Armaghane Danesh Bimonthly Journal (Nov 2015)
Emergence of Multidrug-Resistant Pseudomonas aeruginosa: Detection of Isolates harboring blaCTX gene causing infections in hospital and determination of their susceptibility to antibiotics
Abstract
Background & aim: Because of its ubiquitous nature, ability to survive in moist environments, and innate resistance to many antibiotics and antiseptics, P. aeruginosa is a common pathogen in hospitals. The goals of this study were detection of Psudomonas aeruginosa harboring blaCTX gene causing infections in hospitals and determination of their susceptibility to antibiotics and ESBL production. Methods: In the present cross-sectional study, clinical samples from hospitalized patients were collected and culture was done on apropriate media. Final identification was performed using biochemical tests and API 20NE system. According to the protocol CLSI 2014 disc diffusion, combination disk, modified hodge test (MHT) and E-test were used for antibiotic susceptibility, ESBL production, carbapenemas production, and MIC values of imipenem respectively. The blaCTX gene was detected in the isolates by PCR molecular method. Results: In the current study, 45 isolates of Pseudomonas aeroginosa were obtained from hospitalized patients, consisting of 19 males (42.2%) and 26 females (57.8%). As observed, 57.8% (26 strains) of isolates were recovered from sputum. The most effective antibiotics against isolates were amikacin and colistin with 97.8% suseptibility whereas the highest resistance was to cefotaxime (97.8%). As revealed 77.8% of isolates showed response to group 2 carbapenems (imipenem, meropenem). All imipenem resistant strains had the MIC more than 32. Seventeen strains (37.7%) were showed resistant to quinolones (ciprofloxacin, norfloxacin). The results of PCR on blaCTX gene indicated that 15.5% of the isolates possess the gene. Conclusion: Carbapenem group of antibiotic in 22% of infections caused by Pseudomonas aeruginosa were ineffective and indiscriminate prescribing of these drugs will increase the ratet of resistance.
