Detecting respiratory viruses in children with protracted bacterial bronchitis

The Respiratory Microbiome in Paediatric Chronic Wet Cough: What Is Known and Future Directions

Chronic wet cough for longer than 4 weeks is a hallmark of chronic suppurative lung diseases (CSLD), including protracted bacterial bronchitis (PBB), and bronchiectasis in children. Severe lower respiratory infection early in life is a major risk factor of PBB and paediatric bronchiectasis. In these conditions, failure to clear an underlying endobronchial infection is hypothesised to drive ongoing inflammation and progressive tissue damage that culminates in irreversible bronchiectasis. Historically, the microbiology of paediatric chronic wet cough has been defined by culture-based studies focused on the detection and eradication of specific bacterial pathogens. Various 'omics technologies now allow for a more nuanced investigation of respiratory pathobiology and are enabling development of endotype-based models of care. Recent years have seen substantial advances in defining respiratory endotypes among adults with CSLD; however, less is understood about diseases affecting children. In this review, we explore the current understanding of the airway microbiome among children with chronic wet cough related to the PBB-bronchiectasis diagnostic continuum. We explore concepts emerging from the gut-lung axis and multi-omic studies that are expected to influence PBB and bronchiectasis endotyping efforts. We also consider how our evolving understanding of the airway microbiome is translating to new approaches in chronic wet cough diagnostics and treatments.

Pediatric flexible bronchoscopy: A single-center report

INTRODUCTION

Pediatric flexible laryngotracheal bronchoscopy (FB) is an integral part of diagnostics and treatment at tertiary pediatric respiratory centers.

AIM

FBs performed between 2013 and 2018 at our Pediatric Allergy and Respiratory Medicine Unit of the Department of Women's and Children's Health at Padua University were examined in terms of the indications, findings, and adverse events.

MATERIALS AND METHODS

The electronic medical records of pediatric patients who underwent FB at least once between 1 January 2013 and 31 December 2018 were considered. Patients' clinical data, indications for FB, anatomical findings, information derived from bronchoalveolar lavage (BAL) and bronchial brushing, and possible adverse events were analyzed.

RESULTS

There were 447 pediatric FBs performed in 428 patients (aged from 1 month to 18 years) for diagnostic purposes (92.4%), to clear secretions (3.6%), or to monitor a known condition (4.0%). The main indications were recurrent lower respiratory tract infections (LRTI, 32.2%) and chronic wet cough (9.4%). Lower airway malacia was the most common abnormal finding in these two groups (36.1% and 28.6%, respectively). BAL bacterial culture was positive in 55 children (39.6%) with recurrent LRTI and in 25 (59.5%) with chronic wet cough, being Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis the microorganisms most commonly isolated. FB proved a safe procedure and was well tolerated.

CONCLUSIONS

Pediatric FB is an essential tool at our tertiary pediatric respiratory center. It helps establish the anatomical conditions underlying several chronic respiratory conditions and any correlated microbiological findings, with a significant impact on further patient management.

Etiology of Severe Pneumonia in Children in Alveolar Lavage Fluid Using a High-Throughput Gene Targeted Amplicon Sequencing Assay

Objective: To evaluate the diagnostic value of a high-throughput gene targeted amplicon sequencing (TAS) assay for detecting pathogenic microorganisms in alveolar lavage fluid (ALF) from children with severe community-acquired pneumonia (SCAP). Methods: A retrospective study was performed on 48 frozen ALF samples from 47 severe pneumonia cases admitted to Children's Hospital of Fudan University from January 1, 2019, to March 31, 2019. All samples were tested by a multiplex PCR (Multi-PCR) assay and a TAS assay. The results of the TAS panels were parallel compared with Multi-PCR and Conventional Tests (CT) including culture, direct fluorescent antibody method (DFA), and singleplex polymerase chain reaction (PCR). Results: The proportion of pathogens detection by CT was 81.2% (39/48). The 8 common respiratory viruses including respiratory syncytial virus (RSV), adenovirus (ADV), influenza A virus (FLUA), influenza B virus (FLUB), parainfluenza virus 1-3 (PIV1-3), and human Metapneumovirus (hMPV) were found in 31.2% (15/48) of the 48 samples by DFA. With the criteria of CT results used as "Golden Standard" for determing of TAS results, the proportion of pathogens detection by TAS was 70.8% (34/48). The difference of proportion of pathogens detection between TAS and CT was not statistically significant (p = 0.232). The sensitivity and specificity of TAS for pathogens detection based on CT were 87.1% (95% CI, 71.77-95.18%) and 100.0% (95% CI, 62.88-100%), the positive predictive value (PPV) and negative predictive value (NPV) were 100.0% (95% CI, 87.35-100%) and 64.2% (95% CI, 35.62-86.02%), respectively. While Multi-PCR results were used as "Golden Standard," the total pathogens detection rate of TAS was 83.3% (40/48), which had a significant difference with that of Multi-PCR (p = 0.003). The sensitivity and PPV of TAS compared with Multi-PCR were 83.3% (95% CI, 69.23-92.03%) and 100.0% (95% CI, 89.08-100%), respectively. High rates of co-infection were proved by CT, Multi-PCR, and TAS. Mycoplasma pneumoniae (MP) and ADV were the two most frequently detected pathogens in all three assays. Conclusion: Compared with the CT and Multi-PCR methods, this TAS assay had a good performance in detecting bacteriological and viral pathogens from ALF. More research is needed to establish interpretation criteria based on TAS reads or analysis platforms.

Outcomes of protracted bacterial bronchitis in children: A 5-year prospective cohort study

BACKGROUND AND OBJECTIVE

Long-term data on children with PBB has been identified as a research priority. We describe the 5-year outcomes for children with PBB to ascertain the presence of chronic respiratory disease (bronchiectasis, recurrent PBB and asthma) and identify the risk factors for these.

METHODS

Prospective cohort study was undertaken at the Queensland Children's Hospital, Brisbane, Australia, of 166 children with PBB and 28 controls (undergoing bronchoscopy for symptoms other than chronic wet cough). Monitoring was by monthly contact via research staff. Clinical review, spirometry and CT chest were performed as clinically indicated.

RESULTS

A total of 194 children were included in the analysis. Median duration of follow-up was 59 months (IQR: 50-71 months) post-index PBB episode, 67.5% had ongoing symptoms and 9.6% had bronchiectasis. Significant predictors of bronchiectasis were recurrent PBB in year 1 of follow-up (OR_adj = 9.6, 95% CI: 1.8-50.1) and the presence of Haemophilus influenzae in the BAL (OR_adj = 5.1, 95% CI: 1.4-19.1). Clinician-diagnosed asthma at final follow-up was present in 27.1% of children with PBB. A significant BDR (FEV₁ improvement >12%) was obtained in 63.5% of the children who underwent reversibility testing. Positive allergen-specific IgE (OR_adj = 14.8, 95% CI: 2.2-100.8) at baseline and bronchomalacia (OR_adj = 5.9, 95% CI: 1.2-29.7) were significant predictors of asthma diagnosis. Spirometry parameters were in the normal range.

CONCLUSION

As a significant proportion of children with PBB have ongoing symptoms at 5 years, and outcomes include bronchiectasis and asthma, they should be carefully followed up clinically. Defining biomarkers, endotypes and mechanistic studies elucidating the different outcomes are now required.

Update on protracted bacterial bronchitis in children

BACKGROUND

Chronic cough is a common symptom in children and protracted bacterial bronchitis (PBB) is one of the causes of chronic cough. However, the understanding of this disease remains limited. The present study aims to update PBB in children.

METHODS

The clinical data of children with PBB from 2014 to 2018 were retrospectively analyzed, and PBB clinical features of published studies were summarized. Electronic databases were searched in May 2019. Clinical studies were included in the present study. Reviews were undertaken in duplicate.

RESULTS

Totally 712 cases were analyzed in this study, including 52 cases in our center and 660 cases from 14 studies. In the 52 cases, 88.5% of patients with PBB were less than 6 years old and all of them complained of wet cough. Three cases were confirmed with laryngomalacia, and microbiologically-based-PBB were identified in 13 cases (9 Streptococcus pneumonia, 3 Staphylococcus aureus, and 1 Pseudomonas aeruginosa). Twenty cases were completely remitted after treatment. In the 14 studies, the patients with PBB were typically younger than 3 years old, accompanying wheezing and airway malacia. Co-infection was common in most western cases, Streptococcus pneumonia, Haemophilus influenza and Moraxella catarrhalis were the top three pathogens. Symptoms were improved in most patients, whereas some cases with comorbidities required prolonged antibiotics treatment.

CONCLUSIONS

PBB is common in male infants with chronic wet cough and accompanied by wheezing and airway deformities. Most cases are clinically diagnosed PBB in China and microbiologically-based-PBB is common in western countries. Co-infection could be found, Streptococcus pneumoniae and Haemophilus influenza were the most frequent etiology in China and western countries, respectively. Patients with comorbidities may need extended antibiotics treatment for more than 2 weeks.

When the Cough Does Not Improve: A Review on Protracted Bacterial Bronchitis in Children

Chronic cough is defined as a daily cough that persists longer than 4 weeks. Protracted bacterial bronchitis (PBB) is a common cause of chronic wet cough in preschool children with no symptoms or signs of other specific causes, and resolution usually follows a 2-week course of an appropriate oral antibiotic. The diagnosis is mainly clinical; generally, no instrumental examinations are necessary. The most common bacteria found in the bronchoalveolar lavage (BAL) of subjects with PBB include Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis. Nowadays, there is no certain evidence of the role of viruses in PBB pathogenesis even though different types of viruses have been detected in BAL from children with PBB. Airway malacia is commonly found in children with PBB; conversely, there is no correlation with any type of immunodeficiency. Amoxicillin-clavulanate acid is the most commonly used antibiotic, as first-line, prolonged therapy (longer than 2 weeks) is sometimes required to cough resolution. When the wet cough does not improve despite prolonged antibiotic treatment, an underlying disease should be considered. Moreover, there are several hypotheses of a link between PBB and bronchiectasis, as recent evidences show that recurrent PBB (>3 episodes/years) and the presence of H. influenzae infection in the lower airways seem to be significant risk factors to develop bronchiectasis. This underlines the importance of a close follow-up among children with PBB and the need to consider chest computerized tomography (CT) in patients with risk factors for bronchiectasis. In this brief review, we summarize the main clinical and pathogenetic findings of PBB, a disease that may be related to a relevant morbidity and decreased quality of life during the pediatric age.