– The incidence of infections with multidrug resistant (MDR) Enterobacteriaceae has risen considerably in recent years, associated mostly with ESBL production.

– Tigecycline is a glycylcycline antibiotic that shows good activity against most MDR Enterobacteriaceae and is therefore frequently used in infections with ESBL or carbapenemase producers [1].

– Conflicting data exist on the validity of susceptibility data generated by different susceptibility testing methods [2, 3].

– We therefore compared three different commercial methods to the current gold standard using a set of molecularly characterized E. coliand K. pneumoniaeisolates from invasive infections.

Comparison of four methods for the determination of tigecycline susceptibility in multi-resistant E. coli and K. pneumoniae