%0 Journal Article %A Shimizu, Takae %A Harada, Kazuki %A Tsuyuki, Yuzo %A Kimura, Yui %A Miyamoto, Tadashi %A Hatoya, Shingo %A Hikasa, Yoshiaki %T In vitro efficacy of 16 antimicrobial drugs against a large collection of β-lactamase-producing isolates of extraintestinal pathogenic Escherichia coli from dogs and cats %D 2017 %J Journal of Medical Microbiology, %V 66 %N 8 %P 1085-1091 %@ 1473-5644 %R https://doi.org/10.1099/jmm.0.000535 %K Escherichia coli %K extended-spectrum β-lactamases %K antimicrobial treatment %K companion animals %I Microbiology Society, %X Purpose. The aim of this study was to assess the in vitro efficacy of candidate antimicrobials against extended-spectrum β-lactamase (ESBL)-producing isolates of extraintestinal pathogenic Escherichia coli (ExPEC) from companion animals. Methodology. A total of 90 ESBL-producing ExPEC isolates from dogs and cats were tested for susceptibility to 16 antimicrobials with the agar dilution method. We also identified the ESBLs and AmpC β-lactamases of these isolates with PCR and DNA sequencing. Results/Key findings. All isolates were susceptible to meropenem, tebipenem and amikacin (AMK), and various proportions were susceptible to latamoxef (LMX, 97.8 %), fosfomycin (FOM, 97.8 %), faropenem (FPM, 96.7 %), nitrofurantoin (NFT, 96.7 %), flomoxef (FMX, 93.3 %), piperacillin/tazobactam (PTZ, 92.2 %), cefmetazole (CMZ, 91.1 %), chloramphenicol (80.0 %), trimethoprim/sulfamethoxazole (64.4 %), amoxicillin/clavulanic acid (63.3 %), ceftibuten (60.0 %), tetracycline (52.2 %) and enrofloxacin (10.0 %). A genetic analysis showed that 83 of the 90 (92.2 %) isolates were positive for CTX-M-type genes: CTX-M-14 (n=26), CTX-M-27 (n=20), CTX-M-55 (n=17), CTX-M-15 (n=12), CTX-M-2 (n=5), CTX-M-24 (n=2), CTX-M-104 (n=2) and CTX-M-3 (n=1). Eight isolates also expressed AmpC β-lactamase phenotypes. Conclusion. This study demonstrates that the susceptibility rates to PTZ, CMZ, LMX, AMK, FOM, FPM, NFT and FMX were similar to those to carbapenems (>90 %), implying that these drugs are available alternatives to carbapenems for the treatment of companion animals infected with ExPEC-producing CTX-M-type ESBLs. Further in vivo studies of the effective use of these antimicrobials are required. %U https://www.microbiologyresearch.org/content/journal/jmm/10.1099/jmm.0.000535