Sensititre ast

Phenotypic AST was performed using disc diffusion and Etest (meropenem) methods for A. baumannii. For CRE and CRAB isolates VITEK 2 (bioMerieux, France) and Sensititre AST was used (Thermo Fisher Scientific, UK). The AST panel included 42 (CRE) and 26 antimicrobials (CRAB) (belonging to 13 classes and 10 classes, respectively) (Table S1, available as Supplementary data at JAC-AMR Online). CLSI breakpoints were used for susceptibility interpretation.³² E. coli ATCC 25922 was used for quality control. In this study, isolates that were intermediately resistant to carbapenems were regarded as resistant.

From each sample solution, a volume of 10 μL was cultured on ECC agar (CHROMagar, France), a chromogenic medium allowing the detection of E. coli. One colony per sample showing typical E. coli morphology was selected. E. coli isolates were tested for their susceptibility to 11 antimicrobials belonging to eight classes by Sensititre AST (Thermo Fisher Scientific, UK) comprising colistin (polymyxins), cefpodoxime and ceftiofur (third-generation cephalosporins), azithromycin (macrolides), neomycin and streptomycin (aminoglycosides), amoxicillin (penicillins), enrofloxacin (quinolones), florfenicol (phenicols), doxycycline and oxytetracycline (tetracyclines). Potential production of ESBLs, as indicated by resistance to ceftiofur and/or cefpodoxime, was confirmed by double disc diffusion test according to the CLSI guidelines.