Drug Resistance Current Affairs - 2019
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Researchers have discovered new class of antibiotics called odilorhabdins or ODLs that fights drug resistance. It was produced by symbiotic bacteria found in soil-dwelling nematode worms that colonise insects for food. The bacterium helps to kill insect and secrete antibiotic to keep competing bacteria away.
Researchers had screened 80 cultured strains of ODL bacteria for antimicrobial activity. They had isolated active ODL compounds and studied their chemical structures and engineered more potent derivatives. During research it was found that ODL act on ribosome (molecular machine that makes proteins cells needed to function) of bacterial cells.
ODL like many clinically useful antibiotics, work by targeting ribosome. But ODL is unique because it binds to place on ribosome that has never been used by other known antibiotics. ODL after binding to ribosome disrupts ability of ribosome of bacterial cells to interpret and translate genetic code.
ODL impact reading ability of ribosome and cause ribosome to make mistakes when it creates new protein. This miscoding corrupts cell with flawed proteins and causes bacterial cell to die.
On testing ODL compounds against bacterial pathogens, including many known to develop resistance it was found that these compounds cured mice infected with several pathogenic bacteria and demonstrated activity against both Gram-negative and Gram-positive pathogens, including carbapenem-resistant Enterobacteriacae.
Many antibiotics slow bacterial growth, but antibiotics that actually kill bacteria such as ODLs called bactericidal antibiotics are rare. ODLs has unconventional source and has distinct way of killing bacteria, making it effective at treating drug-resistant or hard-to-treat infections.
Recently Bugworks Research, a Bengaluru-based biotech startup, became India’s and Asia’s first to receive the international CARB-X (Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator) grant for its antibiotic research and development.
Antibiotic resistance has become global crisis that threatens management of infections, both in community and in hospital practice. The major reasons are indiscriminate use of antibiotics, including against viral infections, prolonged use in patients admitted to hospitals and their abuse in animal husbandry as growth promoters. In hospital critical care units, more than 50% organisms are now resistant even to these drugs.
CARB-X is a public-private international partnership set up in 2016 to focus on innovations to improve diagnosis and treatment of drug-resistant infections. It had grown out of US President Barack Obama’s 2015 Combating Antibiotic Resistant Bacteria (CARB) initiative. It is funded by London-based biomedical research charity Wellcome Trust and US Health Department’s Biomedical Advanced Research and Development Authority (BARDA).
The purpose of CARB X is to provide a new, collaborative approach to speed R&D and delivery of new antibiotics, vaccines, diagnostics, and other innovative products to address urgent global problem of drug-resistant bacterial infections. It will provide grants up to $455 million over a five-year period to firms across globe for antibiotics R&D. All of its funding so far is focused on projects to address most resistant “Gram-negative” bacteria.
Bacteria are classified as Gram-positive and Gram-negative, based on a structural difference in their cell walls. Gram-negative bacteria are responsible for 20-25% of bacterial infections and are multi drug resistant i.e. have ability to defend themselves against drugs that try to kill them.