Medical Infection Agents

Medical infection agents comprise a diverse array of bacteria, viruses, fungi and parasites that exploit host tissues to survive, replicate and spread. The outcome of any encounter depends on the pathogen’s virulence programme—including attachment, invasion, immune evasion and toxin production—alongside the host’s innate and adaptive defences, genetic background and environmental factors. Antibiotic-resistant bacteria and emerging viral pathogens pose major global threats by undermining treatment options and public-health resilience. Zoonotic transmission, healthcare-associated infections and microbial evolution drive the relentless emergence of novel strains and outbreaks. Host detection relies on germline-encoded receptors that sense conserved microbial molecules and damage-associated signals, triggering inflammatory cascades and, when required, regulated cell death to restrict infection. Understanding the interactions between infection agents and host responses underpins the development of diagnostics, vaccines, antimicrobial stewardship and novel therapies, and informs surveillance and containment strategies that are critical to preserving both individual and population health.

Research from Nature Portfolio

Large-scale genomic surveillance across multiple European hospitals has revealed the regional and international spread of carbapenem-resistant Klebsiella pneumoniae. Researchers analysed hundreds of clinical isolates to map high-risk clones and plasmids bearing carbapenemase genes, revealing distinct lineages dominating in different regions and uncovering specific mobile genetic platforms driving resistance. This work integrates phylogeography with plasmid epidemiology to guide targeted infection-control measures and surveillance priorities.

An extended family of Pseudomonas megaplasmids has been characterised by long-read sequencing, revealing plasmids over 400 kb that carry arrays of antibiotic-resistance genes within dynamic resistance regions. Comparative pan-genome analysis shows these large transmissible elements circulate in diverse Pseudomonas species across geographical and clinical settings. The study highlights how megaplasmids shape niche adaptation and the evolution of multidrug resistance.

A novel therapeutic combination of colistin and EDTA has been developed to eradicate biofilm-associated infections by colistin-resistant Klebsiella pneumoniae. In vitro and animal model studies demonstrate restoration of colistin susceptibility, effective biofilm disruption on implanted devices and prevention of recurrence. This strategy offers a promising option for difficult-to-treat healthcare-associated infections.

Medical Infection Agents publication trend

The graph below shows the total number of articles in medical infection agents across all publications each year (not limited to Nature Index journals).

Technical terms

Pathogen: A microorganism—bacterium, virus, fungus or parasite—that can cause disease in a host.

Virulence factor: Any microbial component that enhances a pathogen’s ability to infect, damage or evade the host.

Antibiotic resistance: The capacity of bacteria to survive exposure to antibiotics, often mediated by enzymes, efflux pumps or target mutations.

PAMP (Pathogen-associated molecular pattern): Conserved microbial molecules recognised by host receptors to detect infection.

DAMP (Damage-associated molecular pattern): Endogenous host molecules released upon cell stress or injury that trigger inflammatory responses.

Pattern Recognition Receptor (PRR): Germline-encoded host receptors that sense PAMPs and DAMPs to initiate innate immunity.

Zoonosis: An infection transmitted from animal reservoirs to humans.

References

1. International and regional spread of carbapenem-resistant Klebsiella pneumoniae in Europe. Nature Communications (2024).
2. A megaplasmid family driving dissemination of multidrug resistance in Pseudomonas. Nature Communications (2020).
3. Novel colistin-EDTA combination for successful eradication of colistin-resistant Klebsiella pneumoniae catheter-related biofilm infections. Scientific Reports (2021).
4. SARS-CoV-2 prolonged infection during advanced HIV disease evolves extensive immune escape. Cell Host & Microbe (2022).
5. Immediate myeloid depot for SARS-CoV-2 in the human lung. Science Advances (2024).