Mcr-1 isolated in India, a further chapter in antibiotic resistance
Nov 18, 2016
Why in News:
Indian researchers have isolated a strain of E.Coli bacteria, carrying a new gene (mcr -1), described previously as ‘truly pan-drug resistant’. It is resistant to the last mile antibiotic the human race currently has access to —colistin.
What is the importance of it:
While colistin resistance had already been detected in India, it existed thus far only as mutations in the chromosomal/genetic path. Now, mutations do not spread from patient to patient. With mcr-1, however, the gene is found in the plasmid medium, a small DNA molecule outside of the chromosomal DNA, meaning the infection can spread in hospitals, and the community.
What is Antibiotic resistance:
Antimicrobial resistance happens when microorganisms (such as bacteria, fungi, viruses, and parasites) change when they are exposed to antimicrobial drugs (such as antibiotics, antifungals, antivirals, antimalarials, and anthelmintics). Microorganisms that develop antimicrobial resistance are sometimes referred to as “superbugs”
What causes this:
- Evolution:All living things evolve, but bacteria, viruses and parasites are experts at it, and do it very rapidly. Developing resistance to antimicrobials can occur naturally whenever they are used and can happen in several ways, through spontaneous mutation and via the transfer of genes.
- Human Behaviour:The increasing availability and low cost of antibiotics has resulted in their inappropriate use all around the world. This includes their over-use, misuse and underuse in human health, animal husbandry and agriculture. This inappropriate use has been the key driver of increased antibiotic and antimicrobial resistance globally. The emergence and spread is increasing at a pace that exceeds the pharmaceutical industry’s capacity to develop new antimicrobial drugs.
How do bacteria become resistant?
Some bacteria are naturally resistant to certain types of antibiotics.However, bacteria may also become resistant in two ways:
By a genetic mutation:Mutations are rare spontaneous changes of the bacteria's genetic material.Some mutations enable the bacteria to produce potent chemicals (enzymes) that inactivate antibiotics, while other mutations eliminate the cell target that the antibiotic attacks.
By acquiring resistance from another bacterium:Bacteria can acquire antibiotic resistance genes from other bacteria by undergoing a simple mating process called "conjugation” where bacteria can transfer genetic material, including genes encoding resistance to antibiotics from one bacterium to another.Viruses are another mechanism for passing resistance traits between bacteria. The resistance traits from one bacterium are packaged into the head portion of the virus. The virus then injects the resistance traits into any new bacteria it attacks.
Genetically, antibiotic resistance spreads through bacteria populations both "vertically," when new generations inherit antibiotic resistance genes, and "horizontally," when bacteria share or exchange sections of genetic material with other bacteria.
Why this is global concern
- New resistance mechanisms are emerging and spreading globally, threatening our ability to treat common infectious diseases, resulting in prolonged illness, disability, and death.
- Without effective antimicrobials for prevention and treatment of infections, medical procedures such as organ transplantation, cancer chemotherapy, diabetes management and major surgery (for example, caesarean sections or hip replacements) become very high risk.
- Antimicrobial resistance increases the cost of health care with lengthier stays in hospitals and more intensive care required.
- Antimicrobial resistance is putting the gains of the Millennium Development Goals at risk and endangers achievement of the Sustainable Development Goals.