Media becomes rapidly turbid with visible particles or cloudiness. Cells show signs of toxicity, detachment, and death. Microscopy reveals motile bacteria or fungal filaments. Note: mycoplasma rarely causes acute cell death.
Common Causes
1Breach in aseptic technique: inadequate hand hygiene, non-sterile surfaces, unsterilized equipment
2Contaminated reagents: bacteria or fungi introduced via non-sterile water, media, or serum
3Environmental contamination from inadequate biosafety cabinet maintenance or poor HEPA filter integrity
4Cross-contamination between cultures via shared pipettes, media bottles, or incubator surfaces
Solutions
1Discard all contaminated cultures immediately; decontaminate incubator with 70% ethanol and UV exposure
2Re-train personnel on aseptic technique: 70% ethanol hand/glove spray, work in central biosafety cabinet zone
3Use antibiotics only for primary cell isolation, not routine culture; penicillin 100 U/mL + streptomycin 100 μg/mL
4Filter-sterilize all media and supplements through 0.22 μm filters; autoclave glassware at 121 °C for 20 min
5Certify biosafety cabinet every 6 months; clean with 70% ethanol before/after each session
6Implement weekly incubator cleaning with disinfectant; use copper-lined water pans with biocide