Survey of antibiotic resistance of Pseudomonas aeruginosa isolated from patients in hospitals of Tehran in 2013

Pseudomonas aeruginosa is a gram-negative pathogen and one of the main causes of nosocomial infections with its multiresistance mechanisms, is known as the second important cause of infections that despite of existence of several antibiotics, the treatment against it is so difficult. This study has been done to detect the antibacterial sensitivity of P.aeruginosa with the use of two methods of disk-diffusion and microdilution and then to compare between them.
100 clinical isolates of Pseudomonas aeruginosa were collected from selected hospitals of Tehran and then after identification, the resistance pattern of the bacteria were studied with two methods of diskdiffusion and microdilution for these antibiotics: Ampicillin/Sulbactam, Piperacillin, Carbenicillin, Imipenem, Cefteriaxone, Ceftazidime, Cefoperazone, Gentamicin, Tobramycin, Amikacin, Chloramphenicol, Tetracyclin, Ciprofloxacin; then the results were analyzed by statistical tests.
The rate of resistance with the method of disk-diffusion was in the range of 28-100 percent for imipenem and tetracycline and with the method of microdilution was in the range of 30-97 percent for imipenem and ampicillin/sulbactam. Also, K-value which is used for survey of agreement between two methods used in this study, was 0.0 for tetracycline and more than 0.0 for other antibiotics.
P.aeruginosa has the maximum sensitivity to imipenem with both methods, so it is suggested to specialists for clinical use. The results have high agreement in all antibiotics except Tetracycline so the disk-diffusion method has a proper sensitivity for detection the antibacterial resistance of P.aeruginosa as well as microdilution method.