title: Bordetella pertussis in infants hospitalized for acute respiratory symptoms remains a concern.
abstract: BACKGROUND
  Preliminary results suggest that pertussis infection might be considered in infants during a seasonal respiratory syncytial virus (RSV) outbreak.
  
  
  METHODS
  In order to analyze clinical features and laboratory findings in infants with pertussis hospitalized for acute respiratory symptoms during a seasonal RSV outbreak, we conducted a retrospective single-center study on 19 infants with pertussis (6 boys; median age 72 days) and 19 matched controls (RSV-bronchiolitis), hospitalized from October 2008 to April 2010. B. pertussis and RSV were detected from nasopharyngeal washes with Real Time-PCR.
  
  
  RESULTS
  Infants with pertussis were less often breastfeed than infants with RSV bronchiolitis (63.2% vs 89.5%; p <0.06). Clinically, significantly fewer infants with pertussis than controls had more episodes of whooping cough (63.2% vs 0.0%; p < 0.001) and also less frequently fever at admission (15.8% vs 68.4%; p <0.01), apnea (52.6% vs 10.5%; p <0.006), and cyanosis (52.6% vs 10.5%; p < 0.006). Infants with pertussis had more often no abnormal chest sounds on auscultation than infants with RSV bronchiolitis (0% vs 42,1%; p < 0.005). The absolute blood lymphocyte and eosinophil counts were higher in infants with B. pertussis than in controls with bronchiolitis (23886 ± 16945 vs 10725 ± 4126 cells/mm(3), p < 0.0001 and 13.653 ± 10.430 vs 4.730 ± 2.400 cells/mm(3), p < 0.001). The molecular analysis of 2 B. pertussis isolates for ptxA1, ptxP3, and prn2 genes showed the presence of gene variants.
  
  
  CONCLUSIONS
  When infants are hospitalized for acute respiratory symptoms, physicians should suspect a pertussis infection, seek for specific clinical symptoms, investigate lymphocyte and eosinophil counts and thus diagnose infection early enough to allow treatment.
authors.forename: Ambra
authors.initials: A
authors.lastname: Nicolai
authors.forename: Raffaella
authors.initials: R
authors.lastname: Nenna
authors.forename: Paola
authors.initials: P
authors.lastname: Stefanelli
authors.forename: Anna
authors.initials: A
authors.lastname: Carannante
authors.forename: Concetta
authors.initials: C
authors.lastname: Schiavariello
authors.forename: Alessandra
authors.initials: A
authors.lastname: Pierangeli
authors.forename: Carolina
authors.initials: C
authors.lastname: Scagnolari
authors.forename: Corrado
authors.initials: C
authors.lastname: Moretti
authors.forename: Paola
authors.initials: P
authors.lastname: Papoff
authors.forename: Enea
authors.initials: E
authors.lastname: Bonci
authors.forename: Marianna
authors.initials: M
authors.lastname: Ferrara
authors.forename: Stefano
authors.initials: S
authors.lastname: Papasso
authors.affiliation: Department of Paediatrics, "Sapienza" University of Rome, Rome, Italy. midulla@uniroma1.it.
authors.forename: Fabio
authors.initials: F
authors.lastname: Midulla
mesh_terms: D001886:Bordetella pertussis / Q000302:isolation & purification*; D004196:Disease Outbreaks; D005260:Female; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology / Q000821:virology; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000382:microbiology* / Q000821:virology; D012189:Retrospective Studies; D014917:Whooping Cough / Q000453:epidemiology / Q000382:microbiology*