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Updated: May 8, 2026
Anti-virulent Disruption of Pathogenic Biofilms using Engineered Quorum-quenching Lactonases
Published on: January 1, 2016
Stability study in selected conditions and biofilm-reducing activity of phages active against drug-resistant
Natalia Bagińska1, Ilona Grygiel1, Filip Orwat1
1Bacteriophage Laboratory, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114, Wrocław, Poland.
Abstract:
Acinetobacter baumannii is currently a serious threat to human health, especially to people with immunodeficiency as well as patients with prolonged hospital stays and those undergoing invasive medical procedures. The ever-increasing percentage of strains characterized by multidrug resistance to widely used antibiotics and their ability to form biofilms make it difficult to fight infections with traditional antibiotic therapy. In view of the above, phage therapy seems to be extremely attractive. Therefore, phages with good storage stability are recommended for therapeutic purposes. In this work, we present the results of studies on the stability of 12 phages specific for A. baumannii under different conditions (including temperature, different pH values, commercially available disinfectants, essential oils, and surfactants) and in the urine of patients with urinary tract infections (UTIs). Based on our long-term stability studies, the most optimal storage method for the A. baumannii phage turned out to be - 70 °C. In contrast, 60 °C caused a significant decrease in phage activity after 1 h of incubation. The tested phages were the most stable at a pH from 7.0 to 9.0, with the most inactivating pH being strongly acidic. Interestingly, ethanol-based disinfectants caused a significant decrease in phage titers even after 30 s of incubation. Moreover, copper and silver nanoparticle solutions also caused a decrease in phage titers (which was statistically significant, except for the Acba_3 phage incubated in silver solution), but to a much lesser extent than disinfectants. However, bacteriophages incubated for 24 h in essential oils (cinnamon and eucalyptus) can be considered stable.
Insights
Phage therapy offers a promising alternative to antibiotics for Acinetobacter baumannii infections. Studies show A. baumannii phages are most stable at -70°C and pH 7-9, but sensitive to disinfectants.
Area of Science:
- Microbiology
- Biotechnology
Background:
- Acinetobacter baumannii poses a significant threat due to multidrug resistance and biofilm formation.
- Traditional antibiotic therapy is increasingly ineffective against A. baumannii infections.
- Bacteriophage therapy presents an attractive alternative for treating A. baumannii infections.
Purpose of the Study:
- To evaluate the stability of 12 bacteriophages targeting A. baumannii under various conditions relevant to therapeutic use.
- To identify optimal storage and handling conditions for A. baumannii phages.
Main Methods:
- Assessed phage stability across a range of temperatures (-70°C to 60°C) and pH levels (acidic to alkaline).
- Tested phage tolerance to disinfectants (ethanol-based), essential oils (cinnamon, eucalyptus), surfactants, and nanoparticle solutions (copper, silver).
- Incubated phages in patient urine samples to assess stability in a relevant biological matrix.
Main Results:
- Optimal phage stability was observed at -70°C; significant activity loss occurred at 60°C within 1 hour.
- Phages demonstrated highest stability at neutral to alkaline pH (7.0-9.0), with strong inactivation in acidic conditions.
- Ethanol-based disinfectants rapidly reduced phage titers within 30 seconds.
- Copper and silver nanoparticles caused a decrease in phage titers, though less pronounced than disinfectants.
- Bacteriophages remained stable for 24 hours in cinnamon and eucalyptus essential oils.
Conclusions:
- Bacteriophage stability is highly dependent on environmental conditions, with low temperatures and neutral-to-alkaline pH being favorable.
- Phage therapy requires careful consideration of disinfectant use and potential interactions with nanoparticles.
- Long-term storage at -70°C is recommended for maintaining the therapeutic efficacy of A. baumannii phages.
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