Muller hinton agar medium

Antibiotic sensitivity of 20 isolates of P. aeruginosa from patients was evaluated to 12 different antibiotics. Antibiotic susceptibility patterns of isolates were determined by Kirby-Bauer disk diffusion method on the Muller-Hinton agar medium (Hi-Media, India) (21 ).
Different antibiotic discs (Padtan Teb, Iran) including penicillin (10 μg), amoxicillin (25 μg), gentamicin (10 μg), nalidixic acid (30 μg), tetracycline (30 μg), imipenem (10 μg), amikacin (30 μg), kanamycin (30 μg), tobramycin (10 μg), cefepime (30 μg), cefixime (5 μg), rifampicin (5 μg) were used in this study. After incubation time, the diameter of the non-growth holes was measured by the ruler and the isolates were classified into sensitive, semi-sensitive and resistant groups, according to the Clinical & Laboratory Standards Institute (CLSI) guidelines (22 ).

The collected urine samples were directly plated on Cystine Lactose Electrolyte Deficient agar media using a calibrated inoculating wire loop (0.001ml). The culture plates were incubated overnight at 37 °C. After 24–48 h colonies were counted and bacterial growth of ≥10⁵ CFU/ml of urine was considered significant. Using the standard microbiological technique, all positive cultures with significant bacteriuria were identified at the species level by their colony properties, Gram-staining characteristics, and biochemical profiles.
The isolated microbes were subjected to antimicrobial susceptibility testing by Kirby- Bauer disk diffusion technique using Muller-Hinton agar medium (Hi Media Laboratories Pvt, Ltd). The zone of growth inhibition was evaluated and classified as susceptible (S), intermediate (I), or resistant (R) using the Clinical and Laboratory Standards Institute guidelines, after 18–24 h of incubation at 37°C [18] .