Mycoplasma contamination is a persistent challenge in cell culture and biopharmaceutical manufacturing. Because these microorganisms are small, lack a cell wall, and may not cause obvious changes in culture appearance, contamination can remain undetected during routine observation.
For laboratories working with monoclonal antibodies, recombinant proteins, vaccines, and cell and gene therapy (CGT) products, timely mycoplasma screening is an important part of contamination control.
Traditional culture-based methods can require extended incubation, while qPCR offers rapid molecular detection but requires compatible instrumentation and a validated workflow. Loop-mediated isothermal amplification (LAMP) provides another option: it amplifies target DNA at a constant temperature and can support visual result interpretation without gel electrophoresis.
Yeasen's One-Step Rapid Mycoplasma Detection Kit (LAMP, 2G; Cat. No. 40615ES) is designed for rapid qualitative screening of mycoplasma in research and process-monitoring workflows. The assay operates at 63°C for 40 minutes, with a color change from blue-purple to light blue indicating a positive result under the specified conditions.
1. Mycoplasma: A Hidden Risk in Cell Culture
Mycoplasmas are among the smallest self-replicating prokaryotes, typically measuring just 0.1–0.3 μm in diameter. Lacking a cell wall, they can pass through standard 0.22 μm sterilizing-grade filters. In cell culture systems, mycoplasmas are particularly difficult to detect because they rarely cause visible turbidity in culture media and are intrinsically resistant to antibiotics that target cell wall synthesis. They are therefore important adventitious contaminants to monitor throughout the production of biologics, including monoclonal antibodies, recombinant proteins, vaccines, and cell and gene therapy (CGT) products.
1.1 Five Biological Characteristics That Make Mycoplasma Contamination Difficult to Detect
- Extremely small size: Typically 0.1–0.3 μm in diameter. Mycoplasmas lack a cell wall, making Gram staining ineffective, and they are difficult to identify directly by conventional light microscopy.
- Filterable: They can pass through standard 0.22 μm sterilizing-grade filters, and some species may pass through filters with smaller nominal pore sizes. Conventional clarification processes may therefore fail to remove them completely.
- Highly elusive: Contaminated liquid culture media often remain clear, and early-stage contamination may not produce obvious morphological changes in cells. Visual inspection and routine microscopy are insufficient for reliable detection. The reported average incubation period is approximately 2–3 weeks.
- Naturally resistant to certain antibiotics: Mycoplasmas are intrinsically resistant to antibiotics such as penicillin that target cell wall synthesis. Routine antibiotic supplementation cannot reliably eliminate contamination and may mask the problem.
- Multiple transmission routes: Contamination can spread through cells, serum, trypsin, personnel, equipment, and aerosols generated during laboratory operations. It can affect multiple cultures or production batches, potentially resulting in substantial batch losses.
1.2 Industry Data: Contamination Rates and Representative Species
1.3 A Real-World Case: M. arginini Contamination in a CHO Bioreactor Reduced Antibody Purity from 96.2% to 56.3%
Fratz-Berilla and colleagues, including researchers affiliated with the U.S. FDA's Center for Drug Evaluation and Research (CDER), investigated Mycoplasma arginini contamination in a single-use rocking-motion perfusion bioreactor simulating CHO DG44 cell culture for IgG1 monoclonal antibody production. Their work systematically evaluated the effects of contamination on cell growth, metabolism, and critical quality attributes (CQAs).
Two papers were published: the 2019 study examined the impact on bioreactor cultivation (Biotechnology and Bioengineering, 116(12): 3242–3252), while the 2020 study investigated the effects on monoclonal antibody product quality (Biotechnology and Bioengineering, 117(9): 2802–2815).
Table 1. Effects of M. arginini contamination on key CHO bioreactor parameters and antibody quality
|
Metric |
Uninoculated control |
After M. arginini contamination |
Impact / risk |
|
Antibody purity |
96.2% |
56.3% |
Down 40 percentage points — directly hits product quality |
|
High-mannose glycoform share |
Negligible |
16.2–17.4% |
Clearly outside specification; affects potency |
|
Acidic charge variants |
Baseline |
Markedly elevated |
Affects stability and immunogenicity |
|
Arginine concentration |
Stable |
Crashed >90% within 3–4 days |
Medium exhaustion, abnormal cell metabolism |
|
Ammonia concentration |
~4 mM (CHO tolerance threshold) |
25–30 mM (continuous accumulation) |
Far beyond tolerance — directly kills CHO cells |
|
M. arginini peak |
0 CFU/mL |
~10⁷ CFU/mL |
Determined by medium nutrients, independent of inoculum size |
02 | Regulatory Requirements for Mycoplasma Testing
If mycoplasmas enter critical process materials such as harvest fluids or bulk intermediates, they may pose a risk to downstream products and, ultimately, patient safety. Major regulatory frameworks require mycoplasma testing at relevant stages of biologics manufacturing, including cell banks, viral seed stocks, harvests, bulk materials, and finished products. Appropriate testing is therefore a key component of contamination control and product quality assurance.
- Pharmacopoeial and regulatory frameworks: Chinese Pharmacopoeia General Chapter 3301 (ChP 3301), USP , and European Pharmacopoeia 2.6.7 (including the applicable current text) describe requirements for mycoplasma testing. Nucleic acid amplification techniques (NATs), including LAMP, may be used for internal screening and process monitoring. Their suitability for regulated testing depends on the applicable requirements and appropriate method validation.
- NAT method validation: EP 2.6.7 recognizes the use of NAT-based approaches subject to defined suitability and validation requirements. Product-specific validation may include matrix inhibition studies, limit-of-detection confirmation, and qualification of the working concentration of external positive controls.
- LAMP for preliminary screening and process monitoring: LAMP can support rapid screening of research samples, incoming raw materials, process intermediates, and samples from viral or cell banks. Positive results should be investigated using an appropriate pharmacopoeial method or a validated NAT method, according to the intended use and applicable requirements.
- Finished-product release: Finished-product testing must follow the applicable pharmacopoeial requirements or an accepted alternative method that has been appropriately validated. Depending on the product, jurisdiction, and regulatory pathway, this may involve culture-based methods, indicator-cell methods, or validated NAT approaches such as qPCR. Relevant Chinese regulatory guidance may include CDE Notices No. 30 (2022) and No. 33 (2023), where applicable.
03 | Comparison of Mycoplasma Detection Methods: Culture, Indicator-Cell Assays, qPCR, and LAMP
Current mycoplasma testing approaches can be broadly grouped into three categories: traditional culture-based methods, indicator-cell staining methods, and nucleic acid amplification techniques (NATs), including PCR, qPCR, and LAMP.
Different methods offer different advantages in terms of turnaround time, sensitivity, equipment requirements, and regulatory suitability. Selecting and combining methods according to the stage of the manufacturing process is key to establishing a comprehensive mycoplasma control strategy.
Table 2. Comparison of four major mycoplasma detection methods
|
Method |
Principle |
Detection limit / sensitivity |
Turnaround |
Applicable stage |
Equipment |
|
Culture (compendial) |
Culture in liquid/solid media; monitor pH shift and "fried-egg" colonies (colony diameter 0.1–1.0 mm) |
Per compendial medium sensitivity checks (color-unit endpoint); M. pneumoniae must reach 10⁻⁸, M. orale 10⁻⁴ (color units); not expressed directly as CFU/mL |
≥21–28 days |
Final release, filing compliance |
CO₂ incubator, anaerobic / microaerophilic environment |
|
Indicator cell (compendial) |
Mycoplasma DNA binds fluorescent dyes (Hoechst 33258 / DAPI); fluorescent dots appear around indicator cell nuclei |
Judged per compendial indicator cell culture; not expressed alone as CFU/mL |
3–5 days |
Final release (often combined with culture) |
Fluorescence microscope, indicator cells (Vero etc.) |
|
qPCR (NAT; usable for release after method validation) |
TaqMan probe-based quantitative amplification of conserved regions such as 16S rRNA |
≤10 CFU/mL (full method validation per ChP 9201 required) |
2–3 hours |
Process monitoring, release (after validation) |
Real-time PCR instrument |
|
LAMP (this solution) |
Bst polymerase isothermal amplification at 63 °C; dye color change read by eye |
500 copies/µL (DNA level); 100 CFU/mL reference strains still detected at 1:2 dilution |
40 min |
R&D / incoming / in-process screening |
Water bath / heat block / PCR instrument; no electrophoresis |
Recommended combination strategy: LAMP rapid screening (40615) + qPCR confirmation/filing (40619) + compendial culture and indicator cell methods for final release — a "three-tier combination" forming a complete QC line.
04 The Solution: Yeasen One-Step Rapid Mycoplasma Detection Kit (LAMP) (2G)
The Yeasen One-Step Rapid Mycoplasma Detection Kit (LAMP) (2G), Cat. No. 40615ES (5T / 25T / 100T), is based on Yeasen's proprietary loop-mediated isothermal amplification (LAMP) technology. With specific primers designed on conserved 16S–23S rRNA regions of mycoplasma, it completes qualitative screening of cell culture supernatants, serum, harvest fluids and other samples within 40 minutes at a constant 63°C. If mycoplasma is present, the conserved DNA is amplified rapidly and en masse and the reaction turns from violet-blue to sky blue — results readable by eye, no electrophoresis.
Figure 1. Composition of the 40615 kit (40615-A Buffer / 40615-B Enzyme / 40615-C Primer / 40615-D Mineral Oil / 40615-E Positive Control).
4.1 Applications
4.2 Six Key Product Features
Key Operating Notes and Temperature Sensitivity
- Temperature control: The enzyme system is temperature-sensitive. A PCR instrument is recommended for more precise temperature control. If using a water bath, preheat it to 63–65°C before starting the reaction. Reaction temperatures below 63°C may increase the risk of false-positive results under the specified assay conditions.
- Reaction time: Incubate at 63°C for 40 minutes and follow the timing instructions precisely. The reaction may be extended by approximately 10 minutes where permitted by the instructions, but should not be shortened. Exceeding the specified incubation period or opening reaction tubes after amplification may increase the risk of false-positive results.
- Sample collection: For adherent cells, collect the culture supernatant directly. For suspension cells, centrifuge at 500 × g for 5 minutes and collect the supernatant. Where appropriate, collect samples at least 3 days after passaging or medium replacement, when cultures are approximately 90% confluent, as this may improve the likelihood of detecting contamination.
4.3 Performance Validation: Key Parameters at a Glance
|
Item |
40615 performance |
|
Detection principle |
Loop-mediated isothermal amplification (LAMP), Bst DNA polymerase, 63 °C constant temperature |
|
Target region |
Conserved region of mycoplasma 16S–23S rRNA sequences |
|
Coverage |
33 mycoplasma species (confirmed by NCBI BLAST primer alignment; includes the 5 pharmacopeial watch-list species) |
|
DNA-level detection limit |
500 copies/µL |
|
Live-organism detection |
100 CFU/mL reference strains amplify and develop color normally; all 5 species still detected after 1:2 dilution |
|
Reaction conditions |
63 °C for 40 min; time may extend ~10 min, never shortened |
|
Reaction mode |
PCR instrument (recommended) / heat block / water bath (preheated to 63–65 °C) |
|
Sample types |
Culture supernatant, serum, organisms, harvest fluids, etc.; no nucleic acid extraction needed |
|
Readout |
Reaction turns from violet-blue to sky blue; judged by eye |
|
Cross-specificity |
No cross-reactivity with 9 phylogenetically close bacterial genomic DNAs (10 ng/reaction) or cellular genomic DNAs (30 ng/reaction; 293T / CHO / E. coli / S. cerevisiae) |
|
Robustness |
No performance impact after 7 days at 37 °C, 20 freeze–thaw cycles at -20 °C, 50 dry-ice freeze–thaw cycles, or dry-ice shipping |
4.4 Internal Sensitivity Comparison: 100 CFU Mycoplasma Standards
In the reported internal comparison, Yeasen 40615ES produced positive results for the 100 CFU mycoplasma standards in both the original preparations and the twofold-diluted samples. Competitor A did not produce positive results with the original 100 CFU standard preparations under the same reported test conditions.
Figure 2. Internal sensitivity benchmark with 100 CFU standards (Yeasen 40615 vs Company A) — negative (violet-blue) vs positive (sky blue). Original tube photos with English labels.
Samples 1 and 6: M. pneumoniae; samples 2 and 7: M. arginini; samples 3 and 8: M. hyorhinis; samples 4 and 9: M. salivarium; samples 5 and 10: M. orale.
Rapid LAMP Screening and a Combined Mycoplasma Quality-Control Strategy
With its simple workflow and minimal equipment requirements, LAMP is suitable for rapid mycoplasma risk screening in academic and research laboratories, as well as preliminary screening of incoming raw materials and in-process samples in biopharmaceutical manufacturing.
The Yeasen One-Step Rapid Mycoplasma Detection Kit (LAMP) (2G)(Cat#40615ES), uses Yeasen's in-house isothermal amplification technology to support rapid internal screening and early risk identification. It can be used alongside the Yeasen mycoplasma qPCR detection kit (40619ES) and applicable pharmacopoeial methods as part of a broader testing strategy.
For biopharmaceutical manufacturers working with monoclonal antibodies, recombinant proteins, vaccines, and CGT products, as well as research laboratories, this approach can help make routine screening more efficient and support earlier identification of potential cell culture contamination risks. The appropriate testing combination should be determined by the sample type, intended use, validation status, and applicable regulatory requirements.
Related Products
|
Core product |
Cat. No. |
Core application scenario |
|
40615ES |
High-throughput screening, no fluorescence qPCR instrument needed |
|
|
40619ES |
First choice for CGT final-product release, cell bank testing and IND filings |