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[Adherence and invasion-two pathogenicity factors in bacterial and fungal pathogens]
F M Müller1, J Morschhäuser, G Köhler
1Institut für Molekulare Infektionsbiologie, Universität Würzburg, Deutschland. fmmueller@mail.uni-wuerzburg.de
Abstract:
Pathogenicity factors such as adhesins, toxins, capsules, and other microbial gene products are involved as causative agents for infectious diseases. Therefore, the pathogenicity of organisms is increasingly studied on a molecular level. In bacteriology, unspecific adherence mechanisms and receptor-specific adhesins have to be distinguished. An adhesin-mediated invasion of pathogenic organisms in eukaryotic host cells could be relevant for pathogenesis. In mycology, various specific adhesins are involved in colonization of the host. Aspartyl proteases and phospholipases are relevant for adherence and invasion of host structures by pathogenic yeasts. Resistance factors have a central function in the distribution of infectious organisms. Gene-transfer, point mutations and efflux mechanisms are involved in the development of antibiotic drug resistance. Antifungal drug resistance does occur predominantly in Candida albicans against azole drugs. As underlying mechanisms point mutations in the ERG11 gene, encoding for the target enzyme of azoles, as well as energy-dependent efflux mechanisms were identified. Whether these mycotic factors are specific virulence factors or "fitness-factors" for a better survival of these organisms in the host, and if a possible alternating effect exists between resistance and virulence mechanisms is currently under investigation.
Insights
Microbial factors like adhesins and toxins cause infectious diseases. Research is exploring how these virulence factors and drug resistance mechanisms, particularly in Candida albicans, impact pathogen survival and host invasion.
Area of Science:
- Microbiology
- Molecular Biology
- Mycology
Background:
- Infectious diseases are caused by microbial pathogenicity factors including adhesins, toxins, and capsules.
- Molecular-level studies are crucial for understanding organism pathogenicity.
- Bacteriology distinguishes unspecific adherence from receptor-specific adhesins, while mycology highlights adhesins, aspartyl proteases, and phospholipases in host colonization and invasion.
Purpose of the Study:
- To investigate the molecular mechanisms of microbial pathogenicity factors.
- To understand the role of adhesins in bacterial and fungal pathogenesis.
- To examine the mechanisms of antimicrobial drug resistance, focusing on antifungal resistance in Candida albicans.
Main Methods:
- Molecular analysis of pathogenicity factors.
- Distinguishing adherence mechanisms in bacteria.
- Identifying genetic and molecular basis of drug resistance, including point mutations and efflux mechanisms.
Main Results:
- Adhesins play a key role in microbial adherence and invasion of eukaryotic host cells.
- Pathogenic yeasts utilize specific adhesins, aspartyl proteases, and phospholipases for host colonization.
- Antifungal drug resistance in Candida albicans is associated with ERG11 gene mutations and efflux pumps.
Conclusions:
- Virulence factors and resistance mechanisms are critical for infectious disease pathogenesis.
- The interplay between virulence and resistance, and whether these are fitness factors for survival, requires further investigation.
- Understanding these molecular factors is essential for developing new therapeutic strategies against infectious diseases.