Relationship between Ceftolozane-Tazobactam Exposure and Drug Resistance Amplification in a Hollow-Fiber Infection Model

ABSTRACTIn an era of rapidly emerging antimicrobial-resistant bacteria, it is critical to understand the importance of the relationships among drug exposure, duration of therapy, and selection of drug resistance. Herein we describe the results of studies designed to determine the ceftolozane-tazobactam exposure necessary to prevent the amplification of drug-resistant bacterial subpopulations in a hollow-fiber infection model. The challenge isolate was a CTX-M-15-producingEscherichia coliisolate genetically engineered to transcribe a moderate level ofblaCTX-M-15. This organism'sblaCTX-M-15transcription level was confirmed by relative quantitative reverse transcription-PCR (qRT-PCR), β-lactamase hydrolytic assays, and a ceftolozane MIC value of 16 mg/liter. In these studies, the experimental duration (10 days), ceftolozane-tazobactam dose ratio (2:1), and dosing interval (every 8 h) were selected to approximate those expected to be used clinically. The ceftolozane-tazobactam doses studied ranged from 125-62.5 to 1,500-750 mg. Negative- and positive-control arms included no treatment and piperacillin-tazobactam at 4.5 g every 6 h, respectively. An inverted-U-shaped function best described the relationship between bacterial drug resistance amplification and drug exposure. The least- and most-intensive ceftolozane-tazobactam dosing regimens, i.e., 125-62.5, 750-375, 1,000-500, and 1,500-750 mg, did not amplify drug resistance, while drug resistance amplification was observed with intermediate-intensity dosing regimens (250-125 and 500-250 mg). For the intermediate-intensity ceftolozane-tazobactam dosing regimens, the drug-resistant subpopulation became the dominant population by days 4 to 6. The more-intensive ceftolozane-tazobactam dosing regimens (750-375, 1,000-500, and 1,500-750 mg) not only prevented drug resistance amplification but also virtually sterilized the model system. These data support the selection of ceftolozane-tazobactam dosing regimens that minimize the potential for on-therapy drug resistance amplification.

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Relationship between Ceftolozane-Tazobactam Exposure and Selection for Pseudomonas aeruginosa Resistance in a Hollow-Fiber Infection Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02310-13 ◽

2014 ◽

Vol 58 (10) ◽

pp. 6024-6031 ◽

Cited By ~ 27

Author(s):

Brian D. VanScoy ◽

Rodrigo E. Mendes ◽

Mariana Castanheira ◽

Jennifer McCauley ◽

Sujata M. Bhavnani ◽

...

Keyword(s):

Drug Resistance ◽

Infection Model ◽

Drug Resistant ◽

Wild Type ◽

Resistance Selection ◽

Atcc Strain ◽

Dosing Regimens ◽

Selection For ◽

The Relationship ◽

Selection Of

ABSTRACTIt is important to understand the relationship between antibiotic exposure and the selection of drug resistance in the context of therapy exposure. We sought to identify the ceftolozane-tazobactam exposure necessary to prevent the amplification of drug-resistant bacterial subpopulations in a hollow-fiber infection model. TwoPseudomonas aeruginosachallenge isolates were selected for study, a wild-type ATCC strain (ceftolozane-tazobactam MIC, 0.5 mg/liter) and a clinical isolate (ceftolozane-tazobactam MIC, 4 mg/liter). The experiment duration was 10 days, and the ceftolozane-tazobactam dose ratio (2:1) and dosing interval (every 8 h) were selected to approximate those expected to be used clinically. The studied ceftolozane-tazobactam dosing regimens ranged from 62.5/31.25 to 2,000/1,000 mg per dose in step fold dilutions. Negative-control arms included no treatment and tazobactam at 500 mg every 8 h. Positive-control arms included ceftolozane at 1 g every 8 h and piperacillin-tazobactam dosed at 4.5 g every 6 h. For the wild-type ATCC strain, resistance was not selected by any ceftolozane-tazobactam regimen evaluated. For the clinical isolate, an inverted-U-shaped function best described the relationship between the amplification of a drug-resistant subpopulation and drug exposure. The least (62.5/31.25 mg) and most (2,000/1,000 mg) intensive ceftolozane-tazobactam dosing regimens did not select for drug resistance. Drug resistance selection was observed with intermediately intensive dosing regimens (125/62.5 through 1,000/500 mg). For the intermediately intensive ceftolozane-tazobactam dosing regimens, the duration until the selection for drug resistance increased with dose regimen intensity. These data support the selection of ceftolozane-tazobactam dosing regimens that minimize the potential for on-therapy drug resistance selection.

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Adaptation Through Lifestyle Switching Sculpts the Fitness Landscape of Evolving Populations: Implications for the Selection of Drug-Resistant Bacteria at Low Drug Pressures

Genetics ◽

10.1534/genetics.119.301834 ◽

2019 ◽

Vol 211 (3) ◽

pp. 1029-1044 ◽

Cited By ~ 2

Author(s):

Nishad Matange ◽

Sushmitha Hegde ◽

Swapnil Bodkhe

Keyword(s):

Drug Resistance ◽

Drug Exposure ◽

Fitness Landscape ◽

Rifampicin Resistance ◽

Resistant Bacteria ◽

Type I ◽

Drug Resistant ◽

The Impact ◽

Selection Of ◽

Evolving Populations

Novel genotypes evolve under selection through mutations in pre-existing genes. However, mutations have pleiotropic phenotypic effects that influence the fitness of emerging genotypes in complex ways. The evolution of antimicrobial resistance is mediated by selection of mutations in genes coding for antibiotic-target proteins. Drug-resistance is commonly associated with a fitness cost due to the impact of resistance-conferring mutations on protein function and/or stability. These costs are expected to prohibit the selection of drug-resistant mutations at low drug pressures. Using laboratory evolution of rifampicin resistance in Escherichia coli, we show that when exposed intermittently to low concentration (0.1 × minimal inhibitory concentration) of rifampicin, the evolution of canonical drug resistance was indeed unfavorable. Instead, these bacterial populations adapted by evolving into small-colony variants that displayed enhanced pellicle-forming ability. This shift in lifestyle from planktonic to pellicle-like was necessary for enhanced fitness at low drug pressures, and was mediated by the genetic activation of the fim operon promoter, which allowed expression of type I fimbriae. Upon continued low drug exposure, these bacteria evolved exclusively into high-level drug-resistant strains through mutations at a limited set of loci within the rifampicin-resistance determining region of the rpoB gene. We show that our results are explained by mutation-specific epistasis, resulting in differential impact of lifestyle switching on the competitive fitness of different rpoB mutations. Thus, lifestyle-alterations that are selected at low selection pressures have the potential to modify the fitness effects of mutations, change the genetic structure, and affect the ultimate fate of evolving populations.

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Drug Resistance of Ocular Bacteria Considering Biofilm Mechanism

E3S Web of Conferences ◽

10.1051/e3sconf/202127103041 ◽

2021 ◽

Vol 271 ◽

pp. 03041

Author(s):

Yutong Liu ◽

Xuanrong Xu

Keyword(s):

Experimental Study ◽

Drug Resistance ◽

Bacterial Biofilm ◽

Resistant Bacteria ◽

Drug Resistant ◽

Conjugation System ◽

Resistant Genes ◽

Drug Resistant Bacteria ◽

Bacterial Drug Resistance ◽

The Relationship

In order to further analyze the relationship between the coating mechanism of microorganisms and their drug resistance, a study of ocular bacterial drug resistance considering the coating mechanism of microorganisms was proposed. Firstly, the mechanism of drug resistance was analyzed, and on this basis, the experimental study was carried out. Staphylococcus aureus DH5 with RP4 was used as the control α( R) Objective to investigate the relationship between drug-resistant bacteria and coating mechanism in the cross genus conjugation system of Pseudomonas aeruginosa PAOi and donor bacteria. The conclusion is that: under the condition that the horizontal transfer of drug-resistant genes between transgeneric bacteria in biofilm is inhibited, the frequency of drug-resistant gene conjugation and transfer gradually decreases, and the inhibition of the formation of drug-resistant bacterial biofilm will directly lead to the decrease of bacterial drug resistance.

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Emergence of resistance to ceftazidime-avibactam in a derepressed blaPDC producing Pseudomonas aeruginosa isolate in a Hollow Fiber Infection Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00124-21 ◽

2021 ◽

Author(s):

G. L. Drusano ◽

Robert A. Bonomo ◽

Steven M. Marshall ◽

Laura J. Rojas ◽

Mark D. Adams ◽

...

Keyword(s):

Continuous Infusion ◽

Hollow Fiber ◽

Drug Exposure ◽

Threshold Value ◽

Infection Model ◽

Deletion Mutants ◽

Loop Region ◽

Emergence Of Resistance ◽

Inhibitor Combination ◽

Selection Of

Ceftazidime/Avibactam (CAZ/AVI) is a β-lactam/β-lactamase inhibitor combination with activity against type A and C β-lactamases. Resistance emergence has been seen with multiple mechanisms accounting for the resistance. We performed four experiments in the dynamic Hollow Fiber Infection Model, delineating the linkage between drug exposure and both rate of bacterial kill and resistance emergence by all mechanisms. The P. aeruginosa isolate had an MIC of 1.0 mg/L (CAZ)/4 mg/L (AVI). We demonstrated that Time>4.0 mg/L AVI was linked to rate of bacterial kill. Linkage to resistance emergence/suppression was more complex. In one experiment where CAZ/AVI administration was intermittent/continuous and where AVI was given in unitary steps from 1–8 mg/L, AVI up to 3 mg/L allowed resistance emergence, whereas higher values did not. The threshold value was 3.72 mg/L as a continuous infusion to counterselect resistance (AUC of 89.3 mg*h/L AVI). The mechanism was by a 7 amino acid deletion in the Ω-loop region of the PDC β-lactamase. Further experiments, where CAZ/AVI were both administered intermittently with regimens above and below the AUC of 89.3 mg*hr/L resulted in resistance in the lower exposure groups. Deletion mutants were not identified. Finally, an experiment where paired exposures both as continuous and intermittent infusions were performed, the lower value of 25 mg*hr/L by both profiles allowed selection of deletion mutants. Of the five instances where these mutants were recovered, 4/5 were by the continuous infusion profile. Both continuous infusion administration and low avibactam AUC exposures have a role in selection of this mutation.

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Relationship between Fosfomycin Exposure and Amplification of Escherichia coli Subpopulations with Reduced Susceptibility in a Hollow-Fiber Infection Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00355-16 ◽

2016 ◽

Vol 60 (9) ◽

pp. 5141-5145 ◽

Cited By ~ 15

Author(s):

Brian VanScoy ◽

Jennifer McCauley ◽

Sujata M. Bhavnani ◽

Evelyn J. Ellis-Grosse ◽

Paul G. Ambrose

Keyword(s):

Escherichia Coli ◽

Hollow Fiber ◽

Drug Exposure ◽

Drug Susceptibility ◽

Infection Model ◽

Content Type ◽

E Coli ◽

Control Regimen ◽

Dosing Regimens ◽

The Relationship

ABSTRACTUnderstanding the relationship between antibiotic exposure and amplification of bacterial subpopulations with reduced drug susceptibility over time is important for evaluating the adequacy of dosing regimens. We utilized a hollow-fiber infection model to identify the fosfomycin intravenous dosing regimens that prevented the amplification ofEscherichia colibacterial subpopulations with reduced fosfomycin susceptibility. The challenge isolate wasE. coliATCC 25922 (agar MIC with glucose-6-phosphate, 1 mg/liter; agar MIC without glucose-6-phosphate, 32 mg/liter). The fosfomycin dosing regimens studied were 1 to 12 g every 8 h for 10 days to approximate that planned for clinical use. The studies included a no-treatment control regimen. Two bacterial subpopulations were identified, one with reduced susceptibility with agar MIC values ranging from 32 to 128 mg/liter and the other resistant with agar MIC values of 256 to >1,024 mg/liter on plates containing 5× and 256× the baseline MIC value, respectively. An inverted-U-shaped function best described the relationship between the amplification of the two bacterial subpopulations and drug exposure. The lowest fosfomycin dosing regimen that did not amplify a bacterial subpopulation with reduced susceptibility was 4 g administered every 8 h. Nearly immediate amplification of bacterial subpopulations with reduced susceptibility was observed with fosfomycin dosing regimens consisting of 1 to 2 g every 8 h. These data will be useful to support the selection of fosfomycin dosing regimens that minimize the potential for on-therapy amplification of bacterial subpopulations with reduced susceptibility.

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A microfluidic device enabling drug resistance analysis of leukemia cells via coupled dielectrophoretic detection and impedimetric counting

Scientific Reports ◽

10.1038/s41598-021-92647-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yağmur Demircan Yalçın ◽

Taylan Berkin Töral ◽

Sertan Sukas ◽

Ender Yıldırım ◽

Özge Zorlu ◽

...

Keyword(s):

Drug Resistance ◽

K562 Cells ◽

Leukemia Cells ◽

Drug Resistant ◽

Wild Type ◽

Gene Expressions ◽

Before And After ◽

The Difference ◽

Selection Of ◽

Resistant Cells

AbstractWe report the development of a lab-on-a-chip system, that facilitates coupled dielectrophoretic detection (DEP-D) and impedimetric counting (IM-C), for investigating drug resistance in K562 and CCRF-CEM leukemia cells without (immuno) labeling. Two IM-C units were placed upstream and downstream of the DEP-D unit for enumeration, respectively, before and after the cells were treated in DEP-D unit, where the difference in cell count gave the total number of trapped cells based on their DEP characteristics. Conductivity of the running buffer was matched the conductivity of cytoplasm of wild type K562 and CCRF-CEM cells. Results showed that DEP responses of drug resistant and wild type K562 cells were statistically discriminative (at p = 0.05 level) at 200 mS/m buffer conductivity and at 8.6 MHz working frequency of DEP-D unit. For CCRF-CEM cells, conductivity and frequency values were 160 mS/m and 6.2 MHz, respectively. Our approach enabled discrimination of resistant cells in a group by setting up a threshold provided by the conductivity of running buffer. Subsequent selection of drug resistant cells can be applied to investigate variations in gene expressions and occurrence of mutations related to drug resistance.

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1379. Determination of the Arbekacin Exposure Required to Prevent Amplification of Resistant Subpopulations Using Patient Pharmacokinetics Simulated in a Hollow-Fiber Infection Model (HFIM)

Open Forum Infectious Diseases ◽

10.1093/ofid/ofy210.1210 ◽

2018 ◽

Vol 5 (suppl_1) ◽

pp. S422-S423 ◽

Cited By ~ 1

Author(s):

Brian D VanScoy ◽

Elizabeth A Lakota ◽

Sujata M Bhavnani ◽

Greg Giesel ◽

Ana I Carranco ◽

...

Keyword(s):

Drug Exposure ◽

Antimicrobial Agents ◽

Therapy Resistance ◽

Step Function ◽

Infection Model ◽

Drug Resistant ◽

Total Drug ◽

Research Support ◽

Time Curve ◽

Concentration Time

Abstract Background ME1100 (arbekacin inhalational solution) is an aminoglycoside in clinical development for the treatment of patients with hospital-acquired and ventilator-associated bacterial pneumonia (HABP and VABP, respectively). Due to the increase in resistance of Staphylococcus aureus and Pseudomonas aeruginosa to many antimicrobial agents, it is important to understand the relationships between amplification of drug resistance and each of drug exposure and therapy duration. The objective of the studies described herein was to utilize the HFIM to determine the arbekacin exposure after ME1100 administration required to prevent the emergence of drug-resistant subpopulations. Methods Duplicate 10-day HFIM assays were completed in which arbekacin total-drug epithelial lining fluid (ELF) concentration–time profiles following inhalational administration of ME1100 every 12 hours were simulated. Four isolates, two methicillin-resistant S. aureus (Arbekacin MIC = 1 mg/L), and two P. aeruginosa (Arbekacin MIC = 4 mg/L), were exposed to total-drug ELF area under the concentration–time curve (AUC) values ranging from 217 to 25,053 mg hour/L, which were simulated using two different half-lives, 1 hour (α) and 6.93 hours (β). The initial bacterial burden was 1.0 × 108 CFU/mL. Samples were collected for enumeration of both the total and drug-resistant bacterial burdens and evaluation of pharmacokinetic samples using LC/MS–MS. Results Total-drug ELF AUC:MIC ratios required to prevent amplification of MRSA and P. aeruginosa resistance in the HFIM over 10 days were 1,512 and 2,942, respectively. The higher AUC:MIC ratio required to prevent resistance for P. aeruginosa was most likely due to the presence of a small colony variant population. The relationship between total-drug ELF AUC:MIC ratio and change in log10 CFU from baseline of the drug-resistant sub-populations found on agar plates on Day 10 took the form of an inverted-U for three pathogens and a step-function for one (Figure 1). Conclusion These data, which address the goal of considering arbekacin exposures that prevent the development of on-therapy resistance in a clinical setting, will help to provide guidance for future ME1100 dose selection for the treatment of patients with HABP/VABP. Disclosures B. D. VanScoy, Meiji Seika Pharma Co. Ltd.: Research Contractor, Research support. E. A. Lakota, Meiji Seika Pharma Co. Ltd.: Research Contractor, Research support. S. M. Bhavnani, Meiji Seika Pharma Co. Ltd.: Research Contractor, Research support. G. Giesel, Meiji Seika Pharma Co. Ltd.: Research Contractor, Research support. A. I. Carranco, Meiji Seika Pharma Co. Ltd.: Research Contractor, Research support. Y. Nagira, Meiji Seika Pharma Co. Ltd.: Employee, Salary. S. Ouchi, Meiji Seika Pharma Co. Ltd.: Employee, Salary. K. Kondo, Meiji Seika Pharma Co. Ltd.: Employee, Salary. P. G. Ambrose, Meiji Seika Pharma Co. Ltd.: Research Contractor, Research support.

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Pharmacokinetic Data Are Predictive ofIn VivoEfficacy for Cefixime and Ceftriaxone against Susceptible and ResistantNeisseria gonorrhoeaeStrains in the Gonorrhea Mouse Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01644-18 ◽

2019 ◽

Vol 63 (3) ◽

Cited By ~ 9

Author(s):

Kristie L. Connolly ◽

Ann E. Eakin ◽

Carolina Gomez ◽

Blaire L. Osborn ◽

Magnus Unemo ◽

...

Keyword(s):

Single Dose ◽

Mouse Model ◽

Infection Model ◽

Pharmacokinetic Data ◽

Drug Resistant ◽

Genital Tract Infection ◽

Clear Dose Response ◽

Dosing Regimens ◽

Strain Fa1090

ABSTRACTThere is a pressing need for drug development for gonorrhea. Here we describe a pharmacokinetic (PK)/pharmacodynamic (PD) analysis of extended-spectrum cephalosporins (ESC) against drug-susceptible and drug-resistant gonococcal strains in a murine genital tract infection model. The PK determined in uninfected mice displayed a clear dose-response in plasma levels following single doses of ceftriaxone (CRO) (intraperitoneal) or cefixime (CFM) (oral). The observed doses required for efficacy against ESC-susceptible (ESCs) strain FA1090 were 5 mg/kg of body weight (CRO) and 12 mg/kg (CFM); these doses had estimated therapeutic times (the time that the free drug concentration remains above the MIC [fTMIC]) of 24 h and 37 h, respectively. No single dose of CRO or CFM was effective against ESC-resistant (ESCr) strain H041. However, fractionation (three times a day every 8 h [TIDq8h]) of a 120-mg/kg dose of CRO resulted in estimated therapeutic times in the range of 23 h and cleared H041 infection in a majority (90%) of mice, comparable to the findings for gentamicin. In contrast, multiple CFM doses of 120 or 300 mg/kg administered TIDq8h cleared infection in ≤50% of mice, with the therapeutic times estimated from single-dose PK data being 13 and 27 h, respectively. This study reveals a clear relationship between plasma ESC levels and bacterial clearance rates in the gonorrhea mouse model. The PK/PD relationships observed in mice reflected those observed in humans, within vivoefficacy against an ESCsstrain requiring doses that yielded anfTMICin excess of 20 to 24 h. PK data also accurately predicted the failure of single doses of ESCs against an ESCrstrain and were useful in designing effective dosing regimens.

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