High levels of inherent variability in microbiological assessment of bronchoalveolar lavage samples from children with persistent bacterial bronchitis and healthy controls

Abstract

Bronchoalveolar lavage (BAL) is widely regarded as providing "gold standard" samples for infective lower respiratory tract disease. Current approaches have been adopted empirically without robust assessment and hence carry many assumptions that have not been tested. Many of these uncertainties were highlighted in the ATS pediatric bronchoscopy guidelines. This study was designed to explore some of these issues. BAL was undertaken via an endotracheal tube in 13 subjects aged less than 6 years with persistent bacterial bronchitis and five healthy controls. Aliquots of the same pooled BAL sample were sent to two accredited laboratories. one producing semiquantitative results and the other quantitative results. For five patients potentially pathogenic bacteria were grown by one laboratory but not the other, while in three more there were discrepancies in the organisms reported. Despite being symptomatic and off antibiotics, only 3 of 13 patients were reported to have a pathogen at a density of more than 1 × 10 4 colony forming unit. There was at best a poor correlation between semiquantitative and quantitative data. Potential pathogens were cultured in two of five control samples. The results suggest that the results from conventional microbiological assessment of BAL samples can be highly variable and that the proposal that a discrete cutoff is of value in patients with chronic endobronchial infection is probably invalid.

We should not underestimate the role of biofilms in persistent (chronic) bronchitis

“…In a 2020 study involving young patients with persistent bacterial bronchitis from whom aliquots of the same bronchoalveolar lavage sample were sent to two accredited laboratories, the two laboratories generated very different results for the majority of samples. 3 This finding was replicated when aliquots from the same sample were analysed by the same laboratory (Everard M L, unpublished). Third, biofilms arewith the exception of those formed by Pseudomonas-believed to be attached to the endobronchial surface, a feature that limits disruption and dispersion by physical forces.…”

Exploring a case-based guided training model for standardized education of clinical pharmacists addressing national talent shortages

“…Despite multiple negative sputum smear and culture results and ineffective empirical treatments with various antimicrobial agents, the primary concern now revolves around obtaining valuable bacterial culture results. Fiberoptic bronchoscopy alveolar lavage, as an innovative sampling technique, presents increased opportunities for pathogen retrieval with a lower probability of contamination, establishing itself as a reliable method for diagnosing pneumonia pathogens [3] . It is recommended that the patient undergo fiberoptic bronchoscopy alveolar lavage concurrently with relevant cultures for a more targeted and accurate diagnosis.…”

Bronchoalveolar lavage in children: Still the gold standard

“…These studies have been conducted in multiple centers, over many years, and included many children. While the findings of Craven et al 1 highlight there can be inconsistencies in results, this potentially speaks to the methods used by the laboratories involved in handing the small number of samples. When these findings are compared to the large amount of evidence already generated, they should prompt evaluation of local practices and not just a reconsideration of whether BAL is the gold standard method of sampling the lower airway of children with suppurative lung disease.…”

“…In summary, there are significant issues that limit the value of the key findings of the study by Craven et al 1 A large amount of published data in PBB and cystic fibrosis support the use of BAL as a biological specimen associated with important clinical outcomes. These studies have been conducted in multiple centers, over many years, and included many children.…”

“…Hare et al 4 analyzed BAL samples from 655 children collected and analyzed at two different sites compared with 18 samples in the study of Craven et al 1 They compared bacterial pathogen load (control, negative, 10 2 colony forming units per ml (CFU/ml), 10 3 CFU/ml, 10 4 CFU/ml, 10 5 CFU/ml) and inflammatory markers to determine an appropriate definition for infection. They found that a bacterial pathogen load of ≥10 4 CFU/ml was associated with increased markers of inflammation and hence an appropriate threshold for defining infection.…”