title: Relationship between the GOLD combined COPD assessment staging system and bacterial isolation.
abstract: BACKGROUND
  Acute exacerbations, which are a significant cause of mortality and morbidity, adversely affect chronic obstructive pulmonary disease (COPD) prognosis by accelerating loss of lung function. It is important to know the microorganisms that commonly cause exacerbations in the patient groups classified according to clinical and functional characteristics for fast and accurate treatment of acute exacerbations.
  
  
  OBJECTIVE
  The last Global Initiative for Chronic Obstructive Lung Disease (GOLD) publication recommended a new staging system containing obstruction degree, frequency of exacerbations, and quality of life questionnaires. This study is designed to analyze the relationship between the bacteria isolated in acute exacerbations and new GOLD stages.
  
  
  METHODS
  Potentially pathogenic bacteria (PPB) isolation with culture and polymerase chain reaction methods were obtained from 114 acute exacerbation COPD patients, classified into A, B, C, and D groups by analyzing the forced expiratory volume in 1 second (FEV1) value, COPD Assessment Test (CAT) score, and exacerbation frequency according to the new GOLD staging system.
  
  
  RESULTS
  There was a significant correlation between exacerbation frequency and PPB isolation (P=0.002). There was no relationship between GOLD stage, FEV1, and CAT score with PPB isolation. The isolated bacteria diversity and mixed infection frequency were higher in the GOLD stage D group. Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii were isolated only from D group patients.
  
  
  CONCLUSIONS
  Bacterial infection may cause an acute exacerbation equally in each stage for COPD. The difference in bacterial etiology is more related to exacerbation frequency than FEV1 and CAT scores for an acute exacerbation. Determining exacerbation frequency is significant for treatment success in empirical antibiotic selection.
authors.affiliation: Department of Respiratory Medicine, Sakarya University, Sakarya, Turkey.
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Aydemir
authors.affiliation: Department of Microbiology, Sakarya University, Sakarya, Turkey.
authors.forename: Özlem
authors.initials: Ö
authors.lastname: Aydemir
authors.affiliation: Department of Microbiology, Konya Numune Hospital, Konya, Turkey.
authors.forename: Fatma
authors.initials: F
authors.lastname: Kalem
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D015373:Bacterial Typing Techniques / Q000379:methods; D018450:Disease Progression; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000382:microbiology* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D060885:Multiplex Polymerase Chain Reaction; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000382:microbiology / Q000503:physiopathology; D011788:Quality of Life; D012141:Respiratory Tract Infections / Q000175:diagnosis* / Q000382:microbiology / Q000503:physiopathology; D012720:Severity of Illness Index; D013183:Sputum / Q000382:microbiology; D011795:Surveys and Questionnaires
keywords: GOLD; acute exacerbation; bacterial etiology; chronic obstructive pulmonary disease; polymerase chain reaction