The Stealthy Invader
What Are Mycoplasma and Why Are They so Feared?
Mar 26, 2024 | Informative Articles
Featured in this article:
• What is Mycoplasma Contamination?
• What happens when a cell culture is contaminated by Mycoplasma?
In the vast world of microbiology, there exist tiny organisms causing big trouble – Mycoplasma.
Mycoplasma are among the smallest self-replicating prokaryotes and the most common contaminants in cell cultures. They can easily pass through sterile filtering systems and are resistant to commonly used antibiotics. Mycoplasma contamination is a serious problem for academic and biopharmaceutical laboratories due to its impact on cell properties and safety of biological products. A contamination often remains undetected and poses significant challenges to cell culture experiments, potentially comprising data integrity and research outcomes. Mycoplasma contamination is a widespread and costly problem in cell culture laboratories, with studies reporting contamination rates of approximately 5% to 30% among tested cell lines [1].
In this article we give a brief overview of mycoplasma contamination. Learn about the biology of mycoplasma and the consequences of a mycoplasma contamination to understand how cells are contaminated.
Mycoplasma contamination cannot be detected visually and therefore often remains undetected.
Mycoplasma can pass through filtering systems due to their small size and flexible membrane.
The absence of a rigid cell wall makes them resistant to commonly used antibiotics.
Mycoplasma contamination lead to various detrimental effects on the cells and their growth and can falsify experimental results.
What is Mycoplasma Contamination?The Biology of Mycoplasma
Mycoplasma are among the smallest self-replicating bacteria (about 0.15 - 0.3 µm) and belong to the class Mollicutes [1]. In fact, Mycoplasma and Mollicutes are commonly used as synonyms. Unlike other bacteria they lack a cell wall, which makes them capable of assuming various shapes and resistant to commonly used antibiotics. Due to their flexible membrane and small size, mycoplasma are able to pass through filtering systems.
They cannot be detected visually - neither with the naked eye nor by microscopy. Even highly contaminated cell cultures do not show any turbidity or other obvious symptoms.
What makes Mycoplasma so special?
• Absence of cell wall
• Flexible membrane
• Invisible
• Pass through filters
• Resistant to common antibiotics
lightbulb Mycoplasma lack a cell wall, making them resistant to commonly used antibiotics. The flexible membrane allowing them to shrink to diameters < 0.45 µm and pass through filtering systems.
What happens when a cell culture is contaminated by Mycoplasma?Consequences of a mycoplasma contamination
Mycoplasma species are known to infect a variety of eukaryotic cells, including human, animal and plant cells.
When a cell culture becomes infected with Mycoplasma, it can lead to various detrimental effects on the cells and their growth. Mycoplasma, being simple parasitic organisms, rely on the host cells for their metabolic needs. Initially, they attach to the host cell and then can merge with its membrane. Following this, Mycoplasma replicate rapidly, significantly overgrowing the host cells.
Unlike other bacterial contaminants, Mycoplasma contamination doesn't typically cause visible changes in the growth medium. However, its impact on cell cultures can be profound and can lead to:
• Altered cell metabolism
• Inhibition of cell growth and proliferation
• Reduced transfection efficiency
• Changes in gene and protein expression
• Chromosomal abnormalities
• Impair nucleic acid synthesis
• Apoptosis
Photo: Microgen | Depositphotos.comThese effects can vary depending on the cell line and the species of Mycoplasma involved. Nevertheless, Mycoplasma contamination poses a serious challenge to cell culture research, as it can compromise the reliability, reproducibility and validity of experimental results.
The presence of mycoplasma in cell culture has several side effects, including:
• Loss of time
• Loss of money
• Loss of valuable cells
• Potential dissemination of inaccurate findings through publications
• Misleading publications
• Biosafety concerns
If a contamination remains undetected, contaminated cultures can compromise scientific data, delay research projects and jeopardise the safety of biopharmaceutical products. Therefore, it's crucial for researchers to be vigilant in detecting and preventing Mycoplasma contamination in cell cultures.
lightbulb The impact of mycoplasma contamination in cell culture can be profound and represents a serious problem for academic and biopharmaceutical laboratories due to its impact on cell properties and the safety of biological products.
Stay tuned for more articles on how cell cultures become contaminated, detection methods, and prevention and removal strategies.
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FAQ
What are mycoplasma and why are they a problem in cell culture?
Mycoplasma are very small bacteria without a cell wall. In cell culture, they are problematic because they can grow unnoticed and alter cell behavior, metabolism, and experimental results.
How can mycoplasma contamination affect cell culture experiments?
Mycoplasma contamination can change cell growth, gene expression, protein production, and cellular metabolism. This can lead to unreliable or non-reproducible experimental results.
Why is mycoplasma contamination difficult to detect?
Mycoplasma contamination is difficult to detect because it often does not cause visible changes in the culture. Contaminated cultures may look normal under the microscope and show no obvious turbidity.
Can mycoplasma pass through sterile filters?
Yes. Due to their small size and flexible shape, some mycoplasma can pass through standard sterile filters, making prevention and regular testing especially important.
Can antibiotics prevent mycoplasma contamination?
Routine antibiotic use is not a reliable prevention strategy. It can mask contamination, encourage poor culture practices, and may not be effective against mycoplasma because many antibiotics target bacterial cell walls, which mycoplasma lack.
[1] Nikfarjam L, Farzaneh P. Prevention and detection of Mycoplasma contamination in cell culture. Cell J. 2012 Winter;13(4):203-12. Epub 2011 Dec 22. PMID: 23508237; PMCID: PMC3584481.
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