The Increasing Incidence of Extended-Spectrum Beta-Lactamase-producing Strains of Escherichia Coli and Klebsiella Pneumoniae

Purpose: The incidence of extended-spectrum beta-lactamase (ESBL)-producing strains of Escherichia coli and Klebsiella pneumoniae is increasing worldwide, which may change empiric antibiotic treatment. This study was conducted to explore the increasing extent of the incidence of ESBLproducing strains (ESBLPS) in E. coli and K. pneumoniae. Methods: This was a retrospective study at a regional hospital in southern Taiwan. From 2009 to 2013, all E. coli and K. pneumoniae isolates from clinical microbiology laboratory were enrolled in this study. ESBLPS were confirmed by double disk diffusion test. Results: A total of 15954E. coli and5374K. pneumoniae isolateswere enrolled. The ESBLPS accounted for 10.7 % (325/3048) and 16.8% (186/1109), 12.1% (362/ 2989) and 16.1% (155/963), 13.3% (447/3359) and 19.2% (214/1112), 17.4% (633/3635) and 20.8% (219/1051), as well as 20.5 % (753/2923) and 20.2% (230/1139) of E. coli and K. pneumoniae isolates in 2009, 2010, 2011, 2012, and 2013, respectively. The incidence of ESBLPS of E. coli and K. pneumoniae was statistically significant difference between 2009 and 2013 (P < 0.05). Conclusions: As a result of this study, the incidence of ESBLPS of E. coli and K. pneumniae was statistically significant increase from 2009 to 2013 (10.7% versus 20.5% in E. coli and 16.8% versus 20.2% in K. pneumoniae). The incidence of ESBLPS of E. coli was lower than that of K. pneumoniae before 2012, but that was similar in 2013. We think that the rapid increase of ESBLPS of E. coli should be concerned in clinical practice because E. coli is more frequent organism causing infections than K. pneumoniae.