Mycoplasma against Staphylococcus
Scientists have created the first "living medicine"
For the first time, Spanish scientists have used modified bacteria to fight antibiotic-resistant microbes that form biofilms on the surface of catheters, pacemakers, prosthetic joints and other medical implants. The article was published in the journal Molecular Systems Biology (Garrido et al., Engineering a genome-reduced bacterium to eliminate Staphylococcus aureus biofilms in vivo).
The surfaces of medical implants are ideal conditions for the growth of biofilms that form impermeable structures that do not allow antibiotics or the human immune system to destroy the bacteria embedded in them. Pathogenic microorganisms associated with biofilms are thousands of times more resistant to antibiotics than separately existing bacteria. At the same time, they account for up to 80 percent of all infections transmitted in hospitals.
One of the most common types of bacteria that form biofilms is Staphylococcus aureus. The infections caused by it cannot be treated with conventional antibiotics, which requires surgical removal of infected medical implants. Alternative treatments using antibodies or broad-spectrum enzymes are very toxic to healthy tissues and cause undesirable side effects.
Researchers from the Center for Genomic Regulation of the Barcelona Institute of Sciences and Technology (Centre for Genomic Regulation, CRG) together with colleagues from other scientific organizations Spain was proposed to use microorganisms — bacteria that produce these enzymes themselves - for targeted delivery of enzymes directly to biofilms.
The authors believe that such a method can become a safe and cheap way to treat infections resulting from medical intervention. In their opinion, bacteria are an ideal delivery vector, since they have small genomes that can be modified using simple genetic manipulations in such a way that these bacteria do not pose a health hazard.
The experimental treatment method was tested on laboratory mice injected with infected catheters. Injections of a drug containing modified Mycoplasma pneumoniae bacteria with a shortened genome allowed 82 percent of infected animals to be cured.
An image of Mycoplasma pneumoniae cells obtained using a scanning electron microscope. Photo: María Lluch/CRG.
Mycoplasma pneumoniae is a common lung pathogen that lacks a cell wall, which simplifies the release of substances that fight infection, and also helps to avoid detection by the human immune system. First, scientists changed the genome of this bacterium so that it could not reproduce, and then, with the help of further adjustments, they made it so that it began to produce two different enzymes that dissolve biofilms and attack the cell walls of bacteria embedded in them.
"Our technology based on synthetic biology and live biotherapeutic agents has been developed taking into account all safety and efficacy standards for use in the lungs, since respiratory diseases are one of our primary goals," the words of the head of the study, Dr. Maria Lluch, are quoted in a press release from the Center for Genomic Regulation.
The researchers plan to conduct clinical trials in 2023 and after that move to large-scale production of "live drugs".
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