title: [Etiology and outcome of community-acquired pneumonia in relation to age and severity in hospitalized adult patients].
abstract: The aim of this study was to determine the etiology and outcome of community-acquired pneumonia (CAP) in relation to age and severity in hospitalized patients. Overall, 652 consecutive patients with CAP were studied retrospectively during a 4-year period from 2002. Severity of pneumonia was classified according to the guidelines of the Japanese Respiratory Society (JRS 2005) and American Thoracic Society (ATS 2001). The etiology was identified in 401 of 652 (61.5%) cases. The four most frequent pathogens were Streptococcus pneumoniae (26.2%), influenza virus (12.4%), Mycoplasma pneumoniae (10.9%), and Haemophilus influenzae (5.9%). The most common pathogen in the younger (15-44 years) group and very severe patients (JRS) was Mycoplasma pneumoniae (38.4%) and influenza virus (28.6%), respectively. The three most frequent pathogens in severe CAP patients (ATS) were Streptococcus pneumoniae (29.0%), influenza virus (17.4%), and Legionella species (13.0%). The overall mortality was 6.4%. The mortality of CAP patients among aged 1544, 45-64, 65-74, and 75 years or older was 1.4%, 3.3%, 6.9% and 9.3%, respectively. The mortality of mild, moderate, severe, and very severe patients (RS) was 0%, 4.1%, 15.5%, and 53.6%, respectively. The mortality of non-severe and severe patients (ATS) was 1.8% and 23.9%, respectively. Age and severity had influence on the prevalence of the main microbial pathogens. Streptococcus pneumoniae remained the most important pathogen that needs consideration in initial antibiotic therapy in patients with CAP of all ages and severities. Pathogens identified in patients with severe CAP in Japan were similar to those of Western countries, except for the high incidence of the influenza virus.
authors.affiliation: Department of Respiratory Medicine, Saitama Cardiovascular and Respiratory Center.
authors.forename: Noboru
authors.initials: N
authors.lastname: Takayanagi
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Hara
authors.forename: Daidou
authors.initials: D
authors.lastname: Tokunaga
authors.forename: Youtaro
authors.initials: Y
authors.lastname: Takaku
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Minagawa
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Tsuchiya
authors.forename: Naoya
authors.initials: N
authors.lastname: Hijikata
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Yamaji
authors.forename: Hiroo
authors.initials: H
authors.lastname: Saito
authors.forename: Mikio
authors.initials: M
authors.lastname: Ubukata
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Kurashima
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Yanagisawa
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Sugita
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D017714:Community-Acquired Infections / Q000209:etiology* / Q000382:microbiology / Q000401:mortality; D005260:Female; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000209:etiology* / Q000382:microbiology / Q000401:mortality; D011379:Prognosis; D012189:Retrospective Studies; D012720:Severity of Illness Index; D015996:Survival Rate