title: [Study on epidemic characteristics and etiology of community acquired pneumonia in Guangzhou from 2009 to 2012].
abstract: OBJECTIVE
  To investigate the epidemic characteristics and pathogenic spectrum of community acquired pneumonia (CAP) in Guangzhou from 2009 to 2012.
  
  
  METHODS
  14 major comprehensive hospitals were selected from 11 districts as sentinel hospitals for CAP cases surveillance, including 18 982 223 in total during the 4 years. The characteristics of pathogenic spectrum of CAP were stratified and analyzed by year, age and season.
  
  
  RESULTS
  18 982 223 cases were included in the surveillance from year 2009 to 2012, in which 56 618 cases were CAP. The number of CAP cases increased from 8677 in year 2009 to 19 947 in year 2012 in Guangzhou; while the percentage of visits for CAP raised from 0.22% (8677/3 893 800) to 0.41% (19 947/4 839 766). The difference showed statistical significance (χ(2) = 2693.00, P < 0.05). Among the hospitalized CAP cases, 66.05% (10 954/16 585) were aged ≤ 5 years old or > 66 years old. The percentage of cases infected by a single pathogen was 88.11% (14 613/16 585), while co-infected cases accounted for 4.17% (691/16 585). Bacteria accounted for the largest proportion of 65.25% (10 821/16 585) as a single pathogen, followed by mycoplasma 13.54% (2245/16 585), virus 9.01% (1494/16 585) and chlamydia 0.32% (53/16 585). The proportion of virus infection was increasing from 4.74% to 11.64%. The difference showed statistical significance (χ(2) = 135.32, P < 0.05). Bacteria infection was the leading causes for CAP cases in all age groups; however the percentage increased with the increasing of ages. The rate of bacterial infection was increased from 48.35% (2993/6191) among children aged ≤ 5 years old to 81.31% (3873/4763) among adults aged over 65 years (χ(2) = 1632.00, P < 0.05). The rate of atypical pathogens (mycoplasma, chlamydia) for children ( ≤ 15 years old) (25.99%, 1805/6945) was higher than that for adults aged ≥ 16 years old (5.12%, 494/9640) (χ(2) = 2.11, P < 0.05). The effect from season on the pathogenic spectrum was not observed.433 hospitalized CAP cases were dead from 2009 to 2012. Case fatality rate was highest among people aged over 65 years old (4.70%, 224/4763) and lowest among children aged between 6 to 15 years old (0.27%, 2/754).
  
  
  CONCLUSIONS
  The incidence of community acquired pneumonia was rising in Guangzhou from 2009 to 2012. Bacteria was the dominant pathogen. Children and old people were the high-risk population of community acquired pneumonia; while co-infection was still at low level.
authors: Division of Infectious Disease, Guangzhou Center for Disease Control and Prevention, Guang zhou 510440, China.
authors: Hui
authors: H
authors: Liu
authors: Division of Infectious Disease, Guangzhou Center for Disease Control and Prevention, Guang zhou 510440, China. Email: biotin2001@163.com.
authors: Xin-cai
authors: XC
authors: Xiao
authors: Division of Infectious Disease, Guangzhou Center for Disease Control and Prevention, Guang zhou 510440, China.
authors: Jian-yun
authors: JY
authors: Lu
authors: Division of Infectious Disease, Guangzhou Center for Disease Control and Prevention, Guang zhou 510440, China.
authors: Zong-qiu
authors: ZQ
authors: Chen
authors: Division of Infectious Disease, Guangzhou Center for Disease Control and Prevention, Guang zhou 510440, China.
authors: Lei
authors: L
authors: Luo
authors: Division of Infectious Disease, Guangzhou Center for Disease Control and Prevention, Guang zhou 510440, China.
authors: Zhi-cong
authors: ZC
authors: Yang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000453:epidemiology* / Q000382:microbiology; D018571:Sentinel Surveillance; D055815:Young Adult