The Role of Transposons in the Evolution of Drug-Resistant Bacteria
Creators: name: Hussain, Zahid
Publisher: name: Zenodo
Year: 2025
Subjects: The Role
Transposons
Evolution
Drug-Resistant
Bacteria

description: The Role of Transposons in the Evolution of Drug-Resistant Bacteria

Abstract

The alarming rise in antibiotic-resistant bacteria represents a global health crisis, with transposons playing a pivotal role in this phenomenon. Transposons, or "jumping genes," are mobile genetic elements that can transfer between DNA molecules, facilitating the horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs). This report explores the molecular mechanisms underlying transposon activity, their contribution to bacterial adaptability, and their role in the dissemination of resistance genes. Through an examination of recent studies, this document highlights how transposons contribute to the evolution of multidrug-resistant pathogens, posing challenges to healthcare systems worldwide.

1. Introduction

Antibiotic resistance is a critical issue, with the World Health Organization (WHO) identifying it as one of the top ten global public health threats. The evolution of drug-resistant bacteria is a multifaceted process influenced by selective pressures, genetic mutations, and horizontal gene transfer (HGT). Among these factors, transposons have emerged as significant facilitators of ARG dissemination (Partridge et al., 2018).

Transposons are mobile genetic elements capable of moving within and between genomes, mediating genetic diversity and adaptation. By integrating ARGs, transposons enable bacteria to withstand antibiotic therapies, leading to treatment failures and increased mortality rates. This report delves into the mechanisms by which transposons influence the evolution of drug resistance and discusses strategies to mitigate their impact.

2. Mechanisms of Transposon Activity

2.1 Structure and Classification of Transposons

Transposons are broadly classified into two types:



Class I Transposons (Retrotransposons): These move via an RNA intermediate and reverse transcription, primarily found in eukaryotes.

Class II Transposons (DNA Transposons): These move directly via a "cut-and-paste" mechanism, prevalent in prokaryotes (Craig et al., 2015).


DNA transposons consist of inverted terminal repeats (ITRs) flanking a transposase gene, which catalyzes excision and reintegration into new genomic sites. Composite transposons, which carry accessory genes such as ARGs, are particularly relevant to antibiotic resistance.

2.2 Horizontal Gene Transfer via Transposons

Transposons facilitate HGT through conjugation, transformation, and transduction. Integrative conjugative elements (ICEs) and plasmids often harbor transposons, enhancing their mobility across bacterial populations (Frost et al., 2005). Conjugative transposons, such as Tn916, are especially notorious for spreading tetracycline resistance in Gram-positive bacteria (Roberts et al., 2001).

3. Transposons and Antibiotic Resistance

3.1 Acquisition of ARGs

Transposons act as genetic vectors for ARG acquisition, often integrating resistance genes into plasmids or chromosomal DNA. For instance, the Tn3 family transposons are associated with β-lactam resistance genes, enabling bacteria to hydrolyze penicillins and cephalosporins (Partridge et al., 2018).

3.2 Dissemination of Multidrug Resistance

Composite transposons frequently harbor multiple ARGs, contributing to multidrug resistance (MDR). Tn4401, a composite transposon, carries the blaKPC gene responsible for carbapenem resistance in Klebsiella pneumoniae (Canton et al., 2012). The dissemination of such MDR elements exacerbates treatment challenges.

4. Evolutionary Implications

4.1 Genetic Diversity and Adaptation

Transposons generate genetic diversity by facilitating recombination, gene duplication, and genome rearrangements. This enhances bacterial adaptability to environmental stressors, including antibiotic exposure (Aziz et al., 2010).

4.2 Evolution of Pathogenicity

Transposons can influence the evolution of virulence factors, as seen in Escherichia coli and Salmonella enterica. Pathogenicity islands often harbor transposons, enhancing bacterial fitness and survival in host environments (Hacker & Kaper, 2000).

5. Case Studies

5.1 Methicillin-Resistant Staphylococcus aureus (MRSA)

The SCCmec element, a transposon-like structure, carries the mecA gene responsible for methicillin resistance in MRSA. This element's mobility has facilitated the global spread of resistant S. aureus strains (Chambers & DeLeo, 2009).

5.2 Extended-Spectrum β-Lactamase (ESBL)-Producing Enterobacteriaceae

ESBL genes, such as blaCTX-M, are frequently associated with transposons like ISEcp1. This association has accelerated the spread of ESBL-producing E. coli and Klebsiella pneumoniae, posing significant clinical challenges (Carattoli, 2013).

6. Strategies to Combat Transposon-Mediated Resistance

6.1 Surveillance and Monitoring

Enhanced surveillance of transposon-associated ARGs in clinical and environmental settings is crucial for tracking resistance trends (Van Goethem et al., 2018).

6.2 Targeting Transposon Activity

Novel therapeutic strategies targeting transposase enzymes or inhibiting transposon mobility offer potential solutions to curb ARG dissemination.

6.3 Antibiotic Stewardship

Prudent antibiotic use and the implementation of stewardship programs can reduce selective pressures driving transposon-mediated resistance (McEwen & Collignon, 2018).

7. Conclusion

Transposons play a central role in the evolution of antibiotic resistance, facilitating the rapid acquisition and dissemination of ARGs. Their impact on bacterial adaptability underscores the need for innovative approaches to combat MDR pathogens. Addressing transposon-mediated resistance requires a multidisciplinary effort encompassing surveillance, targeted therapies, and global collaboration.

References