Susceptibility of various clinical pathogens to tigecycline in the Tohoku area, Japan

Tigecycline was released in Japan from September, 2012. Bacterial indications are multidrug-resistant Acinetobacter baumannii, NDM-1-producing Escherichia coli, and other multidrug-resistant gram-negative bacilli. Tigecycline had been already used in the US and Europe, and was swiftly introduced into Japan. Therefore, there are few antibiotic susceptibility data for a variety of clinically isolated pathogens in Japan. In this study, we investigated the minimum inhibitory concentration (MIC) of tigecycline against 270 pathogens isolated from patients in 22 hospitals in the Tohoku area, Japan. The MIC was determined with susceptibility testing using the CLSI broth microdilution method. The susceptibility rate of Escherichia coli, Klebsiella spp., and Acinetobacter spp. was demonstrated at 100%. Additionally, the rates of ESBL-producing Enterobacteriaceae and MRSA were 83.1% and 93.3%, respectively. However, 50% of MRSA which demonstrated an MIC for vancomycin of 2 μg/mL showed tigecycline resistance.