Combating E. coli with Combined Antibiotics in Water and Surfaces

Jenn Hoskins
25th March, 2024

Combating E. coli with Combined Antibiotics in Water and Surfaces

Image Source: Natural Science News, 2024

Key Findings

  • In Russia, a study found that combining lantibiotics with polymyxins fights E. coli better
  • This combo reduces E. coli in biofilms by up to tenfold, making infections easier to treat
  • The treatment damages E. coli's protective biofilm and leads to bacterial cell death
In the ongoing battle against antibiotic-resistant bacteria, scientists are constantly searching for new strategies to outsmart these microscopic adversaries. A recent study by researchers at the Ural Branch of the Russian Academy of Sciences[1] has shed light on a promising approach to tackle one of the most prevalent and problematic bacteria, Escherichia coli (E. coli). This study has found that combining two types of antibacterial agents, lantibiotics and polymyxins, can significantly enhance the effectiveness of treatments against E. coli, even among strains that are resistant to multiple drugs. E. coli is a type of bacteria that can cause various infections, ranging from mild gastrointestinal distress to severe, life-threatening conditions. The bacteria are known for their ability to form biofilms—a protective layer that allows them to stick to surfaces and shield themselves from antibiotics. This makes infections particularly challenging to treat. Lantibiotics are a class of potent antibacterial proteins produced by certain strains of bacteria. They have been recognized for their ability to attack other bacteria, making them potential allies in the fight against infections. However, E. coli has typically shown resistance to these lantibiotics, limiting their use. Polymyxins, on the other hand, are antibiotics that disrupt the outer membrane of bacteria, particularly in Gram-negative bacteria like E. coli. They have been used as a last-resort treatment due to their side effects and the emergence of resistance. Interestingly, polymyxins have been noted for their ability to work in concert with other antibiotics to enhance their effectiveness[2]. The researchers discovered that when E. coli was exposed to subinhibitory concentrations of polymyxins—doses that are not high enough to kill the bacteria on their own—there was an increased sensitivity of the bacteria to lantibiotics. This synergistic effect was observed with polymyxins B and M when combined with lantibiotics such as nisin and warnerin. The combination resulted in a substantial decrease in the number of viable E. coli cells, both in their free-swimming (planktonic) state and within biofilms. Biofilms are complex communities of bacteria that are notoriously difficult to eradicate due to their protective matrix and altered metabolic state[3]. They contribute to the persistence and chronic nature of infections. The study found that a 24-hour treatment with the lantibiotic-polymyxin B combination led to a five to tenfold reduction in the number of viable E. coli cells within biofilms. Atomic force microscopy (AFM), a technique that allows scientists to visualize surfaces with nanometer resolution, revealed that the combination of warnerin and polymyxin B not only reduced the number of bacteria but also compromised the structural integrity of the biofilm. This was a significant finding, as biofilms are a major hurdle in treating infections. Moreover, the study showed that pretreatment with polymyxin B altered the levels of essential ions such as calcium (Ca2+) and magnesium (Mg2+) in the culture medium. Following exposure to warnerin, cells lost vital potassium ions (K+), leading to cell death and the release of DNA and proteins—hallmarks of cell destruction. These findings are particularly relevant as they build upon previous research that has explored the synergistic effects of antibiotic combinations[4]. The integration of metabolomic and transcriptomic analyses has provided insights into how antibiotic combinations can disrupt the metabolism and gene expression of bacteria, leading to their demise. The current study extends this knowledge by demonstrating a successful combination that targets the notoriously resistant E. coli biofilms. Additionally, the research aligns with the broader scientific understanding that compounds which disrupt the bacterial outer membrane can potentiate the effects of other antibiotics[2]. This study provides further evidence that such combinations can be effective against E. coli, a member of the ESKAPE group of pathogens that are known for their ability to escape the effects of antibiotics. In summary, the study by the Ural Branch of the Russian Academy of Sciences offers hope in the development of more effective treatments against multidrug-resistant E. coli. By leveraging the synergistic effects of lantibiotics and polymyxins, researchers have identified a combination that can break through the defenses of biofilms, pointing the way to potential new therapies for stubborn bacterial infections.

BiotechBiochemMarine Biology

References

Main Study

1) Suppression of planktonic and biofilm of Escherichia coli by the synergistic lantibiotics-polymyxins combinations.

Published 23rd March, 2024

https://doi.org/10.1007/s00203-024-03922-8

Related Studies

2) Synergy by Perturbing the Gram-Negative Outer Membrane: Opening the Door for Gram-Positive Specific Antibiotics.

https://doi.org/10.1021/acsinfecdis.2c00193

3) Synergistic Inhibitory Effect of Polymyxin B in Combination with Ceftazidime against Robust Biofilm Formed by Acinetobacter baumannii with Genetic Deficiency in AbaI/AbaR Quorum Sensing.

https://doi.org/10.1128/spectrum.01768-21

4) Integrated metabolomic and transcriptomic analyses of the synergistic effect of polymyxin-rifampicin combination against Pseudomonas aeruginosa.

https://doi.org/10.1186/s12929-022-00874-3


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