Scanning-beam electron microscopy of cell wall-defective staphylococci

Area of Science:

• Microbiology
• Cell Biology
• Microscopy

Background:

• Staphylococci are common bacteria with significant clinical relevance.
• Wall-defective forms (WDS) of bacteria can arise under certain conditions, impacting their characteristics.
• Understanding bacterial morphology is crucial for diagnostics and treatment.

Purpose of the Study:

• To characterize the morphology of staphylococci and their wall-defective forms (WDS).
• To compare WDS induced by different agents (methicillin and lysostaphin).
• To observe the dynamic process of WDS induction and formation.

Main Methods:

• Gram staining
• Phase contrast microscopy
• Scanning electron microscopy (SEM)

Main Results:

• Staphylococci appeared smooth, spherical, and uniform.
• Stable WDS exhibited corrugated surfaces and increased size compared to parent cells.
• Methicillin- and lysostaphin-induced WDS were morphologically similar.
• WDS induction in methicillin broth began at 7 hours, with increasing numbers and greater size/shape variability over time.
• Microscopic 'wisps' contained WDS, parent staphylococci, and cell membranes.

Conclusions:

• Both methicillin and lysostaphin induce similar wall-defective staphylococcal forms.
• The induction of WDS is a time-dependent process with significant morphological alterations.
• Microscopy provides detailed insights into the structural changes and composition of bacterial WDS.