title: Differences in Bordetella pertussis DNA load according to clinical and epidemiological characteristics of patients with whooping cough.
abstract: OBJECTIVE
  To identify associations between nasopharyngeal Bordetella pertussis DNA load and clinical and epidemiological characteristics and evaluate DNA load prognostic value in pertussis severity.
  
  
  METHODS
  Prospective observational multi-centre study including nasopharyngeal samples positive to pertussis DNA by real-time PCR collected from children and adult patients in more than 200 health centres of Catalonia (Spain) during 2012-2013.
  
  
  RESULTS
  B. pertussis load was inversely correlated with age (rho = -0.32, p < 0.001), time to diagnosis (rho = -0.33, p < 0.001) and number of symptoms (rho = 0.13, p = 0.002). Median bacterial load was significantly higher in inpatients versus outpatients (4.91 vs. 2.55 log10 CFU/mL, p < 0.001), patients with complications versus those without (6.05 vs. 2.82 log10 CFU/mL, p < 0.001), disease incidence in summer and autumn versus spring and winter (3.50 vs. 2.21 log10 CFU/mL, p = 0.002), and unvaccinated-partially vaccinated patients versus vaccinated (4.20 vs. 2.76 log10 CFU/mL, p = 0.004). A logistic regression model including bacterial load and other candidate prognostic factors showed good prediction for hospital care (AUC = 0.94) although only age and unvaccinated status were found to be prognostic factors.
  
  
  CONCLUSIONS
  We observed strong positive associations of nasopharyngeal bacterial load with severity outcomes of hospitalisation and occurrence of complications. Bacterial load and other independent variables contributed to an accurate prognostic model for hospitalisation.
authors: Molecular Microbiology Department, University Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, 08950, Spain; CIBER of Epidemiology and Public Health (CIBERESP), Instituto de Salud Carlos III, Madrid, 28029, Spain.
authors: Pedro
authors: P
authors: Brotons
authors: Molecular Microbiology Department, University Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, 08950, Spain.
authors: Hector D
authors: HD
authors: de Paz
authors: CIBER of Epidemiology and Public Health (CIBERESP), Instituto de Salud Carlos III, Madrid, 28029, Spain.
authors: Diana
authors: D
authors: Toledo
authors: Molecular Microbiology Department, University Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, 08950, Spain.
authors: Marta
authors: M
authors: Villanova
authors: CIBER of Epidemiology and Public Health (CIBERESP), Instituto de Salud Carlos III, Madrid, 28029, Spain; Public Health Agency of Catalonia, Barcelona, 08005, Spain.
authors: Pedro
authors: P
authors: Plans
authors: CIBER of Epidemiology and Public Health (CIBERESP), Instituto de Salud Carlos III, Madrid, 28029, Spain; Pediatric Intensive Care Unit, Molecular Microbiology Department, University Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, 08950, Spain.
authors: Iolanda
authors: I
authors: Jordan
authors: CIBER of Epidemiology and Public Health (CIBERESP), Instituto de Salud Carlos III, Madrid, 28029, Spain; Department of Public Health, University of Barcelona, Barcelona, 08005, Spain.
authors: Angela
authors: A
authors: Dominguez
authors: Public Health Agency of Catalonia, Barcelona, 08005, Spain.
authors: Mireia
authors: M
authors: Jane
authors: CIBER of Epidemiology and Public Health (CIBERESP), Instituto de Salud Carlos III, Madrid, 28029, Spain; Public Health Agency of Catalonia, Barcelona, 08005, Spain.
authors: Pere
authors: P
authors: Godoy
authors: Molecular Microbiology Department, University Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, 08950, Spain; CIBER of Epidemiology and Public Health (CIBERESP), Instituto de Salud Carlos III, Madrid, 28029, Spain. Electronic address: cma@hsjdbcn.org.
authors: Carmen
authors: C
authors: Muñoz-Almagro
mesh_terms: D000293:Adolescent; D058491:Bacterial Load; D001886:Bordetella pertussis / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000097:blood*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction; D013030:Spain / Q000453:epidemiology; D014917:Whooping Cough / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology / Q000503:physiopathology
chemical_list: D004269:DNA, Bacterial
keywords: Bacterial load; Bordetella pertussis; Children; Prognostics; Real-time PCR; Whooping cough