Abstract

Pseudomonas aeruginosa is a leading cause of infections including pneumonia, urinary tract infections and bacteremia, especially in patients with weakened immune systems. This pathogen is intrinsically resistant to many antibacterial agents, such as most beta lactams. The aim of this study was to survey antibiotic resistance pattern and frequency of bla VEB 1 and bla OXA10 genes in multidrug-resistance P. aeruginosa isolated from non burn patients in Isfahan hospitals. Total of 100 clinical isolates of P. aeruginosa from different samples were collected. Antibiotic susceptibility for antimicrobial agents was carried out according to the Clinical and Laboratory Standards Institute (CLSI) guidelines and the frequency of these genes was studied by polymerase chain reaction (PCR). Among the isolated strains, resistant rate to the antibiotic ciprofloxacin was 56%, gentamicin 59%, tobramycin 61%, amikacin 65%, imipenem 55%, cefepime 55%, ceftazidime 57%, ceftriaxone 60%, cefotaxime 62% and piperacillin was 48%, respectively. P. aeruginosa demonstrated the highest resistance rate to amikacin (65 %), 55% of isolates were resistance to imipenem and cefepime whereas 63% were MDR (resistant to three or more classes of antibiotics). A multidrug-resistant (MDR) phenotype occurred frequently in P. aeruginosa. PCR was performed for all the resistant strains,prevalence of structural genes for VEB-1 and OXA-10 in isolates were 38 (60%) and 40 (64%), respectively. Proper infection control practices are essential to prevent spreading and outbreaks of ESBL-producing P. aeruginosa in hospitals.

Key words: Pseudomonas aeruginosa, ambler class A and D b-lactamase, antibiotic resistance.