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Phenotypic and Genotypic Characterization of Recently Isolated Multidrug-Resistant Acinetobacter baumannii Clinical
Irina Gheorghe-Barbu1,2, Viorica Maria Corbu1,2, Corneliu Ovidiu Vrancianu1,2,3
1Faculty of Biology, University of Bucharest, Intr. Portocalelor No. 1-3, 060101 Bucharest, Romania.
Abstract:
This study aims to demonstrate the effectiveness of silver nanoparticles (Ag NPs) on multidrug-resistant (MDR) Acinetobacter baumannii (AB) strains isolated from the clinical and aquatic environment. Three types of Ag NPs were investigated for their antimicrobial, antibiofilm, and antivirulence properties on a total number of 132 AB strains isolated in the same temporal sequence from intra-hospital infections (IHIs), wastewater (WW), and surface water (SW) samples between 2019 and 2022 from different Romanian locations and characterized at the phenotypic and genotypic levels. The comparative analysis of the antimicrobial resistance (AR) profiles according to the isolation source and the geographical location demonstrated a decrease in MDR level in AB recovered from WW samples in 2022 from north-eastern/central/southern regions (N-E/C-W/analyzed strains S): 87.5/60/32.5%. The AB strains were lecithinase, caseinase, amylase, and lipase producers, had variable biofilm formation ability, and belonged to six genotypes associated with the presence of different virulence genes (ompA, csuE, bap, and bfmS). The Ag NPs synthesized with the solvothermal method exhibited an inhibitory effect on microbial growth, the adherence capacity to the inert substratum, and on the production of soluble virulence factors. We report here the first description of a powerful antibacterial agent against MDR AB strains circulating between hospitals and anthropically polluted water in Romania.
Insights
Silver nanoparticles (Ag NPs) effectively combat multidrug-resistant Acinetobacter baumannii (MDR AB) found in clinical and environmental settings. This research highlights Ag NPs as a promising agent against MDR AB strains in Romania.
Area of Science:
- Nanotechnology
- Microbiology
- Environmental Science
Background:
- Multidrug-resistant Acinetobacter baumannii (MDR AB) poses a significant threat in healthcare and environmental settings.
- AB strains are isolated from clinical (intra-hospital infections) and environmental sources (wastewater, surface water) in Romania.
- Understanding the genotypic and phenotypic characteristics of MDR AB is crucial for developing effective treatments.
Purpose of the Study:
- To evaluate the efficacy of silver nanoparticles (Ag NPs) against MDR AB strains.
- To investigate the antimicrobial, antibiofilm, and antivirulence properties of Ag NPs.
- To identify the prevalence and characteristics of MDR AB in Romanian clinical and aquatic environments.
Main Methods:
- Isolation and characterization of 132 MDR AB strains from clinical and environmental samples (2019-2022).
- Phenotypic and genotypic analysis of AB strains, including virulence gene profiling.
- Testing of three types of Ag NPs for antimicrobial, antibiofilm, and antivirulence effects.
Main Results:
- Ag NPs synthesized via solvothermal method showed significant inhibitory effects on MDR AB growth.
- Ag NPs reduced the adherence capacity of AB to inert surfaces and inhibited soluble virulence factor production.
- A decrease in MDR levels was observed in AB from wastewater samples in 2022 across different Romanian regions.
Conclusions:
- Silver nanoparticles represent a potent antibacterial agent against MDR AB strains.
- Ag NPs demonstrate effectiveness in combating MDR AB circulating between hospital and polluted water environments.
- This study provides the first description of Ag NPs as a powerful agent against Romanian MDR AB strains.
