Thursday, November 6, 2014

Endolysin-A new tool to overwhelm Super Bugs

The so called super bugs which have emerged during the last few years which are resistant to most known antibiotics may imperil the lives of millions of people infected by them if suitable alternative therapy is not developed fast. Though many scientists are working to evolve satisfactory antidotes to them success has been far and few. One of the reasons is lack of investment in developing new classes of antibiotics that can destroy them. Reckless use of antibiotics for even those afflictions not caused by pathogenic bacteria and for non-medical purpose like incorporating in animal feed for fattening the animals or lacing the growing medium by aqua culture industry have greatly contributed to emergence of super bugs not responsive to normal antibiotics. It has been shown clearly that many bacteria can create biofilms around them which are unimpregnable and therefore inaccessible to the antibiotic molecule making it ineffective. If this film can be breached, the bacterial cells are highly vulnerable to destruction. Such an approach seems to have succeeded with a group of scientists in the Netherlands coming out with a biological agent (endolysins) that can be effective in exploiting the chink in the armor of these pathogens offering alternative therapy for killing drug resistant organisms. Here is a take on this new exciting development.

"In a breakthrough, scientists have developed the first effective alternative to antibiotics that may aid the fight against drug-resistant infections.  In a small patient trial, the drug was shown to be effective at eradicating the superbug Methicillin-resistant Staphylococcus aureus (MRSA). Researchers said it is unlikely that the infection could develop resistance against the new treatment, which is already available as a cream for skin infections. They hope to develop a pill or an injectable version of the drug within five years. The treatment marks "a new era in the fight against antibiotic-resistant bacteria," according to Mark Offerhaus, chief executive of the biotechnology company Micreos, which is behind the advance. The treatment attacks infections in an entirely different way from conventional drugs and, unlike them, exclusively targets the Staphylococcus bacteria responsible for MRSA, and leaves other microbes unaffected. The approach is inspired by naturally occurring viruses that attack bacteria using enzymes called endolysins. It uses a 'designer' endolysin, Staphefekt, which the scientists engineered to latch on to the surface of bacteria cells and tear them apart, 'The Times' reported. "Endolysins exist in nature, but we've made a modified version that combines the bit that is best at binding to the bacteria with another bit that is best at killing it," said Bjorn Herpers, a clinical microbiologist, who tested the drug at the Public Health Laboratory in Kennemerland, the Netherlands. Conventional antibiotics need to reach the inside of the cell to work, and part of the reason they are becoming less effective is that certain strains of bacteria, such as MRSA, have evolved impenetrable membranes. By contrast, endolysins target basic building blocks on the outside of bacterial cells that are unlikely to change as infections genetically mutate over time. Scientists believe that the results could mark the first of a wave of endolysin-based therapies for infections that conventional drugs are no longer able to treat. About 80 per cent of gonorrhoea infections are resistant to frontline drugs, and multidrug-resistant salmonella, tuberculosis and E coli are regarded as significant threats. Naturally occurring endolysins can attack all of these diseases, and the challenge is to create stable versions that can be packaged as drugs, researchers said." 

It is encouraging to note that new endolysins are being evolved to attack and kill the organisms concerned containing both the cell membrane busting molecule and the killing molecule. Formulations like skin creams, tablets and injections may be in the offing soon and the specter of epidemics caused by these hitherto indestructible vectors may not be that daunting if these developments are taken to their logical conclusion. Interestingly endolysins do not seem to be affecting normal bacteria unlike antibiotics which when taken orally cause considerable havoc in the intestine harming many beneficial bacteria, part of human microbiome, considered critical to the well being of man. Those afflicted by deadly diseases like gonorrhoea, salmonella, tuberculosis, virulent E.coli, etc can heave a sigh of relief if the new therapy is brought to main the stream medical practices.


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