[A multicentre study on the pathogenic agents in 665 adult patients with community-acquired pneumonia in cities of China].
OBJECTIVE
To investigate the pathogenic causes of community-acquired pneumonia (CAP) in adult patients in China, the relation of previous antibiotic use and the Pneumonia Patient Outcome Research Team (PORT) classification to microbial etiology, and the prevalence of drug resistance of common CAP bacteria.


METHODS
A prospective study was performed on 665 consecutive adult patients with CAP at 12 centers in 7 Chinese cities during one year. The etiology of pneumonia was considered if one of the following criteria was met: (1) valid sputum sample yielding one or more predominant strains; (2) blood cultures yielding a bacterial pathogen; (3) seroconversion, a > or = 4-fold increase or decrease titers of antibodies to Mycoplasma pneumoniae, Chlamydia pneumoniae and Legionella pneumophila. Minimum inhibitory concentration (MIC) of respiratory tract isolates was determined using the agar dilution method.


RESULTS
Pathogens were identified in 324/610 patients (53.1%) with valid serum samples and sputum cultures as follows: Mycoplasma pneumoniae (126, 20.7%), Streptococcus pneumoniae (63, 10.3%), Haemophilus influenzae (56, 9.2%), Chlamydia pneumoniae (40, 6.6%), Klebsiella pneumoniae (37, 6.1%), Legionella pneumophila (31, 5.1%), Staphylococcus aureus (23, 3.8%), Escherichia coli (10, 1.6%), Moraxella catarrhalis (8, 1.3%), Pseudomonas aeruginosa (6, 1.0%). Of 195 patients with a bacterial pathogen, an atypical pathogen was identified in 62 (10.2%) cases. The non-susceptibility rate of Streptococcus pneumoniae to penicillin, azithromycin, and moxifloxacin was 20.3%, 75.4% and 4.3% respectively.


CONCLUSIONS
Atypical pathogens have important role in CAP, with Mycoplasma pneumoniae being the most common pathogen, and mixed infection of atypical pathogens with bacteria was found in 10.2% of the cases. Streptococcus pneumoniae and Haemophilus influenzae remain the most important bacteria for CAP. More than 75.0% of Streptococcus pneumoniae was resistant to macrolides and 20.3% was resistant to penicillin.
Liu
You-ning
YN
Department of Respiratory Medicine, General Hospital of PLA, Beijing 100853, China.
Chen
Min-jun
MJ
Zhao
Tie-mei
TM
Wang
Hui
H
Wang
Rui
R
Liu
Qing-feng
QF
Cai
Bai-qiang
BQ
Cao
Bin
B
Sun
Tie-ying
TY
Hu
Yun-jian
YJ
Xiu
Qing-yu
QY
Zhou
Xin
X
Ding
Xing
X
Yang
Lan
L
Zhuo
Jian-sheng
JS
Tang
Ying-chun
YC
Zhang
Kou-xing
KX
Liang
De-rong
DR
Lü
Xiao-ju
XJ
Li
Sheng-qi
SQ
Liu
Yong
Y
Yu
Yun-song
YS
Wei
Ze-qing
ZQ
Ying
Ke-jing
KJ
Zhao
Feng
F
Chen
Ping
P
Hou
Xiao-na
XN
D000328:Adult; D000368:Aged; D002681:China / Q000453:epidemiology; D016993:Chlamydophila pneumoniae / Q000302:isolation & purification; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D005260:Female; D006193:Haemophilus influenzae / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008875:Middle Aged; D009177:Mycoplasma pneumoniae / Q000302:isolation & purification; D011014:Pneumonia / Q000453:epidemiology* / Q000382:microbiology*; D011446:Prospective Studies; D013296:Streptococcus pneumoniae / Q000302:isolation & purification; D014505:Urban Population