Cefoxitin cfx

The bacterial strains and plasmids used in this study are listed in Table 1. R. anatipestifer strains were grown at 37°C in tryptic soybean broth (TSB, Oxoid) or tryptic soy agar (TSA, Oxoid) in an atmosphere of 5% CO₂. Escherichia coli (E. coli) strains were grown on Luria-Bertani (LB, Oxoid) broth or agar at 37°C. When required, antibiotics were added at the following final concentrations (μg/ml): Chloramphenicol (Cm, Sigma), 25; cefoxitin (Cfx, Sigma), 1; kanamycin (Kan, Sigma), 100; ampicillin (Amp, Sigma), 100 or spectinomycin (Spc, Sigma), 70. Diaminopimelic acid (DAP, 50 μg/ml) to E. coli X7213λpir cultures (Edwards et al., 1998 (link)).

Bacterial strains, plasmids, and primers used in this study are listed in Tables 1, 2, respectively. Riemerella anatipestifer CH-1 (RA CH-1) strain was used as the wild-type strain, and all other strains used were derived from RA CH-1. R. anatipestifer was grown in Tryptic Soy Broth (TSB) or Giolitti-Cantoni Broth (GCB) at 37°C with shaking (Liu et al., 2017 (link)). GCB agar plates were prepared by supplementing GCB with 1.5% agar. Alternatively, R. anatipestifer was also grown on Luria-Bertani (LB) agar plate supplemented with 5% sheep blood. When necessary, appropriate concentrations of antibiotics were added to the media: ampicillin (Amp, Sigma-Aldrich, 100 μg/ml), chloramphenicol (Cm, Sigma-Aldrich, 30 μg/ml), kanamycin (Kan, Sigma-Aldrich, 50 μg/ml), and cefoxitin (Cfx, Sigma-Aldrich, 1 μg/ml).