Bacterial Distribution in the Lungs of Children with Protracted Bacterial Bronchitis

Abstract

ObjectivesFlexible bronchoscopy with bronchoalveolar lavage (FB-BAL) is increasingly used for the microbiological confirmation of protracted bacterial bronchitis (PBB) in children with a chronic wet cough. At our centre, when performing FB-BAL for microbiological diagnosis we sample 6 lobes (including lingula) as this is known to increase the rate of culture positive procedures in children with cystic fibrosis. We investigated if this is also the case in children with PBB.MethodsWe undertook a retrospective case note review of 50 children investigated for suspected PBB between May 2011 and November 2013.ResultsThe median (IQR) age at bronchoscopy was 2.9 (1.7–4.4) years and the median (IQR) duration of cough was 11 (8.0–14) months. Positive cultures were obtained from 41/50 (82%) and 16 (39%) of these patients isolated ≥2 organisms. The commonest organisms isolated were Haemophilus influenzae (25 patients), Moraxella catarrhalis (14 patients), Staphylococcus aureus (11 patients) and Streptococcus pneumoniae (8 patients). If only one lobe had been sampled (as per the European Respiratory Society guidance) 17 different organisms would have been missed in 15 patients, 8 of whom would have had no organism cultured at all. The FB-BAL culture results led to an antibiotic other than co-amoxiclav being prescribed in 17/41 (41%) patients.ConclusionsBacterial distribution in the lungs of children with PBB is heterogeneous and organisms may therefore be missed if only one lobe is sampled at FB-BAL. Positive FB-BAL results are useful in children with PBB and can influence treatment.

ERS statement on protracted bacterial bronchitis in children

“…The distribution of bacteria within the lungs is not uniform. One retrospective study reported that sampling from a single lobe would have missed 17 different organisms in 15 out of 50 patients, eight of whom would not have had any organisms cultured [50]. Nonetheless, it should be noted that this study used nonquantitative bacterial culture methods and failed to report bacterial densities between the various lobes.…”

“…pneumoniae isolates in BAL cultures from fully vaccinated children with PBB in the UK were vaccine-type serotypes [51]. Finally, polymicrobial infections involving multiple respiratory bacterial pathogens were identified in the lower airways of 30-50% of affected children [16,42,[50][51][52].…”

“…When assessing the bacteriology of PBB it is important to note that not all BAL studies are directly comparable with one another, as only some utilised quantitative bacterial culture to describe BAL findings [50,51]. The distribution of bacteria within the lungs is not uniform.…”

Flexible Bronchoscopy Findings in Patient with Protracted Bacterial Bronchitis

“…3 Çocuklardan balgam örneğinin alınmasındaki zorluklara bağlı uzamış bakteriyel bronşitin mikrobiyolojik olarak kanıtlanması zordur, bu nedenle de hastalığın tanı ve tedavisi gecikebilmektedir. 4 Hastalığın tanısının gecikmesi solunum yollarında yapısal hasara yol açmakta ve semptomların uzamasına neden olmaktadır. 5 Tanıda altın standart bronkoskopi ile bronkoalveolar lavaj örneği alın-masıdır.…”

Chronic wet cough in children and further exploration of protracted bacterial bronchitis

“…First, antibiotic exposure at the time of sampling may suppress colony counts to below the threshold to be classified as 'infection'; second, inadequate bronchoalveolar lavage technique with poor return or very localised sampling may miss the infected portion of the lung [86]; and third, sub-optimal sample handling e.g. a delay in processing, inadequate storage, plating etc may result in failure to culture an organism that may be present.…”