Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology


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Characteristics of Microorganisms Isolated from Blood Cultures at Nine University Hospitals in Korea during 2009

Original article

Annals of Clinical Microbiology (Ann Clin Microbiol) 2011 June, Volume 14, Issue 2, pages 48-54.

Characteristics of Microorganisms Isolated from Blood Cultures at Nine University Hospitals in Korea during 2009

Hee-Jung Kim1, Nam Yong Lee1, Sunjoo Kim2,3, Jeong Hwan Shin4,5, Mi-Na Kim6, Eui-Chong Kim7, Sun Hoi Koo8, Nam Hee Ryoo9, Jae-Seok Kim10, Ji-Hyun Cho11
1Department of Laboratory Medicine & Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, 2Department of Laboratory Medicine, 3Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, 4Department of Laboratory Medicine, 5Paik Institute for Clinical Research, Inje University College of Medicine, Busan, Department of Laboratory Medicine, 6Asan Medical Center and University of Ulsan College of Medicine, 7Seoul National University Hospital, Seoul, 8College of Medicine, Chungnam National University, Daejeon, 9School of Medicine, Keimyung University, Daegu, 10Hallym University College of Medicine, Seoul, 11College of Medicine, Wonkwang University, Iksan, Korea


Background: Blood culture is important for determining the etiologic agents of bacteremia and fungemia. Analyses of blood culture results and antimicrobial susceptibility can provide clinicians with relevant information for the empirical treatment of patients. The present study was conducted to assess the frequencies and antimicrobial resistance patterns of clinically important microorganisms from nine hospitals. 

Methods: Data including microbiological isolates and corresponding antimicrobial susceptibility test results were collected during 2009 from nine and five university hospitals, respectively. Microorganism identification was based on conventional methods. Antimicrobial susceptibility was tested using the VITEK II system or the Clinical and Laboratory Standards Institute disk diffusion method. 

Results: Of 397,602 blood specimens cultured from nine hospitals, 34,708 (8.7%) were positive for microorganisms. Excluding coagulase-negative Staphylococci (CoNS), Escherichia coli was the most common isolate (13.5%), followed by Staphylococcus aureus (11.5%), Klebsiella pneumoniae (6.5%) and Enterococcus faecium (3.4%). The isolation rate of CoNS was 23.6%, while that of ceftazidime-resistant E. coli showed geographic differences ranging from 11% to 28%. Among the Gram-negative isolates, A. baumannii displayed the highest levels of resistance. The total isolation rate of the Candida species increased compared to the previous reported rate in Korea. 

Conclusion: Among the isolates, CoNS was the most common, followed by E. coli and S. aureus. The gradual increase in the prevalence of extended-spectrum β-lactamase (ESBL) producers has contributed to the increase in multi-drug resistance among bacterial isolates from bloodstream infections. (Korean J Clin Microbiol 2011;14:48-54)


 Blood culture, Bacteremia, Antimicrobial susceptibility, Fungemia