Diagnosis of whooping cough in Switzerland: differentiating Bordetella pertussis from Bordetella holmesii by polymerase chain reaction

PLoS One. 2014 Feb 19;9(2):e88936. doi: 10.1371/journal.pone.0088936. eCollection 2014.

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.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Bordetella / classification
  • Bordetella / genetics*
  • Bordetella Infections / diagnosis*
  • Bordetella Infections / microbiology*
  • Bordetella pertussis / genetics*
  • Bordetella pertussis / isolation & purification
  • Child
  • Child, Preschool
  • DNA, Bacterial / analysis*
  • DNA, Bacterial / genetics
  • Diagnosis, Differential
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Microbiological Techniques / methods
  • Polymerase Chain Reaction / methods*
  • Switzerland
  • Whooping Cough / diagnosis*
  • Whooping Cough / microbiology
  • Young Adult

Substances

  • DNA, Bacterial

Grants and funding

Research funds were provided by the Genomic Research Laboratory (Division of Infectious Diseases, Geneva University Hospitals) and from the Centre for Vaccinology and Neonatal Immunology (Geneva University Hospitals and Faculty of Medicine of the University of Geneva). The funders were involved in the study design, and data collection, but did not interfere with the analysis and the decision to publish.