Te-Din Huang1, Catherine Berhin, P Bogaerts, Y Glupczynski. 1. National Reference Laboratory for Monitoring of Antimicrobial Resistance in Gram-negative Bacteria, CHU Mont-Godinne, Université Catholique de Louvain, 1 Avenue G. Therasse, 5530 Yvoir, Belgium. te-din.huang@uclouvain.be
Abstract
OBJECTIVES: To assess the in vitro susceptibility of multidrug-resistant Enterobacteriaceae (MDRE) isolates to tigecycline. METHODS: Clinical isolates of MDRE tested in this study were obtained from 91 hospitals in Belgium during the period January 2010 to April 2010. MICs of tigecycline were determined by Vitek 2 (VTK) and by the reference broth microdilution (BMD) method, and the results were interpreted based on the 2011 MIC interpretative criteria recommended by EUCAST. RESULTS: A total of 501 non-duplicate MDRE isolates were tested. These comprised 284 isolates of Escherichia coli [255 (89.7%) were extended-spectrum β-lactamase (ESBL)-producing isolates], 72 isolates of Klebsiella pneumoniae [53 (73.6%) were ESBL-producing isolates], 72 isolates of Enterobacter aerogenes, 33 isolates of Enterobacter cloacae, 19 isolates of Klebsiella oxytoca and 21 miscellaneous others. The MIC(90) values of tigecycline for E. coli and non-E. coli ESBL-producing Enterobacteriaceae isolates were 0.5 and 2 mg/L by BMD, and 0.5 and 8 mg/L by VTK, respectively. The highest essential and categorical agreement rates between VTK and BMD results using EUCAST breakpoints were observed in E. coli isolates (97.2%), while lower and unacceptable essential and categorical agreement rates were obtained for isolates belonging to species other than E. coli (81.1% and 59.4%, respectively). CONCLUSIONS: VTK appears to be a suitable method for routine susceptibility testing of tigecycline only for E. coli isolates, while BMD should be preferred for other Enterobacteriaceae species isolates.
OBJECTIVES: To assess the in vitro susceptibility of multidrug-resistant Enterobacteriaceae (MDRE) isolates to tigecycline. METHODS: Clinical isolates of MDRE tested in this study were obtained from 91 hospitals in Belgium during the period January 2010 to April 2010. MICs of tigecycline were determined by Vitek 2 (VTK) and by the reference broth microdilution (BMD) method, and the results were interpreted based on the 2011 MIC interpretative criteria recommended by EUCAST. RESULTS: A total of 501 non-duplicate MDRE isolates were tested. These comprised 284 isolates of Escherichia coli [255 (89.7%) were extended-spectrum β-lactamase (ESBL)-producing isolates], 72 isolates of Klebsiella pneumoniae [53 (73.6%) were ESBL-producing isolates], 72 isolates of Enterobacter aerogenes, 33 isolates of Enterobacter cloacae, 19 isolates of Klebsiella oxytoca and 21 miscellaneous others. The MIC(90) values of tigecycline for E. coli and non-E. coli ESBL-producing Enterobacteriaceae isolates were 0.5 and 2 mg/L by BMD, and 0.5 and 8 mg/L by VTK, respectively. The highest essential and categorical agreement rates between VTK and BMD results using EUCAST breakpoints were observed in E. coli isolates (97.2%), while lower and unacceptable essential and categorical agreement rates were obtained for isolates belonging to species other than E. coli (81.1% and 59.4%, respectively). CONCLUSIONS: VTK appears to be a suitable method for routine susceptibility testing of tigecycline only for E. coli isolates, while BMD should be preferred for other Enterobacteriaceae species isolates.
Authors: April M Bobenchik; Eszter Deak; Janet A Hindler; Carmen L Charlton; Romney M Humphries Journal: J Clin Microbiol Date: 2014-12-24 Impact factor: 5.948
Authors: D van Duin; E D Cober; S S Richter; F Perez; M Cline; K S Kaye; R C Kalayjian; R A Salata; S R Evans; V G Fowler; R A Bonomo Journal: Clin Microbiol Infect Date: 2014-12-12 Impact factor: 8.067