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result(s) for
"Konstan, Michael W"
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Genomic heterogeneity underlies multidrug resistance in Pseudomonas aeruginosa: A population-level analysis beyond susceptibility testing
by
Konstan, Michael W.
,
Vila, Alejandro J.
,
Martinez, Octavio
in
Accumulation
,
Adaptation
,
Analysis
2022
Pseudomonas aeruginosa is a persistent and difficult-to-treat pathogen in many patients, especially those with Cystic Fibrosis (CF). Herein, we describe a longitudinal analysis of a series of multidrug resistant (MDR) P. aeruginosa isolates recovered in a 17-month period, from a young female CF patient who underwent double lung transplantation. Our goal was to understand the genetic basis of the observed resistance phenotypes, establish the genomic population diversity, and define the nature of sequence evolution over time.
Twenty-two sequential P. aeruginosa isolates were obtained within a 17-month period, before and after a double-lung transplant. At the end of the study period, antimicrobial susceptibility testing, whole genome sequencing (WGS), phylogenetic analyses and RNAseq were performed in order to understand the genetic basis of the observed resistance phenotypes, establish the genomic population diversity, and define the nature of sequence changes over time.
The majority of isolates were resistant to almost all tested antibiotics. A phylogenetic reconstruction revealed 3 major clades representing a genotypically and phenotypically heterogeneous population. The pattern of mutation accumulation and variation of gene expression suggested that a group of closely related strains was present in the patient prior to transplantation and continued to change throughout the course of treatment. A trend toward accumulation of mutations over time was observed. Different mutations in the DNA mismatch repair gene mutL consistent with a hypermutator phenotype were observed in two clades. RNAseq performed on 12 representative isolates revealed substantial differences in the expression of genes associated with antibiotic resistance and virulence traits.
The overwhelming current practice in the clinical laboratories setting relies on obtaining a pure culture and reporting the antibiogram from a few isolated colonies to inform therapy decisions. Our analyses revealed significant underlying genomic heterogeneity and unpredictable evolutionary patterns that were independent of prior antibiotic treatment, highlighting the need for comprehensive sampling and population-level analysis when gathering microbiological data in the context of CF P. aeruginosa chronic infection. Our findings challenge the applicability of antimicrobial stewardship programs based on single-isolate resistance profiles for the selection of antibiotic regimens in chronic infections such as CF.
Journal Article
Genetic Modifiers of Lung Disease in Cystic Fibrosis
by
Zielenski, Julian
,
Konstan, Michael W
,
Schluchter, Mark D
in
Adolescent
,
Adult
,
Biological and medical sciences
2005
It is well known that among patients with cystic fibrosis who have the ΔF508 deletion mutation, there is substantial variation in the severity of clinical disease. These investigators identified, and then replicated in a second population, variants in the DNA encoding of the
TGFβ1
gene that were associated with more severe disease.
These investigators identified, and then replicated in a second population, variants in the DNA encoding of the
TGFβ1
gene that were associated with more severe disease.
Cystic fibrosis is a recessive genetic disorder that reflects mutations in the cystic fibrosis transmembrane conductance regulator (
CFTR
) gene.
1
Classic cystic fibrosis reflects two loss-of-function alleles, whereas nonclassic cystic fibrosis is characterized by at least one mutant
CFTR
allele that confers partial function and, in most cases, better survival.
There is great variability of pulmonary phenotype and survival in cystic fibrosis, even among patients who are homozygous for the most prevalent mutation, ΔF508.
1
,
2
Although environmental influences may modify clinical disease, there is probably additional genetic variation (i.e., the presence of “modifier” genes
3
) that contributes to the . . .
Journal Article
Lumacaftor–Ivacaftor in Patients with Cystic Fibrosis Homozygous for Phe508del CFTR
by
Elborn, J. Stuart
,
Davies, Jane C
,
Konstan, Michael W
in
Adolescent
,
Adult
,
Aminophenols - administration & dosage
2015
This study identified a new combination therapy for patients with cystic fibrosis homozygous for the Phe508del CFTR mutation. Treatment with ivacaftor, a CFTR potentiator, and lumacaftor, a CFTR corrector, resulted in improvement in pulmonary function and clinical status.
Cystic fibrosis is a genetic disease that is associated with high rates of premature death.
1
–
4
It is a multisystem disease that is characterized by pancreatic insufficiency and chronic airway infections associated with loss of lung function, repeated pulmonary exacerbations, and, ultimately, respiratory failure.
5
Cystic fibrosis is caused by gene mutations that result in deficient or dysfunctional cystic fibrosis transmembrane conductance regulator (CFTR) protein, an anion channel that is normally present in the epithelial membrane. Phe508del (c.1521_1523delCTT; formerly F508del) is the most common
CFTR
mutation; approximately 45% of patients with cystic fibrosis are homozygous for this allele.
1
Cystic fibrosis is . . .
Journal Article
Data from the US and UK cystic fibrosis registries support disease modification by CFTR modulation with ivacaftor
by
Bengtsson, Leif
,
Konstan, Michael W
,
Sawicki, Gregory S
in
Adolescent
,
Adult
,
Aminophenols - therapeutic use
2018
BackgroundIvacaftor is the first cystic fibrosis transmembrane conductance regulator (CFTR) modulator demonstrating clinical benefit in patients with cystic fibrosis (CF). As ivacaftor is intended for chronic, lifelong use, understanding long-term effects is important for patients and healthcare providers.ObjectiveThis ongoing, observational, postapproval safety study evaluates clinical outcomes and disease progression in ivacaftor-treated patients using data from the US and the UK CF registries following commercial availability.MethodsAnnual analyses compare ivacaftor-treated and untreated matched comparator patients for: risks of death, transplantation, hospitalisation, pulmonary exacerbation; prevalence of CF-related complications and microorganisms and lung function changes in a subset of patients who initiated ivacaftor in the first year of commercial availability. Results from the 2014 analyses (2 and 3 years following commercial availability in the UK and USA, respectively) are presented here.ResultsAnalyses included 1256 ivacaftor-treated and 6200 comparator patients from the USA and 411 ivacaftor-treated and 2069 comparator patients from the UK. No new safety concerns were identified based on the evaluation of clinical outcomes included in the analyses. As part of safety evaluations, ivacaftor-treated US patients were observed to have significantly lower risks of death (0.6% vs 1.6%, p=0.0110), transplantation (0.2% vs 1.1%, p=0.0017), hospitalisation (27.5% vs 43.1%, p<0.0001) and pulmonary exacerbation (27.8% vs 43.3%, p<0.0001) relative to comparators; trends were similar in the UK. In both registries, ivacaftor-treated patients had a lower prevalence of CF-related complications and select microorganisms and had better preserved lung function.ConclusionsWhile general limitations of observational research apply, analyses revealed favourable results for clinically important outcomes among ivacaftor-treated patients, adding to the growing body of literature supporting disease modification by CFTR modulation with ivacaftor.EU PAS registration numberEUPAS4270
Journal Article
Assessing Priorities in a Statewide Cardiovascular and Diabetes Health Collaborative Based on the Results of a Needs Assessment: Cross-Sectional Survey Study
by
Bolen, Shari D
,
Konstan, Michael W
,
Gubitosi-Klug, Rose
in
Best practice
,
Collaboration
,
Diabetes
2024
The Ohio Cardiovascular and Diabetes Health Collaborative (Cardi-OH) unites general and subspecialty medical staff at the 7 medical schools in Ohio with community and public health partnerships to improve cardiovascular and diabetes health outcomes and eliminate disparities in Ohio's Medicaid population. Although statewide collaboratives exist to address health improvements, few deploy needs assessments to inform their work.
Cardi-OH conducts an annual needs assessment to identify high-priority clinical topics, screening practices, policy changes for home monitoring devices and referrals, and preferences for the dissemination and implementation of evidence-based best practices. The results of the statewide needs assessment could also be used by others interested in disseminating best practices to primary care teams.
A cross-sectional survey was distributed electronically via REDCap (Research Electronic Data Capture; Vanderbilt University) to both Cardi-OH grant-funded and non-grant-funded members (ie, people who have engaged with Cardi-OH but are not funded by the grant).
In total, 88% (103/117) of Cardi-OH grant-funded members and 8.14% (98/1204) of non-grant-funded members completed the needs assessment survey. Of these, 51.5% (53/103) of Cardi-OH grant-funded members and 47% (46/98) of non-grant-funded members provided direct clinical care. The top cardiovascular medicine and diabetes clinical topics for Cardi-OH grant-funded members (clinical and nonclinical) were lifestyle prescriptions (50/103, 48.5%), atypical diabetes (38/103, 36.9%), COVID-19 and cardiovascular disease (CVD; 38/103, 36.9%), and mental health and CVD (38/103, 36.9%). For non-grant-funded members, the top topics were lifestyle prescriptions (53/98, 54%), mental health and CVD (39/98, 40%), alcohol and CVD (27/98, 28%), and cardiovascular complications (27/98, 28%). Regarding social determinants of health, Cardi-OH grant-funded members prioritized 3 topics: weight bias and stigma (44/103, 42.7%), family-focused interventions (40/103, 38.8%), and adverse childhood events (37/103, 35.9%). Non-grant-funded members' choices were family-focused interventions (51/98, 52%), implicit bias (43/98, 44%), and adverse childhood events (39/98, 40%). Assessment of other risk factors for CVD and diabetes across grant- and non-grant-funded members revealed screening for social determinants of health in approximately 50% of patients in each practice, whereas some frequency of depression and substance abuse screening occurred in 80% to 90% of the patients. Access to best practice home monitoring devices was challenging, with 30% (16/53) and 41% (19/46) of clinical grant-funded and non-grant-funded members reporting challenges in obtaining home blood pressure monitoring devices and 68% (36/53) and 43% (20/46) reporting challenges with continuous glucose monitors.
Cardi-OH grant- and non-grant-funded members shared the following high-priority topics: lifestyle prescriptions, CVD and mental health, family-focused interventions, alcohol and CVD, and adverse childhood experiences. Identifying high-priority educational topics and preferred delivery modalities for evidence-based materials is essential for ensuring that the dissemination of resources is practical and useful for providers.
Journal Article
Normalized T1 Magnetic Resonance Imaging for Assessment of Regional Lung Function in Adult Cystic Fibrosis Patients - A Cross-Sectional Study
2013
Cystic fibrosis (CF) patients would benefit from a safe and effective tool to detect early-stage, regional lung disease to allow for early intervention. Magnetic Resonance Imaging (MRI) is a safe, non-invasive procedure capable of providing quantitative assessments of disease without ionizing radiation. We developed a rapid normalized T1 MRI technique to detect regional lung disease in early-stage CF patients.
Conventional multislice, pulmonary T1 relaxation time maps were obtained for 10 adult CF patients with normal spirometry and 5 healthy non-CF control subjects using a rapid Look-Locker MRI acquisition (5 seconds/imaging slice). Each lung absolute T1 map was separated into six regions of interest (ROI) by manually selecting upper, central, and lower lung regions in the left and right lungs. In order to reduce the effects of subject-to-subject variation, normalized T1 maps were calculated by dividing each pixel in the absolute T1 maps by the mean T1 time in the central lung region. The primary outcome was the differences in mean normalized T1 values in the upper lung regions between CF patients with normal spirometry and healthy volunteers.
Normalized T1 (nT1) maps showed visibly reduced subject-to-subject variation in comparison to conventional absolute T1 maps for healthy volunteers. An ROI analysis showed that the variation in the nT1 values in all regions was ≤2% of the mean. The primary outcome, the mean (SD) of the normalized T1 values in the upper right lung regions, was significantly lower in the CF subjects [.914 (.037)] compared to the upper right lung regions of the healthy subjects [.983 (.003)] [difference of .069 (95% confidence interval .032-.105); p = .001). Similar results were seen in the upper left lung region.
Rapid normalized T1 MRI relaxometry obtained in 5 seconds/imaging slice may be used to detect regional early-stage lung disease in CF patients.
Journal Article
A CFTR Potentiator in Patients with Cystic Fibrosis and the G551D Mutation
by
Elborn, J. Stuart
,
Davies, Jane
,
Sermet-Gaudelus, Isabelle
in
Administration, Oral
,
Adolescent
,
Adult
2011
Ivacaftor, a potentiator of CFTR, was studied in patients with cystic fibrosis (CF) who had mutations that reduced the function of the CFTR protein. Ivacaftor significantly improved FEV
1
and reduced pulmonary exacerbations; it holds promise in the treatment of selected patients with CF.
Cystic fibrosis, the most common lethal genetic disease in whites, affects approximately 70,000 people worldwide.
1
–
3
There is no cure for this disease, and the progressive lung disease associated with it is the leading cause of death. Current treatments for cystic fibrosis target the secondary effects of dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) protein.
The CFTR protein is an epithelial ion channel contributing to the regulation of absorption and secretion of salt and water in various tissues, including the lung, sweat glands, pancreas, and gastrointestinal tract.
4
,
5
Cystic fibrosis is caused by mutations in
CFTR
that affect . . .
Journal Article
Sustained Benefit from Ivacaftor Demonstrated by Combining Clinical Trial and Cystic Fibrosis Patient Registry Data
by
Konstan, Michael W.
,
Johnson, Charles A.
,
McKone, Edward F.
in
Aminophenols - pharmacology
,
Aminophenols - therapeutic use
,
Body Mass Index
2015
In clinical trials, patients with cystic fibrosis and a G551D mutation who received ivacaftor experienced improvements in pulmonary and nutritional outcomes. However, whether these improvements reflect a change in disease trajectory cannot be determined without longer-term analyses with an appropriate comparator population.
To examine, over a 3-year period, whether ivacaftor therapy affects pulmonary function and nutritional measures in patients with CF with a G551D mutation compared with patients with CF who are homozygous for the F508del mutation.
A propensity score was used to match patients with CF greater than or equal to 6 years of age who have a G551D mutation and received ivacaftor in clinical trials for up to 144 weeks with data from patients in the U.S. Cystic Fibrosis Foundation Patient Registry who are homozygous for the F508del mutation. Matching was based on variables including age, sex, weight for age, height for age, body mass index for age, % predicted FEV1, and chronic therapies (dornase alfa, inhaled antibiotics, inhaled and oral corticosteroids).
By calculating the annual estimated rate of decline in lung function for G551D patients receiving ivacaftor and comparing it with the rate of decline in lung function for matched F508del control patients, we show that the rate of lung function decline in G551D ivacaftor-treated patients was slower by nearly half. Moreover, treatment with ivacaftor is shown to improve body mass index and weight-for-age z scores for G551D patients over the 3-year analysis period.
These findings suggest that ivacaftor is a disease-modifying therapy for the treatment of cystic fibrosis.
Journal Article
Assessing time to pulmonary function benefit following antibiotic treatment of acute cystic fibrosis exacerbations
by
Blumer, Jeffrey L
,
VanDevanter, Donald R
,
O'Riordan, Mary A
in
Acute Disease
,
Analysis
,
Anti-Bacterial Agents - pharmacology
2010
Background
Cystic Fibrosis (CF) is a life-shortening genetic disease in which ~80% of deaths result from loss of lung function linked to inflammation due to chronic bacterial infection (principally
Pseudomonas aeruginosa
). Pulmonary exacerbations (intermittent episodes during which symptoms of lung infection increase and lung function decreases) can cause substantial resource utilization, morbidity, and irreversible loss of lung function. Intravenous antibiotic treatment to reduce exacerbation symptoms is standard management practice. However, no prospective studies have identified an optimal antibiotic treatment duration and this lack of objective data has been identified as an area of concern and interest.
Methods
We have retrospectively analyzed pulmonary function response data (as forced expiratory volume in one second; FEV
1
) from a previous blinded controlled CF exacerbation management study of intravenous ceftazidime/tobramycin and meropenem/tobramycin in which spirometry was conducted daily to assess the time course of pulmonary function response.
Results
Ninety-five patients in the study received antibiotics for at least 4 days and were included in our analyses. Patients received antibiotics for an average of 12.6 days (median = 13, SD = 3.2 days), with a range of 4 to 27 days. No significant differences were observed in mean or median treatment durations as functions of either treatment group or baseline lung disease stage. Average time from initiation of antibiotic treatment to highest observed FEV
1
was 8.7 days (median = 10, SD = 4.0 days), with a range of zero to 19 days. Patients were treated an average of 3.9 days beyond the day of peak FEV
1
(median = 3, SD = 3.8 days), with 89 patients (93.7%) experiencing their peak FEV
1
improvement within 13 days. There were no differences in mean or median times to peak FEV
1
as a function of treatment group, although the magnitude of FEV
1
improvement differed between groups.
Conclusions
Our results suggest that antibiotic response to exacerbation as assessed by pulmonary function is essentially complete within 2 weeks of treatment initiation and relatively independent of the magnitude of pulmonary function response observed.
Journal Article
Transition to adulthood and adult health care for patients with sickle cell disease or cystic fibrosis: Current practices and research priorities
by
Hassell, Kathryn L.
,
Konstan, Michael W.
,
Liem, Robert I.
in
adolescence
,
Blood
,
Cell culture
2018
A growing population of adults living with severe, chronic childhood-onset health conditions has created a need for specialized health care delivered by providers who have expertise both in adult medicine and in those conditions. Optimal care of these patients requires systematic approaches to healthcare transition (HCT). Guidelines for HCT exist, but gaps in care occur, and there are limited data on outcomes of HCT processes.
The Single Disease Workgroup of the Lifespan Domain Task Force of the National Center for Advancing Translational Sciences Clinical and Translational Science Award programs convened a group to review the current state of HCT and to identify gaps in research and practice. Using cystic fibrosis and sickle cell disease as models, key themes were developed. A literature search identified general and disease-specific articles. We summarized key findings.
We identified literature characterizing patient, parent and healthcare provider perspectives, recommendations for transition care, and barriers to effective transition.
With increased survival of patients with severe childhood onset diseases, ongoing study of effective transition practices is essential as survival increases for severe childhood onset diseases. We propose pragmatic methods to enhance transition research to improve health and key outcomes.
Journal Article