title: Pathogens in COPD exacerbations identified by comprehensive real-time PCR plus older methods.
abstract: 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.
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Shimizu
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yoshii
authors.affiliation: Department of Infectious Diseases, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Morozumi
authors.affiliation: Department of Infectious Diseases, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Chiba
authors.affiliation: Department of Infectious Diseases, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Kimiko
authors.initials: K
authors.lastname: Ubukata
authors.affiliation: Department of Respiratory Medicine, Respiratory Center, Toranomon Hospital, The Jikei University Daisan Hospital, Tokyo, Japan.
authors.forename: Hironori
authors.initials: H
authors.lastname: Uruga
authors.affiliation: Department of Respiratory Medicine, Respiratory Center, Toranomon Hospital, The Jikei University Daisan Hospital, Tokyo, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Hanada
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Nayuta
authors.initials: N
authors.lastname: Saito
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Kadota
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Saburo
authors.initials: S
authors.lastname: Ito
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Wakui
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Takasaka
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Minagawa
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Kojima
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Hara
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Numata
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Kawaishi
authors.affiliation: Department of Respiratory Medicine, The Jikei University Daisan Hospital, Tokyo, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Saito
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Araya
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Kaneko
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Nakayama
authors.affiliation: Department of Respiratory Medicine, Respiratory Center, Toranomon Hospital, The Jikei University Daisan Hospital, Tokyo, Japan.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Kishi
authors.affiliation: Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Kuwano
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D005260:Female; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications*; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D012141:Respiratory Tract Infections / Q000209:etiology* / Q000382:microbiology*; D012307:Risk Factors; D013183:Sputum / Q000382:microbiology
keywords: COPD; etiology; exacerbation; prolonged hospitalization; real-time PCR; risk factor