Cohort Of Cystic Fibrosis Patients Research Articles

Genomic and Functional Characterization of Longitudinal Pseudomonas aeruginosa Isolates from Young Patients with Cystic Fibrosis.

Individuals with cystic fibrosis (CF) suffer from frequent and recurring microbial airway infections. The Gram-negative bacterium Pseudomonas aeruginosa is one of the most common organisms isolated from CF patient airways. P. aeruginosa establishes chronic infections that persist throughout a patient's lifetime and is a major cause of morbidity and mortality. Throughout the course of infection, P. aeruginosa must evolve and adapt from an initial state of early, transient colonization to chronic colonization of the airways. Here, we examined isolates of P. aeruginosa from children under the age of 3 years old with CF to determine genetic adaptations the bacterium undergoes during this early stage of colonization and infection. These isolates were collected when early aggressive antimicrobial therapy was not the standard of care and therefore highlight strain evolution under limited antibiotic pressure. Examination of specific phenotypic adaptations, such as lipid A palmitoylation, antibiotic resistance, and loss of quorum sensing, did not reveal a clear genetic basis for such changes. Additionally, we demonstrate that the geography of patient origin, within the United States or among other countries, does not appear to significantly influence genetic adaptation. In summary, our results support the long-standing model that patients acquire individual isolates of P. aeruginosa that subsequently become hyperadapted to the patient-specific airway environment. This study provides a multipatient genomic analysis of isolates from young CF patients in the United States and contributes data regarding early colonization and adaptation to the growing body of research about P. aeruginosa evolution in the context of CF airway disease. IMPORTANCE Chronic lung infection with Pseudomonas aeruginosa is of major concern for patients with cystic fibrosis (CF). During infection, P. aeruginosa undergoes genomic and functional adaptation to the hyperinflammatory CF airway, resulting in worsening lung function and pulmonary decline. All studies that describe these adaptations use P. aeruginosa obtained from older children or adults during late chronic lung infection; however, children with CF can be infected with P. aeruginosa as early as 3 months of age. Therefore, it is unclear when these genomic and functional adaptations occur over the course of CF lung infection, as access to P. aeruginosa isolates in children during early infection is limited. Here, we present a unique cohort of CF patients who were identified as being infected with P. aeruginosa at an early age prior to aggressive antibiotic therapy. Furthermore, we performed genomic and functional characterization of these isolates to address whether chronic CF P. aeruginosa phenotypes are present during early infection.

Drug Hypersensitivity Reactions in Patients with Cystic Fibrosis: Potential Value of the Lymphocyte Toxicity Assay to Assess Risk.

Cystic fibrosis (CF) is a genetic disease characterized by multi-system dysfunction resulting in recurrent lung infections and progressive pulmonary disease. CF patients are at a higher risk for drug hypersensitivity reactions (DHRs) compared to the general population, which has been attributed to the recurrent need for antibiotics and the inflammation associated with CF disease. In vitro toxicity tests such as the lymphocyte toxicity assay (LTA) offer the potential for risk assessment for DHRs. In the current study, we investigated the utility of the LTA test for diagnosis of DHRs in a cohort of CF patients. Twenty CF patients with suspected DHRs to sulfamethoxazole, penicillins, cephalosporins, meropenem, vancomycin, rifampicin, and tobramycin were recruited to this study and tested using the LTA test along with 20 healthy control volunteers. Demographic data of the patients, including age, sex, and medical history, were obtained. Blood samples were withdrawn from patients and healthy volunteers, and the LTA test was performed on isolated peripheral blood monocytes (PBMCs) from those individuals. Cells from CF patients with DHRs displayed a significant (p < 0.0001) concentration-dependent enhanced cell death upon incubation with the culprit drug compared to cells from healthy volunteers. The positivity rate of the LTA test was over 80% in patients with a medical history and clinical presentation consistent with DHRs. This study is the first to evaluate the use of the LTA test for diagnosis of DHRs in CF patients. According to our results, the LTA test may be a useful tool for diagnosis and management of DHRs in CF patients. Identifying the culprit drug is essential for optimal healthcare for CF patients in the setting of a suspected DHR. The data also provide evidence that accumulation of toxic reactive metabolites could be an important component in the cascade of events leading to the development of DHRs in CF patients. A larger-scale study is needed to confirm the data.

Whole blood RNA-seq demonstrates an increased host immune response in individuals with cystic fibrosis who develop nontuberculous mycobacterial pulmonary disease.

Individuals with cystic fibrosis have an elevated lifetime risk of colonization, infection, and disease caused by nontuberculous mycobacteria. A prior study involving non-cystic fibrosis individuals reported a gene expression signature associated with susceptibility to nontuberculous mycobacteria pulmonary disease (NTM-PD). In this study, we determined whether people living with cystic fibrosis who progress to NTM-PD have a gene expression pattern similar to the one seen in the non-cystic fibrosis population. We evaluated whole blood transcriptomics using bulk RNA-seq in a cohort of cystic fibrosis patients with samples collected closest in timing to the first isolation of nontuberculous mycobacteria. The study population included patients who did (n = 12) and did not (n = 30) develop NTM-PD following the first mycobacterial growth. Progression to NTM-PD was defined by a consensus of two expert clinicians based on reviewing clinical, microbiological, and radiological information. Differential gene expression was determined by DESeq2. No differences in demographics or composition of white blood cell populations between groups were identified at baseline. Out of 213 genes associated with NTM-PD in the non-CF population, only two were significantly different in our cystic fibrosis NTM-PD cohort. Gene set enrichment analysis of the differential expression results showed that CF individuals who developed NTM-PD had higher expression levels of genes involved in the interferon (α and γ), tumor necrosis factor, and IL6-STAT3-JAK pathways. In contrast to the non-cystic fibrosis population, the gene expression signature of patients with cystic fibrosis who develop NTM-PD is characterized by increased innate immune responses.

Non-invasive diagnostics of pathogenic bacteria using a breath sampler in children with cystic fibrosis

Cystic fibrosis (CF) is a common autosomal recessive disease causing thick, viscous secretions leading to pulmonary infections with pathogenic bacteria. As part of routine patient care, colonization and infection with these bacteria is monitored with cough swab or sputum cultures and sometimes bronchoalveolar lavage. In this cross-sectional proof-of-concept study in a cohort of CF patients we collected swabs or sputa and exhaled breath samples with the modular breath sampler (MBS), a newly developed two-way non-rebreathing sampling device. Pathogen specific polymerase chain reactions (PCRs) were performed on the MBS samples and compared with the results obtained with conventional diagnostics (i.e. culturing of swabs and sputa). A control group of stable asthma patients was used as negative control for the MBS measurements. The pathogens detected using MBS and conventional culturing differed: S. aureus was found more often in swab or sputum samples whereas Pseudomonas aeruginosa and S. pneumoniae were found more often in MBS samples. We hypothesize that this is due to sampling of different compartments, MBS samples are derived from the lower respiratory tract while cultures from cough swabs and sputa are dominated by pathogens residing in the upper respiratory tract. Another important difference is the readout, i.e. culture versus PCR. The majority of CF patients in whom P. aeruginosa was found did not have recent positive cultures suggesting higher sensitivity of MBS-based than conventional diagnostics. The majority of parents/patients found the MBS easy to use and less of a burden than respiratory sampling.

High prevalence of Merkel cell polyomavirus is associated with dysregulation in transcript levels of TLR9 and type I IFNs in a large cohort of CF patients from the Italian (Lazio) reference center for cystic fibrosis

Merkel cell polyomavirus (MCPyV) has been detected in respiratory specimens including those from Cystic Fibrosis (CF) patients, raising questions about its immunological and clinical relevance in the respiratory tract. MCPyV might promote an inappropriate antiviral response contributing to a chronic inflammatory response and resulting in detrimental effects in CF. Respiratory samples (n = 1138) were randomly collected from respiratory tract of CF patients (n = 539) during July 2018–October 2019. MCPyV-DNA detection was performed by real time PCR and positive samples were characterized by sequencing of the NCCR genomic region. The transcript levels of Toll-like receptor 9 (TLR9) and type I interferon (IFN–I) genes (IFNα, IFNβ and IFNε) were examined by real-time RT-PCR assays. MCPyV-DNA was detected in 268 out of 1138 respiratory specimens (23.5%) without any difference in the prevalence of MCPyV-DNA according to age, gender or bacteriological status of CF individuals. Thirteen out of 137 CF patients remained positive for MCPyV-DNA over the time (a median follow-up period of 8.8 months). Detection of MCPyV-DNA in respiratory specimens was not associated with the occurrence of exacerbation events. Both MCPyV positive adolescents (11–24 years) and adults (≥25 years) had lower mRNA levels of TLR9, IFNβ, IFNε and IFNα than the negative patients of the same age group, while MCPyV positive children produced increased levels of TLR9 and IFN-I genes (p < 0.05 for TLR9, IFNβ, IFNε) with respect to the negative ones. There were significant differences in TLR9 levels (p < 0.01), but not in those of IFNs, between MCPyV-DNA positive and negative patients with S. aureus, P. aeruginosa or both. Overall, these results indicate that MCPyV-DNA is frequently detected in the respiratory samples of CF patients and might influence the expression levels of IFN-related genes in an age dependent manner. The concomitant detection of MCPyV together with S. aureus and/or P. aeruginosa correlated with alterations in TLR9 levels suggesting that virus-bacteria coinfections might contribute to affect antiviral immunity in CF patients.

Clinical Impact of Aspergillus fumigatus in Children with Cystic Fibrosis.

Background. The clinical relevance of Aspergillus fumigatus (Af) in cystic fibrosis (CF) is controversial. The aims of the study were to assess the prevalence of Af disease in our cohort of CF patients and evaluate whether allergic bronchopulmonary aspergillosis (ABPA) and sensitization to Af affected lung function, body mass index (BMI) and exacerbations. Methods. Clinical data and lung function of CF patients aged 6–18 years followed at the CF Centre of Parma (Italy) were recorded. Patients were classified as: patients with no signs of Af, patients sensitized or colonized by Af, patients with ABPA or patients with Aspergillus bronchitis (Ab). Results. Of 38 CF patients (14.2 years (6.2–18.8) M 23), 8 (21%) showed Af sensitization, 7 (18.4%) showed ABPA, 1 (2.6%) showed Af colonization and 1 (2.6%) showed Ab. Compared to non-ABPA, patients with ABPA had lower BMI (15.9 ± 1.6 vs. 19.7 ± 3.4, p < 0.005), lower lung function (FEV1 61.5 ± 25.9% vs. 92.3 ± 19.3%, p < 0.001) and more exacerbations/year (4.43 ± 2.44 vs. 1.74 ± 2.33, p < 0.005). Patients with Af sensitization showed more exacerbations/year than non-Af patients (3.5 ± 3.2 vs. 0.9 ± 1.2, p < 0.005). ABPA and sensitized patients had more abnormalities on chest CT scans. Conclusion. This study showed the relevant clinical impact of ABPA and Af sensitization in terms of exacerbations and lung structural damage.

Effectiveness and safety of elexacaftor/tezacaftor/ivacaftor in patients with cystic fibrosis and advanced lung disease with the Phe508del/minimal function genotype

BackgroundElexacaftor/tezacaftor/ivacaftor (E/T/I) is a cystic fibrosis transmembrane conductance regulator (CFTR) triple combination therapy used for the treatment of cystic fibrosis (CF) in patients aged ≥12 years who have at least one copy of the Phe508del mutation (F) in the CFTR gene or another mutation that is responsive to treatment with E/T/I. This study determined the effectiveness and safety of E/T/I treatment in a cohort of CF patients. MethodsThis retrospective cohort study collected data from the first 6 months of treatment of patients with CF, compound heterozygotes for the F and a minimal function (MF) mutations, enrolled in an E/T/I compassionate use program only available to patients having ppFEV1<40 or who are considered for lung transplantation. Forty-seven patients were included. Follow-up was performed after 1, 3, and 6 months from the beginning of therapy, assessing lung function, body mass index (BMI), sweat chloride concentration (SCC), quality of life (QoL), and safety. ResultsAfter 6 months of treatment, the mean (standard deviation (SD)) SCC decreased from 91.1 (19.3) mmol/L to 46.2 (24.2) mmol/L. The decrease of SCC was accompanied by improvement of lung function (mean (95% Confidence Interval (CI) absolute increase in ppFEV1 was 10.69 (8.05,13.33) after 1 month and 14.16 (11.43, 16.89) after 6 months of treatment), nutrition (mean (SD) BMI increased from 20.7 (3.0) kg/m2 at baseline to 22.6 (3.1) after 6 months), and QoL. No safety concerns were observed. ConclusionsE/T/I was clinically effective and safe in patients with advanced CF lung disease with an F/MF genotype.

NBD2 Is Required for the Rescue of Mutant F508del CFTR by a Thiazole-Based Molecule: A Class II Corrector for the Multi-Drug Therapy of Cystic Fibrosis.

Cystic fibrosis (CF) is caused by loss-of-function mutations in the CF transmembrane conductance regulator (CFTR) protein, an anion channel that regulates epithelial surface fluid secretion. The deletion of phenylalanine at position 508 (F508del) is the most common CFTR mutation. F508del CFTR is characterized by folding and trafficking defects, resulting in decreased functional expression of the protein on the plasma membrane. Several classes of small molecules, named correctors, have been developed to rescue defective F508del CFTR. Although individual correctors failed to improve the clinical status of CF patients carrying the F508del mutation, better results were obtained using correctors combinations. These results were obtained according to the premise that the administration of correctors having different sites of action should enhance F508del CFTR rescue. We investigated the putative site of action of an aminoarylthiazole 4-(3-chlorophenyl)-N-(3-(methylthio)phenyl)thiazol-2-amine, named FCG, with proven CFTR corrector activity, and its synergistic effect with the corrector VX809. We found that neither the total expression nor the maturation of WT CFTR transiently expressed in human embryonic kidney 293 cells was influenced by FCG, administrated alone or in combination with VX809. On the contrary, FCG was able to enhance F508del CFTR total expression, and its combination with VX809 provided a further effect, being able to increase not only the total expression but also the maturation of the mutant protein. Analyses on different CFTR domains and groups of domains, heterologously expressed in HEK293 cells, show that NBD2 is necessary for FCG corrector activity. Molecular modelling analyses suggest that FCG interacts with a putative region located into the NBD2, ascribing this molecule to class II correctors. Our study indicates that the continuous development and testing of combinations of correctors targeting different structural and functional defects of mutant CFTR is the best strategy to ensure a valuable therapeutic perspective to a larger cohort of CF patients.

Chronic infection by nontypeable Haemophilus influenzae fuels airway inflammation.

Nontypeable Haemophilus influenzae (NTHi) is commonly isolated from airways of patients suffering from chronic respiratory diseases, such as COPD or cystic fibrosis (CF). However, to what extent NTHi long-term infection contributes to the lung inflammatory burden during chronic airway disease is still controversial.Here, we exploited human respiratory samples from a small cohort of CF patients and found that patients chronically infected with NTHi had significantly higher levels of interleukin (IL)-8 and CXCL1 than those who were not infected. To better define the impact of chronic NTHi infection in fuelling inflammatory response in chronic lung diseases, we developed a new mouse model using both laboratory and clinical strains. Chronic NTHi infection was associated with chronic inflammation of the lung, characterised by recruitment of neutrophils and cytokine release keratinocyte-derived chemokine (KC), macrophage inflammatory protein 2 (MIP-2), granulocyte colony-stimulating factor (G-CFS), IL-6, IL-17A and IL-17F) at 2 and 14 days post-infection. An increased burden of T-cell-mediated response (CD4+ and γδ cells) and higher levels of pro-matrix metalloproteinase 9 (pro-MMP9), known to be associated with tissue remodelling, were observed at 14 days post-infection. Of note we found that both CD4+IL-17+ cells and levels of IL-17 cytokines were enriched in mice at advanced stages of NTHi chronic infection. Moreover, by immunohistochemistry we found CD3+, B220+ and CXCL-13+ cells localised in bronchus-associated lymphoid tissue-like structures at day 14.Our results demonstrate that chronic NTHi infection exerts a pro-inflammatory activity in the human and murine lung and could therefore contribute to the exaggerated burden of lung inflammation in patients at risk.

Prevalence and characteristics of cystic fibrosis associated-liver disease in a cohort of cystic fibrosis patients

Prevalence and characteristics of cystic fibrosis associated-liver disease in a cohort of cystic fibrosis patients

Untargeted Metagenomic Investigation of the Airway Microbiome of Cystic Fibrosis Patients with Moderate-Severe Lung Disease.

Although the cystic fibrosis (CF) lung microbiota has been characterized in several studies, little is still known about the temporal changes occurring at the whole microbiome level using untargeted metagenomic analysis. The aim of this study was to investigate the taxonomic and functional temporal dynamics of the lower airway microbiome in a cohort of CF patients. Multiple sputum samples were collected over 15 months from 22 patients with advanced lung disease regularly attending three Italian CF Centers, given a total of 79 samples. DNA extracted from samples was subjected to shotgun metagenomic sequencing allowing both strain-level taxonomic profiling and assessment of the functional metagenomic repertoire. High inter-patient taxonomic heterogeneity was found with short-term compositional changes across clinical status. Each patient exhibited distinct sputum microbial communities at the taxonomic level, and strain-specific colonization of both traditional and atypical CF pathogens. A large core set of genes, including antibiotic resistance genes, were shared across patients despite observed differences in clinical status, and consistently detected in the lung microbiome of all subjects independently from known antibiotic exposure. In conclusion, an overall stability in the microbiome-associated genes was found despite taxonomic fluctuations of the communities.

P257 Assessing possible role of enterovirus infections in diabetes onset in a Swedish cohort of cystic fibrosis patients

P257 Assessing possible role of enterovirus infections in diabetes onset in a Swedish cohort of cystic fibrosis patients

EPS2.02 Assessing cardiovascular risk in an older cystic fibrosis patient cohort: implications of Cystic Fibrosis-Related Diabetes classification

ePS2.02 Assessing cardiovascular risk in an older cystic fibrosis patient cohort: implications of Cystic Fibrosis-Related Diabetes classification

Meeting Cystic Fibrosis Patient Needs in Transition to Lung Transplant

The care of the patient with cystic fibrosis (CF) requires a multidisciplinary approach throughout the lifespan by teams specially trained to deal with the complexities of care. Improvements in therapies have resulted in increased life expectancy of those with CF, yet respiratory failure continues to be the leading cause of death. While lung transplant (LTx) can be a viable treatment option, 35% of CF patients who meet criteria are not referred. We sought to understand patient preferences regarding discussions surrounding LTx in anticipation of referral to the LTx center. A cross-sectional survey was developed to understand the patient's perspective on LTx transition. The survey was sent, via MyChart, to a retrospective cohort of CF patients who were seen as a new patient in the LTx center over a two-year period, and we provided the survey at the end of initial LTx clinic encounter. Patients representing eight CF centers participated. All respondents identified the CF pulmonologist as discussing LTx (N=17). 52% of patients also discussed Ltx with another member of the CF team (Figure 1). Conversely 88% of respondents wanted to hear about LTx from members of the team other than their physician. In fact 35% of respondents did not select the pulmonologist as someone they felt comfortable speaking to regarding LTx. Due to the success of the multidisciplinary approach in CF clinics, patients often prefer to discuss treatment options with a variety of clinicians. The decision to refer to LTx can be overwhelming for the patient and the CF team, who may lack comfort in discussing LTx. The responses reflecting multiple CF programs suggests this problem is not center-specific, but relevant across CF centers.

Cystic Fibrosis: A Simple and Customized Strategy for Genetic Screening Able to Detect Over 90% of Identified Mutated Alleles in Brazilian Newborns.

The incorporation of molecular genetic testing into cystic fibrosis (CF) screening programs increases the specificity of the diagnostic strategy and has the potential to decrease the rate of false- positive results. In this sense, our objective was to develop a genotyping assay that could detect 25 pathogenic variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene with high sensitivity and that couldbe incorporated into the routine of newborn screening, complementing the current existing protocol used in our public health institution. A mini-sequencing assay was standardized using single-base extension in a previously genotyped control sample. This strategy was validated in a Brazilian cohort of CF patients by Sanger sequencing. The inclusion of the 25 variants in the current newborn screening program increased the identification rates of two alleles from 33 to 52.43% in CF patients. This new approach was able to detect a total of 37 variants, which represents 93.01% of all mutated alleles described in the last CF Brazilian Register. Mini-sequencing for the simultaneous detection of 25 CFTR gene variants improves the screening of Brazilian newborns and decreases the number of inconclusive cases. This method uses minimal hands-on time and is suited for rapid screening, which reduces sample processing costs.

Immunomodulatory function of the cystic fibrosis modifier gene BPIFA1

BackgroundCystic fibrosis (CF) is characterized by a progressive decline in lung function due to airway obstruction, infection, and inflammation. CF patients are particularly susceptible to respiratory infection by a variety of pathogens, and the inflammatory response in CF is dysregulated and prolonged. BPI fold containing family A, member 1 (BPIFA1) and BPIFB1 are proteins expressed in the upper airways that may have innate immune activity. We previously identified polymorphisms in the BPIFA1/BPIFB1 region associated with CF lung disease severity.MethodsWe evaluated whether the BPIFA1/BPIFB1 associations with lung disease severity replicated in individuals with CF participating in the International CF Gene Modifier Consortium (n = 6,365). Furthermore, we investigated mechanisms by which the BPIFA1 and BPIFB1 proteins may modify lung disease in CF.ResultsThe association of the G allele of rs1078761 with reduced lung function was replicated in an independent cohort of CF patients (p = 0.001, n = 2,921) and in a meta-analysis of the full consortium (p = 2.39x10-5, n = 6,365). Furthermore, we found that rs1078761G which is associated with reduced lung function was also associated with reduced BPIFA1, but not BPIFB1, protein levels in saliva from CF patients. Functional assays indicated that BPIFA1 and BPIFB1 do not have an anti-bacterial role against P. aeruginosa but may have an immunomodulatory function in CF airway epithelial cells. Gene expression profiling using RNAseq identified Rho GTPase signaling pathways to be altered in CF airway epithelial cells in response to treatment with recombinant BPIFA1 and BPIFB1 proteins.ConclusionsBPIFA1 and BPIFB1 have immunomodulatory activity and genetic variation associated with low levels of these proteins may increase CF lung disease severity.

Sinonasal quality-of-life declines in cystic fibrosis patients with pulmonary exacerbations.

In cystic fibrosis (CF), the relationship between chronic rhinosinusitis (CRS) and pulmonary disease is poorly understood. The purpose of this study was to evaluate the relationship between scores on the 22-item Sino-Nasal Outcome Test (SNOT-22) and CF Questionnaire-revised for adolescents and adults over 14 (CFQ-R 14+), and pulmonary function tests in 2 cohorts of CF patients: those at their baseline health and those with a pulmonary exacerbation. Patients >18 years old seen in a Cystic Fibrosis Foundation-accredited clinic completed the SNOT-22 and CFQ-R 14+ instruments. Patients presenting for routine care represented the baseline cohort. Patients diagnosed with a pulmonary exacerbation represented the exacerbation cohort. Average SNOT-22 and CFQ-R 14+ scores for both groups were compared using a 2-sample t test, and correlation coefficient was calculated. One hundred three patients were enrolled over 3 months (30 exacerbations and 73 baseline). Patients' mean age was 32 years (56% female and 44% male). Average SNOT-22 and CFQ-R 14+ scores were significantly worse for exacerbation patients (p = 0.001 and p = 0.0003, respectively). Percent predicted forced expiratory volume in 1 second and forced vital capacity were both higher for baseline patients (p = 0.002 and p = 0.001, respectively). Average SNOT-22 score for all patients was worse than the average score for non-CF, non-CRS patients. CF patients with pulmonary exacerbations have worse SNOT-22 and CFQ-R 14+ scores than CF patients at their baseline health. This finding suggests a temporal relationship between sinonasal and pulmonary quality of life, and that worsening of both is associated with reduced pulmonary function.

Cross-transmission Is Not the Source of New Mycobacterium abscessus Infections in a Multicenter Cohort of Cystic Fibrosis Patients.

Background Mycobacterium abscessus is an extensively drug–resistant pathogen that causes pulmonary disease, particularly in cystic fibrosis (CF) patients. Identifying direct patient-to-patient transmission of M. abscessus is critically important in directing an infection control policy for the management of risk in CF patients. A variety of clinical labs have used molecular epidemiology to investigate transmission. However, there is still conflicting evidence as to how M. abscessus is acquired and whether cross-transmission occurs. Recently, labs have applied whole-genome sequencing (WGS) to investigate this further and, in this study, we investigated whether WGS can reliably identify cross-transmission in M. abscessus.MethodsWe retrospectively sequenced the whole genomes of 145 M. abscessus isolates from 62 patients, seen at 4 hospitals in 2 countries over 16 years.ResultsWe have shown that a comparison of a fixed number of core single nucleotide variants alone cannot be used to infer cross-transmission in M. abscessus but does provide enough information to replace multiple existing molecular assays. We detected 1 episode of possible direct patient-to-patient transmission in a sibling pair. We found that patients acquired unique M. abscessus strains even after spending considerable time on the same wards with other M. abscessus–positive patients.ConclusionsThis novel analysis has demonstrated that the majority of patients in this study have not acquired M. abscessus through direct patient-to-patient transmission or a common reservoir. Tracking transmission using WGS will only realize its full potential with proper environmental screening, as well as patient sampling.

223-LB: Beta-Cell Function but Not Insulin Sensitivity Is Impaired in Nondiabetic Cystic Fibrosis Adults Assessed with the Oral Minimal Model Method

Insulin deficiency in cystic fibrosis (CF) is the primary cause of impaired glucose tolerance and diabetes. However, along with insulin deficiency, insulin sensitivity may also play an important role. Herein we aimed to quantify insulin action and secretion in nondiabetic CF adults in comparison with healthy controls after an oral glucose tolerance test (OGTT) with the oral minimal model method. Sixteen nondiabetic CF (7F; age=22±2 y; BMI=22±2 kg/m2; BW=66±10 kg) and seven healthy adults (3F; age=22±2 y; BMI=22±2 kg/m2; BW=66±9 kg) underwent an OGTT. Plasma glucose, insulin and C-peptide were measured for 5 h. The oral glucose and C-peptide minimal models were used to quantify indices of glucose absorption, insulin sensitivity, β-cell responsiveness and disposition index. Insulin sensitivity was similar (mean±SE; p-value from two-sample t-test) in CF and healthy (23±3 and 16±3 10-4 dL/kg/min per uU/mL; NS), while percentage of glucose absorbed within the first two hours was significantly higher in CF (70±3 vs. 53±4 %; p&amp;lt;0.005). In contrast, β-cell responsiveness was significantly reduced in CF (42±4 vs. 118±16 10-9 min-1) due to a reduction both in the dynamic (320±45 vs. 1316±172 10-9; p&amp;lt;0.005) and static (42±4 vs. 118±16 10-9 min-1; p&amp;lt;0.005) component. The delay in the static component was also higher, but not significantly, in CF (15±4 vs. 8±3 min; NS). As a consequence, the disposition index was significantly reduced in CF (1659±423 vs. 3303±426 10-14 dL/kg/min2 per pmol/L; p&amp;lt;0.05). Of note, no difference in incremental Area Under Curve (0-5 h) of glucose (6186±884 vs. 3680±1113 mg/dL*min; NS), insulin (4901±559 vs. 8577±2032 uU/mL*min; NS) and C-peptide (331±33 vs. 349±82 nmol/L*min; NS) in CF vs. healthy was observed. In conclusion, the oral minimal model method showed that abnormal glucose tolerance in our cohort of CF patients is due to an impaired β-cell function, while insulin action is similar and glucose absorption is higher. Disclosure M. Schiavon: None. G.M. Toffolo: None. C. Cobelli: None. K. Nair: None. A. Moran: Other Relationship; Self; Novo Nordisk Inc. Funding National Institutes of Health (R01DK101402); National Center for Advancing Translational Sciences (UL1-TR-000114)

P079 Assessment of prevalence of tobacco use and secondhand smoke exposure (SHSe) in a cohort of cystic fibrosis patients, older than 15 years, followed in the North-West Cystic Fibrosis Network (France)

P079 Assessment of prevalence of tobacco use and secondhand smoke exposure (SHSe) in a cohort of cystic fibrosis patients, older than 15 years, followed in the North-West Cystic Fibrosis Network (France)