Detection of Antibiotic Resistance Genes among Pseudomonas aeruginosa Strains Isolated from Burn Patients in Iran
Ali Hashemi *
Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Fatemeh Fallah
Pediatric Infections Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Soroor Erfanimanesh
Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Alireza Salimi Chirani
Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Masoud Dadashi
Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
*Author to whom correspondence should be addressed.
Abstract
Aim: In this study, we evaluated the presence of antibiotic resistance genes among P. aeruginosa strains.
Methodology: From January to September 2012, 100 isolates of P. aeruginosa were collected from burn patients. Antimicrobial susceptibility testing was performed by disk diffusion method. Screening for Metallo-β-lactamases (MBLs) productions were performed by Combination Disk Diffusion Test (CDDT). The frequency of antibiotic resistance encoding genes such as MBLs (IMP, VIM, NDM), ESBLs (CTX-M-15), Amp-C enzyme (CMY), Ambler class A carbapenemases (KPC), Ambler class D β-lactamase (OXA-48), 16S rRNA methylases (armA, rmtB, rmtC, rmtD), Quinolone Resistance Gene (aac(6′)-Ib) and class 1 integron were performed by PCR and Sequencing techniques.
Results: 48(62.33%) of isolates were metallo-beta-lactamase producers. All MBL-producing P. aeruginosawere resistant to antibiotics; while 49% of isolates were resistant to Gentamicin. The aac(6)-Ib, CTX-M-15, int I, CMY, rmtB , rmtD and IMP-1 genes were detected in 57 (74.02%), 48 (62.3%), 48 (62.3%), 7 (9.09%), 11 (14.28%), 9 (11.68%) and 6 (7.7%) isolates respectively, whereas none of them were positive for other genes. The mortality rate due to metallo-β-lactamases-producing P. aeruginosa infection was 5(10.4%).
Conclusions: The prevalence of antibiotic resistance genes producing P. aeruginosa detected in this study is of great concern.
Keywords: Pseudomonas aeruginosa, burn patients, antibiotic resistance genes