Bacterial Infection Assay
Bacterial Infection Assay - Related Videos
14:05
Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes
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Cited by 7 •
2013
Listeria monocytogenes is a Gram positive bacterial pathogen frequently used as a major model for the study of intracellular parasitism. Imaging late L. monocytogenes infection stages within the context of small-interfering RNA screens allows for the global study of cellular pathways required for bacterial infection of target host cells.
03:57
Bacterial Infection Quantitation Assay: A Method to Quantify Intraocular Bacterial Load in Mouse Model of Bacterial Endophthalmitis
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2025
This video describes the technique of quantifying bacterial infection from eye homogenates obtained from a murine model of bacterial endophthalmitis caused by Bacillus cereus. This technique helps study the host immune response and its dependency on the host and ocular bacterial gene expression in murine models.
05:28
A Bacterial Infection Assay for Studying Anaerobic Bacteria-Host Cell Interactions
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2025
This video demonstrates a technique for assessing the ability of Porphyromonas gingivalis, an anaerobic pathogenic bacterium, to adhere to and invade human umbilical vein endothelial cells (HUVECs). After infecting the host cells with the bacteria, the host cells are lysed to release both adhered and internalized bacteria. When the lysate is plated in an appropriate medium, the presence of colonies indicates successful bacteria-host cell interactions.
04:10
An Assay to Study the Impact of Extracellular Matrix Stiffness on Bacterial Infection
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2025
This video demonstrates an assay to study the effect of extracellular matrix (ECM) stiffness on bacterial infection of adherent cells. Polyacrylamide hydrogels of varying stiffness, overlaid with collagen, are layered in a multi-well plate to mimic the stiffness of physiological ECM. Upon overlaying human endothelial cells on the hydrogels and infecting the cells with Listeria monocytogenes bacteria engineered to express a fluorescent protein once intracellular, flow cytometry is used to...
03:33
Quantification of Bacterial Infection in Host Cells by the Colony-Forming Unit Assay
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2025
This video demonstrates an in vitro quantification technique to determine Listeria monocytogenes infection of macrophages by the colony-forming unit assay. The bacterial colonies on the agar plate represent the intracellular bacterial population that escapes the host-defense mechanism and survives within the macrophages.
FAQs
The readout determines which aspect of infection the experiment can quantify. Colony formation focuses on recoverable bacterial viability, whereas fluorescence or luminescence provides a signal associated with bacterial presence or viability. Measuring cytokine production or host-cell survival in parallel adds information about the host response, helping distinguish bacterial effects from changes in immune or cellular function.
Combining bacterial burden with cytokine production or host-cell survival connects pathogen behavior to immune consequences. A change in bacterial recovery alone shows an altered bacterial outcome, while the paired host measurement indicates whether immune activation or cellular damage also changed. This design supports more informative analysis of host-pathogen interactions than either measurement considered separately.
The same assay framework can compare bacterial survival under antimicrobial treatment or compare how different bacteria affect host cells. Reduced bacterial viability supports an antimicrobial effect, whereas differences in bacterial burden, cytokine production, or host-cell survival can indicate variation in virulence. Standardized readouts make these comparisons more consistent across experimental conditions.
Planning begins by selecting the measurable outcome, such as bacterial burden, viability, fluorescence, luminescence, cytokine production, or host-cell survival. Researchers then align the assay design with the question, include the relevant bacterial and host-cell measurements, and apply a standardized readout. This workflow helps ensure that the resulting signal directly addresses infection, immune defense, or treatment effects.
These assays are useful when investigators need to examine pathogen biology, immune recognition, or bacterial control by host cells. They can quantify bacterial burden, evaluate antimicrobial activity, compare virulence, and measure cellular responses such as cytokine production or survival. In this context, the assays provide a common experimental framework for connecting bacterial behavior with immune defense.
Standardized measurements can show whether an intervention changes bacterial viability, bacterial burden, host-cell survival, or immune-associated responses. These outcomes help compare antimicrobial activity across conditions and support mechanistic studies of how treatment influences infection. Consistent readouts are particularly valuable when evaluating candidate drugs or interpreting differences between bacterial strains and host responses.