Induced sputum to detect lung pathogens in young children with cystic fibrosis

Sputum induction and its diagnostic applications in inflammatory airway disorders: a review

Sputum induction is a technique that covers the induction and the subsequent processing of the expectorate primarily for the analysis of cells and different inflammatory biomarkers present in the airways to further understand the pathophysiology of different inflammatory respiratory disorders such as asthma and chronic obstructive pulmonary disease (COPD) as well as the diagnosis of lung diseases such as lung cancer, tuberculosis, and Pneumocystis jirovecii pneumonia. It is a non-invasive, safe, cost-effective, and reliable technique reported to exhibit a high success rate. However, due to being technically demanding and time-consuming and having the need of employing trained staff, this technique is only used in restricted research centres and in limited centres of clinical use. When the sputum is collected after induction, the primary goal is to obtain a differential cell count and evaluate the molecular biomarkers of airway inflammation such as eosinophil cationic protein, eosinophil-derived neurotoxin, major basic protein, tryptase, cytokine production [e.g., interleukin (IL)-5], albumin, and fibrinogen. In addition, cytospins from the processed sputum are used for immunocytochemical staining of cellular products such as EG-2 reactive protein, granulocyte-macrophage colony-stimulating factor, tumour necrosis factor alpha, and IL-8 that play significant roles in understanding the pathophysiology of inflammatory airway diseases. Nowadays, this technique can be further used by performing an additional analysis such as flow cytometry and in situ hybridisation on the sputum supernatant to investigate more the immune response and pathophysiological process of such various respiratory diseases. In addition, the application of sputum fluid phase to assess the biomarkers could be used more routinely in pathological laboratories for diagnosing lung cancer, COPD, and asthma as well as for monitoring lung cancer progression and asthma and COPD treatment, allowing for early detection and a better treatment provided by the clinicians.

The clinical yield of bronchoscopy in the management of cystic fibrosis: A retrospective multicenter study

BACKGROUND

Pulmonary disease is the leading cause of morbidity and mortality in people with cystic fibrosis (pwCF). Several studies have shown no benefit for bronchoscopy and bronchoalveolar lavage (BAL) over sputum to obtain microbiological cultures, hence the role of bronchoscopy in pwCF is unclear.

AIM

To analyze how bronchoscopy results affected clinical decision-making in pwCF and assess safety.

METHODS

A retrospective analysis of all charts of pwCF from three CF centers in Israel, between the years 2008 and 2019. We collected BAL culture results as well as sputum cultures obtained within 1 month of the BAL sample. A meaningful yield was defined as a decision to start antibiotics, change the antibiotic regimen, hospitalize the patient for treatment, or the resolution of the problem that led to bronchoscopy (e.g., atelectasis or hemoptysis).

RESULTS

During the study years, of the 428 consecutive patient charts screened, 72 patients had 154 bronchoscopies (2.14 bronchoscopies/patient). Forty-five percent of the bronchoscopies had a meaningful clinical yield. The finding of copious sputum on bronchoscopy was strongly associated with a change in treatment (OR: 5.25, 95%CI: 2.1-13.07, p < 0.001). BAL culture results were strongly associated with a meaningful yield, specifically isolation of Aspergillus spp. (p = 0.003), Haemophilus influenza (p = 0.001). Eight minor adverse events following bronchoscopy were recorded.

CONCLUSIONS

In this multicenter retrospective analysis of bronchoscopy procedures from three CF centers, we have shown that a significant proportion of bronchoscopies led to a change in treatment, with no serious adverse events. Our findings suggest that bronchoscopy is a safe procedure that may assist in guiding treatment in some pwCF. Future studies should evaluate whether BAL-guided decision-making may also lead to a change in clinical outcomes in pwCF.

Enigma variations: The multi-faceted problems of pre-school wheeze

Numerous publications on wheezing disorders in children younger than 6 years have appeared in the medical literature over the last decades with the aim of shedding light on the mechanistic pathways (endotypes) and treatment. Nevertheless, there is yet no consensus as to the appropriate way to manage preschool wheeze mainly because of the lack of a clear definition of "preschool asthma" and the paucity of scientific evidence concerning its underlying endotypes. A symptom-based approach is inadequate since the human airway can respond to external stimuli with a limited range of symptoms and signs, including cough and wheeze, and these manifestations represent the final expression of many clinical entities with potentially different pathophysiologies requiring different individualized treatments. Hence, new studies challenge the symptom-based approach and promote the importance of managing the wheezy child based on the "airway phenotype." This will enable the clinician to identify not only the child with a serious underlying pathology (e.g., a structural airway disorder or immunodeficiency) who is in need of prompt and specific treatment but also increase the specificity of treatment for the child with symptoms suggestive of an "asthma" syndrome. In the latter case, focus should be given to the identification of treatable traits. This review summarizes the current understanding in management of preschool wheezing and highlights the unmet need for further research.

Specificity of Immunoglobulin Response to Nontuberculous Mycobacteria Infection in People with Cystic Fibrosis

Nontuberculous mycobacteria (NTM) infections are increasingly prevalent in chronic lung diseases, including cystic fibrosis (CF). Mycobacterium abscessus is of particular concern due to relatively greater virulence and intrinsic antimicrobial resistance. Airway culture identification, the standard method for detecting pulmonary infection, is hindered by low sensitivity, long culture times, and reliance on sputum production or lavage. A culture-independent test for detecting NTM infection could complement, or replace, sputum culture, which is becoming more difficult to obtain with reduced sputum production by people with CF (pwCF) on highly effective modulator therapy. We describe an assay for the detection of plasma anti-M. abscessus antibodies of pwCF to antigens from M. abscessus lysates. Anti-M. abscessus IgG and IgA, but not IgM, discriminated with high specificity subjects infected with M. abscessus from those infected by M. avium complex, and from those with distant or no NTM infections. The IgG3 subclass predominated with minor contributions by other subclasses. Both aqueous and organic soluble antigens were recognized by plasma IgG. A validation cohort measuring IgG and IgG3 identified M. abscessus positive subjects, and elevated IgG was sustained over several years. These studies show the benefit of M. abscessus cell lysates to detect plasma IgG of subjects with CF and M. abscessus infections. Subclass analysis suggests that IgG3 is the predominant subtype in these subjects with chronic bacterial infections suggesting a defect in class maturation. Serodiagnosis could be useful to monitor M. abscessus group infections in chronic lung disease as an adjunct or alternative to culture. IMPORTANCE Lung infections with nontuberculous mycobacteria (NTM), and particularly Mycobacterium abscessus, a pathogen with high antibiotic resistance, are of great concern due to poor clinical outcomes and challenging detection in people with cystic fibrosis and other diseases. Standard detection methods are insensitive and increasingly difficult. We describe the measurement of NTM-specific antibodies from plasma to identify subjects infected with M. abscessus. The assay is sensitive and provides information on the immune response to NTM infections. This assay could be used to help identify subjects with NTM pulmonary infections and track disease progression, either alone or in conjunction with other tests.

Validation of nasal tracheal aspiration in children with lung disease

Background

Nasal tracheal aspiration (NTA) is a frequently used diagnostic method to assess of infections in the lower airways. However, the validity of the method has not previously been compared to bronchoalveolar lavage (BAL) in non-intubated children with a lung disease. We hypothesised that NTA performed by health professionals using the nares vocal cord distance to be placed at the entrance of the trachea, will result in same finding of bacteria in the lower airways as the gold standard of BAL.

Methods

In a prospective study, 173 paired samples of NTA and BAL were obtained between June 2016 to August 2018. Samples were collected from all patients undergoing bronchoscopy with spontaneous breathing during general anaesthesia. This study compares the microbiological results from the cultures obtained by investigating complete concordance i.e. identical pathogenic bacteria and coherence i.e. absence or presence of pathogenic bacteria growth between NTA and BAL.

Results

Samples were collected in 164 patients, 158 children between 21 days and 18 years of age and six young adults still treated at the paediatric department. The overall similarity (complete agreement) was found in 49% [41–56], sensitivity was 35% [27–45], specificity was 66% [55–76], positive predictive value was 36% [27–46] and negative predictive value was 64% [54–64] concerning complete pathogenic bacteria concordance. If we only considered coherence growth of pathogenic bacteria, similarity was 71% [63–79], sensitivity was 74% [64–81], specificity was 66% [55–76], positive predictive value was 75% [65–82] and negative predictive value was 65% [54–75]. Patients with cystic fibrosis showed a similarity of 88% [73–95], a sensitivity of 92% [76–99], a specificity of 71% [36–95], a positive predictive value of 92% [76–99] and a negative predictive value of 71% [36–95] concerning coherence growth of pathogenic bacteria.

Conclusion

The study indicates that NTA compared to BAL as the gold standard is not clinically useful to assess positive findings of specific bacteria in the lower airway tract. Statistically significantly increased sensitivity and positive predictive value were found in cystic fibrosis patients concerning coherence growth. The clinical usage of NTA remains important as negative findings are of clinical value. However, BAL continues to be preferred as a significantly superior diagnostic tool.

Recent advances in the early treatment of cystic fibrosis: Bridging the gap to highly effective modulator therapy

Highly effective modulator therapy (HEMT) for cystic fibrosis (CF) has been touted as one of the greatest advances to date in CF care. As these therapies are now available for many older children and adults with CF, marked improvement of their nutritional status, pulmonary and gastrointestinal symptoms has been observed. However, most infants and younger children are not current candidates for HEMT due to age and/or cystic fibrosis transmembrane conductance regulator (CFTR) mutation. For these young children, it is essential to provide rigorous monitoring and care to avoid potential disease sequelae while awaiting HEMT availability. The following article highlights recent advances in the care of infants and young children with CF with regard to surveillance and treatment of nutritional, pulmonary, and gastrointestinal disorders. Recent clinical trials in this population are also reviewed.

Monitoring disease progression in childhood bronchiectasis

Bronchiectasis (not related to cystic fibrosis) is a chronic lung disease caused by a range of etiologies but characterized by abnormal airway dilatation, recurrent respiratory symptoms, impaired quality of life and reduced life expectancy. Patients typically experience episodes of chronic wet cough and recurrent pulmonary exacerbations requiring hospitalization. Early diagnosis and management of childhood bronchiectasis are essential to prevent respiratory decline, optimize quality of life, minimize pulmonary exacerbations, and potentially reverse bronchial disease. Disease monitoring potentially allows for (1) the early detection of acute exacerbations, facilitating timely intervention, (2) tracking the rate of disease progression for prognostic purposes, and (3) quantifying the response to therapies. This narrative review article will discuss methods for monitoring disease progression in children with bronchiectasis, including lung imaging, respiratory function, patient-reported outcomes, respiratory exacerbations, sputum biomarkers, and nutritional outcomes.

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.

Diagnostic Accuracy of Nasopharyngeal Swab Cultures in Children Less Than Five Years with Chronic Wet Cough

Background: It is necessary to find a non-invasive and accurate procedure to predict persistent bacterial bronchitis (PBB) causative organisms and guide antibiotic therapy. The study objective was to compare the diagnostic accuracy of nasopharyngeal swab cultures with bronchoalveolar lavage (BAL) cultures in children with PBB. Methods: Nasopharyngeal swab and BAL fluid specimens were collected and cultured for bacterial pathogens prospectively from less than five-year-old children undergoing flexible bronchoscopy for chronic wet cough. Results: Of the 59 children included in the study, 26 (44.1%) patients had a positive BAL bacterial culture with neutrophilic inflammation. Prevalence of positive cultures for any of the four common respiratory pathogens implicated in PBB (Moraxella catarrhalis, Streptococcus pneumoniae, Staphylococcus aureus, and Haemophilus influenzae) was significantly higher (p = 0.001) in NP swabs compared to BAL fluids (86.4% and 44.1% of PBB cases, respectively). NP swab cultures for any of the four main bacterial pathogens had 85% (95% CI: 65–96%) and 48% (95% CI: 31–66%) sensitivity and specificity of detecting PBB, respectively. Positive and negative predictive values were 56% (95% CI: 47–65%) and 80% (95% CI: 60–91%), respectively. In conclusion, in children less than 5 years of age with chronic wet cough (PBB-clinical), a negative NP swab result reduces the likelihood of lower airway infection; however, a positive NP swab does not accurately predict the presence of lower airway pathogens. Flexible bronchoscopy should be considered in those with recurrent PBB-clinical or with clinical pointers of central airway anomalies.

Clinical value of serum and exhaled breath condensate inflammatory factor IL-11 levels in non-small cell lung cancer: Clinical value of IL-11 in non-small cell lung cancer

OBJECTIVE

Our study aimed to observe and evaluate the clinical value of interleukin (IL)-11 in the serum and exhaled breath condensate of patients with non-small cell lung cancer (NSCLC).

METHODS

A total of 91 patients with NSCLC and 72 healthy volunteers were included in this study. IL-11 concentration was determined by ELISA, and the relationship between IL-11 expression in serum and exhaled breath condensate specimens, and the clinicopathological characteristics of patients with NSCLC were analyzed. The relationship between serum IL-11 expression and traditional tumor markers and inflammation indicators of NSCLC was also analyzed. The correlation between serum IL-11 and exhaled breath condensate IL-11 level was determined. The receiver operating characteristic curve was used to evaluate the diagnostic value of IL-11 and carcinoembryonic antigen single and combined detection for NSCLC. The published data from online databases were used to analyze the relationship between the expression of IL-11 and the prognosis of NSCLC.

RESULTS

IL-11 concentration in serum and exhaled breath condensate specimens of patients with NSCLC were significantly increased. IL-11 expression was positively correlated with lymph node metastasis, distant metastasis, tumor node metastasis stage, and tumor differentiation degree of NSCLC. The expression of IL-11 in serum was positively correlated with that in exhaled breath condensate specimens. IL-11 expression was closely related to that of neutrophil-to-lymphocyte ratio and carcinoembryonic antigen. The combination of serum IL-11 with exhaled breath condensate IL-11 and carcinoembryonic antigen showed significantly higher diagnostic value than any one marker alone. Besides, the high IL-11 expression was closely related to the poor prognosis of NSCLC.

CONCLUSION

IL-11 can be used as a potential diagnostic and prognostic biomarker for NSCLC.

Chest physiotherapy enhances detection of Pseudomonas aeruginosa in nonexpectorating children with cystic fibrosis

Lung damage in cystic fibrosis (CF) is strongly associated with lower airway infections. Early treatment of Pseudomonas aeruginosa is recommended. Pathogen detection requires sampling of lower airway secretions, which remains a challenge in nonexpectorating patients. Our hypothesis was that chest physiotherapy would improve the quality of airway secretion samples and increase the rates of pathogens detected in nonexpectorating patients.

This prospective multicentre study compared three successive methods for sampling airway secretions applied through the same session: 1) an oropharyngeal swab (OP), 2) a chest physiotherapy session followed by a provoked cough to obtain sputum (CP-SP) and 3) a second oropharyngeal swab collected after chest physiotherapy (CP-OP). Haemophilus influenzae, Staphylococcus aureus and P. aeruginosa growth cultures were assessed. Accuracy tests and an equivalence test were performed to compare the three successive methods of collection.

300 nonexpectorating children with CF were included. P. aeruginosa was detected cumulatively in 56 (18.9%) children, and according to the different collection methods in 28 (9.8%), 37 (12.4%) and 44 (14.7%) children by using OP, CP-OP and CP-SP, respectively. Compared with OP, the increased detection rate was +22% for CP-OP (p=0.029) and +57% for CP-SP (p=0.003). CP-SP had the best positive predictive value (86.3%) and negative predictive value (96.0%) for P. aeruginosa compared with the overall detection.

The results of this adequately powered study show differences in the rates of pathogens detected according to the sampling method used. Chest physiotherapy enhanced detection of P. aeruginosa in nonexpectorating children with CF.

Sputum collection after a chest physiotherapy session strongly enhances the detection of P. aeruginosa in nonexpectorating CF children compared with the commonly used oropharyngeal swab method. Oropharyngeal swab after physiotherapy may be an acceptable alternative.https://bit.ly/3757ewq

Changing Prevalence of Lower Airway Infections in Young Children with Cystic Fibrosis

Rationale: Historical studies suggest that airway infection in cystic fibrosis initiates with Staphylococcus aureus and Haemophilus influenzae, with later emergence of Pseudomonas aeruginosa. Aspergillus species are regarded as relatively infrequent, late-occurring infections.Objectives: To assess the prevalence and change in prevalence of early lower airway infections in a modern cohort of children with cystic fibrosis.Methods: All infants diagnosed with cystic fibrosis after newborn screening participating in the Australian Respiratory Early Surveillance Team for Cystic Fibrosis (AREST CF) cohort study between 2000 and 2018 were included. Participants prospectively underwent BAL at 3-6 months, 1 year, and annually up to 6 years of age. Lower airway infection prevalence was described. Changes in prevalence patterns were assessed longitudinally using generalized estimating equations controlling for age and repeated visits.Measurements and Main Results: A total of 380 infants underwent 1,759 BALs. The overall prevalence and median age of first acquisition of the most common infections were as follows: S. aureus, 11%, 2.5 years; P. aeruginosa, 8%, 2.4 years; Aspergillus species, 11%, 3.2 years; and H. influenzae, 9%, 3.1 years. During the study, a significant decrease in prevalence of P. aeruginosa (P < 0.001) and S. aureus (P < 0.001) was observed with a significant change toward more aggressive treatment. Prevalence of Aspergillus infections did not significantly change (P = 0.669).Conclusions: Aspergillus species and P. aeruginosa are commonly present in the lower airways from infancy. The decrease in prevalence of P. aeruginosa and S. aureus since 2000, coinciding with a more aggressive therapeutic approach, has resulted in Aspergillus becoming the most commonly isolated pathogen in young children. Further research is warranted to understand the implication of these findings.

Detecting respiratory infection in children with cystic fibrosis: Cough swab, sputum induction or bronchoalveolar lavage

Young children with cystic fibrosis (CF) are generally very well, cough free and non-productive, and are often incapable of spontaneously expectorating sputum even if actively coughing during an exacerbation. Obtaining a meaningful airway sample for microbiological analysis is therefore problematic, yet essential if lower airway infection is to be detected and adequately treated. Recently there has been increasing interest in the use of sputum-induction in young children with CF, as a simple, cost effective, well tolerated and frequently repeatable approach to sampling the lower airway, and the relative merits of this approach to bacterial sampling are discussed. Culture-independent microbiology has increased our understanding of the respiratory microbiota and has challenged the current paradigm of "single pathogen causes disease". Understanding how to diagnose infection using these new, highly sensitive technologies will be important. How we should best intervene to optimise, manipulate and prevent disruption of the respiratory microbiota is likely to greatly influence how we manage infection in the future.

Do combined upper airway cultures identify lower airway infections in children with chronic cough?

BACKGROUND

Obtaining lower airway specimens is important for guiding therapy in chronic lung infection but is difficult in young children unable to expectorate. While culture-based studies have assessed the diagnostic accuracy of nasopharyngeal or oropharyngeal specimens for identifying lower airway infection, none have used both together. We compared respiratory bacterial pathogens cultured from nasopharyngeal and oropharyngeal swabs with bronchoalveolar lavage (BAL) cultures as the "gold standard" to better inform the diagnosis of lower airway infection in children with chronic wet cough.

METHODS

Nasopharyngeal and oropharyngeal swabs and BAL fluid specimens were collected concurrently from consecutive children undergoing flexible bronchoscopy for chronic cough and cultured for bacterial pathogens.

RESULTS

In cultures from 309 children (median age, 2.3 years) with chronic endobronchial suppuration, all main pathogens detected (Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis) were more prevalent in nasopharyngeal than oropharyngeal swabs (37%, 34%, and 23% vs 21%, 6.2%, and 3.2%, respectively). Positive and negative predictive values for lower airway infection by any of these three pathogens were 63% (95% confidence interval [95% CI] 55, 70) and 85% (95% CI, 78, 91) for nasopharyngeal swabs, 65% (95% CI, 54, 75), and 66% (95% CI, 59, 72) for oropharyngeal swabs, and 61% (95% CI, 54,68), and 88% (95% CI, 81, 93) for both swabs, respectively.

CONCLUSIONS

Neither nasopharyngeal nor oropharyngeal swabs, alone or in combination, reliably predicted lower airway infection in children with chronic wet cough. Although upper airway specimens may be useful for bacterial carriage studies and monitoring antimicrobial resistance, their clinical utility in pediatric chronic lung disorders of endobronchial suppuration is limited.

Paediatric and adult bronchiectasis: Monitoring, cross-infection, role of multidisciplinary teams and self-management plans

Bronchiectasis is a chronic lung disease associated with structurally abnormal bronchi, clinically manifested by a persistent wet/productive cough, airway infections and recurrent exacerbations. Early identification and treatment of acute exacerbations is an integral part of monitoring and annual review, in both adults and children, to minimize further damage due to infection and inflammation. Common modalities used to monitor disease progression include clinical signs and symptoms, frequency of exacerbations and/or number of hospital admissions, lung function (forced expiratory volume in 1 s (FEV₁ )% predicted), imaging (radiological severity of disease) and sputum microbiology (chronic infection with Pseudomonas aeruginosa). There is good evidence that these monitoring tools can be used to accurately assess severity of disease and predict prognosis in terms of mortality and future hospitalization. Other tools that are currently used in research settings such as health-related quality of life (QoL) questionnaires, magnetic resonance imaging and lung clearance index can be burdensome and require additional expertise or resource, which limits their use in clinical practice. Studies have demonstrated that cross-infection, especially with P. aeruginosa between patients with bronchiectasis is possible but infrequent. This should not limit participation of patients in group activities such as pulmonary rehabilitation, and simple infection control measures should be carried out to limit the risk of cross-transmission. A multidisciplinary approach to care which includes respiratory physicians, chest physiotherapists, nurse specialists and other allied health professionals are vital in providing holistic care. Patient education and personalized self-management plans are also important despite limited evidence it improves QoL or frequency of exacerbations.

Pediatric pulmonology year in review 2017: Part 1

Pediatric Pulmonology publishes original research, case reports and review articles on topics related to a wide range of children's respiratory disorders. In this article (Part 1 of a series), we summarize the past year's publications in our major topic areas, as well as selected literature in these areas from other journals. In Part 1, we review selected articles on diagnostic testing/endoscopy, respiratory complications of neuromuscular disorders, and rare lung diseases.

Bronchiectasis in children: diagnosis and treatment

Bronchiectasis is conventionally defined as irreversible dilatation of the bronchial tree. Bronchiectasis unrelated to cystic fibrosis is an increasingly appreciated cause of chronic respiratory-related morbidity worldwide. Few randomised controlled trials provide high-level evidence for management strategies to treat the children affected by bronchiectasis. However, both decades-old and more recent studies using technological advances support the notion that prompt diagnosis and optimal management of paediatric bronchiectasis is particularly important in early childhood. Although considered to be of a non-reversible nature, mild bronchiectasis determined by radiography might be reversible at any age if treated early, and the lung function decline associated with disease progression could then be halted. Although some management strategies are extrapolated from cystic fibrosis or adult-based studies, or both, non-cystic fibrosis paediatric-specific data to help diagnose and manage these children still need to be generated. We present current knowledge and an updated definition of bronchiectasis, and review controversies relating to the management of children with bronchiectasis, including applying the concept of so-called treatable traits.

Cystic fibrosis year in review 2017

In this article, we highlight cystic fibrosis (CF) reports published in Pediatric Pulmonology during 2017. We also include articles from a variety of journals that are related or are of special interest to clinicians.

The clinical significance of oropharyngeal cultures in young children with cystic fibrosis

In children with cystic fibrosis (CF) the associations between oropharyngeal swabs (OPSs) for detection of Pseudomonas and lung disease have not been evaluated.OPS and bronchoalveolar lavage (BAL) samples were obtained annually in children with CF from 2005 to 2017. OPS test characteristics were calculated using BAL as "gold standard". Results were related to lung inflammation (BAL neutrophil elastase and interleukin-8), structural lung disease (chest computed tomography PRAGMA-CF (Perth-Rotterdam Annotated Grid Morphometric Analysis for CF) scores), respiratory exacerbations and future detection of Pseudomonas on BAL.From 181 patients, 690 paired OPS-BAL cultures were obtained. Prevalence of Pseudomonas in BAL was 7.4%. OPS sensitivity was 23.0% and specificity was 91.4%, reducing the post-test probability for a positive BAL following a negative OPS to 6.3%. Pseudomonas on OPS was not associated with lung inflammation or respiratory exacerbations, but was weakly associated with current PRAGMA-CF %Disease score (p=0.043). Pseudomonas on BAL was associated with positive neutrophil elastase (OR 4.17, 95% CI 2.04-8.53; p<0.001), increased interleukin-8 (p<0.001), increased all baseline PRAGMA computed tomography scores (p<0.001), progression of PRAGMA computed tomography scores (p<0.05) and increased risk of respiratory exacerbations (incidence rate ratio 2.11, 95% CI 1.15-3.87; p=0.017).In children with CF OPSs only marginally change the probability of detecting lower airway Pseudomonas and are not associated with lung disease indices nor exacerbations risk.

The CF-Sputum Induction Trial (CF-SpIT) to assess lower airway bacterial sampling in young children with cystic fibrosis: a prospective internally controlled interventional trial

Background

Pathogen surveillance is challenging but crucial in children with cystic fibrosis—who are often non-productive of sputum even if actively coughing—because infection and lung disease begin early in life. The role of sputum induction as a diagnostic tool for infection has not previously been systematically addressed in young children with cystic fibrosis. We aimed to assess the pathogen yield from sputum induction compared with that from cough swab and single-lobe, two-lobe, and six-lobe bronchoalveolar lavage.

Methods

This prospective internally controlled interventional trial was done at the Children's Hospital for Wales (Cardiff, UK) in children with cystic fibrosis aged between 6 months and 18 years. Samples from cough swab, sputum induction, and single-lobe, two-lobe, and six-lobe bronchoalveolar lavage were matched for within-patient comparisons. Primary outcomes were comparative pathogen yield between sputum induction and cough swab for stage 1, and between sputum induction, and single-lobe, two-lobe, and six-lobe bronchoalveolar lavage for stage 2. Data were analysed as per protocol. This study is registered with the UK Clinical Research Network (14615) and with the International Standard Randomised Controlled Trial Network Registry (12473810).

Findings

Between Jan 23, 2012, and July 4, 2017, 124 patients were prospectively recruited to the trial and had 200 sputum induction procedures for stage 1. 167 (84%) procedures were successful and the procedure was well tolerated. Of the 167 paired samples, 63 (38%) sputum-induction samples were pathogen positive compared with 24 (14%) cough swabs (p<0·0001; odds ratio [OR] 7·5; 95% CI 3·19–17·98). More pathogens were isolated from sputum induction than cough swab (79 [92%] of 86 vs 27 [31%] of 86; p<0·0001). For stage 2, 35 patients had a total of 41 paired sputum-induction and bronchoalveolar lavage procedures. Of the 41 paired samples, 28 (68%) were positive for at least one of the concurrent samples. 39 pathogens were isolated. Sputum induction identified 27 (69%) of the 39 pathogens, compared with 22 (56%; p=0·092; OR 3·3, 95% CI 0·91–12·11) on single-lobe, 28 (72%; p=1·0; OR 1·1, 95% CI 0·41–3·15) on two-lobe, and 33 (85%; p=0·21; OR 2·2, 95% CI 0·76–6·33) on six-lobe bronchoalveolar lavage.

Interpretation

Sputum induction is superior to cough swab for pathogen detection, is effective at sampling the lower airway, and is a credible surrogate for bronchoalveolar lavage in symptomatic children. A substantial number of bronchoscopies could be avoided if sputum induction is done first and pathogens are appropriately treated. Both sputum induction and six-lobe bronchoalveolar lavage provide independent, sizeable gains in pathogen detection compared with the current gold-standard two-lobe bronchoalveolar lavage. We propose that sputum induction and six-lobe bronchoalveolar lavage combined are used as standard of care for comprehensive lower airway pathogen detection in children with cystic fibrosis.

Funding

Health and Care Research Wales—Academic Health Science Collaboration and Wellcome Trust Institutional Strategic Support Fund.

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

Purpose: Different respiratory sampling methods exist to identify lower airway pathogens in patients with cystic fibrosis (CF), of which bronchoalveolar lavage (BAL), and expectorated sputum are considered the "gold standard." Because BAL cannot be repeated limitless, the diagnosis of lower respiratory tract infections in non-expectorating patients is challenging. Other sampling techniques are nasal swab, cough swab, and induced sputum. The purpose of this study (NCT02363764) was to compare concordance between the microbiological yield of nasal swab, cough swab, and expectorated sputum in expectorating patients; nasal swab, cough swab, and induced sputum in non-expectorating patients; nasal swab, cough swab, induced sputum, and BAL in patients requiring bronchoscopy ("BAL-group"); and to determine the clinical value of cough swab in non-expectorating patients with CF. Methods: Microbiological yield detected by these different sampling techniques was compared between and within 105 expectorating patients, 30 non-expectorating patients and BAL-group (n = 39) in a single CF clinic. Specificity, sensitivity, positive (PPV), and negative (NPV) predictive values were calculated. Results: Overall low sensitivity (6.3-58.0%) and wide-ranging predictive values (0.0-100.0%) indicated that nasal swab was not appropriate to detect lower airway pathogens [Pseudomonas aeruginosa (Pa), Staphylococcus aureus (Sa), and Haemophilus influenzae (Hi)] in all three patient groups. Microbiological yield, specificity, sensitivity, PPV, and NPV of cough swab and induced sputum were largely similar in non-expectorating patients and in BAL-group (except sensitivity (0.0%) of induced sputum for Hi in BAL-group). Calculations for Pa and Hi could not be performed for non-expectorating patients because of low prevalence (n = 2 and n = 3, respectively). In expectorating patients, concordance was found between cough swab and expectorated sputum, except for Hi (sensitivity of 40.0%). Conclusion: Our findings suggest that cough swab might be helpful in detecting the presence of some typical CF pathogens in the lower airways of clinically stable patients with CF. However, in symptomatic patients, who are unable to expectorate and who have a negative cough swab and induced sample, BAL should be performed as it currently remains the "gold standard."

The airway microbiota in early cystic fibrosis lung disease

Infection plays a critical role in the pathogenesis of cystic fibrosis (CF) lung disease. Over the past two decades, the application of molecular and extended culture-based techniques to microbial analysis has changed our understanding of the lungs in both health and disease. CF lung disease is a polymicrobial disorder, with obligate and facultative anaerobes recovered alongside traditional pathogens in varying proportions, with some differences observed to correlate with disease stage. While healthy lungs are not sterile, differences between the lower airway microbiota of individuals with CF and disease-controls are already apparent in childhood. Understanding the evolution of the CF airway microbiota, and its relationship with clinical treatments and outcome at each disease stage, will improve our understanding of the pathogenesis of CF lung disease and potentially inform clinical management. This review summarizes current knowledge of the early development of the respiratory microbiota in healthy children and then discusses what is known about the airway microbiota in individuals with CF, including how it evolves over time and where future research priorities lie.