Pseudomonas aeruginosaisolates in severe chronic obstructive pulmonary disease: characterization and risk factors

Abstract

BackgroundPatients with severe chronic obstructive pulmonary disease (COPD) are at increased risk of infection by P. aeruginosa. The specific role of bronchiectasis in both infection and chronic colonization by this microorganism in COPD, however, remains ill defined.To evaluate the prevalence and risk factors for P. aeruginosa recovery from sputum in outpatients with severe COPD, characterizing P. aeruginosa isolates by pulsed-field gel electrophoresis (PFGE) and focusing on the influence of bronchiectasis on chronic colonization in these patients.MethodsA case-cohort study of 118 patients with severe COPD attended at a Respiratory Day Unit for an acute infectious exacerbation and followed up over one year. High-resolution CT scans were performed during stability for bronchiectasis assessment and sputum cultures were obtained during exacerbation and stability in all patients. P. aeruginosa isolates were genotyped by PFGE. Determinants of the recovery of P. aeruginosa in sputum and chronic colonization by this microorganism were assessed by multivariate analysis.ResultsP. aeruginosa was isolated from 41 of the 118 patients studied (34.7%). Five of these 41 patients (12.2%) with P. aeruginosa recovery fulfilled criteria for chronic colonization. In the multivariate analysis, the extent of bronchiectasis (OR 9.8, 95% CI: 1.7 to 54.8) and the number of antibiotic courses (OR 1.7, 95% CI: 1.1 to 2.5) were independently associated with an increased risk of P. aeruginosa isolation. Chronic colonization was unrelated to the presence of bronchiectasis (p=0.75). In patients with chronic colonization the isolates of P. aeruginosa retrieved corresponded to the same clones during the follow-up, and most of the multidrug resistant isolates (19/21) were harbored by these patients.ConclusionsThe main risk factors for P. aeruginosa isolation in severe COPD were the extent of bronchiectasis and exposure to antibiotics. Over 10% of these patients fulfilled criteria for chronic colonization by P. aeruginosa and showed clonal persistence, independently of the presence of bronchiectasis.

Bronchiectasis as a Comorbidity of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-analysis

“…A total of 14 studies met the inclusion criteria, including 5329 COPD patients, and1572 (29.5%) patients were comorbid with bronchiectasis. Association of the presence of bronchiectasis with COPD exacerbations (ECOPD) [9][10][11][12]18,19,20]was reported in seven studies, isolation of PPMs [9,10,12,21,22]and specifically of Pseudomonas aeruginosa (P. aeruginosa) [9,10,23,24]in five and four studies respectively, severe airflow obstruction [9,11,12,18,19,25,26] in seven studies, mortality in four studies [10,19,23,27], and higher levels of inflammatory cytokines in three studies [10,11,21]which were not enough to conduct a metaanalysis.…”

“…One study was conducted in the United States, 2 in the United Kingdom, 4 in Spain, 1 in France, 1 in Egypt, 1 in Azerbaijan, and 1 in Turkey. Follow-up varied from one year [24] to five years [27]. Most studies lacked adjustment for potential confounders.…”

“…Most studies lacked adjustment for potential confounders. In seven articles, bronchiectasis was graded by scoring systems proposed by Smith [21,24], Naidich [10,12] and Bhalla [11], and other systems [18,20] respectively. Selection of subjects was either from primary care, outpatient recruitment, or from hospitalization.…”

Clinical Characteristics of Patients With Chronic Obstructive Pulmonary Disease With Comorbid Bronchiectasis: A Systemic Review and Meta-analysis

“…After reviewing the abstracts and full texts, 12 manuscripts about bronchiectasis in patients with COPD were found. 1,4,6,[11][12][13][14][15][16][17]21,22 Of those, six studies met the inclusion criteria, which included patients with COPD and comorbid bronchiectasis (n=550) and patients with COPD and without comorbid bronchiectasis (n=331). 1,4,7,[11][12][13] The flow diagram of the database search is represented in Figure 1.…”

“…3,10 However, in previous studies, controversial results on clinical outcomes, such as lung function and exacerbations, have been reported with relatively small patient populations (44-118 patients). 1,4,7,9,10,[11][12][13][14][15][16][17] Hence, the present meta-analysis was aimed at summarizing the reports on the comorbidity of bronchiectasis and COPD and further clarifying the impact of bronchiectasis on patients with COPD.…”