Keywords
CTX-M Escherichia coli Extended-spectrum β-lactamase Klebsiellapneumoniae
Acknowledgements
This research was supported by a fund (2017E4400100#) from the Research Program of Korea Centers for Disease Control and Prevention.
Figures & Tables
Fig. 1. Zone diameter of the four drugs (A and C) and the synergy with clavulanic acid (SC) (B and D) by bacterial species (A and B) and by groups of CTX-M (C and D). A total of 269 E. coli (ECO) and 76 K.pneumoniae (KPN) CTX-M producers (A and B) including 211 group 1 CTX-M producers and 123 group 9 CTX-M producers (C and D) were plotted. Boxplots present the 1 and 3 quartiles with whiskers showing either the maximum and minimum values. The thick horizontal line indicates median values, black lines for E. coli or group 1 CTX-M and gray lines for K.pneumoniae or group 9 CTX-M ESBL producers. The SC value was calculated by dividing the enlarged zone diameter near the CA disk by inhibition zone diameter of each drug. The statistical significance was calculated using Pearson’s chi-square test [16] by using SPSS statistics (version 23, IBM Corp., Armonk, NY, USA) and the significance (P) was indicated by using asterisks: **P<0.01; *P<0.05.