Tn3-derived inverted-repeat miniature elements that mobilize antibiotic resistance genes

Area of Science:

• Genetics
• Microbiology
• Bioinformatics

Background:

• Miniature inverted-repeat transposable elements (MITEs) are mobile genetic elements mobilized by autonomous transposases.
• Tn3-derived inverted-repeat miniature elements (TIMEs) are a class of MITEs that can form composite structures (TIME-COMPs) capable of mobilizing intervening DNA.
• The association of TIME-COMPs with antibiotic resistance genes (ARGs) has not been systematically investigated.

Purpose of the Study:

• To identify novel TIME-COMP-like structures harboring ARGs within the Enterobacteriaceae family.
• To investigate the prevalence and characteristics of TIME-COMPs carrying antibiotic resistance.

Main Methods:

• Bioinformatic analysis of plasmid (PLSDB) and nucleotide (NCBI) databases.
• Utilized blastn for self-against-self searches to identify repeated elements indicative of TIME-COMPs.
• Screened for known and novel MITEs, including TIMEs, within bacterial genomic sequences.

Main Results:

• Identified multiple previously unreported TIME-COMPs containing ARGs in Enterobacteriaceae.
• Discovered new TIME-COMPs bounded by IS101, MITESen1, and a novel 244 bp TIME (TIME244).
• Found ARGs including blaKPC-2, floR, qnrS1, and tet(A) within these TIME-COMPs, with blaKPC-2 notably present in structures bounded by TIME244 and IS101.

Conclusions:

• TIMEs play a significant role in the dissemination of diverse antibiotic resistance genes.
• Newly identified TIME-COMPs represent a novel mechanism for ARG spread in clinically important bacteria.
• The findings underscore the importance of studying MITEs in the context of antimicrobial resistance evolution.