title: Is the improvement of CF patients, hospitalized for pulmonary exacerbation, correlated to a decrease in bacterial load?
abstract: BACKGROUND
  Cystic Fibrosis (CF) patients are vulnerable to airway colonization with Pseudomonas aeruginosa. In case eradication fails after antibiotic treatment, patients become chronically colonized with P. aeruginosa, with recurrent pulmonary exacerbation, for which patients typically are hospitalized for 2 weeks and receive intravenous antibiotic treatment. Normally, improvement of the patients' health is established.
  
  
  OBJECTIVE
  Determination of the correspondence between patient improvement and changes of the P. aeruginosa and total bacterial load in the sputum.
  
  
  METHODS
  Eighteen CF patients with exacerbation were included for a total of 27 hospitalization episodes. At day 1, 8 and 15, inflammation and lung function parameters were determined, together with the P. aeruginosa load in the sputum using culture, quantitative PCR (qPCR) and propidium monoazide qPCR.
  
  
  RESULTS
  Patients improved during hospitalization (decrease in levels of C-reactive protein, white blood cell counts and erythrocyte sedimentation rate, increase of FEV1), reaching normal values already after one week. Also the P. aeruginosa load and the total bacterial load decreased during the first week of antibiotic treatment (p<0.05), except for patients with a low lung function (FEV1≤39.4%), for whom no significant decrease of P. aeruginosa was established. Comparison of culture-based and propidium monoazide qPCR-based quantification of P. aeruginosa showed that at the end of the treatment on average 62% of the P. aeruginosa cells are not cultivable, indicating that many cells are alive but dormant, or dead but still structurally intact.
  
  
  CONCLUSIONS
  Improvement of the clinical status is accompanied with a decrease of the P. aeruginosa load, whereby both occur mainly during the first week of antibiotic treatment. However, for patients with a low lung function, no decrease of the P. aeruginosa load is observed. Comparison of detection techniques shows that a large amount of noncultivable or dead bacteria are present in the samples.
authors: Laboratory Bacteriology Research (LBR), Faculty of Medicine & Health Sciences, Universiteit Gent, Ghent, Belgium.
authors: Pieter
authors: P
authors: Deschaght
authors: Petra
authors: P
authors: Schelstraete
authors: Leen
authors: L
authors: Van Simaey
authors: Marleen
authors: M
authors: Vanderkercken
authors: Ann
authors: A
authors: Raman
authors: Linda
authors: L
authors: Mahieu
authors: Sabine
authors: S
authors: Van Daele
authors: Frans
authors: F
authors: De Baets
authors: Mario
authors: M
authors: Vaneechoutte
mesh_terms: D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D058491:Bacterial Load; D003550:Cystic Fibrosis / Q000150:complications* / Q000503:physiopathology*; D005260:Female; D006760:Hospitalization; D006801:Humans; D008297:Male; D017063:Outcome Assessment, Health Care; D018410:Pneumonia, Bacterial / Q000188:drug therapy / Q000382:microbiology* / Q000503:physiopathology*; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000382:microbiology / Q000503:physiopathology; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000302:isolation & purification; D013183:Sputum / Q000382:microbiology; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents