title: A Multicenter Study of Pertussis Infection in Adults with Coughing in Korea: PCR-Based Study.
abstract: BACKGROUND
  Limited data on the incidence and clinical characteristics of adult pertussis infections are available in Korea.
  
  
  METHODS
  Thirty-one hospitals and the Korean Centers for Disease Control and Prevention collaborated to investigate the incidence and clinical characteristics of pertussis infections among adults with a bothersome cough in non-outbreak, ordinary outpatient settings. Nasopharyngeal aspirates or nasopharyngeal swabs were collected for polymerase chain reaction (PCR) and culture tests.
  
  
  RESULTS
  The study enrolled 934 patients between September 2009 and April 2011. Five patients were diagnosed as confirmed cases, satisfying both clinical and laboratory criteria (five positive PCR and one concurrent positive culture). Among 607 patients with cough duration of at least 2 weeks, 504 satisfied the clinical criteria of the US Centers for Disease Control and Prevention (i.e., probable case). The clinical pertussis cases (i.e., both probable and confirmed cases) had a wide age distribution (45.7±15.5 years) and cough duration (median, 30 days; interquartile range, 18.0~50.0 days). In addition, sputum, rhinorrhea, and myalgia were less common and dyspnea was more common in the clinical cases, compared to the others (p=0.037, p=0.006, p=0.005, and p=0.030, respectively).
  
  
  CONCLUSIONS
  The positive rate of pertussis infection may be low in non-outbreak, ordinary clinical settings if a PCR-based method is used. However, further prospective, well-designed, multicenter studies are needed.
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Korea.
authors.forename: Sunghoon
authors.initials: S
authors.lastname: Park
authors.forename: Myung-Gu
authors.initials: MG
authors.lastname: Lee
authors.forename: Kwan Ho
authors.initials: KH
authors.lastname: Lee
authors.forename: Yong Bum
authors.initials: YB
authors.lastname: Park
authors.forename: Kwang Ha
authors.initials: KH
authors.lastname: Yoo
authors.forename: Jeong-Woong
authors.initials: JW
authors.lastname: Park
authors.forename: Changhwan
authors.initials: C
authors.lastname: Kim
authors.forename: Yong Chul
authors.initials: YC
authors.lastname: Lee
authors.forename: Jae Seuk
authors.initials: JS
authors.lastname: Park
authors.forename: Yong Soo
authors.initials: YS
authors.lastname: Kwon
authors.forename: Ki-Hyun
authors.initials: KH
authors.lastname: Seo
authors.forename: Hui Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Seung Min
authors.initials: SM
authors.lastname: Kwak
authors.forename: Ju-Ock
authors.initials: JO
authors.lastname: Kim
authors.forename: Seong Yong
authors.initials: SY
authors.lastname: Lim
authors.forename: Hwa-Young
authors.initials: HY
authors.lastname: Sung
authors.forename: Sang-Oun
authors.initials: SO
authors.lastname: Jung
authors.forename: Ki-Suck
authors.initials: KS
authors.lastname: Jung