Why In News?

An editorial by Dr. Govindan Rajamohan (CSIR-Institute of Microbial Technology, Chandigarh) explained how engineering microbiomes and manipulating the mobilome disrupts horizontal resistance gene transfer to combat global antimicrobial resistance (AMR).

 

What is Antimicrobial Resistance?

Antimicrobial Resistance (AMR) occurs when microorganisms like bacteria, viruses, fungi, and parasites evolve over time to defeat the medicines designed to kill them.

 

Antimicrobial-resistant microorganisms: Include resistant bacteria, viruses, fungi, and parasites; Gram-negative bacteria generally deploy multiple resistance mechanisms simultaneously, making them particularly difficult to treat.

 

Superbugs: Popular term for multidrug-resistant (MDR) organisms that have evolved resistance to multiple classes of antimicrobials, rendering standard treatments ineffective.

 

Key Types of Resistance

  • Antibiotic Resistance: Bacteria become immune to antibiotics, making common bacterial infections untreatable.

  • Antiviral Resistance: Viruses stop responding to antiviral drugs, impacting treatments for illnesses like HIV or influenza.

  • Antifungal Resistance: Fungi resist antifungal treatments, threatening vulnerable or immunocompromised patients.

  • Antiparasitic Resistance: Parasites evade antiparasitic medications, complicating the treatment of diseases like malaria. 



Primary Drivers of Drug Resistance

While resistance can develop naturally through spontaneous genetic mutations, human activity drastically accelerates the process: 

  • Misuse and Overuse of Drugs: Taking antibiotics for viral infections (like colds or flu) or using them incorrectly creates selective pressure that leaves only the strongest, most resistant bugs alive. 

  • Agricultural Overprescription: Heavy use of critical antimicrobials in livestock farming and aquaculture to promote animal growth accelerates the spread of resistant strains into food supplies and ecosystems. 

  • Poor Sanitation & Infection Control: Inadequate hygiene, restricted access to clean water, and poor sterilization in healthcare settings allow resistant superbugs to rapidly multiply and pass between patients.  

  • The Mobilome Link: Bacteria use mobile genetic networks—the mobilome—to actively trade resistance genes directly with neighboring species, skipping traditional generation-by-generation evolution.  

 

 

What is the Mobilome?

The mobilome is the entire collection of mobile genetic elements (MGEs) present within a genome, a microbiome, or a specific ecological niche. 

 

It consists of all the genetic segments capable of moving around within a single host organism's DNA or jumping entirely between different bacterial cells. 

 

Core Components of the Mobilome

The components of a mobilome are highly diverse. They vary based on whether they belong to eukaryotes (like animals and plants) or prokaryotes (like bacteria). 

  • Plasmids: Small, circular DNA molecules that replicate independently from the bacterial chromosome and easily pass between cells.

  • Transposons (Jumping Genes): DNA sequences that can physically change their position within a genome.

  • Bacteriophages (Prophages): Viruses that infect bacteria and can accidentally carry host bacterial DNA with them.

  • Integrons & Gene Cassettes: Genetic mechanisms that capture, assemble, and express functional genes.

  • Insertion Sequences (IS): Simple, small transposable elements that encode only the enzymes needed for their own movement.

  • Integrative and Conjugative Elements (ICEs): Chromosomal segments that can excise themselves and transfer to other cells. 

 

Relevance to Antimicrobial Resistance (AMR)

The mobilome acts as the primary engine driving the spread of antibiotic resistance genes (ARGs). 

  • Horizontal Gene Transfer (HGT): MGEs share resistance genes across different species of bacteria.

  • Rapid Adaptation: Bacteria utilize the mobilome to quickly evolve and survive antibiotic treatments.

  • Superbug Creation: Diverse MGEs can combine multiple resistance traits inside a single pathogen.  

 

Genetic & Microbiome Engineering

Scientists are trying to manipulate the mobilome to fight superbug

  • CRISPR-Cas Systems: Programming molecular scissors to target and slice up specific resistance-carrying plasmids.

  • Plasmid Curing: Using natural or engineered agents to stop plasmid replication, effectively disarming bacteria without killing them. 

  

 

Source: FRONTIERSIN

 

 

 

PRACTICE QUESTION

Q. Consider the following statements regarding the "mobilome" in the context of antimicrobial resistance:

  1. The mobilome refers to the entire collection of mobile genetic elements present in a particular ecological niche.

  2. Plasmids, transposons, integrons, and bacteriophages are examples of mobile genetic elements.

  3. Horizontal gene transfer refers exclusively to the transfer of resistance genes from parent bacteria to offspring bacteria.

Which of the statements given above is/are correct? 

(a) 1 and 2 only 

(b) 2 and 3 only 

(c) 1, 2 and 3 

(d) 1 only

Answer: (a)

Explanation:

Statement 1 is correct: The mobilome comprises the entire pool of mobile genetic elements (MGEs) within a genome, a bacterial population, or a specific ecological niche (like the human gut or soil). 

Statement 2 is correct: Elements like plasmids, transposons ("jumping genes"), integrons, and bacteriophages (viruses that infect bacteria) are classic examples of MGEs. They physically move DNA within a genome or between different bacterial cells.

Statement 3 is incorrect: The transfer of genetic material from parent bacteria to offspring bacteria is called vertical gene transfer. In contrast, horizontal gene transfer (HGT) is the sharing of genetic material between unrelated organisms that are not in a parent-offspring relationship.