Related Experiment Video
Updated: Jan 23, 2026
Rapid and Specific Detection of Acinetobacter baumannii Infections Using a Recombinase Polymerase Amplification/Cas12a-based System
Published on: April 25, 2025
Urinary tract colonization is enhanced by a plasmid that regulates uropathogenic Acinetobacter baumannii chromosomal
Gisela Di Venanzio1, Ana L Flores-Mireles2,3, Juan J Calix4
1Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, 63110, USA.
Abstract:
Multidrug resistant (MDR) Acinetobacter baumannii poses a growing threat to global health. Research on Acinetobacter pathogenesis has primarily focused on pneumonia and bloodstream infections, even though one in five A. baumannii strains are isolated from urinary sites. In this study, we highlight the role of A. baumannii as a uropathogen. We develop the first A. baumannii catheter-associated urinary tract infection (CAUTI) murine model using UPAB1, a recent MDR urinary isolate. UPAB1 carries the plasmid pAB5, a member of the family of large conjugative plasmids that represses the type VI secretion system (T6SS) in multiple Acinetobacter strains. pAB5 confers niche specificity, as its carriage improves UPAB1 survival in a CAUTI model and decreases virulence in a pneumonia model. Comparative proteomic and transcriptomic analyses show that pAB5 regulates the expression of multiple chromosomally-encoded virulence factors besides T6SS. Our results demonstrate that plasmids can impact bacterial infections by controlling the expression of chromosomal genes.
Insights
Multidrug-resistant Acinetobacter baumannii is a significant threat. This study reveals its role as a uropathogen, demonstrating how plasmids influence bacterial infections by regulating chromosomal genes.
Area of Science:
- Microbiology
- Infectious Diseases
- Genetics
Background:
- Multidrug-resistant (MDR) Acinetobacter baumannii is a critical global health concern.
- Pathogenesis research has largely overlooked urinary tract infections (UTIs), despite frequent isolation of A. baumannii from urinary sites.
Purpose of the Study:
- To investigate the role of A. baumannii as a uropathogen.
- To develop a murine model for catheter-associated urinary tract infection (CAUTI) caused by A. baumannii.
- To elucidate the impact of plasmid pAB5 on A. baumannii virulence and niche adaptation.
Main Methods:
- Development of a novel murine CAUTI model using a clinical MDR A. baumannii isolate (UPAB1).
- Characterization of plasmid pAB5, identified as a repressor of the type VI secretion system (T6SS).
- Comparative proteomic and transcriptomic analyses to identify plasmid-regulated chromosomal virulence factors.
Main Results:
- The plasmid pAB5 enhances A. baumannii survival in the urinary tract (CAUTI model) but reduces virulence in a pneumonia model, indicating niche specificity.
- pAB5 was shown to regulate multiple chromosomally-encoded virulence factors beyond the T6SS.
- The study established a functional link between plasmid carriage and modulation of chromosomal gene expression.
Conclusions:
- Plasmids play a significant role in bacterial pathogenesis by controlling the expression of chromosomal genes.
- Acinetobacter baumannii is an important uropathogen, and its virulence is influenced by extrachromosomal elements like plasmids.
- The developed CAUTI model provides a valuable tool for studying A. baumannii urinary tract infections.
Related Concept Videos
01:28Urinary Tract Calculi I: Introduction
01:26Urinary Tract Infection I: Introduction
01:25Urinary Tract Infection II: Pathophysiology
01:28Urinary Tract Calculi V: Nursing Management
01:25Urinary Tract Calculi VI: Surgical Management
01:17Urinary Tract Infection IV: Nursing Management