title: Diagnosis of whooping cough in Switzerland: differentiating Bordetella pertussis from Bordetella holmesii by polymerase chain reaction.
abstract: Bordetella holmesii, an emerging pathogen, can be misidentified as Bordetella pertussis by routine polymerase chain reaction (PCR). In some reports, up to 29% of the patients diagnosed with pertussis have in fact B. holmesii infection and invasive, non-respiratory B. holmesii infections have been reported worldwide. This misdiagnosis undermines the knowledge of pertussis' epidemiology, and may lead to misconceptions on pertussis vaccine's efficacy. Recently, the number of whooping cough cases has increased significantly in several countries. The aim of this retrospective study was to determine whether B. holmesii was contributing to the increase in laboratory-confirmed cases of B. pertussis in Switzerland. A multiplex species-specific quantitative PCR assay was performed on 196 nasopharyngeal samples from Swiss patients with PCR-confirmed Bordetella infection (median age: 6 years-old, minimum 21 days-old, maximum 86 years-old), formerly diagnosed as Bordetella pertussis (IS481+). No B. holmesii (IS481+, IS1001-, hIS1001+) was identified. We discuss whether laboratories should implement specific PCR to recognize different Bordetella species. We conclude that in Switzerland B. holmesii seems to be circulating less than in neighboring countries and that specific diagnostic procedures are not necessary routinely. However, as the epidemiological situation may change rapidly, periodic reevaluation is suggested.
authors.affiliation: Department of Paediatrics, Division of General Paediatrics, Children's Hospital, University Hospitals of Geneva, Geneva, Switzerland.
authors.forename: Laure F
authors.initials: LF
authors.lastname: Pittet
authors.affiliation: Laboratory of Bacteriology, Department of Genetics and Laboratory Medicine, Department of Medical Specialties, University Hospitals of Geneva, University of Geneva, Geneva, Switzerland.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Emonet
authors.affiliation: Genomic Research Laboratory, Department of Genetics and Laboratory Medicine, Department of Medical Specialties, University Hospitals of Geneva, University of Geneva, Geneva, Switzerland.
authors.forename: Patrice
authors.initials: P
authors.lastname: François
authors.affiliation: Genomic Research Laboratory, Department of Genetics and Laboratory Medicine, Department of Medical Specialties, University Hospitals of Geneva, University of Geneva, Geneva, Switzerland.
authors.forename: Eve-Julie
authors.initials: EJ
authors.lastname: Bonetti
authors.affiliation: Laboratory of Bacteriology, Department of Genetics and Laboratory Medicine, Department of Medical Specialties, University Hospitals of Geneva, University of Geneva, Geneva, Switzerland.
authors.forename: Jacques
authors.initials: J
authors.lastname: Schrenzel
authors.affiliation: Bioanalytica AG, Luzern, Switzerland.
authors.forename: Melanie
authors.initials: M
authors.lastname: Hug
authors.affiliation: Bioanalytica AG, Luzern, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Altwegg
authors.affiliation: Department of Paediatrics, Division of General Paediatrics, Children's Hospital, University Hospitals of Geneva, Geneva, Switzerland ; Centre for Vaccinology and Neonatal Immunology, Departments of Pathology-Immunology and Paediatrics, University of Geneva, Geneva, Switzerland.
authors.forename: Claire-Anne
authors.initials: CA
authors.lastname: Siegrist
authors.affiliation: Department of Paediatrics, Division of General Paediatrics, Children's Hospital, University Hospitals of Geneva, Geneva, Switzerland.
authors.forename: Klara M
authors.initials: KM
authors.lastname: Posfay-Barbe
mesh_terms: D000293:Adolescent; D000328:Adult; D001884:Bordetella / Q000145:classification / Q000235:genetics*; D001885:Bordetella Infections / Q000175:diagnosis* / Q000382:microbiology*; D001886:Bordetella pertussis / Q000235:genetics* / Q000302:isolation & purification; D002648:Child; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000032:analysis* / Q000235:genetics; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008828:Microbiological Techniques / Q000379:methods; D016133:Polymerase Chain Reaction / Q000379:methods*; D013557:Switzerland; D014917:Whooping Cough / Q000175:diagnosis* / Q000382:microbiology; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial