Colistin sulfate

Thirty-one (31) diarrheagenic Eschericia coli (DEC) were subjected to the antimicrobial susceptibility testing. It was carried out by disk diffusion method on Müller-Hinton agar (Liofilchem, Italy) according to the recommendations of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) [10 ]. After depositing the antibiotics, the plates were incubated at +37 °C for 18–24 h. The diameters of the antibiotic sensitivity halos were recorded according to the recommendations of EUCAST. Intermediary (I) susceptibility of pathovars was classified as resistant (R). According to EUCAST recommendations on antibiotics used in case of infection with enterobacteria and in view of the multidrug resistance observed in recent years, 19 antibiotics divided into 7 different families were tested. These include amoxicillin (25 µg), amoxicillin–clavulanic acid (20/10 µg), ceftriaxone (30 µg), cefotaxime (30 µg), cefepime (30 – g), cefixime (10 µg), piperacillin (75 µg), piperacillin–tazobactam (100 +10 µg), imipenem (10 µg), tetracycline (30 µg), chloramphenicol (30 µg), trimethoprim–sulfametoxazole (1.25 ± 23.75 µg), aztreonam (30 µg), colistin sulfate (50 µg), ciprofloxacin (5 µg), nalidixic acid (30 µg), gentamycin (15 µg), netilmicin (10 µg), and tobramycin (10 µg) (Bio-Rad, France).