Changing trends in clinical characteristics and antibiotic susceptibility of Klebsiella pneumoniae bacteremia

Background/Aims: Klebsiella pneumoniae is second most common organism of gram-negative bacteremia in Korea and one of the most common cause of urinary tract infection, and intra-abdominal infection. Methods: We compared clinical and microbiological characteristics about K. pneumoniae bacteremia in a tertiary hospital between 10 years. Group A is who had K. pneumoniae bacteremia at least one time from January 2004 to December 2005. Group B is from January 2012 to December 2013. We also analyzed antibiotic resistance, clinical manifestation of the K. pneumoniae bacteremia divided into community-acquired infections, healthcare associated infections, and nosoco mial infections. Results: The resistance for ampicillin, aztreonam, cefazolin, and cefotaxime sig nificantly increased compared to 10 years ago. Extended spectrum β-lactamase positivity surged from 4.3% to 19.6%. Ten years ago, 1st, 2nd cephalosporin, and aminoglycoside were used more as empirical antibiotics. But these days, empiri cal antibiotics were broad spectrum such as 3rd and 4th cephalosporin. In treat ment outcome, acute kidney injury decreased from 47.5% to 28.7%, and mortality decreased from 48.9% to 33.2%. In community-acquired infections, there was similar in antimicrobial resistance and mortality. In healthcare-associated and nosocomial infections, there was significantly increasing in antibiotic resistance, decreasing in mortality, and acute kidney injury. Conclusions: In community-acquired infections, broader antibiotics were more used than 10 years ago despite of similar antimicrobial resistance. When K. pneu moniae bacteremia is suspected, we recommend to use the narrow spectrum anti biotics as initial therapy if there are no healthcare-associated risk factors, because the antibiotic resistance is similar to 10 years ago in community-acquired infec tions.