Trinity College Dublin Research & Berkeley College Research On Superbug Evolution And Microbial Antibiotic Resistance With Horizontal Gene Transfer (HGT)

Horizontal gene transfer (HGT) is the movement of genetic material between unicellular and/or multicellular organisms other than via vertical transmission (the transmission of DNA from parent to offspring.) HGT is synonymous with lateral gene transfer (LGT) and the terms are interchangeable.

Horizontal gene transfer (HGT) is the sharing of genetic material between organisms that are not in a parent–offspring relationship. HGT is a widely recognized mechanism for adaptation in bacteria and archaea. Microbial antibiotic resistance and pathogenicity are often associated with HGT, but the scope of HGT extends far beyond disease-causing organisms.

Horizontal gene transfer is the primary reason for the spread of antibiotic resistance in bacteria and plays an important role in the evolution of bacteria that can degrade novel compounds such as human-created pesticides and in the evolution, maintenance, and transmission of virulence.

Genes that are responsible for antibiotic resistance in one species of bacteria can be transferred to another species of bacteria through various mechanisms, subsequently arming the antibiotic resistant genes’ recipient against antibiotics, which is becoming a medical challenge to deal with.

Trinity College Dublin Research is focusing to understand how do genetic variations determine individual traits?  Horizontal gene transfer (HGT),

Horizontal gene transfer, or the process of swapping genetic material between neighboring “contemporary” bacteria, is another means by which resistance can be acquired.  Many of the antibiotic resistance genes are carried on plasmids, transposons or integrons that can act as vectors that transfer these genes to other members of the same bacterial species, as well as to bacteria in another genus or species.  Horizontal gene transfer may occur via three main mechanisms: transformation, transduction or conjugation.
Transformation involves uptake of short fragments of naked DNA by naturally transformable bacteria. Transduction involves transfer of DNA from one bacterium into another via bacteriophages.  Conjugation involves transfer of DNA via sexual pilus and requires cell –to-cell contact.  DNA fragments that contain resistance genes from resistant donors can then make previously susceptible bacteria express resistance as coded by these newly acquired resistance genes.

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Genes provide the blueprint for the proteins which make us what we are.   The project to sequence the human genome has inspired knowledge and technologies of tremendous consequence.

Society is in the midst of a transformation that places Biology at the centre of scientific and societal change. Central to this is the accumulation of vast sequence information on genomes, which reveals their organisation and diversity across individuals, species and time.This information, together with remarkable technologies to assess and manipulate gene function, will impact human knowledge, medicine, and technology in myriad ways, most of which remain to be identified.

Berkeley College Study shows how superbug are evolving super-fast because of  Horizontal gene transfer (HGT)

MRSA (methicillin-resistant Staphylococcus aureus) now contributes to more US deaths than does HIV, and as its threat level has risen, so has the attention lavished on it by the media. At this point, almost any move the bug makes is likely to show up in your local paper. Last month saw reporting on studies of hospital screening for MRSA (which came up with conflicting results), stories on MRSA outbreaks (involving both real and false alarms), and media flurries over the finding that humans and their pets can share the infection with one another.

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MRSA is resistant not only to the antibiotic methicillin, but also to whole other suites of our drugs, making it very difficult to treat and, occasionally, deadly. Modern strains of MRSA did not, however, show up out of the blue. In the early 1940s, when penicillin was first used to treat bacterial infections, penicillin-resistant strains of S. aureus were unknown — but by the 1950s, they were common in hospitals. Methicillin was introduced in 1961 to treat these resistant strains, and within one year, doctors had encountered methicillin-resistant S. aureus. Today, we have strains of MRSA that simultaneously resist a laundry list of different antibiotics, including vancomycin — often considered our last line of antibacterial defense.

How did S. aureus morph from a minor skin infection to a big issue. When the media report on MRSA and other drug resistant pathogens, they often say that such pathogens have recently “emerged” — that they’ve “developed” resistance or “learned” to evade our drugs. In fact, it’s more accurate to say that these bugs have evolved resistance. It’s particularly ironic that newspapers might shy away from describing bacterial evolution as such because, when it comes to evolution, bacteria have most of the rest of us beat.

Bacteria are great evolvers for many reasons. For example, their short generation times and large population sizes boost the rate at which they can evolve. In addition, one quirk of bacterial genetics is particularly salient to the evolution of antibiotic resistance.

MRSA

 

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