Biology Department, Faculty of Science, Shahid Beheshti University. Evin, Tehran, Iran.
Children’s Hospital Medical Center, Tehran University of Medical Sciences, Tehran, Iran.
British Columbia’s Research Institute for Children’s and Women’s Health. Vancouver, British Columbia, Canada.
British Columbia’s Research Institute for Children’s and Women’s Health. Vancouver, British Columbia, Canada
Division of Infectious Diseases, Department of Pediatrics, Faculty of Medicine, University of British Columbia, Vancouver, Canada.
Sixty four Iranian patients with cystic fibrosis (CF) were studied for colonization with Pseudomonas
aeruginosa. The patient’s age ranged between 2 months to 18 years old. Twenty one patients were
colonized, 15 with non-mucoid and 6 with mucoid strains of P. aeruginosa. The colonization rate
increased with age and the mucoid phenotype was only recovered from the older patients. All mucoid
strains came from patients with respiratory disease whereas most of the non-mucoid isolates (n=13)
were from patients with gastrointestinal disorder. The antibiograms of the isolates showed 100% sensitivity
to Imipenem and Collistin followed by Ciprofloxacin (90.5%), Ceftazidime, and Tobramycin (85.7%),
Amikacin, Piperacillin and Tazobactam-Piperacillin (81%), Ticarcillin (76%), Gentamycin (62%),
Mezlocillin (52.4%) and Carbenicillin (43%). The MICs for Ceftazidime, Gentamycin and Tobramycin
agreed with the disk test results. However, MIC determination for Amikacin showed a 100% sensitivity
compared to the disk test where 81% sensitivity was observed. The discrepancy may be due to the fact
that over 20% of the isolates had borderline MIC values for Amikacin. The genomic fingerprinting of the
21 isolates as well as the non-mucoid revertants ofthe mucoid strains was carried out by RAPD-PCR
using primer 272 which was previously used for typing P. aeruginosa isolates from CF patient’s. Thirteen
genotypes were found among the 21 isolates. One fingerprint (A) was found in 6 patients and another
(B) was shared by 2 patients, all from the same health center. The idea of the hospital as environmental
source or cross infection between patients cannot be ruled out.