Demonstration of the phenomena of microbial persistence and reversion with bacterial L-forms in human embryonic...

Area of Science:

• Microbiology
• Cell Biology
• Bacterial Pathogenesis

Background:

• L-forms are cell-wall-deficient variants of bacteria.
• Understanding bacterial persistence and reversion is crucial for infectious disease research.

Purpose of the Study:

• To investigate the in vitro persistence and reversion of Streptococcus faecalis L-forms in human embryonic kidney cells.
• To characterize the morphological changes and culturability of L-forms within host cells over time.

Main Methods:

• Infection of human embryonic kidney (HEK) fibroblasts with stable and relatively stable Streptococcus faecalis L-forms.
• Long-term cell culture (1-2 months) with serial sampling.
• Bacterial culturing and electron microscopy for morphological analysis.
• Immunofluorescence staining with L-form antiserum.

Main Results:

• Relatively stable L-forms were culturable only during the first week, though L-form-like material persisted.
• Stable L-forms were culturable throughout the experimental period.
• Electron microscopy revealed intracellular L-forms, transitional forms, and reversion to bacterial forms at later stages.
• Infected cells showed positive immunofluorescence regardless of culturability.

Conclusions:

• Demonstrates in vitro phenomena of bacterial L-form persistence and reversion within host cells.
• Suggests L-forms can undergo morphological changes (elementary bodies) and persist intracellularly before reverting.
• Highlights the potential for L-forms to evade culturing-based detection while remaining viable within cells.