Characterization of Toxin-Antitoxin (TA) Systems in Pseudomonas aeruginosa Clinical Isolates in Iran.
BACKGROUND
Pseudomonas aeruginosa is among the most problematic hospital and community-acquired pathogens. Toxin-antitoxin (TA) systems are maintenance regulatory systems in bacteria and have recently been considered new targets for antimicrobial therapy. The prevalence and transcription of these systems in clinical isolates are still unknown.


OBJECTIVE
The aim of this study was to characterize three types of TA systems (parDE, relBE, and higBA) among P. aeruginosa clinical isolates.


METHODS
We typed our clinical isolates by ERIC-PCR (enterobacterial repetitive intergenic consensus sequence-based polymerase chain reaction) and BOX-PCR. We then investigated 174 P. aeruginosa clinical isolates from three hospitals in Ahvaz, Iran, for the presence of TA system genes, and determined whether these systems were encoded on chromosomes or plasmids by amplification of the flanking regions.


RESULTS
Our results showed that in the 174 P. aeruginosa isolates, relBE and higBA were universal, but parDE was less prevalent. Both of the flanking regions of the parDE genes in all positive isolates were amplified. The flanking regions of nearly all relBE genes were amplified. Amplification was observed for the downstream sequence of every higBA locus, as well as for the region upstream of higBA, except in 14 strains.


CONCLUSIONS
Based on the presence of TA systems in the majority of P. aeruginosa isolates, these could be used as a novel target for antimicrobial therapy.
Department of Microbiology, Medicine school, Tehran University of Medical Sciences, Tehran, IR Iran.
Mohammad
M
Savari
Infectious Disease and Tropical Medicine Research Center, Isfahan University of Medical Sciences, Isfahan, IR Iran.
Soodabeh
S
Rostami
Department of Laboratory Medical Sciences, Faculty of Para Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran.
Alireza
A
Ekrami
Department of Microbiology, Medicine school, Tehran University of Medical Sciences, Tehran, IR Iran.
Abbas
A
Bahador
Gene Regulatory Networks; Genotyping; Pseudomonas aeruginosa; Resistance