Pathogens in COPD exacerbations identified by comprehensive real-time PCR plus older methods

Kenichiro Shimizu, Yutaka Yoshii, Miyuki Morozumi, Naoko Chiba, Kimiko Ubukata, Hironori Uruga, Shigeo Hanada, Nayuta Saito, Tsukasa Kadota, Saburo Ito, Hiroshi Wakui, Naoki Takasaka, Shunsuke Minagawa, Jun Kojima, Hiromichi Hara, Takanori Numata, Makoto Kawaishi, Keisuke Saito, Jun Araya, Yumi KanekoKatsutoshi Nakayama, Kazuma Kishi, Kazuyoshi Kuwano

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)


Respiratory infection is a major cause of exacerbation in chronic obstructive pulmonary disease (COPD). Infectious contributions to exacerbations remain incompletely described. We therefore analyzed respiratory tract samples by comprehensive real-time polymerase chain reaction (PCR) in combination with conventional methods. We evaluated multiple risk factors for prolonged hospitalization to manage COPD exacerbations, including infectious agents. Over 19 months, we prospectively studied 46 patients with 50 COPD exacerbations, collecting nasopharyngeal swab and sputum samples from each. We carried out real-time PCR designed to detect six bacterial species and eleven viruses, together with conventional procedures, including sputum culture. Infectious etiologies of COPD exacerbations were identified in 44 of 50 exacerbations (88%). Infections were viral in 17 of 50 exacerbations (34%). COPD exacerbations caused by Gram-negative bacilli, including enteric and nonfermenting organisms, were significantly associated with prolonged hospitalization for COPD exacerbations. Our results support the use of a combination of real-time PCR and conventional methods for determining both infectious etiologies and risk of extended hospitalization.

Original languageEnglish
Pages (from-to)2009-2016
Number of pages8
JournalInternational Journal of COPD
Issue number1
Publication statusPublished - 2015 Sept 23


  • COPD
  • Etiology
  • Exacerbation
  • Prolonged hospitalization
  • Real-time PCR
  • Risk factor

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Health Policy
  • Public Health, Environmental and Occupational Health


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