Vancomycin Resistance in MRSA: A Growing Threat
- September 23, 2024
- Posted by: OptimizeIAS Team
- Category: DPN Topics
Vancomycin Resistance in MRSA: A Growing Threat
Sub : Sci
Sec: Health
Why in News
Recent research indicates that vancomycin, a long-standing treatment for methicillin-resistant Staphylococcus aureus (MRSA), may soon lose its efficacy. The study published in PLoS Pathogens on August 29 highlights that MRSA is developing the ability to resist vancomycin while overcoming the associated fitness costs.
About methicillin-resistant Staphylococcus aureus (MRSA): MRSA is a bacterium that causes infections in different parts of the body, known for its resistance to methicillin and other antibiotics used to treat Staphylococcus aureus infections
Strains:
Hospital-associated MRSA (HA-MRSA): Occurs in healthcare settings, especially in people with weakened immune systems.
Community-associated MRSA (CA-MRSA): Found outside hospitals, often affecting healthy individuals through skin-to-skin contact, and is linked to factors like crowded places
Transmission and Risk Factors: About 30% of the population carries S. aureus bacteria on their skin or in their nostrils without showing symptoms
Environmental Presence: MRSA can survive on surfaces and in environments like gyms, hospitals, prisons, and beaches.
Antibiotic Resistance Mechanism:
Mutation: Resistance in S. aureus occurs due to a mutation in the penicillin-binding protein, making it resistant to β-lactam antibiotics.
Transfer of Resistance: The resistance gene is transferred between bacteria through bacteriophages (viruses that infect bacteria).
Implications and Treatment: MRSA is a major cause of hospital-acquired infections, contributing to significant morbidity, mortality, and prolonged hospital stays.
Treatment Challenges: Due to its resistance to multiple antibiotics, MRSA requires alternative treatments like vancomycin and other newer antibiotics.
Vancomycin: A Reliable Treatment for MRSA
Type: Glycopeptide antibiotic.
Uses: Primarily treats severe bacterial infections, including MRSA (Methicillin-resistant Staphylococcus aureus), by inhibiting bacterial cell wall synthesis.
Spectrum: Effective against Gram-positive bacteria.
Resistance: Increasing cases of vancomycin-resistant enterococci (VRE) and vancomycin-resistant Staphylococcus aureus (VRSA) threaten its long-term effectiveness.
Vancomycin has been the first-line treatment for MRSA infections for over 40 years. Despite the growing antimicrobial resistance crisis, vancomycin has remained effective, with S. aureus rarely developing resistance.
Mechanism of Vancomycin Resistance
Vancomycin resistance in MRSA occurs through the transfer of the vanA operon from another bacterium during a simultaneous infection.
Even after growing VRSA in vancomycin-free media for 10 life cycles, many strains retained their resistance, unlike the original strains, which lost it in the absence of the antibiotic.
| What is vanA operon? The vanA operon is a cluster of genes responsible for vancomycin resistance in bacteria. It alters the target site of vancomycin by modifying cell wall precursors, preventing the antibiotic from binding effectively. The vanA gene cluster is usually transferred horizontally between bacteria, particularly from Enterococcus to Staphylococcus aureus, causing vancomycin-resistant strains (VRSA). vanA-mediated resistance presents a major challenge in treating Gram-positive bacterial infections. |
About Gram-Positive Bacteria: Gram-positive bacteria have thick peptidoglycan cell walls that retain the crystal violet stain in the Gram staining process.
Examples: Staphylococcus aureus, Streptococcus pneumoniae, Bacillus, Clostridium.
Characteristics: They lack an outer membrane and often possess teichoic acids in their cell walls.
Medical Importance: Many are pathogenic, causing diseases like pneumonia, sepsis, and skin infections. They are also susceptible to antibiotics like penicillin, though antimicrobial resistance is rising (e.g., MRSA).
About Antimicrobial Resistance (AMR):
Antimicrobial Resistance (AMR) is the ability of a microbe to resist the effects of medication previously used to treat them. It is also known as antibiotic resistance.
As a result, the medicines become ineffective and infections persist in the body.
The WHO defines antimicrobial resistance as a microorganism’s resistance to an antimicrobial drug that was once able to treat an infection by that microorganism.
The resistance to antimicrobials is a natural biological phenomenon. However, the misuse and overuse of antibiotics accelerates the development of AMR.
Microbial resistance to antibiotics has made it harder to treat infections such as pneumonia, tuberculosis (TB), blood poisoning (septicaemia) and several food-borne diseases.