Respiratory Bacterial Culture Sampling in Expectorating and Non-expectorating Patients With Cystic Fibrosis

Bronchoscopy-guided antimicrobial therapy for cystic fibrosis

BACKGROUND

Early diagnosis and treatment of lower respiratory tract infections is the mainstay of management of lung disease in cystic fibrosis (CF). When sputum samples are unavailable, diagnosis relies mainly on cultures from oropharyngeal specimens; however, there are concerns about whether this approach is sensitive enough to identify lower respiratory organisms. Bronchoscopy and related procedures such as bronchoalveolar lavage (BAL) are invasive but allow the collection of lower respiratory specimens from non-sputum producers. Cultures of bronchoscopic specimens provide a higher yield of organisms compared to those from oropharyngeal specimens. Regular use of bronchoscopy and related procedures may increase the accuracy of diagnosis of lower respiratory tract infections and improve the selection of antimicrobials, which may lead to clinical benefits. This is an update of a previous review that was first published in 2013 and was updated in 2016 and in 2018.

OBJECTIVES

To evaluate the use of bronchoscopy-guided (also known as bronchoscopy-directed) antimicrobial therapy in the management of lung infection in adults and children with cystic fibrosis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched three registries of ongoing studies and the reference lists of relevant articles and reviews. The date of the most recent searches was 1 November 2023.

SELECTION CRITERIA

We included randomised controlled studies involving people of any age with CF that compared the outcomes of antimicrobial therapies guided by the results of bronchoscopy (and related procedures) versus those guided by any other type of sampling (e.g. cultures from sputum, throat swab and cough swab).

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed their risk of bias and extracted data. We contacted study investigators for further information when required. We assessed the certainty of the evidence using the GRADE criteria.

MAIN RESULTS

We included two studies in this updated review. One study enrolled 170 infants under six months of age who had been diagnosed with CF through newborn screening. Participants were followed until they were five years old, and data were available for 157 children. The study compared outcomes for pulmonary exacerbations following treatment directed by BAL versus standard treatment based on clinical features and oropharyngeal cultures. The second study enrolled 30 children with CF aged between five and 18 years and randomised participants to receive treatment based on microbiological results of BAL triggered by an increase in lung clearance index (LCI) of at least one unit above baseline or to receive standard treatment based on microbiological results of oropharyngeal samples collected when participants were symptomatic. We judged both studies to have a low risk of bias across most domains, although the risk of bias for allocation concealment and selective reporting was unclear in the smaller study. In the larger study, the statistical power to detect a significant difference in the prevalence of Pseudomonas aeruginosa was low because Pseudomonas aeruginosa isolation in BAL samples at five years of age in both groups were much lower than the expected rate that was used for the power calculation. We graded the certainty of evidence for the key outcomes as low, other than for high-resolution computed tomography scoring and cost-of-care analysis, which we graded as moderate certainty. Both studies reported similar outcomes, but meta-analysis was not possible due to different ways of measuring the outcomes and different indications for the use of BAL. Whether antimicrobial therapy is directed by the use of BAL or standard care may make little or no difference in lung function z scores after two years (n = 29) as measured by the change from baseline in LCI and forced expiratory volume in one second (FEV1) (low-certainty evidence). At five years, the larger study found little or no difference between groups in absolute FEV1 z score or forced vital capacity (FVC) (low-certainty evidence). BAL-directed therapy probably makes little or no difference to any measure of chest scores assessed by computed tomography (CT) scan at either two or five years (different measures used in the two studies; moderate-certainty evidence). BAL-directed therapy may make little or no difference in nutritional parameters or in the number of positive isolates of P aeruginosa per participant per year, but may lead to more hospitalisations per year (1 study, 157 participants; low-certainty evidence). There is probably no difference in average cost of care per participant (either for hospitalisations or total costs) at five years between BAL-directed therapy and standard care (1 study, 157 participants; moderate-certainty evidence). We found no difference in health-related quality of life between BAL-directed therapy and standard care at either two or five years, and the larger study found no difference in the number of isolates of Pseudomonas aeruginosa per child per year. The eradication rate following one or two courses of eradication treatment and the number of pulmonary exacerbations were comparable in the two groups. Mild adverse events, when reported, were generally well tolerated. The most common adverse event reported was transient worsening of cough after 29% of procedures. Significant clinical deterioration was documented during or within 24 hours of BAL in 4.8% of procedures.

AUTHORS' CONCLUSIONS

This review, limited to two well-designed randomised controlled studies, shows no evidence to support the routine use of BAL for the diagnosis and management of pulmonary infection in preschool children with CF compared to the standard practice of providing treatment based on results of oropharyngeal culture and clinical symptoms. No evidence is available for adults.

Impact of elexacaftor/tezacaftor/ivacaftor on respiratory colonization in an adult cystic fibrosis clinic

BACKGROUND

Little research has been completed on the correlation between cystic fibrosis (CF) modulator therapy and its effect on respiratory cultures in CF patients. This study evaluated the effect of elexacaftor/tezacaftor/ivacaftor (ETI) on respiratory colonization with Pseudomonas aeruginosa.

METHODS

This single center, IRB approved, retrospective chart review compared patient data two years immediately prior to ETI initiation with patient data two years post-initiation from January 2017-December 2022. Patients were included in the study if they were at least 18 years old with a diagnosis of CF and had at least one month of ETI dispensed, at least one sputum culture obtained, and were currently on ETI. Those who had not been seen since ETI initiation or received a bilateral lung transplant were excluded. The primary outcome was rate of patients with respiratory colonization post-ETI. Colonization was defined as two or more positive P. aeruginosa cultures in a 12-month period. Decolonization was defined as three consecutive negative P. aeruginosa cultures after previous colonization. Key secondary outcomes included average time to discontinuation of mucolytic therapy and relative risk of pulmonary exacerbation.

RESULTS

A significant reduction (p<0.001) in colonization with P. aeruginosa was observed with 49 patients in the pre-ETI group compared to 25 in the post-ETI group meeting the definition of colonization (n=79). Average time to discontinuation of mucolytic therapy was 14 months (p=0.002). Relative risk of pulmonary exacerbation was 4.80 (p<0.001).

CONCLUSIONS

ETI use resulted in reduced colonization with P. aeruginosa, discontinuation of mucolytic therapy, and decreased frequency of pulmonary exacerbation.

Effect of Elexacaftor/Tezacaftor/Ivacaftor on Pseudomonas aeruginosa Acquisition and Chronic Infection at a Single Pediatric Cystic Fibrosis Care Center

OBJECTIVES

As cystic fibrosis (CF) lung disease progresses, the airways become infected with opportunistic pathogens, such as Pseudomonas aeruginosa (PA). In October 2019, the US Food and Drug Administration approved elexacaftor/tezacaftor/ivacaftor (ETI), a highly effective modulator therapy (HEMT), for individuals 12 years and older with 1 copy of the F508del cystic fibrosis transmembrane conductance regulator (CFTR) mutation. ETI increases the amount of and function of CFTR in the respiratory epithelium, improving mucociliary clearance and reducing static airway mucus, a major trigger for chronic infection and inflammation.

METHODS

A retrospective analysis of inhaled tobramycin (iTOB) prescriptions between January 1, 2016, and December 31, 2021, was performed. This captured data before and after ETI approval at Children's Mercy Kansas City (CMKC). The number of individuals with new PA acquisition and individuals considered -chronically infected was analyzed.

RESULTS

The number of eradication prescriptions declined in 2020 and 2021, with 15 (7%) and 12 (5%) -individuals prescribed therapy for those years, respectively. A similar pattern was observed for -prescriptions for chronic infection. A reduction was seen in 2020 and 2021, with 28 (13%) and 20 (9%) individuals -prescribed therapy for the respective years.

CONCLUSIONS

The CMKC experienced a decrease in the number of courses of iTOB prescribed during the last 6 years. The reasons for this are likely multifactorial and may include the implementation of standardized PA surveillance and eradication protocols, the effect of HEMT on mucociliary clearance and airway microbiology, and the poorly understood effects of the SARS-CoV-2 pandemic on the epidemiology of respiratory infections.

Emerging strategies to target virulence in Pseudomonas aeruginosa respiratory infections

Pseudomonas aeruginosa is an opportunistic pathogen that is responsible for infections in people living with chronic respiratory conditions, such as cystic fibrosis (CF) and non-CF bronchiectasis (NCFB). Traditionally, in people with chronic respiratory disorders, P. aeruginosa infection has been managed with a combination of inhaled and intravenous antibiotic therapies. However, due in part to the prolonged use of antibiotics in these people, the emergence of multi-drug resistant P. aeruginosa strains is a growing concern. The development of anti-virulence therapeutics may provide a new means of treating P. aeruginosa lung infections whilst also combatting the AMR crisis, as these agents are presumed to exert reduced pressure for the emergence of drug resistance as compared to antibiotics. However, the pipeline for developing anti-virulence therapeutics is poorly defined, and it is currently unclear as to whether in vivo and in vitro models effectively replicate the complex pulmonary environment sufficiently to enable development and testing of such therapies for future clinical use. Here, we discuss potential targets for P. aeruginosa anti-virulence therapeutics and the effectiveness of the current models used to study them. Focus is given to the difficulty of replicating the virulence gene expression patterns of P. aeruginosa in the CF and NCFB lung under laboratory conditions and to the challenges this poses for anti-virulence therapeutic development.

Microbiology sampling in non-cystic fibrosis bronchiectasis cases from northern Alberta

Non-cystic fibrosis bronchiectasis (NCFB) is a chronic respiratory disease resulting in chronic cough, thick sputum, and lower airway microbial colonization, akin to patients with cystic fibrosis (CF). NCFB is a common, yet under recognized entity which inflicts significant morbidity and mortality particularly to older individuals, with a rising prevalence in the developed world. Given that sputum cultures are a non-invasive method to characterize the lower airway microbiota in NCFB patients, for which pathogenic organisms are associated with worsened outcomes, we sought to characterize the microbiological pattern and clinical outcomes associated with sputum culture in a cohort of NCFB patients from Western Canada. A total of 20 subjects were prospectively recruited from various bronchiectasis clinics across the Greater Edmonton area. A retrospective chart review and a symptoms questionnaire was performed, gathering information not limited to symptoms, comorbidities, exacerbations, hospitalizations, sputum production, and sputum culture results over the prior 5 years. Subjects reported frequent hospitalization alongside a significant burden of symptoms. A large majority of sputum cultures grew pathogenic organisms such as Haemophilus influenzae and Pseudomonas aeruginosa. We also note the considerable waste and inefficiency associated with sputum cultures, outlining areas for which this important diagnostic modality can be improved. Accurate characterization of the airway microbiota alongside efficient delivery of health services are key to ensuring the proper treatment of individuals with NCFB, given their high disease burden and frequent hospitalization.

Combination of Serologic Tests and Sputum Culture Results as the Best Diagnostic Method of Pseudomonas aeruginosa Infection in Cystic Fibrosis Patients

Background

One of the most common reasons for mortality in patients with cystic fibrosis (CF) is lung infections, among which Pseudomonas aeruginosa (Pa) infection has the largest share. Diagnosis of Pa can be assessed by various methods such as sputum culture results and IgG antibody level via measuring the specific anti-Pa antibodies. This study aimed to select the best predictive technique in the diagnosis of Pa in CF patients through spirometry, sputum culture, and serum IgG antibody levels.

Materials and Methods

In this cross-sectional study, blood and sputum or pharyngeal samples were taken from 68 patients with cystic fibrosis. Because spirometry was not possible in all patients, 34 patients could do the spirometry. The samples were studied concerning Pa infection. The data including variables such as age, sex, and spirometry results were obtained. Then, in the serologic method, 3 serum-specific antibody levels were determined by enzyme-linked immune sorbent assay (ELISA).

Results

The average age of children was 7.4 ± 5.6 (ranging from 0.5 to 23) years. Generally, the percentage of Pa infection increased in CF patients with higher ages. A statistically direct significant relationship was observed between the concentration of serum IgG antibodies in patients with CF and Pa-positive sputum culture results (p<0.05).

Conclusion

Serum IgG antibodies against specific Pa antigens could be a diagnostic method against Pa infection, especially in patients who cannot expectorate. However, because of the positive and negative predictive value of both serum IgG antibody levels and the results of the sputum culture, we suggested that utilizing the combination of these methods could be beneficial in earlier diagnosis of Pa.

Evaluation of a Novel Chromogenic Medium for the Detection of Pseudomonas aeruginosa in Respiratory Samples from Patients with Cystic Fibrosis

Pseudomonas aeruginosa is a dominant cause of respiratory infection in individuals with cystic fibrosis (CF), leading to significant morbidity and mortality. Detection of P. aeruginosa is conducted by culture of respiratory samples but this process may occasionally be compromised due to overgrowth by other bacteria and fungi. We aimed to evaluate a novel chromogenic medium, Pseudomonas aeruginosa chromogenic agar (PACA), for culture of P. aeruginosa from respiratory samples, from patients with CF. A total of 198 respiratory samples were cultured onto PACA and three other media: CHROMID^®P. aeruginosa, CHROMagar™ Pseudomonas and MacConkey agar. P. aeruginosa was recovered from 66 samples (33%), using a combination of all media. After 72 h incubation, the sensitivity of the four chromogenic media was as follows: 91% for PACA and CHROMagar™ Pseudomonas, 85% for CHROMID^®P. aeruginosa and 83% for MacConkey agar. For the three chromogenic media, the positive predictive value after 72 h was as follows: 95% for PACA, 56% for CHROMagar™ Pseudomonas and 86% for CHROMID^®P. aeruginosa. PACA proved to be a highly effective culture medium for the isolation and specific detection of P. aeruginosa from respiratory samples.

The Use of Tobramycin for Pseudomonas aeruginosa: A Review

INTRODUCTION

Pseudomonas aeruginosa is a common respiratory pathogen that contributes to chronic pulmonary infection in individuals with cystic fibrosis. Guidelines recommend early intervention upon positive P. aeruginosa culture. Tobramycin has in vitro activity against Gram-negative bacteria, including P. aeruginosa, and TOBI Podhaler is indicated for the management of individuals with cystic fibrosis with P. aeruginosa infection. The dry powder inhaler formulation decreases the time required for treatment compared with nebulized solution and therefore may improve quality of life and adherence, which have a positive impact on disease progression.

AREAS COVERED

In this review, we discuss the safety and efficacy of tobramycin inhaled powder and provide insights into appropriate individuals who might benefit from a dry powder inhaler, keeping in mind that patient preference is an important consideration for therapy selection.

EXPERT OPINION

Providing a less burdensome alternative to delivering inhaled antibiotics that is more portable with a significantly shorter administration time may help improve adherence, and therefore improve outcomes. Continued development of new antibiotics to add to current regimens for eradication and control of airway microbiology, combined with more efficient delivery systems such as tobramycin inhaled powder, will help evolve the treatment of patients with CF.

Management of respiratory tract exacerbations in people with cystic fibrosis: Focus on imaging

Respiratory tract exacerbations play a crucial role in progressive lung damage of people with cystic fibrosis, representing a major determinant in the loss of functional lung tissue, quality of life and patient survival. Detection and monitoring of respiratory tract exacerbations are challenging for clinicians, since under- and over-treatment convey several risks for the patient. Although various diagnostic and monitoring tools are available, their implementation is hampered by the current definition of respiratory tract exacerbation, which lacks objective "cut-offs" for clinical and lung function parameters. In particular, the latter shows a large variability, making the current 10% change in spirometry outcomes an unreliable threshold to detect exacerbation. Moreover, spirometry cannot be reliably performed in preschool children and new emerging tools, such as the forced oscillation technique, are still complementary and need more validation. Therefore, lung imaging is a key in providing respiratory tract exacerbation-related structural and functional information. However, imaging encompasses several diagnostic options, each with different advantages and limitations; for instance, conventional chest radiography, the most used radiological technique, may lack sensitivity and specificity in respiratory tract exacerbations diagnosis. Other methods, including computed tomography, positron emission tomography and magnetic resonance imaging, are limited by either radiation safety issues or the need for anesthesia in uncooperative patients. Finally, lung ultrasound has been proposed as a safe bedside option but it is highly operator-dependent and there is no strong evidence of its possible use during respiratory tract exacerbation. This review summarizes the clinical challenges of respiratory tract exacerbations in patients with cystic fibrosis with a special focus on imaging. Firstly, the definition of respiratory tract exacerbation is examined, while diagnostic and monitoring tools are briefly described to set the scene. This is followed by advantages and disadvantages of each imaging technique, concluding with a diagnostic imaging algorithm for disease monitoring during respiratory tract exacerbation in the cystic fibrosis patient.

Aminoglycoside dosing and monitoring for Pseudomonas aeruginosa during acute pulmonary exacerbations in cystic fibrosis

Aminoglycosides are commonly used for the treatment of Pseudomonas aeruginosa (PsA) in the setting of acute pulmonary exacerbations (PEx) in pediatric patients with cystic fibrosis (CF). There are controversies and practice differences between institutions related to aminoglycoside dosing and monitoring strategies. The purpose of this review article is to summarize the currently available literature and identify gaps in the literature related to pharmacokinetic parameter goals, aminoglycoside dosing strategies, and methods for monitoring serum aminoglycoside concentrations for treatment of PsA in CF PEx, and throughout will discuss anticipated changes with the increasing availability of highly effective CF transmembrane conductance regulator modulators. This review focuses on tobramycin, as it is the most commonly used aminoglycoside in CF PEx, and will briefly discuss special circumstances surrounding use of amikacin and gentamicin.

Comparison of microbiota in the upper versus lower respiratory tract in children during health and respiratory disease: protocol for a systematic review

BACKGROUND

The upper respiratory tract of children is colonized by various microbial species during the healthy state, whereas the lungs are believed to be sterile. In children with respiratory infections, micro-organisms can be recovered from the upper respiratory sites, as well as the lungs. However, the correlation of microbial yield between the two sites is unclear. This systematic review is designed to explore the microbial composition of the respiratory system in healthy children, comparing the organisms identified in the upper airways versus the lungs. We will also compare the prevalence and pattern of upper respiratory micro-organisms in healthy children versus those with various respiratory diseases. We will additionally compare the organisms identified in the upper airway versus the lungs in children with respiratory disease.

METHODS

We will search the following electronic databases: Epistemonikos and Cochrane Library for systematic reviews and MEDLINE (through PubMed), EMBASE, Cochrane CENTRAL, LIVIVO, Web of Science, Scopus, and CINAHL databases for primary studies. Reference lists of relevant studies will be examined for links to potential related articles. Two reviewers will independently determine eligibility for inclusion. The methodological quality and risk of bias of the included observational studies will be scored using the Newcastle-Ottawa Scale tool, and JBI Critical Appraisal Checklist for case series. We will present the data with descriptive statistics and provide pooled estimates of outcomes, wherever it is feasible to perform a meta-analysis. Heterogeneity in studies will be explored by using the Higgins and Thompson I² method. Sensitivity analysis will be done to explore the impact of study quality, and subgroup analysis will be done based on age, health condition, type of respiratory specimen, and method of identifying organisms. We will prepare a summary of findings' table and assess the confidence in the evidence using the GRADE methodology.

RESULTS

This is a protocol; hence, there are no results at this stage.

DISCUSSION

The proposed systematic review will provide comparisons of the microbiota in the upper respiratory tract versus the lungs, in children, during health as well as respiratory disease. Similarly, the site-specific yield will be compared between healthy children and those with respiratory disease. This will provide clinicians, microbiologists, and respiratory therapists a better understanding of the respiratory system microbiota, suitability (or otherwise) of upper airway specimens in various respiratory diseases, and the potential role of upper airway colonization on specific respiratory diseases. We will disseminate the review through a peer-reviewed journal publication. Data that cannot be included in the published version will be made available on request.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020202115 .

Sputum and Plasma Neutrophil Elastase in Stable Adult Patients With Cystic Fibrosis in Relation to Chronic Pseudomonas Aeruginosa Colonization

Background and purpose

Neutrophil elastase (NE) has been implicated in the pathogenesis of airway inflammation in cystic fibrosis (CF) patients and it impairs defenses against Pseudomonas aeruginosa (PA) infection or colonization. Sputum NE may act as a biomarker of neutrophilic inflammation in CF patients. This study aimed to determine sputum and plasma total NE levels in clinically stable adult CF patients and control subjects, and their correlation to PA colonization and lung functions.

Methods

This is a cross-sectional study. Total NE was measured on spontaneously expectorated sputum and plasma obtained from 21 CF patients, aged 18-40 years, during routine visits to the adult CF clinic. This was compared to plasma obtained from 22 matching healthy controls. The levels of NE were measured by the magnetic bead-based multiplex assay.

Results

Sputum and plasma NE levels had a significant positive correlation (Pearson r=0.533, P=0.013) with PA colonization. Sixteen CF patients (76.2%) were chronically colonized with PA. Both median sputum and plasma NE were found to be higher in CF patients with PA as compared with non-PA patients, even though this difference was statistically insignificant. Sputum and plasma NE levels did not correlate with the percentage predicted forced expiratory volume in one second (FEV1), the forced vital capacity (FVC), and FEV1/FVC and no association with PA.

Conclusion

The findings suggest that clinically stable adult CF patients colonized with PA may have higher NE levels in both plasma and sputum as compared to non-PA CF patients and probably total NE does not influence lung functions.

Sustained Coinfections with Staphylococcus aureus and Pseudomonas aeruginosa in Cystic Fibrosis

Rationale: Staphylococcus aureus and Pseudomonas aeruginosa often infect the airways in cystic fibrosis (CF). Because registry studies show higher prevalence of P. aeruginosa versus S. aureus in older patients with CF, a common assumption is that P. aeruginosa replaces S. aureus over time. In vitro, P. aeruginosa can outgrow and kill S. aureus. However, it is unknown how rapidly P. aeruginosa replaces S. aureus in patients with CF.Methods: We studied a longitudinal cohort of children and adults with CF who had quantitative sputum cultures. We determined the abundance of P. aeruginosa and S. aureus in cfu/ml. We determined the duration and persistence of infections and measured longitudinal changes in culture positivity and abundance for each organism.Measurements and Main Results: Between 2004 and 2017, 134 patients had ≥10 quantitative cultures, with median observation time of 10.15 years. One hundred twenty-four patients had at least one positive culture for P. aeruginosa, and 123 had at least one positive culture for S. aureus. Both species had median abundance of >10⁶ cfu/ml. Culture abundance was stable over time for both organisms. There was an increase in the prevalence of S. aureus/P. aeruginosa coinfection but no decrease in S. aureus prevalence within individuals over time.Conclusions: S. aureus and P. aeruginosa are abundant in CF sputum cultures. Contrary to common assumption, we found no pattern of replacement of S. aureus by P. aeruginosa. Many patients with CF have durable long-term coinfection with these organisms. New strategies are needed to prevent and treat these infections.

Evaluation of Inflammatory Biomarkers in Iranian Patients with Cystic Fibrosis

Background::

Cystic fibrosis (CF) is an autosomal recessive disease characterized by a progressive and recurrent lung infection.

Objective::

This study aimed to evaluate the levels of pro-inflammatory cytokines and their correlations with lung function in CF patients.

Methods::

A matched case-control study was conducted among 18 CF (children and adults) and 18 control patients (age and gender-matched) who were admitted to Masih Daneshvari Hospital (Tehran, Iran). The controls had no obvious inflammatory lung disease. The samples of bronchoalveolar lavage (BAL) fluid, serum, and sputum of participants were collected to determine concentrations of inflammatory cytokines such as interleukins (IL-8, IL-1β) and tumour necrosis factor- alpha (TNF-α) using enzyme-linked immunosorbent assay (ELISA). Spirometry was applied and functional pulmonary indices [forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1)] were assessed.

Results::

The mean age of CF patients was 15.43 ± 5.970 years (range 4-24). The FVC in a majority of the CF patients (66.7%) was below 60% and only 33.3% of the patients exhibited normal or mild respiratory dysfunction. There were significant differences between FVC and FEV1 measurements before and after bronchoscopy. In addition, IL-8 levels in all three samples (serum, sputum, and BAL) of CF patients and levels of IL-1β and TNF-α in BAL and sputum samples of CF patients were significantly higher than the control group (p<0.001). However, increased cytokine levels were not associated with lung function.

Conclusion::

Increased IL-8 and TNF-α levels seemed to be associated with signs of clinical deterioration and might be useful as diagnostic markers.

Safety of research bronchoscopy with BAL in stable adult patients with cystic fibrosis

Data on adverse events from research bronchoscopy with bronchoalveolar lavage (BAL) in patients with cystic fibrosis (CF) is lacking. As research bronchoscopy with BAL is useful for isolation of immune cells and investigation of CF lung microbiome, we sought to investigate the safety of bronchoscopy in adult patients with CF. Between November 2016 and September 2019, we performed research bronchoscopies on CF subjects (32) and control subjects (82). Control subjects were nonsmokers without respiratory disease. CF subjects had mild or moderate obstructive lung disease (FEV1 > 50% predicted) and no evidence of recent CF pulmonary exacerbation. There was no significant difference in the age or sex of each cohort. Neither group experienced life threatening adverse events. The number of adverse events was similar between CF and control subjects. The most common adverse events were sore throat and cough, which occurred at similar frequencies in control and CF subjects. Fever and headache occurred more frequently in CF subjects. However, the majority of fevers were seen in CF subjects with FEV1 values below 65% predicted. We found that CF subjects had similar adverse event profiles following research bronchoscopy compared to healthy subjects. While CF subjects had a higher rate of fevers, this adverse event occurred with greater frequency in CF subjects with lower FEV1. Our data demonstrate that research bronchoscopy with BAL is safe in CF subjects and that safety profile is improved if bronchoscopies are limited to subjects with an FEV1 > 65% predicted.

The human respiratory tract microbial community structures in healthy and cystic fibrosis infants

The metagenome development of the human respiratory tract was investigated by shotgun metagenome metagenomic sequencing of cough swabs from healthy children and children with cystic fibrosis (CF) between 3 weeks and 6 years of age. A healthy microbial community signature was associated with increased absolute abundances in terms of bacterial–human cell ratios of core and rare species across all age groups, with a higher diversity of rare species and a tightly interconnected species co-occurrence network, in which individual members were found in close proximity to each other and negative correlations were absent. Even without typical CF pathogens, the CF infant co-occurrence network was found to be less stable and prone to fragmentation due to fewer connections between species, a higher number of bridging species and the presence of negative species correlations. Detection of low-abundant DNA of the CF hallmark pathogen Pseudomonas aeruginosa was neither disease- nor age-associated in our cohort. Healthy and CF children come into contact with P. aeruginosa on a regular basis and from early on.

A case report of successful eradication of new isolates of Burkholderia cenocepacia in a child with cystic fibrosis

Chronic respiratory infection with Burkholderia cenocepacia (Bc) in patients with cystic fibrosis (CF) is associated with accelerated decline in lung function and increased mortality. It is therefore important to attempt to eradicate new isolates, especially in children. However, there are no standardized guidelines to eradicate Bc. We report a case of successful eradication of new isolates of Bc in a 2-year-old child with CF using a combination of IV, nebulized antibiotics and sinus surgery.

Impaired Ratio of Unsaturated to Saturated Non-Esterified Fatty Acids in Saliva from Patients with Cystic Fibrosis

Impaired salivary non-esterified fatty acids (NEFA) levels have been previously observed in cystic fibrosis (CF). This study aimed to characterize the salivary NEFA profile in CF and to examine whether the alterations are related to the pancreatic status and/or lung disease severity. We analyzed salivary NEFA, cholesterol and interleukin-6 (IL-6) in CF patients (n = 66) and healthy subjects (n = 48). CF patients showed higher salivary levels of cholesterol, total NEFA (that was negatively correlated with serum triglycerides), unsaturated NEFA/saturated NEFA (U/S NEFA) ratio and IL-6 than controls. The U/S NEFA ratio was positively correlated with IL-6 in both patients and controls, suggesting an association between this parameter and local inflammation independently from the disease. No correlation between salivary lipids and pancreatic status was observed, while the U/S NEFA ratio was higher in patients with severe lung disease than mild/moderate severity and may represent a prognostic marker of lung disease in CF.

Prevention of chronic infection with Pseudomonas aeruginosa infection in cystic fibrosis

PURPOSE OF REVIEW

This review provides an update on definitions of chronicity of infection, approaches to airway sampling to detect infection, strategies for Pseudomonas aeruginosa eradication, impact of cystic fibrosis transmembrane regulator protein (CFTR) modulators and future challenges for clinical trials.

RECENT FINDINGS

Rates of P. aeruginosa have decreased over the past two decades with establishment of effective eradication protocols. Definitions of chronic P. aeruginosa infection have required adaptation for healthier populations. Although molecular (PCR) approaches to early P. aeruginosa detection are sensitive, to date, earlier diagnosis has not impacted on clinical outcomes. Despite eradication regimens, some people with early P. aeruginosa fail to clear their infection. Most people also experience a recurrence and eventual transition to chronic infection. Several recent studies sought to address this gap. CFTR modulators (predominantly ivacaftor) demonstrated reduced P. aeruginosa density, although infection may persist or recur demonstrating the need for continued antiinfective therapies in the modulator era.

SUMMARY

Future studies of approaches to P. aeruginosa eradication will be complex due to expanded availability and ongoing competitive clinical trials of CFTR modulators. Studies to address optimal eradication therapy, particularly in adults, will be required, though adequate recruitment to power these studies may prove challenging.

Salivary Cytokines and Airways Disease Severity in Patients with Cystic Fibrosis

About 50% of patients with cystic fibrosis (CF) have sinonasal complications, which include inferior turbinate hypertrophy (NTH) and/or nasal polyposis (NP), and different degrees of lung disease, which represents the main cause of mortality. Monitoring of sinonasal disease requires complex instrumental procedures, while monitoring of lung inflammation requires invasive collection of bronchoalveolar lavage fluid. The aim of this study was to investigate the associations between salivary cytokines levels and CF-related airway diseases. Salivary biochemical parameters and cytokines, i.e., interleukin-6 (IL-6), IL-8, and tumor necrosis factor alpha (TNF-α), were analyzed in resting saliva from healthy subjects and patients with CF. Patients with CF showed significantly higher levels of salivary chloride, IL-6, IL-8, and TNF-α and lower calcium levels than healthy subjects. Among patients with CF, IL-6 and IL-8 were significantly higher in patients with NTH, while TNF-α was significantly lower in patients with NP. A decreasing trend of TNF-α in patients with severe lung disease was also observed. On the other hand, we did not find significant correlation between cytokine levels and Pseudomonas aeruginosa or Stenotrophomonas maltophilia colonization. These preliminary results suggest that salivary IL-6 and IL-8 levels increase during the acute phase of sinonasal disease (i.e., NTH), while the end stages of pulmonary disease and sinonasal disease (i.e., NP) show decreased TNF-α levels.