Characterization of Distal Bronchial Microflora during Acute Exacerbation of Chronic Bronchitis: Use of the Protected Specimen Brush Technique in 54 Mechanically Ventilated Patients

Abstract

To obtain accurate information on distal bronchial microflora during acute exacerbation in patients with chronic bronchitis, we prospectively studied 54 such patients who had been receiving mechanical ventilation because of hypercapnic respiratory failure. Fiberoptic bronchoscopy using a protected specimen brush (PSB) was performed on each patient within the first 24 h after admission. Cultures of protected brush specimens demonstrated no growth in 27 patients (50%). With the exception of fever (38.2 +/- 0.8 versus 37.7 +/- 0.6 degrees C; p less than 0.05), the initial severity of the episode of exacerbation was similar in patients with and without infection. A total of 44 organisms were isolated in the 27 patients with positive cultures; the predominant pathogens were Hemophilus spp. and Streptococcus spp. (involved in 74% of cases), but other organisms were isolated in 12 of 27 patients. Mortality rates, duration of mechanical ventilation, and duration of hospitalization were not significantly different between patients with bronchial microflora treated with appropriate antimicrobial therapy (n = 27) and patients without bronchial microflora either receiving empirical antibiotic therapy (n = 18) or not (n = 9). These data suggest that distal bronchial infection due to the usual pathogens, as far as shown by protected specimen brush cultures, may not be the sole or even the predominant cause of acute exacerbation of chronic bronchitis in patients requiring mechanical ventilation.

Significance of the Microbiome in Chronic Obstructive Pulmonary Disease

“…The limitations of sputum culture include methodological issues regarding sputum processing, culture techniques, contamination of the upper airway, and colonization. Bronchoscopic studies have confirmed that PPM are identified in many patients with stable COPD and during AECOPDs (38)(39)(40)(41). Two bronchoscopic studies have related the identification of PPM in bronchoalveolar lavage with increased markers of predominantly neutrophilic inflammation (36,42).…”

Pathogen-directed Therapy in Acute Exacerbations of Chronic Obstructive Pulmonary Disease

“…Bronchoscopically collected samples have confirmed that potentially pathogenic microorganisms are identified in many patients with COPD at baseline and during AE-COPDs (74)(75)(76)(77)(78). A recent review pooled data from six published studies suggesting that there was a clear shift to organisms with a higher pathogenic potential (79).…”

Monografia Giovani FADOI: dalle evidenze alla pratica clinica

“…Studi broncoscopici hanno mostrato che almeno il 50 % dei pazienti presentano batteri nelle vie aeree distali durante la riacutizzazione della BPCO (192), ma una significativa proporzione di questi pazienti sono colonizzati dai batteri anche nelle fasi di stabilità della malattia. D'altra parte, ci sono dei dati che indicano un aumento della carica batterica durante la riacutizzazione della BPCO (193).…”