Monday 30 January 2023

New spray fights infections and antibiotic resistance


Image: By robin_24 -, CC BY 2.0,

A group of researchers (Chalmers University of Technology in Sweden) have developed a spray that can kill even antibiotic-resistant bacteria. The spray can be used for wound care and directly on implants and other medical devices.


It is estimated that antibiotic-resistant bacteria cause nearly 1.3 million deaths a year worldwide. As part of the effort to slow down the spread and development of drug resistance, researchers at Chalmers are developing a new antibacterial material that can be used in healthcare and become an effective tool to fight antibiotic resistance.


The material consists of small hydrogel particles equipped with a type of peptide that effectively kills and binds bacteria. Attaching the peptides to the particles provides a protective environment and increases the stability of the peptides. This allows them to work together with body fluids such as blood, which otherwise inactivates the peptides, making them difficult to use in healthcare. In previous studies, the researchers showed how the peptides can be used for wound care materials such as wound dressings. 


A hydrogel is a biphasic material, a mixture of porous, permeable solids and at least 10% by weight or volume of interstitial fluid composed completely or mainly by water.


The wound spray, which can reach into deep wounds and other open areas on the body where bacteria can enter, is flexible and very useful for treating and preventing infection. The new material has many advantages over existing sprays and disinfectants. Unlike existing bactericidal sprays, it does not inhibit the body's healing process.


For treatments in which materials such as implants and catheters are inserted into human bodies, infections are a major problem. Therefore, there is great need for new antibacterial biomaterials, i.e. materials that treat, replace or modify organs, tissue or functions in a biological body. One of the major sources for hospital-acquired infection comes from the usage of urinary catheters. The Chalmers researchers' new coating is additionally an effective new tool for reducing this risk and preventing infections.



Journal references:


Edvin Blomstrand, Anand K. Rajasekharan, Saba Atefyekta, Martin Andersson. Cross-linked lyotropic liquid crystal particles functionalized with antimicrobial peptides. International Journal of Pharmaceutics, 2022; 627: 122215 DOI: 10.1016/j.ijpharm.2022.122215


Annija Stepulane, Anand Kumar Rajasekharan, Martin Andersson. Multifunctional Surface Modification of PDMS for Antibacterial Contact Killing and Drug-Delivery of Polar, Nonpolar, and Amphiphilic Drugs. ACS Applied Bio Materials, 2022; 5 (11): 5289 DOI: 10.1021/acsabm.2c00705


Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (

Friday 27 January 2023

The chase: viruses vs bacteria


We are all aware of the presence of microbes, such as bacteria, fungi, and viruses, which wreak havoc on our well-being in our daily lives when we come into contact with the bad ones. Many people are unaware that the raging war does not spare the microscopic world. Humans have used the enmity of microbes for hundreds of years to treat infectious diseases. Among the scenarios that revealed the imperceptible microscopic wars were Alexander Fleming's discovery of penicillin and Twort and D'Herelle's discovery of bacteriophages. A virus is the smallest entity known to humans; it is capable of colonizing both the macroscopic and microscopic worlds without concern. They are well suited to infiltrate host cells and trigger a series of events that favor either their survival in the cell or their multiplication in order to infect other cells. Bacteriophages are among the most well-known bacterial killers; in recent years, they have gained popularity as the last resort when antibiotics have failed.

By Raphael Hans

What are bacteriophages?

 Bacteriophages  possesses viral proteins capable of disrupting the host cell. It attaches itself to a susceptible bacterial cell and injects its genetic material into it. The viral genome takes over the host cell's machinery and uses bacterial components to release viral proteins. Bacteriophage attacks are natural, but scientists have attempted to manipulate them to fit the needs of experiments or applications. These particles, like other viruses, are specific to the host they infect, so phages that affect one strain of bacteria may or may not be able to infect another. Furthermore, bacteriophages do not infect human cells at all. Phages, like bacteria, are found everywhere; in fact, they exist whenever bacteria do because they rely on the host cells to multiply. Places rich in bacteria, such as sewage, dumps, fertile soil, and many others, will also have a variety of viral particles that prey on the available bacteria.

The natural effect of bacteriophage on the environment

Bacteriophages maintain the ecosystem's balance by acting as bacteria predators. Because organic matter derived from lysed host cells is immediately consumed by heterotrophic bacteria, lytic bacteriophages are recognized as important regulators of nutrient cycles. Bacteriophages, as a natural enemy of bacteria, including pathogenic bacteria, have also been studied as biological control agents. Phage aids in the balance of microflora in the human gut, among other places. Despite their susceptibility to UV light from the sun, phages can survive in the environment for extended periods of time.

Phage resistant bacteria

Bacteria, as usual, are not helpless in the face of phages; instead, bacteria have developed a number of mechanisms to neutralize or resist phage actions. The most well-known is a CRISPR region that protects bacteria by releasing CAS9 enzymes against bacteriophages, though phages have reversed the action by developing anti-CRISPR mechanisms. Another method of phage infection resistance is a suicidal mission involving bacterial abortive infection (programmed cell death), which involves cell death once the cell is infected by the phage so that the infection does not spread to the entire population.

Application of bacteriophages

Bacteriophages have got numerous applications in this world we are living in, starting from the production of phage-based vaccines, Disinfecting equipment, Diagnosis of bacterial diseases, cleaning fresh food products, phage display, and clinical phage applications like phage therapy. As much as phage technology is considered naive to the world, everyday discoveries are lining up so that the world can appreciate the potential of these particles.

Bacteriophage therapy

Because of their uniqueness and effectiveness in eradicating superbugs, scientists all over the world have been on the lookout for these natural bacterial predators in recent years (multidrug-resistant strains of bacteria). Phages are capable of auto-dosing once applied; they are also capable of mutating in the event that bacteria mutate to gain resistance against them; they have no adverse effects on humans; they are easily removed by the immune system; and they have no effect on other microflora. It has already been reported that these particles have successfully treated multidrug-resistant bugs. When antibiotics failed, phages became the last line of defense.

Despite their colorful properties that apprehend their usefulness, phages have got a negative side too. Among them are; they are capable of causing horizontal antibiotic resistance genes between a bacterium and a bacterium to occur, can be easily removed by the immunity hence act only for short time in case of systemic application, they have a narrow host range and lastly but not least they take a long duration to prepare. To counteract the negative side effects of phage application, scientists have proposed several solutions such as using micelle-like structures to increase phage persistence in the circulation system, creating bacteriophage cocktails to broaden the host range, and having a phage bank that can be used in an emergency. Some people have expressed concern about using the entire virus for treatment, so the solution has been to extract the enzyme lysins and use them against bacteria.


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