ISAba825, a functional insertion sequence modulating genomic plasticity and bla(OXA-58) expression in Acinetobacter
Pablo Ravasi1, Adriana S Limansky, Ramiro E Rodriguez
1Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
Antimicrobial Agents and Chemotherapy
|November 25, 2010
Summary
The insertion sequence ISAba825 can enhance carbapenem resistance in Acinetobacter baumannii by creating a hybrid promoter. This sequence also inactivates the carO gene and shows specific transposition preferences.
Area of Science:
- Microbiology
- Genetics
- Molecular Biology
Background:
- Acinetobacter baumannii is a significant opportunistic pathogen.
- Carbapenem resistance is a growing public health concern.
- Insertion sequences play a role in bacterial genome evolution and adaptation.
Purpose of the Study:
- To investigate the transposition characteristics of ISAba825 in Acinetobacter baumannii.
- To determine the impact of ISAba825 on gene expression and antibiotic resistance.
Main Methods:
- Tagging ISAba825 with a kanamycin resistance cassette.
- Transposition assays in Acinetobacter baumannii.
- Sequence analysis to identify target sites and promoter regions.
Main Results:
- ISAba825::Kn effectively transposed in A. baumannii.
- ISAba825 demonstrated a preference for short, AT-enriched target sequences, creating 6- to 9-bp duplications.
- ISAba825 was found upstream of bla(OXA-58), forming a hybrid promoter that enhanced gene expression and conferred carbapenem resistance.
Conclusions:
- ISAba825 is an active transposable element in Acinetobacter baumannii.
- ISAba825 contributes to carbapenem resistance by modulating bla(OXA-58) expression.
- ISAba825 has implications for understanding carbapenem resistance mechanisms in A. baumannii.
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