S. Choleraesuis isolates were tested for susceptibility to antimicrobial agents using the agar disk diffusion method (Kirby Bauer test) following the guidelines and criteria of the Clinical and Laboratory Standards Institute (CLSI) [26 ]. The antibiotics tested (Oxoid, England) were
ampicillin (10 µg), amoxicillin–calvulanic acid (20/10 µg), aztreonam (30 µg), cefepime (30 µg), ceftazidime (30 µg), cefoxitin (30 µg),
cefotaxime (30 µg),
cefpodoxime (10 µg), cephalothin (30 µg),
cefuroxime (30 µg),
ceftriaxone (30 µg), ceftiofur (30 µg), ciprofloxacin (5 µg), chloramphenicol (30 µg), nalidixic acid (30 µg), norfloxacin (10 µg), streptomycin (10 µg), tetracycline (30 µg), and trimethoprim/sulfamethoxazole (25 µg). Furthermore,
cefotaxime-resistant
S. Choleraesuis isolates were screened for ESBL producers by the combination disk method (CLSI, 2008) [12 (
link)]. The MICs for ciprofloxacin (32–0.002 µg/mL),
cefotaxime (256-0.016 µg/mL), ceftazidime (256-0.016 µg/mL),
ceftriaxone (256-0.016 µg/mL) and
cefpodoxime (256-0.016 µg/mL) were determined using the
Liofilchem MIC test strip (Liofilchem, Roseto degli Abruzzi, Italy), according to the manufacturer’s instructions.
Escherichia coli ATCC 25922 was used as the quality control strain for antimicrobial susceptibility testing.
Sriyapai P., Pulsrikarn C., Chansiri K., Nyamniyom A, & Sriyapai T. (2021). Molecular Characterization of Cephalosporin and Fluoroquinolone Resistant Salmonella Choleraesuis Isolated from Patients with Systemic Salmonellosis in Thailand. Antibiotics, 10(7), 844.