Sputum color as a marker of acute bacterial exacerbations of chronic obstructive pulmonary disease

Luigi Allegra, Francesco Blasi, PierLuigi Diano, Roberto Cosentini, Paolo Tarsia, Marco Confalonieri, Katerina Dimakou, Vincenzo Valenti

Research output: Contribution to journalArticlepeer-review


We analyzed 795 sputa from 315 patients (233 males, mean age 69.3±8.8 years, mean number of exacerbations 2.52/patient) with acute exacerbations of moderate-to-severe chronic obstructive pulmonary disease (COPD) (mean steady-state FEV 1 42.5±7.8% of predicted). 581/795 sputa were considered adequate. Sputum was analyzed by a quali-quantitative colorimetric scale allowing both color distinction and color degree of intensity. Quantitative culture was then performed (threshold: >10 6 CFU/mL). Samples were distinguished in mucoid (145) and purulent (436) sputa. Absence of bacterial growth was observed in 22% and 5% of mucoid and purulent sputa, respectively. Among mucoid sputa, Gram positive bacterial growth occurred more commonly compared to Gram negative and Pseudomonas aeruginosa/Enterobacteriaceae (56%, 24%, 20%, respectively). In purulent sputa, Gram positives were found in 38% of cases, Gram negatives in 38%, and P. aeruginosa/Enterobacteriaceae in 24%. We evaluated whether functional impairment (FEV 1) orientates as to the infectious etiology of exacerbations. Significant differences were observed in the distribution of pathogens. Gram negative and P. aeruginosa/ Enterobacteriaceae were isolated more frequently in the sputum when FEV 1 was

Original languageEnglish
Pages (from-to)742-747
Number of pages6
JournalRespiratory Medicine
Issue number6
Publication statusPublished - Jun 2005


  • COPD exacerbations
  • Lung function
  • Sputum purulence

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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