In recent years, there has been an increased regulatory and compendial focus on the use of in-house isolates during method suitability and qualification of methods. For many companies, there have been questions on why an in-house library is necessary and how to set up this library of isolates. This paper describes the basis for needing this type of library as well as a way to establish this type of library.
Dr. Tim Sandle (2010) states, “There is a strong argument that environmental isolates are the best challenge to media and for validation studies like sterility test validation. They are the most sensitive micro-organisms, having been exposed recently to disinfectants, particular soils, etc.” It is believed that environmental isolates have been stressed similarly to the organisms that you actually find in the pharmaceutical manufacturing environment that could be likely to affect the product being manufactured. Dr. Andrew Sage (2013) stated, “Model stressed populations should reflect the bioburden of the sample, and mimic exposure to the stress factors that are present in the sample matrix as closely as possible, in order to achieve this, the isolates obtained from the sample environment should be identified and used.”