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Host and Pathogen Biomarkers for Severe Pseudomonas aeruginosa Infections
Carlos Juan1, Carmen Peña2, Antonio Oliver1
1Servicio de Microbiología and Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria de Palma, Palma de Mallorca, and.
Insights
Pseudomonas aeruginosa infections are a major threat to vulnerable patients. Understanding pathogen, host, and treatment factors, including antibiotic resistance and virulence, is crucial for improving outcomes.
Area of Science:
- Infectious Diseases
- Microbiology
- Clinical Medicine
Background:
- Pseudomonas aeruginosa is a leading cause of severe hospital-acquired infections, especially in critically ill and immunocompromised individuals.
- Factors influencing patient outcomes include pathogen characteristics, host susceptibility, and treatment effectiveness.
Purpose of the Study:
- To review current knowledge on factors affecting the outcome of Pseudomonas aeruginosa nosocomial infections.
- To analyze the interplay between antibiotic resistance, virulence, and host factors in P. aeruginosa infections.
Main Methods:
- Literature review of studies on Pseudomonas aeruginosa nosocomial infections.
- Analysis of pathogen-related factors (resistance, virulence), host factors (underlying disease, colonization), and treatment aspects (antimicrobial therapy).
Main Results:
- Intestinal colonization and prior antibiotic use are key risks. Host factors like underlying disease and infection source significantly modulate outcomes.
- Antibiotic resistance, especially multidrug resistance, impacts empirical therapy choices. The direct effect of resistance on infection severity requires further study.
- Virulence factors, such as the type III secretion system (T3SS) and ExoU toxin, are linked to worse outcomes. Specific clones and host genetics may also play a role.
Conclusions:
- Improving outcomes for Pseudomonas aeruginosa infections requires a comprehensive understanding of pathogen, host, and treatment interactions.
- Further research is needed to elucidate the direct impact of antibiotic resistance and the role of virulence factors and host genetics.
Abstract:
Pseudomonas aeruginosa is among the leading causes of severe nosocomial infections, particularly affecting critically ill and immunocompromised patients. Here we review the current knowledge on the factors underlying the outcome of P. aeruginosa nosocomial infections, including aspects related to the pathogen, the host, and treatment. Intestinal colonization and previous use of antibiotics are key risk factors for P. aeruginosa infections, whereas underlying disease, source of infection, and severity of acute presentation are key host factors modulating outcome; delayed adequate antimicrobial therapy is also independently associated with increased mortality. Among pathogen-related factors influencing the outcome of P. aeruginosa infections, antibiotic resistance, and particularly multidrug-resistant profiles, is certainly of paramount relevance, given its obvious effect on the chances of appropriate empirical therapy. However, the direct impact of antibiotic resistance in the severity and outcomes of P. aeruginosa infections is not yet well established. The interplay between antibiotic resistance, virulence, and the concerning international high-risk clones (such as ST111, ST175, and ST235) still needs to be further analyzed. On the other hand, differential presence or expression of virulence factors has been shown to significantly impact disease severity and mortality. The likely more deeply studied P. aeruginosa virulence determinant is the type III secretion system (T3SS); the production of T3SS cytotoxins, and particularly ExoU, has been well established to determine a worse outcome both in respiratory and bloodstream infections. Other relevant pathogen-related biomarkers of severe infections include the involvement of specific clones or O-antigen serotypes, the presence of certain horizontally acquired genomic islands, or the expression of other virulence traits, such as the elastase. Finally, recent data suggest that host genetic factors may also modulate the severity of P. aeruginosa infections.
