Introduction
Bioburden is the level of contamination by microbials of an object before sterilizing. The process of testing for bioburden involves counting the number of these biomicrobials in order to ensure that a certain level of cleanliness has been attained before sterilization.
How bioburden may affect sterilization
Before medical devices and instruments are presented for sterilization, they are first taken through a cleaning process to remove some of the physical dirt and microorganisms which can easily be taken out by simply soaking in disinfectants. Bioburden if they exist a certain limit that a dose used for sterilization is meant to take care of can result in ineffective sterilization. This in the end has dire consequences including patient infection and law suits as a result of malpractice.
Any sterilization process can only deal with upto a certain number of microorganisms. Analyzing the bioburden levels prior to starting can help ensure that the sterilization process is not overburdened.
If the weight of bioburden on a given piece of equipment supersedes a certain level, the dose of the solution used for sterilization needs to be increased; consequently increasing the cost of sterilization.
Reasons for bioburden testing
The process of testing for bioburden is carried out to establish the quantity of viable microorganisms in or on equipment prior to sterilization (LeBlanc, 2000). This is done for two primary reasons top on the list being to act as an early warning call for inadequate sterilization, a factor which could lead to detrimental outcomes in the long run. Second, testing for bioburden will come in handy in the determination of the required dosage of radiation to effectively sterilize the equipment (Yan, 1994).
As much as the process of monitoring for bioburden may appear as a minute step in the cleaning and sterilization of equipment, it may in the long run help analyze the effectiveness of an entire process from where the equipment are manufactured to the rooms in which they are cleaned.
Procedure
To perform an effective bioburden testing procedure, two key steps must be followed, viz.:
Extraction
This is the process of picking up microorganisms from the medical device on which the test is being carried out. There are four commonly used methods of extraction and these are:
- Immersion – this is carried out by physically dipping the equipment or product into a vessel containing dye that has the capability to develop fluorescence when combined with biological material (Booth, 2001).
- Flush/Rinse – this is used for particularly small and exceptionally complex devices. Dye is flushed through the device and the draining solution is inspected for traces of biological material. This process is at times referred to as the exhaustive rinse method (Rubino, 1986).
- Surface Sampling – this procedure is carried out particularly on large equipment. A small sample swab is taken from the surface of the equipment and effectively analyzed for the presence of microbials. This procedure is also called recovery qualification (Clontz, 1997).
- Dilution – this method is sometimes called the inoculate product method and it involves mixing an already established amount of culture obtained from the source (medical device) with a sterilized liquid. Incubating the ensuing solution with an agar will result in the formation of a number of colonies which can be counted and calculations of microbials on the original source culture established (Reynolds, 2005).
Enumeration
This is the process of establishing the number of microorganisms that were obtained from the device/equipment under study. There are a number of processes which have been established to carry out this function and they include:
- Membrane Filtration – the eluate discharged after immersion or rinsing is passed through a membrane filter designed to trap even the smallest of microorganisms. This membrane is the studied appropriately to figure out the type of microbes that were on the device under study (Agalloco & Carleton, 2007). This method is the most effective of all enumeration method because it allows for all amount or eluate to be properly analyzed.
- Direct Plating – this is where all the microbial samples taken by swabs are grown into cultures which are then directly placed on slides and analyzed under microscopes (Faruque, 2000).
- Most Probable Number (MPN) – this method is also known as the method of poisson zeros (Nail & Akers,2002). This method involves taking the entire eluate and subdividing it into portions then evaluating the resultant portions for the presence or absence of microbials.
Conclusion
It is worth noting that bioburden can greatly influence the outcome of a sterilization process. This as has been explained in the essay above can lead to an increase in the operational costs of the enterprise. It is therefore of prime importance that adequate measures be taken to ensure that the most minimum amount of bioburden is left on devices and equipment before they are taken to sterilization. This may prove an expensive procedure especially for small establishment but its importance cannot just be wished away. It is therefore of paramount importance that hospitals and other healthcare facilities invest in decent bioburden testing facilities.
Reference
Agalloco, J.P. & Carleton, F.J., 2007. Validation of Pharmaceutical Processes. USA: CRC Press.
Booth, F.A., 2001. Sterilization validation & routine operation handbook: radiation. USA: CRC Press.
Clontz, L., 1997. Microbial Limit and Bioburden Tests: Validation Approaches and Global Requirements. USA: CRC Press.
Faruque, S., 2000. Evaluation of disinfection procedures and measurement of bioburden in an aseptic manufacturing unit. London: King’s College.
LeBlanc, D.A., 2000. Validated Cleaning Technologies for Pharmaceutical Manufacturing. London: Informa Health Care.
Nail, S.L. & Akers, M.J., 2002. Development and manufacture of protein pharmaceuticals. United Kingdom: Springer.
Reynolds, J., 2005. Validation development of a bioburden extraction and determination procedure for a medical device. Northridge: California State University.
Rubino, J.R., 1986. Bioburden dynamics: the viability of microorganisms on medical devices before and after sterilization. New Jersey: Montclair State College.
Yan, A., 1994. Radiation sterilisation-verification of dose setting methods based on bioburden information. England: University of Manchester.