The plasmid-borne hipBA operon of Klebsiella michiganensis encodes a potent plasmid stabilization system

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Klebsiella michiganensis is a medically significant bacterium with limited research.
• Type II toxin-antitoxin (TA) systems on plasmids influence bacterial phenotypes like plasmid stability and antibiotic persistence.
• The HipBA TA locus is investigated within the Klebsiella oxytoca species complex (KoSC).

Purpose of the Study:

• To characterize the HipBA toxin-antitoxin system in Klebsiella michiganensis.
• To understand the role of HipBA in plasmid maintenance and bacterial phenotypes.
• To analyze the distribution of HipBA systems across the KoSC.

Main Methods:

• Plasmid DNA analysis from K. michiganensis strains.
• Viability and plasmid stability assays using the K. michiganensis PS_Koxy4 strain.
• In silico comparative analysis of HipBA modules across the KoSC.

Main Results:

• The HipBA system is present on a plasmid in K. michiganensis PS_Koxy4, isolated from an infection outbreak.
• PS_Koxy4 HipA functions as a potent antibacterial toxin, and HipBA significantly contributes to plasmid maintenance.
• Comparative in silico data reveal the presence and variations of HipBA modules within the KoSC.

Conclusions:

• This study provides the first evidence for a plasmid-encoded HipBA system's role in mobile genetic element stability.
• The research expands knowledge of a common enterobacterial TA system and its relevance in a medically important bacterial group.
• Findings contribute to understanding K. michiganensis and TA system functions in bacterial pathogenesis and evolution.