So called "Junk DNA" explains Antibiotic Resistance without Darwin



“Most antibiotic resistance genes in bacteria are in mobile genetic elements and acquired by horizontal gene transfer (HGT)”

Article:”Antimicrobial Resistance,”by Michael Milgroom, Biology of Infectious Disease (11/23)

Introduction

Antimicrobial resistance (AMR) is the ability of microorganisms, such as bacteria, viruses, fungi, and parasites, to survive and thrive in the presence of antimicrobial agents that were once effective in killing or stopping their growth. AMR is a growing global public health threat that is estimated to cause 10 million deaths annually by 2050 if no action is taken.

Causes of AMR

The main causes of AMR is the horizontal gene transport of transposable elements (so called Junk DNA) not neo darwinian random mutations. This occurs through the misuse and overuse of antimicrobial agents. This includes the use of antibiotics in humans and animals for non-therapeutic purposes, such as low-dose antibiotics in animal feed to promote growth. It also includes the use of antibiotics to treat viral infections, which is ineffective and can contribute to AMR.

Other factors that contribute to AMR include the use of antibiotics in agriculture, the spread of antibiotic-resistant microorganisms through human contact and travel, and the lack of new antibiotics being developed.

Consequences of AMR

AMR has a number of serious consequences for human health. These include:

  • Increased risk of infection

  • Increased severity of infections

  • Increased length of hospital stays

  • Increased healthcare costs

  • Increased mortality

Antimicrobial Stewardship

Antimicrobial stewardship is a set of strategies that aim to ensure that antimicrobial agents are used effectively and appropriately to minimize the development and spread of AMR. These strategies include:

  • Promoting the use of narrow-spectrum antibiotics over broad-spectrum antibiotics

  • Using antibiotics for the shortest duration possible

  • Only using antibiotics to treat bacterial infections

  • Educating healthcare providers and patients about AMR

Conclusion

AMR is a complex problem that requires a multifaceted approach to solve. Antimicrobial stewardship is an essential part of this approach, but it is also important to address the other factors that contribute to AMR, such as the misuse and overuse of antimicrobial agents. By taking action now, we can prevent AMR from becoming a global catastrophe.

The widespread presence of antibiotic resistance genes (ARGs) in bacteria and their ability to spread rapidly through horizontal gene transfer (HGT) poses a significant challenge to Neo-Darwinian evolutionary theory. Traditional Neo-Darwinian explanations for the evolution of antibiotic resistance typically focus on mutations that occur within a bacterial cell's genome. These mutations can lead to changes in the structure or function of proteins, potentially conferring resistance to specific antibiotics.

However, the rapid spread of ARGs through HGT suggests that this process plays a more prominent role in the evolution of antibiotic resistance than previously thought. HGT allows bacteria to acquire resistance genes from other bacteria, even if those genes did not arise through mutations within the recipient cell's genome. This means that antibiotic resistance can spread much more quickly than if it were solely dependent on mutations.

This rapid spread of ARGs through HGT challenges Neo-Darwinian explanations for the evolution of antibiotic resistance in several ways:

  1. Undermines the role of gradualism: Neo-Darwinism typically emphasizes gradual, incremental changes that occur over many generations. However, the rapid spread of ARGs through HGT can lead to sudden increases in antibiotic resistance, which is difficult to explain under a purely gradualist model.

  2. Questions the importance of adaptation: Neo-Darwinism suggests that antibiotic resistance should arise through adaptations that benefit the bacteria in their environment. However, HGT can transfer ARGs to bacteria that do not face antibiotic pressure, suggesting that these genes may not always be the result of direct adaptation.

  3. Challenges the idea of individual organisms as the units of selection: Neo-Darwinism typically focuses on selection at the level of individual organisms. However, HGT can effectively transfer ARGs between different bacterial species, blurring the lines between individual organisms and potentially suggesting a more fluid concept of selection.

These challenges suggest that Neo-Darwinian explanations for the evolution of antibiotic resistance may need to be refined or replaced to account for the rapid spread of ARGs through HGT. Understanding the mechanisms and implications of HGT is crucial for developing effective strategies to combat antibiotic resistance and protect human health.

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