What is mycoplasma sterilization?
What is sterilization, and why is it essential for medical devices and parenteral products?
Sterilization keeps patients safe from toxins and microbial illnesses when therapies or devices are consumed or used. Sterilization is any process that removes, kills, or deactivates all forms of life. Under the strictest definition of sterility, an item or product is sterile when there is the complete absence of viable microorganisms (bacteria, yeasts, viruses, and molds). For regulatory purposes, sterility is defined by acceptance criteria based on calculated contamination probability. An acceptable level of contamination risk for most items is the probability of a single contaminated product out of a million manufactured products. However, sterility criteria may be more stringent or lax depending upon the intended use of the medical device or product. Sterile products that undergo sterilization are often chemical, heat, or filter sterilized. Sterilization kills any microorganisms products collect during manufacturing. For chemical and heat sterilization, sterilization occurs after the product is placed in its final packaging. The product is often filtered and then aseptically filled into a sterile container for sterilization by filtration. Mycoplasma contamination, what is mycoplasma, what is mycoplasma sterilization, mycoplasma in cell culture, and how to remove mycoplasma will be covered in this article.
What are mycoplasmas?
Mycoplasma is a term used to describe the Mollicutes class of bacteria. These bacteria lack a cell wall around their cellular membranes, a feature that makes them naturally resistant to antibiotics that target cell wall synthesis. The Mollicutes class contains multiple genera, including Mycoplasma, Ureaplasma, Acholeplasma, Anaeroplasma, and Asteroloplasma.
mycoplasma contamination Areas
Mycoplasmas are found in biopharmaceutical, biologic, and mammalian cell culture processes. Raw materials can also contain plasmas. Plasmas are more likely to contaminate eukaryotic cells and protein biologics than small-molecule pharmaceutical products. Thus, mycoplasma sterilization methods (removal methods) are important for biological products.
How do you remove mycoplasma from sterile products?
Mycoplasmas contamination can be easily inactivated with autoclaving, dry heat, ethylene oxide, and irradiation. Raw materials often provide the greatest risk of mycoplasma contamination. Thus, it is recommended to use a lethal sterilization process on raw materials before sterile product manufacture when possible.
Mycoplasmas can also be removed from products using filtration. Sterile filtration is excellent for products that cannot be sterilized with heat or products containing a biological agent, such as an antibody or enzyme. However, special care must be taken for mycoplasma filtration vs. traditional microbial filtration. Special care must be taken because the conventional 0.2-micrometer (μm) microporous membrane filters will not catch the small (0.15–0.3 μm) plasmas. Filter sterilization is a “cold” sterilization method that removes microbes instead of killing them. Since sterilization by filtration works by removing microbes (including mycoplasma), sterile filtration is the only sterilization method that doesn’t rely on an elevated temperature, toxic chemicals, or another form of energy (such as gamma radiation) to destroy microorganisms.
Plasma-retentive filters often have a pore size rating of 0.1 μm at minimum. Filters with a rating of 0.1 μm would still be considered microporous membrane filters. Charge depth filters and ultrafiltration can also be used to remove plasmas and any residual pyrogens from liquid products. Due to their deformable membranes, high differential pressure can force mycoplasmas through microporous filter membranes. Further, the nutritional conditions of the mycoplasmas can affect their size. Other factors influencing mycoplasma filter retention are filter type, pore size rating, organism concentration, fluid viscosity, and filtered fluid volume.
How are mycoplasma filtration (removal) processes validated?
The Parenteral Drug Association (PDA) Technical Report No. 755 shows how to prove mycoplasma removal is comparable to the American Society for Testing and Materials (ASTM) Standard F838 for bacterial retention. A filter’s mycoplasma retentivity is often assessed using the microorganism A. laidlawii at a concentration of at least 1 x 107 colony forming units per centimeter squared. If complete retention is not achievable, a log reduction value for the filtration process is calculated to ensure mycoplasma removal meets sterility requirements.
Summary
Overall, sterilization keeps patients safe from toxins and microbial illnesses when therapies or devices are consumed or used. Mycoplasma is a term used to describe the Mollicutes class of bacteria. These bacteria lack a cell wall around their cellular membranes, a feature that makes them naturally resistant to antibiotics that target cell wall synthesis. Mycoplasmas are found in biopharmaceutical, biologic, and mammalian cell culture processes, as well as raw materials. Plasmas can be easily inactivated with autoclaving, dry heat, ethylene oxide, and irradiation. Mycoplasmas can also be removed from products using filtration. However, special care must be taken for mycoplasma filtration vs. traditional microbial filtration. Care must be taken because the traditional 0.2-micrometer (μm) microporous membrane filters will not catch the small (0.15–0.3 μm) mycoplasmas. All in all, ensure your contract testing organization can provide appropriate sterility testing and sterilization validations for your parenteral product or medical device needs.
Ethide Labs is a contract testing organization specializing in Sterilization Validations and Sterility Testing. Ethide Labs also offers Microbiology Testing, Bioburden Testing, Bacterial Endotoxin Testing, EO Residual Testing, Cytotoxicity Testing, Environmental Monitoring & Package Integrity Testing services for medical device companies and allied industries. Ethide is an ISO 13485 certified facility.
References
Adeeti Gupta . Mycoplasma and Ureaplasma – The big conundrum. Walking GYN. June 2019.
Michael J. Akers. Sterile Drug Products Formulation, Packaging, Manufacture, and Quality. Drugs and the Pharmaceutical Sciences. Informa Healthcare. 2010.
United States Pharmacopeial Convention. <1115> Bioburden Control of Non-Sterile Drug Substances and Products. Rockville, MD, USA. 2021. (USPC <1115>).
United States Pharmacopeial Convention. <1211> Sterility Assurance. Rockville, MD, USA. 2021. (USPC <1211>).
United States Pharmacopeial Convention. <1229.17> Mycoplasma Sterilization. Rockville, MD, USA. 2021. (USPC <1229.17>).
