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.
Bordetella pertussis in infants hospitalized for acute respiratory symptoms remains a concern / Nicolai, Ambra; Nenna, Raffaella; Stefanelli, P.; Carannante, A.; Schiavariello, C.; Pierangeli, Alessandra; Scagnolari, Carolina; Moretti, Corrado; Papoff, Paola; Bonci, Enea; Ferrara, M.; Papasso, S.; Midulla, Fabio. - In: BMC INFECTIOUS DISEASES. - ISSN 1471-2334. - ELETTRONICO. - 13:1(2013), p. 526. [10.1186/1471-2334-13-526]