial infections optimally without dose-limiting constraints. Further studies are warranted to optimize drug delivery and dosing in humans.
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Affiliation(s)
- Cole S Hudson
- Department of Pharmacological & Pharmaceutical Sciences, University of Houston College of Pharmacy, 4849 Martin Luther King Boulevard, Houston, TX, USA
| | - James E Smith
- Department of Pharmacy Practice & Translational Research, University of Houston College of Pharmacy, 4849 Martin Luther King Boulevard, Houston, TX, USA
| | - Brianna M Eales
- Department of Pharmacological & Pharmaceutical Sciences, University of Houston College of Pharmacy, 4849 Martin Luther King Boulevard, Houston, TX, USA
| | - Shama Kajiji
- Emergent System Analytics, LLC, 24 W Main St Suite 216, Clinton, CT, USA
| | - Xinli Liu
- Department of Pharmacological & Pharmaceutical Sciences, University of Houston College of Pharmacy, 4849 Martin Luther King Boulevard, Houston, TX, USA
| | - Luan D Truong
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, 6565 Fannin St, Houston, TX, USA
| | - Vincent H Tam
- Department of Pharmacological & Pharmaceutical Sciences, University of Houston College of Pharmacy, 4849 Martin Luther King Boulevard, Houston, TX, USA
- Department of Pharmacy Practice & Translational Research, University of Houston College of Pharmacy, 4849 Martin Luther King Boulevard, Houston, TX, USA
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Hudson CS, Smith JE, Eales BM, Nikolaou M, Tam VH. In vitro model to simulate multiple drugs with distinct elimination half-lives. Int J Antimicrob Agents 2023; 62:106924. [PMID: 37433386 DOI: 10.1016/j.ijantimicag.2023.106924] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 01/07/2023] [Revised: 06/19/2023] [Accepted: 07/05/2023] [Indexed: 07/13/2023]
Abstract
OBJECTIVE The prevalence of drug resistance in pathogens such as HIV and selected bacteria has been steadily rising, resulting in an increased need for using multiple agents concurrently. Agents used in these combination therapies may have different elimination half-lives in humans. There is an unmet need for in vitro models to evaluate the efficacy of these combinations to guide early drug development. In order to realistically reflect in vivo conditions, useful in vitro model systems must be capable of simulating multiple pharmacokinetic profiles with distinct elimination half-lives. The goal of this study was to experimentally simulate four pharmacokinetic profiles with distinct elimination half-lives in an in vitro hollow-fibre system. METHODS For illustrative purposes, fluctuating exposures of ceftriaxone were simulated with distinct half-lives of 1, 2.5, 8, and 12 hours. A parallel experimental setup was used to independently connect four supplemental reservoirs to a central reservoir. Target maximum concentration was achieved by direct drug dosing into the central reservoir; supplemental reservoirs were also dosed to offset the rapid drug elimination rate from the central reservoir. Serial pharmacokinetic samples were obtained from the central reservoir, assayed by a spectrophotometric method, and characterized by a one-compartment model. RESULTS The observed maximum concentrations and elimination half-lives were in agreement with the expected values obtained from the mathematical predictions. CONCLUSIONS This in vitro experimental system can be used to evaluate the efficacy of up to four-drug combinations against multidrug-resistant bacteria or HIV-infected mammalian cells. The established framework represents an adaptable tool to advance the field of combination therapy.
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Affiliation(s)
- Cole S Hudson
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, Texas, USA
| | - James E Smith
- Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, Texas, USA
| | - Brianna M Eales
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, Texas, USA
| | - Michael Nikolaou
- Department of Chemical and Biomolecular Engineering, University of Houston College of Engineering, Houston, Texas, USA
| | - Vincent H Tam
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, Texas, USA; Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, Texas, USA; Department of Chemical and Biomolecular Engineering, University of Houston College of Engineering, Houston, Texas, USA.
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Eales BM, Bai B, Merlau PR, Tam VH. Growth of Acinetobacter baumannii impacted by iron chelation. Lett Appl Microbiol 2023; 76:ovad019. [PMID: 36731874 PMCID: PMC9990167 DOI: 10.1093/lambio/ovad019] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 10/03/2022] [Revised: 01/26/2023] [Accepted: 02/01/2023] [Indexed: 02/04/2023]
Abstract
Acinetobacter baumannii (AB) has become multidrug-resistant (MDR) in recent years, and, currently, there are limited effective treatment options. Nutrient metals (e.g. iron) are essential to the metabolic functions of AB. This study examined the impact of iron chelation on the growth of AB in vitro and in vivo. Susceptible and MDR-AB bloodstream isolates (n = 9) were recovered from different patients between 2011 and 2018. Clonal diversity was ascertained by Fourier-transform infrared spectroscopy. In vitro bacterial densities were measured over 20 h to determine growth profiles. Variable amounts of a chelating agent [deferiprone (DFP)] were added to create a concentration gradient. Galleria mellonella larvae were inoculated with an isolate, with and without DFP. Quantitative culture was used to ascertain the bacterial burden of aggregate larvae immediately and 4 h post-infection. Increasing concentrations of DFP caused a transient and concentration-dependent hindrance to in vitro growth, compared to the no-treatment group. In vivo bacterial burden immediately post-infection in both groups was comparable. After 4 h, the burden was much higher in the control group comparatively (8.7 and 6.7 log CFU g-1). These results support that micro-nutrient limitation has the potential of being a novel approach for treating high-risk infections due to MDR-AB.
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Affiliation(s)
- Brianna M Eales
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, TX 77204, USA
| | - Bing Bai
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, TX 77204, USA
- Department of Infectious Diseases and Shenzhen Key Laboratory for Endogenous Infections, The 6th Affiliated Hospital of Shenzhen University Health Center, Shenzhen, Guangdong 518052, China
| | - Paul R Merlau
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, TX 77204, USA
| | - Vincent H Tam
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, TX 77204, USA
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Bai B, Eales BM, Huang W, Ledesma KR, Merlau PR, Li G, Yu Z, Tam VH. Clinical and genomic analysis of virulence-related genes in bloodstream infections caused by Acinetobacter baumannii. Virulence 2022; 13:1920-1927. [PMID: 36308002 PMCID: PMC9621070 DOI: 10.1080/21505594.2022.2132053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Acinetobacter baumannii has emerged as a common cause of bloodstream infections, which is associated with high mortality and long periods of hospitalization. To advance the medical care of our patients, the study was designed to identify microbial characteristics associated with poor clinical outcomes. A collection of 32 A. baumannii bloodstream isolates with diverse genetic backgrounds (as determined by multilocus sequence typing) was studied. These isolates were recovered by unique patients (18 males, 14 females; age range: 17 days to 87 years) between 2011 and 2018. A sequential screening approach (cross-referencing analyses using different endpoints) was used to identify isolates with the best correlation between bacterial virulence and clinical prognosis. Isolates associated with more rapid in vitro growth rate, shorter median survival time in pre-clinical infection models, and hospital mortality were selected as candidates for high virulence, while those with opposite characteristics were selected as controls with low virulence. Whole genome sequencing was undertaken in the most promising clinical isolates. We found five virulence genes (beta-hemolysin/cytolysin, Cpi-1a + Cpi-1 (SPI-1 like), enhanced entry proteins, FbpABC, Paa) and 1 secretory system (T6SS) only present in a highly virulent isolate (AB23), compared to a low virulence control isolate (AB6). These genetic elements could be associated with the poor prognosis of A. baumannii bacteraemia and further investigations are warranted.
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Affiliation(s)
- Bing Bai
- Department of Infectious Diseases and Shenzhen Key Laboratory for Endogenous Infections, The 6th Affiliated Hospital of Shenzhen University Health Center, Shenzhen, Guangdong, China,Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas, USA
| | - Brianna M. Eales
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas, USA
| | - Wei Huang
- Bacteriology & Antibacterial Resistance Surveillance Laboratory, Shenzhen Institute of Respiratory Diseases, Shenzhen People’s Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, Guangdong, China
| | - Kimberly R. Ledesma
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas, USA
| | - Paul R. Merlau
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas, USA
| | - Guiqiu Li
- Department of Infectious Diseases and Shenzhen Key Laboratory for Endogenous Infections, The 6th Affiliated Hospital of Shenzhen University Health Center, Shenzhen, Guangdong, China
| | - Zhijian Yu
- Department of Infectious Diseases and Shenzhen Key Laboratory for Endogenous Infections, The 6th Affiliated Hospital of Shenzhen University Health Center, Shenzhen, Guangdong, China,Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas, USA
| | - Vincent H. Tam
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, Texas, USA,CONTACT Vincent H. Tam
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Kesisoglou I, Eales BM, Merlau PR, Tam VH, Nikolaou M. Deciphering longitudinal optical-density measurements to guide clinical dosing regimen design: A model-based approach. Comput Methods Programs Biomed 2022; 227:107212. [PMID: 36335752 PMCID: PMC10225978 DOI: 10.1016/j.cmpb.2022.107212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 10/23/2022] [Accepted: 10/30/2022] [Indexed: 05/31/2023]
Abstract
BACKGROUND Model-based analysis of longitudinal optical density measurements from a bacterial suspension exposed to antibiotics has been proposed as a potentially efficient and effective method for extracting useful information to improve the individualized design of treatments for bacterial infections. To that end, the authors developed in previous work a mathematical modeling framework that can use such measurements for design of effective dosing regimens. OBJECTIVES Here we further explore ways to extract information from longitudinal optical density measurements to predict bactericidal efficacy of clinically relevant antibiotic exposures. METHODS Longitudinal optical density measurements were collected in an automated instrument where Acinetobacter baumannii, ATCC BAA747, was exposed to ceftazidime concentrations of 1, 4, 16, 64, and 256 mg/L and to ceftazidime/amikacin concentrations of 1/0.5, 4/2, 16/8, 64/32, and 256/128 (mg/L)/(mg/L) over 20 h. Calibrated conversion of measurements produced total (both live and dead) bacterial cell concentration data (CFU/mL equivalent) over time. Model-based data analysis predicted the bactericidal efficacy of ceftazidime and of ceftazidime/amikacin (at ratio 2:1) for periodic injection every 8 h and subsequent exponential decline with half-life of 2.5 h. Predictions were experimentally tested in an in vitro hollow-fiber infection model, using peak concentrations of 60 and 150 mg/L for injected ceftazidime and of 40/20 (mg/L)/(mg/L) for injected ceftazidime/amikacin. RESULTS Model-based analysis predicted low (<62%) confidence in clinically relevant suppression of the bacterial population by periodic injections of ceftazidime alone, even at high peak concentrations. Conversely, analysis predicted high (>95%) confidence in bacterial suppression by periodic injections of ceftazidime/amikacin combinations at a wide range of peak concentrations ratioed at 2:1. Both predictions were experimentally confirmed in an in vitro hollow fiber infection model, where ceftazidime was periodically injected at peak concentrations 60 and 150 mg/L (with predicted suppression confidence 38% and 59%, respectively) and a combination of ceftazidime/amikacin was periodically injected at peak concentrations 40/20 (mg/L)/(mg/L) (with predicted suppression confidence 98%). CONCLUSIONS The paper highlights the potential of clinicians using the proposed mathematical framework to determine the utility of different antibiotics to suppress a patient-specific isolate. Additional studies will be needed to consolidate and expand the utility of the proposed method.
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Affiliation(s)
- Iordanis Kesisoglou
- Department of Chemical & Biomolecular Engineering, University of Houston, 4226 Martin Luther King Boulevard, Houston TX 77204, United States of America
| | - Brianna M Eales
- Department of Pharmacy Practice and Translational Research, University of Houston, 4349 Martin Luther King Boulevard, Houston TX 77204, United States of America
| | - Paul R Merlau
- Department of Pharmacy Practice and Translational Research, University of Houston, 4349 Martin Luther King Boulevard, Houston TX 77204, United States of America
| | - Vincent H Tam
- Department of Chemical & Biomolecular Engineering, University of Houston, 4226 Martin Luther King Boulevard, Houston TX 77204, United States of America; Department of Pharmacy Practice and Translational Research, University of Houston, 4349 Martin Luther King Boulevard, Houston TX 77204, United States of America
| | - Michael Nikolaou
- Department of Chemical & Biomolecular Engineering, University of Houston, 4226 Martin Luther King Boulevard, Houston TX 77204, United States of America.
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Tam VH, Merlau PR, Hudson CS, Kline EG, Eales BM, Smith J, Sofjan AK, Shields RK. Optimal ceftazidime/avibactam dosing exposure against KPC-producing Klebsiella pneumoniae. J Antimicrob Chemother 2022; 77:3130-3137. [PMID: 36031868 PMCID: PMC10205629 DOI: 10.1093/jac/dkac294] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [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: 05/11/2022] [Accepted: 08/05/2022] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVES Infections due to carbapenem-resistant Enterobacterales are considered urgent public health threats and often treated with a β-lactam/β-lactamase inhibitor combination. However, clinical treatment failure and resistance emergence have been attributed to inadequate dosing. We used a novel framework to provide insights of optimal dosing exposure of ceftazidime/avibactam. METHODS Seven clinical isolates of Klebsiella pneumoniae producing different KPC variants were examined. Ceftazidime susceptibility (MIC) was determined by broth dilution using escalating concentrations of avibactam. The observed MICs were characterized as response to avibactam concentrations using an inhibitory sigmoid Emax model. Using the best-fit parameter values, %fT>MICi was estimated for various dosing regimens of ceftazidime/avibactam. A hollow-fibre infection model (HFIM) was subsequently used to ascertain the effectiveness of selected regimens over 120 h. The drug exposure threshold associated with bacterial suppression was identified by recursive partitioning. RESULTS In all scenarios, ceftazidime MIC reductions were well characterized with increasing avibactam concentrations. In HFIM, bacterial regrowth over time correlated with emergence of resistance. Overall, suppression of bacterial regrowth was associated with %fT>MICi ≥ 76.1% (100% versus 18.2%; P < 0.001). Using our framework, the optimal drug exposure could be achieved with ceftazidime/avibactam 2.5 g every 12 h in 5 out of 7 isolates. Furthermore, ceftazidime/avibactam 2.5 g every 8 h can suppress an isolate deemed resistant based on conventional susceptibility testing method. CONCLUSIONS An optimal drug exposure to suppress KPC-producing bacteria was identified. The novel framework is informative and may be used to guide optimal dosing of other β-lactam/β-lactamase inhibitor combinations. Further in vivo investigations are warranted.
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Affiliation(s)
- Vincent H Tam
- Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, TX 77204, USA
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, TX 77204, USA
| | - Paul R Merlau
- Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, TX 77204, USA
| | - Cole S Hudson
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, TX 77204, USA
| | - Ellen G Kline
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Brianna M Eales
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, TX 77204, USA
| | - James Smith
- Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, TX 77204, USA
| | - Amelia K Sofjan
- Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, TX 77204, USA
| | - Ryan K Shields
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
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Kesisoglou I, Eales BM, Ledesma KR, Merlau PR, Tam VH, Wang W, Nikolaou M. SIMULTANEOUS IN VITRO SIMULATION OF MULTIPLE ANTIMICROBIAL AGENTS WITH DIFFERENT ELIMINATION HALF-LIVES IN A PRE-CLINICAL INFECTION MODEL. Comput Chem Eng 2021; 155. [PMID: 34924641 DOI: 10.1016/j.compchemeng.2021.107540] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 10/20/2022]
Abstract
Combination therapy for treatment of multi-drug resistant bacterial infections is becoming common. In vitro testing of drug combinations under realistic pharmacokinetic conditions is needed before a corresponding combination is eventually put into clinical use. The current standard for design of such in vitro simulations for drugs with different half-lives is heuristic and limited to two drugs. To address that void, we develop a rigorous design method suitable for an arbitrary number of N drugs with different half-lives. The method developed offers substantial flexibility and produces novel designs even for two drugs. Explicit design equations are rigorously developed and are suitable for immediate use by experimenters. These equations were used in experimental verification using a combination of three antibiotics with distinctly different half-lives. In addition to antibiotics, the method is applicable to any anti-infective or anti-cancer drugs with distinct elimination pharmacokinetics.
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Affiliation(s)
- Iordanis Kesisoglou
- Chemical & Biomolecular Engineering Department, University of Houston, 4726 Calhoun Rd. Houston TX 77204-4004, USA
| | - Brianna M Eales
- Department of Pharmacy Practice and Translational Research, University of Houston, 4849 Calhoun Rd. Houston TX 77204-4004, USA
| | - Kimberly R Ledesma
- Department of Pharmacy Practice and Translational Research, University of Houston, 4849 Calhoun Rd. Houston TX 77204-4004, USA
| | - Paul R Merlau
- Department of Pharmacy Practice and Translational Research, University of Houston, 4849 Calhoun Rd. Houston TX 77204-4004, USA
| | - Vincent H Tam
- Chemical & Biomolecular Engineering Department, University of Houston, 4726 Calhoun Rd. Houston TX 77204-4004, USA.,Department of Pharmacy Practice and Translational Research, University of Houston, 4849 Calhoun Rd. Houston TX 77204-4004, USA
| | - Weiqun Wang
- Department of Pharmacy Practice and Translational Research, University of Houston, 4849 Calhoun Rd. Houston TX 77204-4004, USA
| | - Michael Nikolaou
- Chemical & Biomolecular Engineering Department, University of Houston, 4726 Calhoun Rd. Houston TX 77204-4004, USA
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Eales BM, Hudson CS, Kesisoglou I, Wang W, Nikolaou M, Tam VH. Experimental Validation of a Mathematical Framework to Simulate Antibiotics with Distinct Half-Lives Concurrently in an In Vitro Model. Antibiotics (Basel) 2021; 10:1256. [PMID: 34680836 PMCID: PMC8532833 DOI: 10.3390/antibiotics10101256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/07/2021] [Accepted: 10/13/2021] [Indexed: 11/24/2022] Open
Abstract
Antimicrobial resistance has been steadily increasing in prevalence, and combination therapy is commonly used to treat infections due to multidrug resistant bacteria. Under certain circumstances, combination therapy of three or more drugs may be necessary, which makes it necessary to simulate the pharmacokinetic profiles of more than two drugs concurrently in vitro. Recently, a general theoretical framework was developed to simulate three drugs with distinctly different half-lives. The objective of the study was to experimentally validate the theoretical model. Clinically relevant exposures of meropenem, ceftazidime, and ceftriaxone were simulated concurrently in a hollow-fiber infection model, with the corresponding half-lives of 1, 2.5, and 8 h, respectively. Serial samples were obtained over 24 h and drug concentrations were assayed using validated LC-MS/MS methods. A one-compartment model with zero-order input was used to characterize the observed concentration-time profiles. The experimentally observed half-lives corresponding to exponential decline of all three drugs were in good agreement with the respective values anticipated at the experiment design stage. These results were reproducible when the experiment was repeated on a different day. The validated benchtop setup can be used as a more flexible preclinical tool to explore the effectiveness of various drug combinations against multidrug resistant bacteria.
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Affiliation(s)
- Brianna M. Eales
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX 77204, USA; (B.M.E.); (C.S.H.); (W.W.)
| | - Cole S. Hudson
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX 77204, USA; (B.M.E.); (C.S.H.); (W.W.)
| | - Iordanis Kesisoglou
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204, USA; (I.K.); (M.N.)
| | - Weiqun Wang
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX 77204, USA; (B.M.E.); (C.S.H.); (W.W.)
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, TX 77204, USA
| | - Michael Nikolaou
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204, USA; (I.K.); (M.N.)
| | - Vincent H. Tam
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX 77204, USA; (B.M.E.); (C.S.H.); (W.W.)
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204, USA; (I.K.); (M.N.)
- Department of Pharmacy Practice and Translational Research, University of Houston, Houston, TX 77204, USA
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Zidaru A, Eales BM, Wang W, Merlau P, Lasco T, Sofjan AK, H TV. 1313. MIC Profiling of Ceftazidime-Avibactam (CAZ/AVI) Against Two Carbapenemase producing Klebsiella pneumoniae Isolates. Open Forum Infect Dis 2020. [PMCID: PMC7776625 DOI: 10.1093/ofid/ofaa439.1495] [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
Abstract
Background
Carbapenemases confer resistance against a broad range of beta-lactams with a prevalence of 40-60% among CRE (carbapenem-resistant Enterobacteriaceae). CAZ-AVI is commonly used to treat infections due to CPE (carbapenemase-producing Enterobacteriaceae), typically guided by susceptibility testing with a single AVI concentration. This methodology does not take into consideration varying AVI concentration observed in vivo, and may not reliably predict positive clinical outcomes. Our objective was to investigate a novel susceptibility testing method to guide CAZ-AVI therapy.
Methods
Two bloodstream K. pneumoniae isolates (CAZ/AVI susceptible) from an abdominal source were recovered from 2 unrelated patients. Both patients were treated with CAZ/AVI, but had discordant outcomes: KP118 (eradication within 24h) and KP286 (persistent bacteremia for over 30 days). Carbapenemase production in the 2 isolates was confirmed via Carba NP test, and CAZ susceptibility was determined in a clinically relevant range of AVI concentration (0 - 16 mg/L). The concentration-response was characterized by the sigmoid inhibitory maximum effect (Emax) model. The best-fit parameter values were used to predict %T > MICi associated with CAZ/AVI exposures expected in peritoneal fluid after standard dosing (2.5g q8h). These CAZ/AVI exposures were simulated in the hollow-fiber infection model (HFIM), and the bacterial responses were correlated to observed clinical outcomes.
Results
The AVI-dependent reduction in CAZ MIC was well characterized in both strains (R2 > 0.98). In HFIM, sustained suppression of KP118 (T > MICi = 100%) was observed over 5 days, but not with KP286 (T > MICi < 100%). These observations are consistent with the clinical courses of the patients.
Conclusion
The discordant patient outcomes could be explained by MIC profiling of CAZ/AVI. This method appears to be more robust than conventional susceptibility testing, and the clinical utility of this approach should be further investigated.
Disclosures
All Authors: No reported disclosures
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Affiliation(s)
- Andrei Zidaru
- Baylor St. Luke’s Medical Center and University of Houston College of Pharmacy, Houston, Texas
| | | | - Weiqun Wang
- University of Houston, College of Pharmacy, Houston, Texas
| | - Paul Merlau
- University of Houston College of Pharmacy, Houston, Texas
| | - Todd Lasco
- Baylor St. Luke’s Medical Center, The Woodlands, Texas
| | | | - Tam Vincent H
- University of Houston College of Pharmacy, Houston, Texas
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