Laboratory diagnosis of a family cluster of pertussis in Shanxi

  Objective   To analyze the epidemiologic and etiologic characteristics of the laboratory diagnosis of a family cluster of pertussis in Shanxi province and provide evidence to improve the clinical and laboratory diagnosis and detection of pertussis.

  Methods   The incidence data of pertussis in a family were collected. The nasopharyngeal swabs of the patient (child) and the close contact (mother) were used for isolation, identification, nucleic acid detection of Bordetella pertussis, and the gene sequencing of the strains was conducted.

  Results   The nasopharyngeal swabs of the child and his mother were positive for B. pertussis culture. The nasopharyngeal swab of the child was negative but the nasopharyngeal swab of his mother was positive in nucleic acid test. The multilocus-sequence typing (MLST) gene sequencing results showed that all the strains were ST-2, belonging to ST-2 complex. Cluster analysis was conducted with the genomes of 890 strains of B. pertussis download from National Center forBiotechnology  Information(NCBI) database, and it was found that the MLST of the strains was closely related to the genetic evolution of 25 strains of B. pertussis.

  Conclusion   The child and his mother were confirmed to be infected with B pertussis by laboratory tests, indicating a family cluster of pertussis. Laboratory testing can provide timely and accurate etiological information for the diagnosis of pertussis and the surveillance of pertussis epidemic.