Tae Sang Oh1,2, You Sun Nam2, Young Jin Kim1, Hyung-seok Yang1, Min-young Lee1, Hyun Jung Gu1, Hee Joo Lee1
1Department of Laboratory Medicine, Kyung Hee University Medical Center, School of Medicine, Kyung Hee University, 2Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Korea
Background: Blood culture remains the definitive method for diagnosing bacteremia and fungemia. In this study, we investigated the incidence of bacterial and fungal infections along with the trends in antimicrobial susceptibility in blood cultures collected from 2008 to 2013.
Methods: We performed a retrospective analysis of blood cultures performed at Kyung Hee University Hospital, Seoul, South Korea, between 2008 and 2013 to determine the bacterial and fungal species isolated, and their antimicrobial susceptibilities. Additional analyses were performed comparing these results to that of a prior study examining blood cultures collected from 2003-2007.
Results: Of the 102,257 specimens collected, 8,452 (8.3%) were culture positive, with Staphylococcus epidermidis being the most common species isolated (17.3%), followed by Escherichia coli (16.9%), Staphylococcus aureus (8.1%), and Klebsiella pneumoniae (6.5%). Fungal species accounted for 3.7% of all isolates. Methicillin resistance was seen in 54.3% of S. aureus isolates. The frequencies of extended-spectrum β-lactamase (ESBL)-producing E. coli and K. pneumoniae were 13.1% and 10.3%; imipenem resistance was seen in 19.5% of Pseudomonas aeruginosa isolates.
Conclusion: Although the number of blood specimens analyzed increased steadily over the course of this study, the rate of positive blood cultures declined. The most common microorganisms isolated were coagulase-negative staphylococci, E. coli, S. aureus, and K. pneumoniae, consistent with our prior analysis. This analysis of blood culture isolate frequencies and antibiotic susceptibilities can be used to inform antibiotic therapy decisions. (Ann Clin Microbiol 2015;18: 14-19)