Hello Everyone,
You all might be aware of antimicrobial resistance and its alarming concern for human society. According to a recent survey by the world health organization (WHO), showed almost 65% of the populations in twelve different nations believe that antimicrobial resistance is a major threat and can cause severe health issues to their families. Some of you might know how these bacterial populations become antimicrobial-resistant and what basically poses a threat to make it a superbug.
Microbial populations when subjected to antibiotics they tend to develop certain genetic modifications to overcome those antibiotics over several generations. The microbial genetic system is very smart. Upon exposure to antibiotic the bacterial population dies but some population who survives tend to incorporate a gene for that antibiotic. So, the next time when the same population is treated with the same antibiotics, they survive easily. This process takes certain generations to achieve that, but bacterial populations divide every 20 minutes, so you can do the math. It’s not that slow, though. There are also beliefs that continuous use of an antibiotic leads to this situation, and sometime you may find some of the antibiotics are not showing any effect in case of an infection.
One of the major causes is when people don’t complete their course of medicine, once they start feeling better, they stop taking medicines. This is one of the reasons; when you don’t neutralize the whole population, and now, they are exposed to the antibiotic for a little time or half time. So, next time when they rise again, they will be much strong and more resistant to that old antibiotic.
Recently, a new process was discovered through which bacteria develop antimicrobial resistance. A group of scientists from the National University of Singapore (NUS) and the Imperial College of London (ICL) discovered that there’s another way the bacterial population can transfer their genetic material, and with this new method, the resistance can grow much faster than previously known methods.
Bacteriophage (viruses) are the most common example of transferring genetic material to the bacterial cells. This process of genetic transfer is called transduction, and transduction can be generalized, specialized, and lateral. Out of these, lateral transduction possesses the most reliable and efficient transfer of genetic materials from viruses to bacteria, which is recently discovered by the same group of scientists. Staphylococcus aureus pathogenicity island (SaPIs), is one of the examples of bacterial evolution. SaPIs are considered to be selfish DNA elements, which are commonly found integrated with the chromosome of this bacterial population. The bacterial population is primarily known for its infectious capability to skin and cause Staph infections. The infection can be dangerous if it spreads reach to the bloodstream or the other body parts especially different glands, organs, or bones.
Pathogenic bacterial population has a gene pool that encodes virulence and its accessory proteins. The reason which makes them more effective and dangerous is their ability to transfer the whole gene via gene transfer and make a non-virulent bacterium into a deadly pathogen. Pathogenic Island from Staphylococcus aureus are small and highly mobile family, and the gene is encoded with potential toxins and superantigens. SaPIs are among the most common family of phage-induced chromosomal islands and result from phage infection. Interestingly, due to that, they are able to infect the phage gene with their virulent gene and are considered the molecular parasite to viruses. The SaPIs stay senescent in the S.aureus cell, only upon infection with phage, the life cycle of these genes starts and transfers the DNA. The phage life cycle generally has two phases: lytic and lysogenic, and in both cases, the viral genome of the phage gets incorporated inside the bacterial genome and circularizes episomally. In the case of SaPIs, the DNA packaging process gets hijacked by their genome and replaces the terminase gene. This leads to the packaging of the SaPIs DNA into the phage head, which poses a more efficient transfer of the pathogenic genes to the new bacterial population.
The newly developed method is called lateral co-transduction, which is way more efficient, versatile, and complex. The lateral co-transduction occurs during the reactivation of dormant phages present within the bacterial genome. More surprisingly, the gene (SaPIs) transfer from phage to new bacterial population completes with a transfer of genetic material through lateral co-transduction. It is a self-driven bacterial gene transfer mechanism, which happens repeatedly, making it a more potent and efficient way of genetic transfer.
Advancement in the genetic transfer among bacterial populations and the emergence of superbug has invited scientists to look for a new methodology or technique to overcome these bacterial populations.
Well, it is very clear that the phage which was earlier used to neutralize bacterial population are now the reason for spreading more threatening genes to other population. According to this new finding, it is recommended to put a bar or limitation on the usage of these phage therapeutic systems or at least proper study and records of the patient should be performed.
Chee et. al., 2023 Dual pathogenicity island transfer by piggybacking lateral transduction.
Chen et. al., 2015 Pathogenicity Island-Directed Transfer of Unlinked Chromosomal Virulence Genes.
