2.6. Antibiotic susceptibility assay of isolates
Disc diffusion method was exploited against clinically important antibiotics listed in Table 3 to determine the antibiotic suscepti- bility of isolates. The antibiotic disks were purchased from Padtan Teb Co. (Tehran, Iran). They were manually placed on Muel- lereHinton agar plates by using sterile forceps, with inoculated isolated strains on each plate. After 24 h incubation at 37 C, clear zones were measured in accordance with disks producer guide- lines. Data were analyzed in accordance with recommended stan- dards (Performance Standards for Antimicrobial Susceptibility Testing from the Clinical and Laboratory Standards Institute, Wayne, PA, CLSI, 2007). The isolated strains were classified as sensitive, intermediate, or resistant on the basis of clear zone size