Microbiome networks and change-point analysis reveal key community changes associated with cystic fibrosis pulmonary exacerbations.

Over 90% of cystic fibrosis (CF) patients die due to chronic lung infections leading to respiratory failure. The decline in CF lung function is greatly accelerated by intermittent and progressively severe acute pulmonary exacerbations (PEs). Despite their clinical impact, surprisingly few microbiological signals associated with PEs have been identified. Here we introduce an unsupervised, systems-oriented approach to identify key members of the microbiota. We used two CF sputum microbiome data sets that were longitudinally collected through periods spanning baseline health and PEs. Key taxa were defined based on three strategies: overall relative abundance, prevalence, and co-occurrence network interconnectedness. We measured the association between changes in the abundance of the key taxa and changes in patient clinical status over time via change-point detection, and found that taxa with the highest level of network interconnectedness tracked changes in patient health significantly better than taxa with the highest abundance or prevalence. We also cross-sectionally stratified all samples into the clinical states and identified key taxa associated with each state. We found that network interconnectedness most strongly delineated the taxa among clinical states, and that anaerobic bacteria were over-represented during PEs. Many of these anaerobes are oropharyngeal bacteria that have been previously isolated from the respiratory tract, and/or have been studied for their role in CF. The observed shift in community structure, and the association of anaerobic taxa and PEs lends further support to the growing consensus that anoxic conditions and the subsequent growth of anaerobic microbes are important predictors of PEs.

Penicillin-binding protein 3 is a common adaptive target among Pseudomonas aeruginosa isolates from adult cystic fibrosis patients treated with ß-lactams.

OBJECTIVE: Determining the mechanisms that modulate ß-lactam resistance in clinical Pseudomonas aeruginosa (P. aeruginosa) isolates can be challenging, as the molecular profiles identified in mutation-based or expression-based resistance determinant screens may not correlate with in vitro phenotypes. One of the lesser studied resistance mechanisms in P. aeruginosa is the modification of penicillin-binding protein 3 (pbpB/ftsI). This study reported that nonsynonymous polymorphisms within pbpB frequently occur among ß-lactam resistant sputum isolates, and are associated with unique antibiotic susceptibility patterns. METHODS: Longitudinally collected isolates (n = 126) from cystic fibrosis (CF) patients with or without recent ß-lactam therapy or of non-clinical origin were tested for susceptibility to six ß-lactams (aztreonam, ceftazidime, cefsulodin, cefepime, meropenem, and piperacillin). Known ß-lactam resistance mechanisms were characterised by polymerase chain reaction (PCR)-based methods, and polymorphisms in the transpeptidase-encoding domain of pbpB identified by sequencing. RESULTS: Twelve nonsynonymous polymorphisms were detected among 86 isolates (67%) from five CF patients with a history of ß-lactam therapy, compared with one polymorphism in 30 (3.3%) from three patients who had not received ß-lactam treatments. No nonsynonymous polymorphisms were found in ten environmental isolates. Multiple pbpB alleles, often with different combinations of polymorphisms, were detected within the population of strains from each CF patient for up to 2.6 years. Traditional patterns of ampC or mexA de-repression reduced expression of oprD or the presence of extended-spectrum ß-lactamases were not observed in resistant isolates with nonsynonymous polymorphisms in pbpB. CONCLUSION: This study's findings suggest that pbpB is a common adaptive target, and may contribute to the development of ß-lactam resistance in P. aeruginosa.

A genome-wide association analysis reveals a potential role for recombination in the evolution of antimicrobial resistance in Burkholderia multivorans.

Cystic fibrosis (CF) lung infections caused by members of the Burkholderia cepacia complex, such as Burkholderia multivorans, are associated with high rates of mortality and morbidity. We performed a population genomics study of 111 B. multivorans sputum isolates from one CF patient through three stages of infection including an early incident isolate, deep sampling of a one-year period of chronic infection occurring weeks before a lung transplant, and deep sampling of a post-transplant infection. We reconstructed the evolutionary history of the population and used a lineage-controlled genome-wide association study (GWAS) approach to identify genetic variants associated with antibiotic resistance. We found the incident isolate was basally related to the rest of the strains and more susceptible to antibiotics from three classes (ß-lactams, aminoglycosides, quinolones). The chronic infection isolates diversified into multiple, distinct genetic lineages and showed reduced antimicrobial susceptibility to the same antibiotics. The post-transplant reinfection isolates derived from the same source as the incident isolate and were genetically distinct from the chronic isolates. They also had a level of susceptibility in between that of the incident and chronic isolates. We identified numerous examples of potential parallel pathoadaptation, in which multiple mutations were found in the same locus or even codon. The set of parallel pathoadaptive loci was enriched for functions associated with virulence and resistance. Our GWAS analysis identified statistical associations between a polymorphism in the ampD locus with resistance to ß-lactams, and polymorphisms in an araC transcriptional regulator and an outer membrane porin with resistance to both aminoglycosides and quinolones. Additionally, these three loci were independently mutated four, three and two times, respectively, providing further support for parallel pathoadaptation. Finally, we identified a minimum of 14 recombination events, and observed that loci carrying putative parallel pathoadaptations and polymorphisms statistically associated with ß-lactam resistance were over-represented in these recombinogenic regions.

Clinical Outcomes Associated with Achromobacter Species Infection in Patients with Cystic Fibrosis.

RATIONALE: Achromobacter species are increasingly identified in individuals with cystic fibrosis (CF), but the clinical outcomes in these patients remain poorly understood. OBJECTIVES: We aimed to determine the association of Achromobacter infection on clinical outcomes in pediatric and adult patients with CF. METHODS: A cohort study of pediatric and adult patients with CF was conducted from 1997 to 2014 in Toronto, Ontario, Canada. Achromobacter spp. infection was categorized as no history of infection, intermittent infection, and chronic infection (two or more positive cultures in the preceding 12 months). Cox models were used to estimate risk of death or transplantation. Mixed-effects models were used to assess odds of pulmonary exacerbations and effect on lung function (FEV1%) by Achromobacter spp. RESULTS: A total of 1,103 patients were followed-up over the course of 18 years; 88 patients (7.3%) had one or more culture for Achromobacter species. Chronic Achromobacter infection was associated with a greater risk of death or transplantation compared with in patients with no history of infection (adjusted hazard ratio, 2.03; 95% confidence interval, 1.05-3.95; P = 0.036). Pulmonary exacerbations were more common in patients with chronic infection, but after adjusting for confounding factors, the effect was no longer significant. The chronic group had lower FEV1%, but it did not worsen after developing chronic infection. CONCLUSIONS: Patients with CF and chronic Achromobacter infection are at increased risk of death or transplantation.

Navigating social and ethical challenges of biobanking for human microbiome research.

BACKGROUND: Biobanks are considered to be key infrastructures for research development and have generated a lot of debate about their ethical, legal and social implications (ELSI). While the focus has been on human genomic research, rapid advances in human microbiome research further complicate the debate. DISCUSSION: We draw on two cystic fibrosis biobanks in Toronto, Canada, to illustrate our points. The biobanks have been established to facilitate sample and data sharing for research into the link between disease progression and microbial dynamics in the lungs of pediatric and adult patients. We begin by providing an overview of some of the ELSI associated with human microbiome research, particularly on the implications for the broader society. We then discuss ethical considerations regarding the identifiability of samples biobanked for human microbiome research, and examine the issue of return of results and incidental findings. We argue that, for the purposes of research ethics oversight, human microbiome research samples should be treated with the same privacy considerations as human tissues samples. We also suggest that returning individual microbiome-related findings could provide a powerful clinical tool for care management, but highlight the need for a more grounded understanding of contextual factors that may be unique to human microbiome research. CONCLUSIONS: We revisit the ELSI of biobanking and consider the impact that human microbiome research might have. Our discussion focuses on identifiability of human microbiome research samples, and return of research results and incidental findings for clinical management.

Continuous alternating inhaled antibiotics for chronic pseudomonal infection in cystic fibrosis.

BACKGROUND: Inhaled antibiotics are standard of care for treating chronic pseudomonal respiratory infections in cystic fibrosis patients, initially approved for intermittent administration. However, use of continuous inhaled antibiotic regimens of differing combinations is growing. METHODS: This double-blind trial compared continuous alternating therapy (CAT) to an intermittent treatment regimen. Subjects were treated with 3cycles of 28-days inhaled aztreonam (AZLI) or placebo 3-times daily alternating with 28-days open-label tobramycin inhalation solution (TIS). RESULTS: 90 subjects were randomized over 18months. Study enrollment was limited, in part because of evolving practices by clinicians of adopting a CAT regimen in clinical practice; consequently the study was underpowered. AZLI/TIS treatment reduced exacerbation rates by 25.7% (p=0.25; primary endpoint) and rates of respiratory hospitalizations by 35.8% compared with placebo/TIS (p=0.14). AZLI/TIS CAT therapy was well tolerated. CONCLUSIONS: This trial illustrates challenges with studying treatment regimens in a constantly evolving CF care environment. Nonetheless, the results of this trial indicate that AZLI/TIS CAT is well tolerated and may provide additional clinical benefit in CF patients compared with intermittent use of TIS alone. Clinicaltrials.gov: NCT01641822.

Conducting Effective Physician Performance Feedback: A Primer for Healthcare Leaders.

Physician performance feedback (PPF) can help physicians gain insight into their practice, to identify areas for improvement, and to implement changes to improve care. There is increasing interest in the use of PPF in Canada. However, little is known about the different types of PPF methods and whether PPF can lead to improved physician performance and patient outcomes. We provide a primer for healthcare leaders interested in doing PPF by reviewing common PPF methods. We then describe our institution's experience with physician multi-source feedback and provide strategies to conduct meaningful PPF.

Global Analysis of the Fungal Microbiome in Cystic Fibrosis Patients Reveals Loss of Function of the Transcriptional Repressor Nrg1 as a Mechanism of Pathogen Adaptation.

The microbiome shapes diverse facets of human biology and disease, with the importance of fungi only beginning to be appreciated. Microbial communities infiltrate diverse anatomical sites as with the respiratory tract of healthy humans and those with diseases such as cystic fibrosis, where chronic colonization and infection lead to clinical decline. Although fungi are frequently recovered from cystic fibrosis patient sputum samples and have been associated with deterioration of lung function, understanding of species and population dynamics remains in its infancy. Here, we coupled high-throughput sequencing of the ribosomal RNA internal transcribed spacer 1 (ITS1) with phenotypic and genotypic analyses of fungi from 89 sputum samples from 28 cystic fibrosis patients. Fungal communities defined by sequencing were concordant with those defined by culture-based analyses of 1,603 isolates from the same samples. Different patients harbored distinct fungal communities. There were detectable trends, however, including colonization with Candida and Aspergillus species, which was not perturbed by clinical exacerbation or treatment. We identified considerable inter- and intra-species phenotypic variation in traits important for host adaptation, including antifungal drug resistance and morphogenesis. While variation in drug resistance was largely between species, striking variation in morphogenesis emerged within Candida species. Filamentation was uncoupled from inducing cues in 28 Candida isolates recovered from six patients. The filamentous isolates were resistant to the filamentation-repressive effects of Pseudomonas aeruginosa, implicating inter-kingdom interactions as the selective force. Genome sequencing revealed that all but one of the filamentous isolates harbored mutations in the transcriptional repressor NRG1; such mutations were necessary and sufficient for the filamentous phenotype. Six independent nrg1 mutations arose in Candida isolates from different patients, providing a poignant example of parallel evolution. Together, this combined clinical-genomic approach provides a high-resolution portrait of the fungal microbiome of cystic fibrosis patient lungs and identifies a genetic basis of pathogen adaptation.

Selective Sweeps and Parallel Pathoadaptation Drive Pseudomonas aeruginosa Evolution in the Cystic Fibrosis Lung.

UNLABELLED: Pulmonary infections caused by Pseudomonas aeruginosa are a recalcitrant problem in cystic fibrosis (CF) patients. While the clinical implications and long-term evolutionary patterns of these infections are well studied, we know little about the short-term population dynamics that enable this pathogen to persist despite aggressive antimicrobial therapy. Here, we describe a short-term population genomic analysis of 233 P. aeruginosa isolates collected from 12 sputum specimens obtained over a 1-year period from a single patient. Whole-genome sequencing and antimicrobial susceptibility profiling identified the expansion of two clonal lineages. The first lineage originated from the coalescence of the entire sample less than 3 years before the end of the study and gave rise to a high-diversity ancestral population. The second expansion occurred 2 years later and gave rise to a derived population with a strong signal of positive selection. These events show characteristics consistent with recurrent selective sweeps. While we cannot identify the specific mutations responsible for the origins of the clonal lineages, we find that the majority of mutations occur in loci previously associated with virulence and resistance. Additionally, approximately one-third of all mutations occur in loci that are mutated multiple times, highlighting the importance of parallel pathoadaptation. One such locus is the gene encoding penicillin-binding protein 3, which received three independent mutations. Our functional analysis of these alleles shows that they provide differential fitness benefits dependent on the antibiotic under selection. These data reveal that bacterial populations can undergo extensive and dramatic changes that are not revealed by lower-resolution analyses. IMPORTANCE: Pseudomonas aeruginosa is a bacterial opportunistic pathogen responsible for significant morbidity and mortality in cystic fibrosis (CF) patients. Once it has colonized the lung in CF, it is highly resilient and rarely eradicated. This study presents a deep sampling examination of the fine-scale evolutionary dynamics of P. aeruginosa in the lungs of a chronically infected CF patient. We show that diversity of P. aeruginosa is driven by recurrent clonal emergence and expansion within this patient and identify potential adaptive variants associated with these events. This high-resolution sequencing strategy thus reveals important intraspecies dynamics that explain a clinically important phenomenon not evident at a lower-resolution analysis of community structure.

Effects of Recipient Age and Diagnosis on Health-related Quality-of-Life Benefit of Lung Transplantation.

RATIONALE: The average age of lung transplant recipients is increasing, and the mix of recipient indications for transplantation is changing. OBJECTIVES: To determine whether the health-related quality-of-life (HRQL) benefit of lung transplantation differs by recipient age and diagnosis. METHODS: In this prospective cohort study, we obtained serial HRQL measurements in adults with advanced lung disease who subsequently underwent lung transplantation (2004-2012). HRQL assessments included the St. George's Respiratory Questionnaire, 36-Item Short-Form Health Survey (SF-36), EQ-5D, Standard Gamble, and Visual Analog Scale for current health. We used linear mixed effects models for associations between age or diagnosis and changes in HRQL with transplantation. To address potential survivorship bias, we fitted Markov models to the distribution of discrete post-transplant health states (HRQL better than pretransplant, not better, or dead) and estimated quality-adjusted life-years post-transplant. MEASUREMENTS AND MAIN RESULTS: A total of 430 subjects were listed, 387 were transplanted, and 326 provided both pretransplant and post-transplant data. Transplantation conferred large improvements in all HRQL measures: St. George's change of -47 units (95% confidence interval, -48 to -44), 36-Item Short-Form Health Survey physical component summary score of 17.7 (16.5-18.9), EQ-5D of 0.27 (0.24-0.30), Standard Gamble of 0.48 (0.44-0.51), and Visual Analog of 44 (42-47). Age was not associated with meaningful differences in the HRQL benefits of transplantation. There was less HRQL benefit in interstitial lung disease than in cystic fibrosis. CONCLUSIONS: Lung transplantation confers large HRQL benefits, which vary by recipient diagnosis, but do not differ substantially in older recipients.

Inhaled aztreonam for chronic Burkholderia infection in cystic fibrosis: a placebo-controlled trial.

BACKGROUND: Individuals with Burkholderia spp. infection have historically been excluded from efficacy trials of inhaled antibiotics, including aztreonam for inhalation solution (AZLI). METHODS: A double-blind, placebo-controlled, 24-week trial of continuous AZLI/placebo treatment was undertaken in individuals with cystic fibrosis (CF) and chronic Burkholderia spp. infection. All subjects also received usual medical care (determined by their physicians). Additional antibiotic use was not restricted. RESULTS: Baseline FEV1% predicted values ranged from 15.8% to 114.6%. No significant treatment differences (AZLI vs. placebo) were observed at week 24 for any endpoints, including FEV1% predicted, number of respiratory exacerbations requiring systemic/inhaled antibiotics, or hospitalizations. Continuous AZLI administration was well tolerated. Burkholderia spp. susceptibility to antibiotics commonly used in CF therapy showed little change. CONCLUSIONS: 24-weeks of continuous AZLI treatment did not significantly improve lung function in CF subjects with chronic Burkholderia spp. infection. Non-study antibiotic use may have confounded any potential AZLI effects.

Analysis of the cystic fibrosis lung microbiota via serial Illumina sequencing of bacterial 16S rRNA hypervariable regions.

The characterization of bacterial communities using DNA sequencing has revolutionized our ability to study microbes in nature and discover the ways in which microbial communities affect ecosystem functioning and human health. Here we describe Serial Illumina Sequencing (SI-Seq): a method for deep sequencing of the bacterial 16S rRNA gene using next-generation sequencing technology. SI-Seq serially sequences portions of the V5, V6 and V7 hypervariable regions from barcoded 16S rRNA amplicons using an Illumina short-read genome analyzer. SI-Seq obtains taxonomic resolution similar to 454 pyrosequencing for a fraction of the cost, and can produce hundreds of thousands of reads per sample even with very high multiplexing. We validated SI-Seq using single species and mock community controls, and via a comparison to cystic fibrosis lung microbiota sequenced using 454 FLX Titanium. Our control runs show that SI-Seq has a dynamic range of at least five orders of magnitude, can classify >96% of sequences to the genus level, and performs just as well as 454 and paired-end Illumina methods in estimation of standard microbial ecology diversity measurements. We illustrate the utility of SI-Seq in a pilot sample of central airway secretion samples from cystic fibrosis patients.

Pulmonary bacterial communities in surgically resected noncystic fibrosis bronchiectasis lungs are similar to those in cystic fibrosis.

Background. Recurrent bacterial infections play a key role in the pathogenesis of bronchiectasis, but conventional microbiologic methods may fail to identify pathogens in many cases. We characterized and compared the pulmonary bacterial communities of cystic fibrosis (CF) and non-CF bronchiectasis patients using a culture-independent molecular approach. Methods. Bacterial 16S rRNA gene libraries were constructed from lung tissue of 10 non-CF bronchiectasis and 21 CF patients, followed by DNA sequencing of isolates from each library. Community characteristics were analyzed and compared between the two groups. Results. A wide range of bacterial diversity was detected in both groups, with between 1 and 21 bacterial taxa found in each patient. Pseudomonas was the most common genus in both groups, comprising 49% of sequences detected and dominating numerically in 13 patients. Although Pseudomonas appeared to be dominant more often in CF patients than in non-CF patients, analysis of entire bacterial communities did not identify significant differences between these two groups. Conclusions. Our data indicate significant diversity in the pulmonary bacterial community of both CF and non-CF bronchiectasis patients and suggest that this community is similar in surgically resected lungs of CF and non-CF bronchiectasis patients.

Feasibility of internet-based health-related quality of life data collection in a large patient cohort.

BACKGROUND: Patient registries are commonly used to track survival and medical outcomes in large cohorts. However, large-scale collection of health-related quality of life (HRQOL) data is more challenging because such data must be collected directly from patients. Internet-based HRQOL questionnaires are a potential solution, allowing home data collection with immediate storage in a central database. OBJECTIVES: Our objectives were to investigate the sociodemographic predictors of Internet use and willingness to convey HRQOL information over the Internet in a Canadian tertiary care patient population and to determine whether Internet use patterns of tertiary care patients differ from those of the general Canadian population. Additionally, we sought to identify the success of home completion of Internet-based HRQOL questionnaires, as well as factors hindering home completion. METHODS: We surveyed 644 patients at the Toronto General and St. Michael's Hospitals from November 2003 through July 2006 within a prospective, longitudinal cohort study of HRQOL in patients with lung disease or lung transplants. Using multiple logistic regression, we assessed patient age, gender, rurality, marital status, and employment or education status as potential sociodemographic predictors of having an Internet-accessible home computer, using email at least weekly, and willingness to complete a quality of life questionnaire over the Internet. Patients electing to complete questionnaires over the Internet were followed from September 2005 through March 2008 to assess completion of HRQOL questionnaires from home, identify barriers for noncompletion, and determine sociodemographic predictors for home completion. RESULTS: Of the 644 patients, the median age was 51 years, with a similar number of males and females. Most were urban Ontario residents, were unemployed, and were married or in a common-law relationship. Having an Internet-accessible home computer was reported by 79.7% (513/644) of patients and use of email at least weekly by 66.5% (414/623) of patients. A majority of patients (57.1% 368/644) were willing to complete HRQOL questionnaires over the Internet via an emailed link. Of the participating 644 patients, 368 elected to complete future questionnaires from home and, as part of a gradual roll-out of the home HRQOL questionnaire, 211 were sent emails inviting them to do so. Of the invited patients, 78% (165/211) completed at least one questionnaire from home. The most common reason for noncompletion was a lack of or an inability to find time to complete the questionnaire. No statistically significant sociodemographic predictors of Internet use were associated with completion or noncompletion of questionnaires from home. CONCLUSIONS: Home, Internet-based HRQOL assessment is feasible in tertiary care patient populations with a high predicted rate of Internet usage based on sociodemographic parameters. A large minority of patients were unwilling or unable to take part in home HRQOL assessments indicating that alternative methods of data collection are still required. However, the majority of patients electing to complete home HRQOL assessments went on to do so over the Internet.

Amiloride-insensitive nasal potential difference varies with the menstrual cycle in cystic fibrosis.

RATIONALE: There is no adequate explanation for gender-based differences in rates of mortality and of deterioration in pulmonary function in cystic fibrosis (CF) patients. One potential explanation is that gender hormones (sex steroids) may modulate the severity of CF lung disease, the principal cause of mortality in CF, by altering respiratory transepithelial ion transport. OBJECTIVE: To determine whether respiratory epithelial ion transport varied during the menstrual cycle of CF females. METHODS: The nasal transepithelial electrical potential difference (NPD) was determined as a measure of ion transport across human respiratory epithelium, coincident with measurements of endogenous serum hormone levels in the luteal and follicular phases of the menstrual cycle in CF females aged 16-22 years. RESULTS: The component of the NPD that is insensitive to the Na(+) transport blocker amiloride, but not the amiloride-sensitive component, changed in association with endogenous, menstrual cycle-induced changes in serum levels of progesterone and estrogen (P=0.02, n=7, paired t-test). Measurements using Cl(-) free perfusates suggested that the changes are not a result of Cl(-) conductance. CONCLUSIONS: Our results suggest that in CF respiratory epithelium amiloride-insensitive, but not amiloride-sensitive, ion transport is altered by female gender hormones in vivo. We speculate that amiloride-insensitive ion transport may contribute to the regulation of human airway surface fluid.

Clinical manifestations of cystic fibrosis among patients with diagnosis in adulthood.

OBJECTIVE: To define the clinical characteristics and diagnostic parameters of patients with cystic fibrosis (CF) diagnosed in adulthood. DESIGN: Retrospective cohort study. SETTING: Tertiary care center. PATIENTS AND METHODS: All patients with a diagnosis of CF made at the Toronto CF Clinics between 1960 and June 2001. Data were collected prospectively and analyzed retrospectively. RESULTS: There were 73 of 1,051 patients (7%) with CF diagnosed in adulthood. Over time, an increasing number and proportion of patients received a diagnosis in adulthood: 27 patients (3%) before 1990, compared to 46 patients (18%) after 1990 (p < 0.001). The mean sweat chloride level was lower for those with CF diagnosed as adults, compared to those with a diagnosis as children (75 +/- 26 mmol/L and 100 +/- 19 mmol/L, respectively; p < 0.001) [mean +/- SD], and adults were more likely to have pancreatic sufficiency (PS) than children (73% vs 13%, respectively; p < 0.0001). In 46 adults who received a diagnosis since 1990, the reason for the initial sweat test was pancreatitis (2 patients, 4%), pulmonary symptoms (18 patients, 39%), pulmonary and GI symptoms (10 patients, 22%), infertility (12 patients, 26%), and genetic screening (4 patients, 9%). Other manifestations were biliary cirrhosis (one patient) and diabetes mellitus (four patients, 9%). The diagnosis could be confirmed by sweat test alone in 30 of 46 patients (65%), by mutation analysis alone in 15 patients (33%), and by a combination in 31 patients (67%). Nasal potential difference (PD) measurements alone confirmed the diagnosis in the remaining 15 patients (33%). CONCLUSION: Patients with CF presenting in adulthood often have PS, inconclusive sweat test results, and a high prevalence of mutations that are not commonly seen in CF diagnosed in childhood. Although most patients have lung disease of variable degrees, single-organ manifestations such as congenital bilateral absence of the vas deferens and pancreatitis are seen. Repeated sweat tests and extensive mutation analysis are often required. Nasal PD may aid the diagnosis, but has not been standardized for clinical diagnosis.

The repeatability of forced expiratory volume measurements in adults with cystic fibrosis.

STUDY OBJECTIVE: To determine the repeatability of measurements of FEV(1) in adults with lung disease due to cystic fibrosis (CF). DESIGN: Single cohort study nested within a randomized controlled trial. SETTING: Adult CF of a university teaching hospital. Subjects were participants in a randomized trial of an experimental mucolytic drug. PATIENTS: Twenty-one adults (mean age, 27.5 +/- 9.2 years [+/- SD]) with CF and mild-to-moderate airflow obstruction (FEV(1) 70 +/- 15% predicted). Patients were in clinically stable condition prior to and during the study. INTERVENTIONS: Repeated FEV(1) measurements were obtained at specific times of the day for 9 consecutive days, for a total of 31 measurements from each subject. Statistical measures of repeatability were calculated. Variation over the course of 1 day and variation from 1 day to the next were examined separately. MEASUREMENTS AND RESULTS: For day-to-day FEV(1) measurements, the within-subject SD was 0.145 L (4.5% of predicted), indicating greater variation compared to values previously established in normal subjects. The coefficient of repeatability indicated that day-to-day measurements could differ by as much as 13% of predicted in the absence of clinical change. For measurements within a single day, variation was not observed to be greater than normal. CONCLUSIONS: In adults with CF, day-to-day variation in FEV(1) measurements is greater than normal and similar to that seen in other obstructive lung diseases. Changes in FEV(1) over time in adults with CF can likely be interpreted using the same criteria that apply to asthma or COPD.

Airway inflammation and infection in congenital bilateral absence of the vas deferens.

In cystic fibrosis (CF), airway disease begins early in life. Bacteria and elevated levels of neutrophils and inflammatory mediators have been detected in bronchoalveolar lavage (BAL) fluid from infants with CF. Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) are common in men with congenital bilateral absence of the vas deferens (CBAVD) and it has been suggested that this syndrome represents a mild form of CF. We hypothesized that men with CBAVD also have subclinical pulmonary disease. Bronchoscopy with BAL, viral and quantitative bacterial cultures, and analyses of total and differential cell count, cytokines, and free neutrophil elastase was performed in eight men with CBAVD, who had mutations in the CFTR and intermediate or elevated sweat chloride levels, and in four healthy control subjects. There was light growth of Staphylococcus aureus in one of eight men with CBAVD, and small numbers of opportunistic gram-negative bacteria in six of eight men with CBAVD and in one control subject. BAL cell counts and neutrophil elastase were within the normal range. Interleukin-8 and tumor necrosis factor-alpha levels were higher for men with CBAVD than for control subjects. These data suggest that mutations in the CFTR in men with CBAVD, in addition to causing infertility, lead to subclinical bacterial pulmonary infection and inflammation consistent with mild CF.