Bioburden Testing vs. Microbiology Testing
What is bioburden?
The “bio” in bioburden refers to live biological organisms, and the “burden” in bioburden refers to the concentration of the viable biological organisms. Thus, bioburden is the concentration or quantity of microorganisms in a given area or from a particular sample. The higher the concentration of viable organisms on a device or product, the higher the burden is to kill those organisms, whether it is killing the organisms through sterilization procedures or killing the organisms through the effort of the human immune system.
What is microbiology?
Microbiology can be broken down into the Greek and Latin roots of “micro,” “bio,” “ology.” The “micro” stands for small, the “bio” stands for biology, and the “ology” stands for “the study of.” Microbiology can also be defined by “microbial,” which refers to microorganisms. Suppose we put all of those Geek and Latin roots in combination with the definition of microbial. In that case, we understand that microbiology is the study of microorganisms, where microorganisms are small living components of the broad field of biology. Additionally, the microbiology field involves the analysis of small details of the microbes themselves (their growth, attributes, types, etc.).
What are the differences between bioburden and microbiology?
Bioburden has to do with identifying the microbial burden in a sample. Microbiology has more to do with the specifics of the microbes, such as identifying the species and genus of different microbes in a sample. In contrast, bioburden generally refers to and quantifies all microorganisms (fungi, bacteria, etc.). Both microbiology and bioburden quantify the number of microbes in a sample using colony-forming units (CFU’s). However, bioburden generally quantifies all microorganisms together, while microbiology can be used to quantify the relative amount of specific types of microbes within a sample.
What are the differences between bioburden testing and microbiology testing?
Bioburden testing measures the viable organisms present in a sample. The total viable organisms present is expressed as a total viable count. This total viable count (expressed as CFU’s) provides a value for the microbial contamination level within a particular sample. Combined bioburden and microbiology testing can identify what types of live microorganisms are present in a sample from a product, package, or manufacturing environment. Though bioburden testing may be referred to synonymously with microbiology testing, microbiology testing is what allows for the specific type of live microorganism to be identified and quantified. Bioburden testing follows the methods outlined in USP 60, USP 61, and USP 62.
As mentioned above, microbiology testing is often used in conjunction with bioburden testing. In fact, USP 61 and USP 62 also govern microbiology testing. Broadly, microbiology testing identifies the presence and the type of microbes in a manufacturing environment, medical product, or medical device. Specific regulatory testing for microbiology may include assays such as microbial enumeration testing, particulate analysis, yeast analysis, antifungal activity assessment, growth promotion testing, microbial limits testing, zone of inhibition testing, water analysis, bacteriostasis/fungistasis testing, bacteria identification, yeast identification, fungi identification, gram-negative staining, product inoculations, biological indicator tests, and BI incubation time reduction studies.
Why are both bioburden testing and microbiological testing important?
Bioburden testing is an important quality control step that detects the level of contamination of a product at any stage, from initial product manufacture to final distribution. As microorganisms exist on every surface (including our body), bioburden can be accidentally introduced during the manufacturing or packaging process in many ways. Some of the most common examples are contamination through the raw materials used, technicians, tubing/piping used to transfer product between development stages in a process, or the manufacturing environment itself. With such abundant sources of contamination, regular bioburden testing supports the long-term control of manufacturing sites.
Microbiological testing is imperative for the same reasons as bioburden testing, preventing product-induced infections at the time of use and as a risk mitigation strategy for manufacturing environments, especially aseptic manufacturing environments. Aseptic manufacturing environments rely so heavily on microbiological testing because aseptic processing requires the exclusion of microorganisms from the manufacturing methods. Thus, microorganisms must be prevented from entering open containers or product materials during aseptic processing. As a result, microbial tests are used to monitor clean rooms and facilities that manufacture products using aseptic processing.
Summary
Overall, both bioburden testing and microbiological testing are imperative for regulatory approval of medical devices or products and their packaging. These tests ensure that medical devices, medical products, and medical packaging are sterile and maintain sterility. Maintenance of sterility ensures that patients will not be at risk of infection following device exposure or product implantation.
Ethide Labs is a contract testing organization that specializes in Microbiology Testing and Bioburden Testing. Ethide Labs also offers Environmental Monitoring, Sterilization Validations, Bacterial Endotoxin Testing, EO Residual Testing, Package Integrity Testing & Cytotoxicity Testing services for medical device companies and allied industries. Ethide is an ISO 13485 certified facility.
References
Frank R. Noyes. Noyes’ Knee Disorders: Surgery, Rehabilitation, Clinical Outcomes. Elsevier. 2010.
United States Pharmacopeial Convention. <60> Microbiological Examination of Nonsterile Products- Tests for Burkholderia Cepacia Complex. Rockville, MD, USA. 2021. (USPC <60>)
United States Pharmacopeial Convention. <61> Microbiological Examination of Nonsterile Products: Microbial Enumeration Tests. Rockville, MD, USA. 2021. (USPC <61>)
United States Pharmacopeial Convention. <62> Microbiological Examination Of Nonsterile Products: Tests For Specified Microorganisms. Rockville, MD, USA. 2021. (USP <62>)
