Trimethoprim-induced structural alterations in Staphylococcus aureus and the recovery of bacteria in drug-free medium

Area of Science:

• Microbiology
• Bacterial Ultrastructure
• Antimicrobial Action

Background:

• Trimethoprim is an antibiotic that inhibits bacterial growth, possibly by interfering with DNA synthesis.
• Staphylococci are bacteria known for their cell wall structure and autolytic systems.
• Previous growth inhibitors often induced thickened cell walls in staphylococci.

Purpose of the Study:

• To investigate the ultrastructural effects of bacteriostatic trimethoprim concentrations on staphylococci.
• To determine if trimethoprim induces cell wall thickening, unlike other growth inhibitors.
• To observe the recovery process after trimethoprim removal.

Main Methods:

• Exposure of staphylococci to bacteriostatic concentrations of trimethoprim.
• Electron microscopy to examine cellular ultrastructure.
• Observation of bacterial morphology after drug removal and subsequent growth.

Main Results:

• Trimethoprim induced swelling and affected staphylococcal cell walls, cytoplasmic membranes, and autolytic systems.
• Unlike other inhibitors, trimethoprim did not cause thickened cell walls.
• Mesosome-like structures appeared, and incomplete cross walls formed, while initiation continued.
• Rapid growth restoration occurred post-trimethoprim, with new cell wall formation and subsequent autolysis of old material.

Conclusions:

• Trimethoprim exhibits unique effects on staphylococcal cell wall synthesis and integrity.
• The drug does not induce cell wall thickening, distinguishing it from other growth inhibitors.
• Staphylococci can rapidly restore growth after trimethoprim exposure through a process involving new cell wall deposition and autolysis.