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Published on: May 4, 2018
Characteristics of multiresistant Pseudomonas aeruginosa isolates from burn patients in Iran
Arash Abednezhad1, Bita Bakhshi2, Nastaran Asghari Moghadam1
11Department of Biology, Central Tehran Branch, Islamic Azad University, Tehran, Iran.
Abstract:
Infections caused by multidrug resistant (MDR) Pseudomonas aeruginosa isolates in burn patients restrict therapeutic strategies. The current study aimed to analyze antibiotic resistance genes and multilocus sequence typing (MLST) of P. aeruginosa strains isolated from burn patients in Shahid Motahari hospital in Tehran, Iran.Altogether 63 P. aeruginosa isolates were characterized in this study. Antibiotic susceptibility testing was performed by disc diffusion method. PCR was performed to determine the frequency of resistance genes. The expression rates of mexB, mexY genes were evaluated by Real-Time PCR. Genotyping of isolates was performed by MLST analysis. All isolates were MDR in this study. The highest resistance was detected against gentamicin, tobramycin, and cefoxitin (100%), while all isolates were susceptible to colistin. Altogether 14 resistance profiles were determined, and profile 1 included more than 50% of the isolates with the highest resistance. In this study blaampC, blaVIM-2, blaOXA-10, and aac(6')-Ib resistance genes were detected in all isolates. The expression levels of mexB and mexY genes were upregulated in 66.6 and 88.8% of MDR isolates, respectively. Overexpression of both genes was detected in 55.5% of the isolates.MLST analysis revealed five sequence types (STs), including ST235, ST664, ST532, ST2637, and ST230, which showed a significant relationship with antibiotic resistance profiles. The present study indicates an increase in antibiotic resistance against different antibiotic families among P. aeruginosa isolates. We describe the circulation of globally distributed STs among hospitalized patients, and we report ST235 as the most common MDR clone in our study.
Insights
Multidrug-resistant Pseudomonas aeruginosa strains from burn patients show high resistance to common antibiotics. Multilocus sequence typing identified specific clones, including ST235, as prevalent in this hospital setting.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Burn Care
Background:
- Multidrug-resistant (MDR) Pseudomonas aeruginosa poses a significant challenge in treating burn wound infections.
- Limited therapeutic options exist for MDR P. aeruginosa infections, necessitating detailed molecular characterization.
Purpose of the Study:
- To analyze antibiotic resistance genes and perform multilocus sequence typing (MLST) of P. aeruginosa strains from burn patients.
- To identify prevalent resistance mechanisms and genetic lineages of MDR P. aeruginosa in a Tehran hospital.
Main Methods:
- Antibiotic susceptibility testing using disc diffusion.
- Polymerase Chain Reaction (PCR) for resistance gene detection.
- Real-Time PCR for mexB and mexY gene expression analysis.
- MLST for P. aeruginosa isolate genotyping.
Main Results:
- All 63 P. aeruginosa isolates were MDR, with 100% resistance to gentamicin, tobramycin, and cefoxitin; all were susceptible to colistin.
- blaampC, blaVIM-2, blaOXA-10, and aac(6')-Ib genes were present in all isolates.
- mexB and mexY gene expression was upregulated in a high percentage of MDR isolates (66.6% and 88.8%, respectively).
- MLST identified five sequence types (STs), with ST235 being the most common MDR clone and showing a significant relationship with resistance profiles.
Conclusions:
- There is a concerning increase in antibiotic resistance among P. aeruginosa isolates in burn patients.
- Globally distributed STs, particularly ST235, are circulating in hospitalized patients, contributing to MDR infections.
- Understanding the molecular epidemiology of MDR P. aeruginosa is crucial for effective infection control and treatment strategies in burn units.
