Duration of initial antibiotic course is associated with recurrent relapse in protracted bacterial bronchitis

Time to re-set our thinking about airways disease: lessons from history, the resurgence of chronic bronchitis / PBB and modern concepts in microbiology

In contrast to significant declines in deaths due to lung cancer and cardiac disease in Westernised countries, the mortality due to 'chronic obstructive pulmonary disease' (COPD) has minimally changed in recent decades while 'the incidence of bronchiectasis' is on the rise. The current focus on producing guidelines for these two airway 'diseases' has hindered progress in both treatment and prevention. The elephant in the room is that neither COPD nor bronchiectasis is a disease but rather a consequence of progressive untreated airway inflammation. To make this case, it is important to review the evolution of our understanding of airway disease and how a pathological appearance (bronchiectasis) and an arbitrary physiological marker of impaired airways (COPD) came to be labelled as 'diseases'. Valuable insights into the natural history of airway disease can be obtained from the pre-antibiotic era. The dramatic impacts of antibiotics on the prevalence of significant airway disease, especially in childhood and early adult life, have largely been forgotten and will be revisited as will the misinterpretation of trials undertaken in those with chronic (bacterial) bronchitis. In the past decades, paediatricians have observed a progressive increase in what is termed 'persistent bacterial bronchitis' (PBB). This condition shares all the same characteristics as 'chronic bronchitis', which is prevalent in young children during the pre-antibiotic era. Additionally, the radiological appearance of bronchiectasis is once again becoming more common in children and, more recently, in adults. Adult physicians remain sceptical about the existence of PBB; however, in one study aimed at assessing the efficacy of antibiotics in adults with persistent symptoms, researchers discovered that the majority of patients exhibiting symptoms of PBB were already on long-term macrolides. In recent decades, there has been a growing recognition of the importance of the respiratory microbiome and an understanding of the ability of bacteria to persist in potentially hostile environments through strategies such as biofilms, intracellular communities, and persister bacteria. This is a challenging field that will likely require new approaches to diagnosis and treatment; however, it needs to be embraced if real progress is to be made.

Cough in Protracted Bacterial Bronchitis and Bronchiectasis

Chronic cough in children is a common condition for which patients seek medical attention, and there are many etiologies. Of the various causes of chronic cough in children, protracted bacterial bronchitis (PBB) is one of the commonest causes, and bronchiectasis is one of the most serious. Together, they lie on different ends of the spectrum of chronic wet cough in children. Cough is often the only symptom present in children with PBB and bronchiectasis. This review highlights the role of cough as a marker for the presence of these conditions, as well as an outcome endpoint for treatment and research.

Clinical characteristics of protracted bacterial bronchitis in adults

There are few data regarding adult protracted bacterial bronchitis (PBB). This study aimed to delineate the clinical features of PBB and evaluate their potential diagnostic value in adults. We recruited 55 adult patients with PBB and selected randomly 220 patients with non-PBB as control. A diagnosis of PBB was considered if patients had a cough lasting ≥3 weeks, no abnormalities of chest computed tomography, positive bacterial culture in sputum and/or response well to oral moxifloxacin for 1-4 weeks. The clinical manifestations and laboratory investigations were compared between PBB patients and non-PBB patients. Of the 55 patients with PBB, approximately three-fifths (34, 61.8%) were females with a median age of 46.0 years, which were similar to that of patients with non-PBB. We observed a shorter cough duration in PBB than non-PBB (median 3.0 versus 24.0 months, p < 0.001). Compared to non-PBB patients, PBB patients had higher incidences of productive cough, yellow phlegm and a sensation of mucus in the throat (SMIT) (all p < 0.001). Sputum neutrophils and lymphocytes were markedly elevated in PBB patients than non-PBB patients (both p = 0.004). Bacterial pathogens were detected in eight (28.6%) of 28 cases with PBB. The multivariate analyses showed yellow phlegm, productive cough, SMIT, increased sputum lymphocytes (≥2.3%) and cough duration ≤8.5 months with moderate sensitivity (50.9-81.8%) and moderate-high specificity (60.5-94.4%) for determining PBB. In summary, adults with PBB are characterized by productive cough, yellow phlegm, SMIT and neutrophilic airway inflammation. These cough features and increased sputum lymphocytes may be useful to indicate PBB.

Type-1 Laryngeal Cleft and Pathogenic Bacterial Growth in the Lower Airway in Children

OBJECTIVES/HYPOTHESIS

The purpose of this study is to evaluate the association between type-1 laryngeal clefts and pathogenic bacterial growth in the lower airway in children.

STUDY DESIGN

Retrospective chart review.

METHODS

A retrospective chart review was conducted for all children who underwent direct laryngoscopy, flexible bronchoscopy with bronchoalveolar lavage (BAL), and esophagogastroduodenoscopy, under a single anesthetic event from 2015 until 2018 at an academic tertiary referral center. Type-1 laryngeal clefts were diagnosed as an interarytenoid depth at or below the level of the vocal folds, on direct laryngoscopy, via palpation by a fellowship-trained pediatric otolaryngologist. Pathogenic bacterial growth in the lower airway was defined as presence of BAL culture growth of nonrespiratory flora.

RESULTS

A total of 217 patients were identified. Type-1 laryngeal cleft was significantly associated with chronic cough (P = .0016) and cough with feeds (P < .0001). However, an abnormal video fluoroscopic swallow study was not found to be significantly associated with type-1 laryngeal cleft (P = .92) or pathogenic bacterial growth in the lower airway (P = 0.19). Overall, 122 (56%) patients were diagnosed with type-1 laryngeal cleft, 75 (35%) had pathogenic bacterial growth in the lower airway and 50 (23%) had both type-1 laryngeal cleft and pathogenic bacterial growth in the lower airway. Type-1 laryngeal cleft was significantly associated with pathogenic bacterial growth in the lower airway on both univariate analysis (P = .0307) and multivariate analysis (P = .0298, odds ratio 1.922, 95% confidence interval 1.066-3.467).

CONCLUSION

Children with type-1 laryngeal clefts are at higher risk of having pathogenic bacterial growth in the lower airway.

LEVEL OF EVIDENCE

4 Laryngoscope, 2022.

Is secondary tracheomalacia associated with airway inflammation and infection?

BACKGROUND

Recurrent lower respiratory tract infections are among the most prevalent symptoms in secondary tracheomalacia due to mediastinal vascular anomalies (MVAs). It is not known whether this condition could result in persistent lower respiratory tract inflammation and subclinical infection.

METHODS

A retrospective study was performed on records of children with tracheomalacia due to MVAs and recurrent respiratory infections who underwent computed tomography scan, bronchoscopy, and bronchoalveolar lavage (BAL) as part of their clinical evaluation.

RESULTS

Thirty-one children were included in the study: 21 with aberrant innominate artery, four with right aortic arch, one with double aortic arch, and five with aberrant innominate artery associated with right aortic arch. Cytological evaluation of bronchoalveolar lavage fluid showed increased neutrophil percentages and normal lymphocyte and eosinophil proportions. Microorganism growth was detected in 13 BAL samples, with a bacterial load ≥10⁴ colony-forming units/mL in eight (25.8%) of them. Most isolates were positive for Haemophilus influenzae. Bronchiectasis was detected in four children, all with BAL culture positive for H. influenzae. Four patients underwent MVA surgical correction and 27 conservative management, i.e., respiratory physiotherapy in all and high-dose amoxicillin/clavulanic acid (40 mg/kg/day) for 2-4 weeks in those with significant bacterial growth. There was an excellent outcome in most of them.

CONCLUSIONS

Neutrophilic alveolitis is detectable in secondary tracheomalacia but is associated with a clinically significant bacterial load only in a quarter of the patients. Caution should be used regarding inappropriate antibiotic prescriptions to avoid the emergence of resistance, whilst airway clearance maneuvers and infection preventive measures should be promoted.

Duration of amoxicillin-clavulanate for protracted bacterial bronchitis in children (DACS): a multi-centre, double blind, randomised controlled trial

BACKGROUND

Protracted bacterial bronchitis (PBB) is a leading cause of chronic wet cough in children. The current standard treatment in European and American guidelines is 2 weeks of antibiotics, but the optimal duration of therapy is unknown. We describe the first randomised controlled trial to assess the duration of antibiotic treatment in children with chronic wet cough and suspected PBB. We hypothesise that 4 weeks of amoxicillin-clavulanate is superior to 2 weeks for improving clinical outcomes.

METHODS

Our parallel, double-blind, placebo-controlled, randomised controlled trial was completed in four Australian hospitals. Children aged 2 months to 19 years with chronic (>4 weeks duration) wet cough, and suspected PBB were randomly assigned (1:1) using permuted block randomisation (stratified by age and site) to 4 weeks of amoxicillin-clavulanate (25-35 mg/kg twice daily oral suspension; 4-week group) or 2 weeks of amoxicillin-clavulanate followed by 2 weeks of placebo (2-week group). The children, caregivers, all the study coordinators, and investigators were masked to treatment assignment until data analysis was completed. The primary outcome was clinical cure (cough resolution) by day 28. Secondary outcomes were recurrence of PBB at 6 months, time to next exacerbation, change in Parent-proxy Cough-Specific Quality-of-Life (PC-QoL) score from baseline to day 28 and from day 28 to 7 months, adverse events, nasal swab bacteriology, and antimicrobial resistance. Analyses followed the intention-to-treat principle. This trial is complete and registered with Australian/New Zealand Registry, ACTRN12616001725459.

FINDINGS

Between March 8, 2017, and Sept 30, 2019, 106 children were randomly assigned (52 in the 4-week group, median age 2·2 years [IQR 1·3-4·1]; 54 in the 2-week group, median age 1·7 years [1·2-3·8]) with 90 children completing the 4-week treatment. By day 28, the primary endpoint of clinical cure in the 4-week group (32 [62%] of 52 patients) was not significantly different to the 2-week group (38 [70%] of 54 patients; adjusted relative risk 0·87 [95% CI 0·60 to 1·28]; p=0·49). Time to next wet cough exacerbation was significantly longer in the 4-week group than the 2-week group (median 150 days [IQR 38-181] vs 36 days [15-181]; adjusted hazard ratio 0·47 [0·25 to 0·90]; p=0·02). The rate of recurrence of PBB at 6 months was 17 (53%) of 32 patients in the 4-week group vs 28 (74%) of 38 patients in the 2-week group, but the difference between the groups was not significant (adjusted odds ratio 0·39 [0·14 to 1·04]; p=0·07). PC-QoL significantly improved from baseline to day 28 in both groups, but there was no significant difference between them (mean difference in change -0·2 [95% CI -1·0 to 0·6]; p=0·64). From day 28 to 7 months, median PC-QoL remained stable in both groups with no difference in change between them. Data on respiratory pathogens and antimicrobial resistance (paired swabs available for 48 children) were similar between groups. Adverse events occurred in 13 (25%) children in the 2-week group and ten (19%) in the 4-week group (p=0·57).

INTERPRETATION

A 4-week course of amoxicillin-clavulanate for treating children with chronic wet cough and suspected PBB confers little advantage compared with a 2-week course in achieving clinical cure by 28 days. However, as a 4-week duration led to a longer cough-free period, identifying children who would benefit from a longer antibiotic course is a priority.

FUNDING

Queensland Children's Hospital Foundation.

Diagnosis and management of protracted bacterial bronchitis: a survey of Chinese pediatricians

BACKGROUND

Protracted bacterial bronchitis (PBB) is a common cause of chronic wet cough in children. However, it is often misdiagnosed and inappropriately treated in clinical practices. This study aims to investigate the current diagnosis and management of PBB among Chinese pediatricians.

METHODS

An electronic questionnaire designed to assess the diagnosis and management of PBB was sent to pediatricians in China.

RESULTS

A total of 1,022 pediatricians completed the questionnaire. Most (68.8%) of the pediatricians diagnosed PBB in compliance with the guidelines, 44.3% and 24.5% of them followed microbiology-based and clinical-based diagnosis criteria, respectively. Only 40.4% of the pediatricians chose amoxicillin-clavulanate as the first-line antibiotic for PBB treatment, 23.7% and 23.5% of them chose third-generation cephalosporins and macrolides, respectively. The majority of pediatricians (75.4%) reported 2-4 weeks of antibiotics course, 19.3% of them prescribed a shorter course and 5% of them selected a longer course. Only 26.3% of the pediatricians performed combined investigations of chest high-resolution computed tomography scan (c-HRCT), bronchoscopy, and immunological tests for recurrences of PBB. Compared with general pediatricians (GP), pediatric pulmonologists (PP) preferred microbiology-based diagnosis criteria, prescribed more amoxicillin-clavulanate, and performed more investigations for recurrent patients (P<0.05).

CONCLUSIONS

The majority of Chinese pediatricians diagnosed PBB in compliance with guidelines. However, the reasonable antibiotics applications and the investigations for recurrent PBB need to be improved.

ERS International Congress, Madrid, 2019: highlights from the Paediatric Assembly

In this article, the Group Chairs and the Early Career Members of the Paediatric Assembly of the European Respiratory Society (ERS) highlight some of the most interesting findings in the field of paediatrics presented at the 2019 ERS International Congress, which was held in Madrid, Spain. The main findings from each group are summarised at the end of each chapter.

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.