This study presents a rapid, simple filtration method for purifying Chlamydia trachomatis elementary bodies from infected cell cultures. Researchers passed crude homogenates through a glass prefilter and 0.6 μm polycarbonate filter to remove large cellular debris, then trapped chlamydiae on a 0.2 μm filter before back-washing to collect purified organisms. The method effectively removed cell debris and soluble proteins while maintaining a narrow size distribution of particles. Mean viable chlamydial recovery was 64% when filters were washed at each stage. Scanning electron microscopy showed filter-purified particles were more uniformly sized and circular than centrifugally-purified controls, though both appeared qualitatively similar. The authors note this rapid method is particularly suitable for small- to medium-scale purification in cell culture experiments requiring uncontaminated viable chlamydiae, though density-gradient centrifugation remains preferable for large-scale preparations. The technique can be completed within minutes, offering significant practical advantages over conventional centrifugation-based purification approaches for routine laboratory use.

Key findings

• A two-stage filtration procedure using 0.6 μm and 0.2 μm polycarbonate filters efficiently purifies C. trachomatis from infected cell homogenates with mean 64% recovery of viable organisms
• Filtration effectively removes cellular debris and soluble proteins while producing chlamydiae with narrower size distribution compared to density-gradient centrifugation
• Filter-purified particles showed more uniform size and shape (mean 0.34 μm longest dimension) than centrifugally-purified controls (mean 0.47 μm)
• The method is rapid (complete within minutes) and practical for small- to medium-scale purification but limited to single tissue culture flasks per filter set