Investigating alterations in the cellular envelope of Staphylococcus aureus in simulated microgravity using a random...

Area of Science:

• Microbiology
• Space Biology
• Biophysics

Background:

• Microgravity environments, such as spaceflight or simulated microgravity using a random positioning machine (RPM), prevent normal sedimentation and convection in liquid cultures.
• This lack of sedimentation alters the bacterial cell's microenvironment compared to standard gravity conditions.
• Bacterial cells possess surface sensors that detect environmental changes, potentially leading to modifications in cell wall and surface properties.

Purpose of the Study:

• To investigate the effects of simulated microgravity on the growth kinetics, cell wall composition, cell surface hydrophobicity, autoaggregation, and antibiotic susceptibility of Staphylococcus aureus.
• To determine if microgravity induces changes in the cellular envelope of planktonic S. aureus cultures.

Main Methods:

• Utilized a random positioning machine (RPM) to simulate microgravity conditions for Staphylococcus aureus NCIM 2079 cultures.
• Assessed growth kinetics, cell wall constitution via Fourier Transform Infrared Spectroscopy (FTIR), cell surface hydrophobicity, and autoaggregation ability.
• Evaluated antibiotic susceptibility, particularly to Erythromycin and Clindamycin.

Main Results:

• Observed significant alterations in growth kinetics under simulated microgravity.
• FTIR analysis revealed changes in cell wall constitution.
• Cell surface hydrophobicity and autoaggregation ability were notably affected.
• Antibiotic susceptibility showed noteworthy changes, especially towards Erythromycin and Clindamycin.

Conclusions:

• Simulated microgravity induces significant changes in the growth and surface properties of Staphylococcus aureus.
• Microgravity appears to alter the cellular envelope of planktonic S. aureus.
• These findings highlight the potential impact of microgravity on bacterial physiology and antibiotic resistance.