DefinePK

Abstract

Background:   The type II toxin-antitoxin system consists of tightly linked genetic units that produce  a toxin and its specific antitoxin. Under typical circumstances, the antitoxin  neutralizes the toxic effects caused by the toxin. However, the toxin-antitoxin systems during stress regulate bacterial growth and persistence by affecting translation or DNA replication. This study aimed to assess how variations in temperature and pH stress influence the regulation of type II toxin-antitoxin gene expression  within  Klebsiella pneumoniae  isolates. Methods:  Sixty-five  Klebsiella pneumoniae  isolates were identified by the VITEK®2 compact system and confirmed identity by Polymerase Chain Reaction assay by amplified  rpoB  gene (Housekeeping gene). The isolates were subjected to Reverse Transcriptase-polymerase chain Reaction assay to determine the transcriptional variations of the type II toxin-antitoxin system genes at diverse temperature and pH values. Results:  The results of the current study demonstrated higher expression levels of the antitoxin  hipB  gene at (37℃, 30℃, 44℃, pH 7, pH 9),  mqsR  toxin gene at (37℃, 30℃, pH 7, pH 5, pH 11) and  relE  toxin gene at (pH 5, pH 11). Conclusion:  These findings suggest the possible influence of pH and temperature on toxin-antitoxin systems, which might enhance bacterial antibiotic tolerance and persistence. Keywords: Toxin-antitoxin systems; pH stress; Temperature stress;  Klebsiella pneumoniae ; Gene expression; Reverse Transcriptase PCR