Comprehensive Guide to Laboratory Contamination Management

In the process of cell culture, laboratory contamination remains a prevalent issue. Reagents, consumables, the environment, and operational procedures can all lead to contamination, including mycoplasma and bacterial contamination. Contamination can alter cell growth, morphology, and even functionality, ultimately compromising experimental accuracy.

Therefore, preventing, identifying, and eliminating contamination are crucial. This article provides a comprehensive guide to help you manage and eliminate laboratory contamination efficiently.

01 Prevention of Contamination

Enforce Strict Laboratory Regulations

• Implement and refine aseptic laboratory rules and regulations.

• Provide thorough training and education for interns and visiting researchers before they begin experimental work. Only after mastering basic theory, lab skills, and protocols should they be allowed to perform experiments under supervision.

Regular Disinfection of Incubators, Biosafety Cabinets, and Clean Rooms

• Disinfect workbenches with UV light for 30 minutes before experiments and wipe down surfaces with 75% ethanol after use.

• Autoclave laboratory waste before discarding it in medical waste bins.

• Periodically disinfect clean rooms with formaldehyde (40%) at 10 mL/m² and potassium permanganate at 5 g/m². Ensure formaldehyde gas reaches every corner of the room. Alternatively, tools like Pricella^® Room SafeGuard or Bath SafeGuard can be used for routine sterilization.

Eliminate Infection Sources

• Laboratory personnel must wear isolation gowns and minimize movement in and out of cell culture areas.

• Perform operations gently to avoid generating microbial aerosols.

• Immediately investigate any contamination and adopt effective methods to eliminate the source to prevent widespread contamination.

Control Laboratory Temperature and Humidity

Bacteria and fungi are opportunistic pathogens with strong reproductive capacity. Warm and humid environments promote their growth. Maintain appropriate temperature and humidity to keep the lab dry and clean, thereby preventing microbial growth and cutting off transmission pathways.

02 Contamination Identification

Common laboratory contaminants include bacteria, fungi, mycoplasma, and nanobacteria. When contamination is suspected, follow these steps for identification:

(1) Sampling

Use sterile medical-grade cotton swabs dipped in a sampling solution (saline) to collect samples from suspected areas such as workbenches, incubators, and microscopes. Collect samples from suspicious reagents or culture media. For potentially contaminated cells, aspirate the supernatant for testing.

(2) Cultivation

Inoculate the collected samples onto agar medium and into DMEM medium:

• Incubate the agar medium in a biochemical incubator for 48 hours.

• Incubate DMEM medium at 37°C, 5% CO₂ for 7 days.

(3) Detection

Observe agar plates for bacterial or fungal colonies. Use PCR, colorimetric assays, or fluorescent staining to detect mycoplasma contamination. For nanobacteria, no definitive identification method is currently available.

03 Post-Contamination Management

Environmental Contamination

Wipe contaminated surfaces and equipment with 75% ethanol for disinfection. Perform formaldehyde fumigation using formaldehyde (40%) at 10 mL/m² and potassium permanganate at 5 g/m². Alternatively, use tools like the Pricella^® Room SafeGuard or Bath SafeGuard for sterilization.

Cellular Contamination

① Bacterial Contamination: For mild contamination, wash cells with 10× Penicillin-Streptomycin Solution. For severe contamination, discard the cells and disinfect thoroughly.

② Fungal Contamination: Treat with Amphotericin B to inhibit fungal growth. Since fungi are difficult to eliminate completely, discarding contaminated cultures is recommended.

③ Mycoplasma or Nanobacteria Contamination: If the cells remain viable, treat with Anti-Mycoplasma Treatment Reagent or Anti-Nanobacteria Treatment Reagent for 2-3 passages and monitor cell status.

If cell condition is poor, discard the cells and disinfect the area.