Related Experiment Video
Updated: Mar 27, 2026
17:16
Development of an Electrochemical DNA Biosensor to Detect a Foodborne Pathogen
Published on: June 3, 2018
14.5K
Different food sources elicit fast changes to bacterial virulence
T Ketola1, L Mikonranta2, J Laakso3
1Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, Jyväskylä 40014, Finland tketola@jyu.fi.
Biology Letters
|January 15, 2016
Summary
Opportunistic bacterial pathogens like Serratia marcescens can rapidly alter their virulence. Exposure to low-resource or animal-based environments outside the host significantly increases their pathogenicity.
Area of Science:
- Microbiology
- Pathogen Ecology
- Infectious Disease
Background:
- Opportunistic bacterial pathogens cycle between hosts and environmental reservoirs.
- Environmental conditions, including resource availability, can influence pathogen survival and virulence.
- Understanding these environmental influences is crucial for managing infectious diseases.
Purpose of the Study:
- To investigate how short-term exposure to different environmental resource types and concentrations affects the virulence of Serratia marcescens.
- To determine if prior environmental conditions can prime bacteria for increased pathogenicity upon host entry.
Main Methods:
- Serratia marcescens was exposed to varying concentrations and types of resources (animal-based vs. plant-based) for 48 hours.
- Bacterial virulence was assessed by injecting treated bacteria into Galleria mellonella (moth) larvae.
- Infection severity was correlated with bacterial dose and prior environmental conditions.
Main Results:
- Bacterial dose was the primary determinant of virulence.
- Serratia marcescens exhibited increased virulence after exposure to low-resource environments compared to high-resource environments.
- Exposure to animal-based resources led to higher virulence than exposure to plant-based resources.
Conclusions:
- Temporal changes in a pathogen's resource environment can rapidly alter its virulence.
- These rapid virulence shifts may play a role in host-pathogen interactions, host range expansion, and disease outbreak dynamics.
- Findings have implications for managing opportunistic pathogens and predicting disease outbreaks.
Related Concept Videos
01:28Regulation of Bacterial Virulence
17
Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
17
01:31Defense Against Bacterial Pathogens
3.4K
The human immune system is a complex network of cells, tissues, and organs that work together to defend the body against bacterial infections. It consists of various immune cells, each playing a specific role in the defense mechanism.
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
3.4K
01:18Bacterial Gastroenteritis
20
Bacterial gastroenteritis, characterized by diarrhea, abdominal cramps, and vomiting, is often caused by ingestion of contaminated food or water and is frequently associated with pathogenic Escherichia coli strains. These microbes exploit two principal mechanisms to inflict disease.Shiga toxin–producing E. coli, also referred to as STEC—notably O157:H7—release Shiga toxins that target ribosomes, blocking protein synthesis. The B subunit of the toxin binds the host glycolipid...
20
01:12Bacterial Toxins
34
Bacterial toxins are sophisticated virulence factors that enable pathogenic bacteria to interact with, invade, and damage host tissues. These toxins fall broadly into two types: protein exotoxins, which are secreted into the environment and target specific host receptors, and lipopolysaccharide endotoxins, which are structural components of the bacterial outer membrane released primarily during bacterial lysis or membrane shedding. Exotoxins generally act more selectively, binding to cell...
34
01:33Bacterial Transformation
62.8K
In 1928, bacteriologist Frederick Griffith worked on a vaccine for pneumonia, which is caused by Streptococcus pneumoniae bacteria. Griffith studied two pneumonia strains in mice: one pathogenic and one non-pathogenic. Only the pathogenic strain killed host mice.
Griffith made an unexpected discovery when he killed the pathogenic strain and mixed its remains with the live, non-pathogenic strain. Not only did the mixture kill host mice, but it also contained living pathogenic bacteria that...
Griffith made an unexpected discovery when he killed the pathogenic strain and mixed its remains with the live, non-pathogenic strain. Not only did the mixture kill host mice, but it also contained living pathogenic bacteria that...
62.8K
01:23Stringent Response in E. coli
466
Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
466