ABSTRACT
Background: Pseudomonas aeruginosa causes large percentages of nosocomial infections with high rates of treatment failure due to antibiotic resistance. The production of extended spectrum beta lactamases [ESBLs] is a principal mechanism of antibiotic resistance of this bacterium. Such infections represent a great challenge in our hospitals
Objectives: Application of phenotypic methods and PCR for detection of bla[OXA-10] and bla[GES-1] extended-spectrum beta-lactamases in Pseudomonas aeruginosa isolated from cases of nosocomial infections in Ismailia city, Egypt
Methodology: Forty five isolates of P. aeruginosa isolated from cases of surgical site infection were submitted for antibiotic susceptibility testing, followed by phenotypic screening for both OXA-10 and GES-1 beta lactamases using disc combination method of ceftazidime-clavulanic acid and cefotaxime- clavulanic acid disks. PCR targeting genes of these ESBLs was applied for more accurate detection
Results: The resistance rates were 100% for ampicillin, cefoxitin, cefuroxime, and cefazolin while for cefotaxime, ceftriaxone, ceftazidime and cefepime, the resistance reached 84.5%, 68.9%, 57.8% and 37.8%, respectively. Imipenem, ciprofloxacin and gentamicin were the most effective antibiotics as they had sensitivity rates of 77.8%, 68.9%, and 73.4%, respectively. Disc combination tests were positive in more than two thirds of isolates. PCR detected blaOXA-10 and blaGES-1 in fifteen and twelve isolates, respectively
Conclusion: ESBLs are still playing major role in marked antibiotic resistance P. aeruginosa against the extended beta lactam antibiotics in Ismailia, Egypt as OXA-10 and GES-1 beta lactamases were isolated at rates of 33.3% and 26.7%, respectively. The current study provides a new report for detection of GES-1 in Egypt