Hydrophobicity, cell adherence, cytotoxicity, and enterotoxigenicity of starved Vibrio parahaemolyticus

Area of Science:

• Microbiology and Food Safety
• Bacterial Pathogenesis and Stress Response

Background:

• Vibrio parahaemolyticus is a common Gram-negative enteropathogen found in various environments.
• Bacterial cells encounter stress conditions like starvation during food processing and infection, potentially altering their characteristics.

Purpose of the Study:

• To investigate the impact of starvation on the virulence and stress resistance of pathogenic Vibrio parahaemolyticus ST550.
• To compare the adherence, hydrophobicity, cytotoxicity, and lethality of starved V. parahaemolyticus cells against exponentially growing cells.

Main Methods:

• Starvation of V. parahaemolyticus ST550 cultures in a modified Morita mineral salt solution with varying NaCl concentrations.
• Assessment of bacterial resistance to environmental stresses.
• Evaluation of virulence using HEp-2 cell adherence assays, hydrophobicity measurements, in vitro cytotoxicity assays, and suckling mouse lethality studies.

Main Results:

• Starved V. parahaemolyticus cultures demonstrated similar resistance to environmental stresses compared to control cultures.
• Starved cells exhibited significantly increased cell adherence and hydrophobicity relative to cells in the exponential growth phase.
• Cytotoxicity and mouse lethality were lower in starved cells than in exponential-phase cells at equivalent post-infection times, with a 1-hour catch-up period observed.

Conclusions:

• Starvation enhances bacterial adherence and hydrophobicity in V. parahaemolyticus but temporarily reduces its cytotoxic and lethal potential.
• These findings suggest that stressed V. parahaemolyticus may require a period of adaptation or recovery to regain full virulence, with implications for infection control and food safety risk assessment.