Microbial Ingress Testing - Bioscience Labs
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Microbial Ingress Testing

Posted On: Jan 24, 2020

by Daryl. S. Paulson, PhD

For intravascular devices that are needle-less and facilitate bidirectional flow can cause serious infection, if microorganisms are allowed to enter into the sterile fluid path.

To prevent this from happening, the Food and Drug Administration (FDA) has developed guidelines for a testing method known as the Microbial Ingress Test. It is a bench top procedure yet should simulate the device’s use in the clinical setting. For example, the challenge microorganisms should be the number of microorganisms expected to be eliminated and the types of microorganisms encountered. The level of challenge microorganisms is 103, but many companies have chosen to inoculate the microorganisms at higher levels, mainly because they sell to a variety of hospitals, each having a different bioburden level with the hospital setting, and they do not want the test active to be faulty.

In FDA guidelines, the stated requirements are two gram-negative and two gram-positive microorganisms, but many clients use more. Some clients also evaluate fungi, because they are particularly hard to kill. Fungi do not usually cause problems in immunocompetent people, but many in the hospital settings are patients who are immunocompetent due to a pre-existing illness or physical condition.

The main issues we have found in testing the device is the disinfectant solution, its application procedures, and length of time. These are critical and are the key determinants of the test’s success. It is also wise to run a series of replicates in the study to show that the device can be cleansed repeatedly. Eight to ten replicates are usually used.

BioScience Laboratories, Inc. conducts GLP microbial ingress studies routinely, typically for submission to regulatory bodies. Our ability to develop custom protocols along with 30 years of microbiology experience allows us to accurately evaluate your medical device’s microbial barrier properties across various physical shapes and material types.