Recent changes in healthcare systems have changed the epidemiologic paradigms in many infectious fields including bloodstream infection (BSI). We compared clinical characteristics of community-acquired (CA), hospital-acquired (HA), and healthcare-associated (HCA) BSI. We performed a prospective nationwide multicenter surveillance study from 9 university hospitals in Korea. Total 1,605 blood isolates were collected from 2006 to 2007, and 1,144 isolates were considered true pathogens. HA-BSI accounted for 48.8%, CA-BSI for 33.2%, and HCA-BSI for 18.0%. HA-BSI and HCA-BSI were more likely to have severe comorbidities. Escherichia coli was the most common isolate in CA-BSI (47.1%) and HCA-BSI (27.2%). In contrast, Staphylococcus aureus (15.2%), coagulase-negative Staphylococcus (15.1%) were the common isolates in HA-BSI. The rate of appropriate empiric antimicrobial therapy was the highest in CA-BSI (89.0%) followed by HCA-BSI (76.4%), and HA-BSI (75.0%). The 30-day mortality rate was the highest in HA-BSI (23.0%) followed by HCA-BSI (18.4%), and CA-BSI (10.2%). High Pitt score and inappropriate empirical antibiotic therapy were the independent risk factors for mortality by multivariate analysis. In conclusion, the present data suggest that clinical features, outcome, and microbiologic features of causative pathogens vary by origin of BSI. Especially, HCA-BSI shows unique clinical characteristics, which should be considered a distinct category for more appropriate antibiotic treatment.
Adult ; Aged ; Anti-Bacterial Agents/therapeutic use ; Bacteremia/drug therapy/*epidemiology/microbiology/mortality ; Community-Acquired Infections/drug therapy/*epidemiology/microbiology/mortality ; Cross Infection/drug therapy/*epidemiology/microbiology/mortality ; Humans ; Korea/epidemiology ; Male ; Middle Aged ; Prospective Studies ; Risk Factors ; Treatment Outcome ; Young Adult

BACKGROUNDAppropriate antimicrobial therapy of community-acquired pneumonia (CAP) is mainly based on the distribution of etiology and antimicrobial resistance of major pathogens. We performed a prospective observational study of adult with CAP in 36 hospitals in China.

METHODSEtiological pathogens were isolated in each of the centers, and all of the isolated pathogens were sent to Zhongshan Hospital for antimicrobial susceptibility tests using agar dilution.

RESULTSA total of 593 patients were enrolled in this study, and 242 strains of bacteria were isolated from 225 patients. Streptococcus pneumoniae (79/242, 32.6%) was the most frequently isolated pathogen, followed by Haemophilus influenzae (55/242, 22.7%) and Klebsiella pneumoniae (25/242, 10.3%). Totally 527 patients underwent serological tests for atypical pathogens; Mycoplasma pneumoniae and Chlamydia pneumoniae infections were identified in 205 (38.9%) and 60 (11.4%) patients respectively. Legionella pneumophila infections were identified in 4.0% (13/324) of patients. The non-susceptibility rate of isolated Streptococcus pneumoniae to erythromycin and penicillin was 63.2% and 19.1% respectively. Six patients died from the disease, the 30-day mortality rate was 1.1% (6/533).

CONCLUSIONSThe top three bacteria responsible for CAP in Chinese adults were Streptococcus pneumonia, Haemophilus influenza and Klebsiella pneumonia. There was also a high prevalence of atypical pathogens and mixed pathogens. The resistance rates of the major isolated pathogens were relatively low except for the high prevalence of macrolide resistance in Streptococcus pneumoniae.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Bacteria ; drug effects ; isolation & purification ; pathogenicity ; China ; epidemiology ; Colony Count, Microbial ; Community-Acquired Infections ; drug therapy ; etiology ; microbiology ; mortality ; Drug Resistance, Bacterial ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Pneumonia, Bacterial ; drug therapy ; etiology ; microbiology ; mortality ; Prospective Studies