Isolation and Genetic Fingerprinting of Pseudomonas aeruginosa from Iranian Patients with Cystic Fibrosis Using RAPD-PCR

Sixty four Iranian patients with cystic fibrosis (CF) were studied for colonization with Pseudomonasaeruginosa. The patient’s age ranged between 2 months to 18 years old. Twenty one patients werecolonized, 15 with non-mucoid and 6 with mucoid strains of P. aeruginosa. The colonization rateincreased with age and the mucoid phenotype was only recovered from the older patients. All mucoidstrains 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% sensitivityto 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 Tobramycinagreed with the disk test results. However, MIC determination for Amikacin showed a 100% sensitivitycompared to the disk test where 81% sensitivity was observed. The discrepancy may be due to the factthat over 20% of the isolates had borderline MIC values for Amikacin. The genomic fingerprinting of the21 isolates as well as the non-mucoid revertants ofthe mucoid strains was carried out by RAPD-PCRusing primer 272 which was previously used for typing P. aeruginosa isolates from CF patient’s. Thirteengenotypes 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 environmentalsource or cross infection between patients cannot be ruled out.