Investigating the Effectiveness of mqsR-Peptide Nucleic Acid as a Novel Solution for the Eradication of Persister Cells in Clinical Isolates of Escherichia coli

Background: Bacterial persisters are non- or slow -growing phenotypic variants that may be responsible for recalcitrance and relapse of persistent infections and antibiotic failure. In Escherichia coli, mqsRA is a well-known type II toxin -antitoxin system associated with persister cell formation. This study aimed to investigate the efficiency of an anti -sense peptide nucleic acid (PNA) targeting mqsRA in eliminating E. coli persisters. Methods: The study included 600 non -duplicated urine samples from adult patients with suspected urinary tract infections. The isolates were subjected to antimicrobial susceptibility testing and bacterial persister cells assay. The presence of mqsRA in the isolates was evaluated by polymerase chain reaction. Finally, expression of the mqsR and mqsA genes was assessed after exposure to normal conditions, stress, and different concentrations of mqsR- PNA (1 - 35 mu M). Results: The mqsR gene was significantly overexpressed under stress conditions, which was compensated by the PNA treatment. Complete inhibition of E. coli persister cells was achieved after overnight treatment with the antimqsR-PNA at concentrations >= 15 mu M. Conclusions: The growth of E. coli persister cells can be inhibited by the anti-mqsR-PNA. Further studies are required to evaluate the effectiveness of this antisense PNA in both preclinical and clinical settings.