If you have questions about how to comply with the latest revisions to USP <797>, you’re not alone. Even though the standard has been in effect since November of 2023, we’re still getting a lot of foundational questions about specific requirements.
If you have a question, you can count on us to follow up with a personal response. However, to help the greatest number of clients, we thought we’d also share some of the most common questions – and maybe a few unusual ones – in a series of posts. Today’s question is:
USP <797> mentions having a microbiologist review sampling results. Does that mean I need to have a microbiologist on staff?
Why the question?
When answering customer questions, it helps to consider what the questioner might have in mind so we can provide the most appropriate response. In this case, the question was specifically about the need to have a microbiologist on staff.
It may not be the case here, but many questions of this sort are from compounding pharmacies looking to do sampling in-house. That’s understandable. The latest revisions to USP <797> require more sampling, so it makes sense to explore the options. They may have also taken a class or watched a webinar that encouraged them to strengthen their in-house compliance program. That’s certainly good advice.
Of course, no webinar or class is going to give you the kind of experience and knowledge a credentialed microbiologist gains through their extensive training and on-the-job experience. Genus identification may sound easy, but there’s a lot more to assessing those dots than meets the eye. Literally, as many bacterial colonies resemble each other. The first step in identification often requires Gram staining and a microscope with 100x magnification (oil lens) to characterize the bacteria. Even then, you’re still a long way from being able to identify the genus or species. A microbiologist with significant expertise might be able to do it, but additional laboratory equipment is often required to ensure accuracy.
What USP Chapter <797> says about microbiologists
To provide a thorough response, let’s start by revisiting what the most recently revised standards say about microbiologists. The 2022 revisions mention microbiologists only twice in the entire chapter:
Section 6.2.3: If levels measured during viable air sampling exceed the levels in Table 7. an attempt must be made to Identify any microorganisms recovered to the genus level (see Microbial Characterization, Identification. and Strain Ty,mJg_(1113).} with the assistance of a microbiologist.
Section 6.3.3: If levels measured during surface sampling exceed the levels in Table8, an attempt must be made to identify any microorganism recovered to the genus level (see .(1113).) with the assistance of a microbiologist.
So, if the number of CFUs on a plate is below the action level, there is no need for genus identification, right? Well...maybe not.
Microbiologists wanted!
Read: USP <797> Compliance: It's as Easy as A,B,C,..1,2,3. Or is it?
But let’s say for sake of argument that you’ve conducted a risk assessment and decided that your risks don’t warrant genus identification on every sample. You’ve also decided to incubate and read your samples in-house. If you exceed the action level on a sample, you are required by USP <797> to identify the microorganism.
If you don’t have a microbiologist on staff and the required equipment, you’ll need to send the plate to a microbiologist for microbial identification anyway. This introduces all kinds of shipping and handling complexities. It’s doable, but we highly recommend you develop a relationship with a USP <797> laboratory ahead of time. They can provide specific instructions in the event of an exceedance so your plates arrive safely with colonies intact.
Moreover, if you already have your hands full as you work to meet the needs of your patients and customers, sending plates to a lab staffed by trained microbiologists can really simplify your day. At Pace® we like to simplify things even more for our clients, by allowing them to set up subscription delivery of routine sampling supplies, shipping labels (prescription test kits), etc. Shop our USP <797> store to learn more.
Clinical and Environmental Laboratories are Not the Same Thing
One quick word of caution. Many of our clients, especially those that are part of a larger healthcare system, have laboratories onsite. However, these labs are usually clinical labs. Clinical microbiologists are trained to assess substances like blood and urine, not to identify microbial growth in a USP <797> sample. In addition, clinical labs aren’t typically held to the same cleanroom standards as an environmental laboratory. Since cross-contamination of samples can also occur in these settings, some state pharmaceutical standards prohibit handling USP <797> samples in a lab that also handles bodily fluids.
The Bottomline
You may need a microbiologist on staff if you treat USP <797> as a D-I-Y program and process samples in house. At the very least, you’ll need to develop a relationship with an environmental laboratory ahead of time. On the other hand, a professional environmental laboratory with trained microbiologists experienced with USP <797> can effectively perform genus identification on every sample if your risk assessment warrants it. They can also dramatically simplify your USP <797> program so you can get back to focusing on your patients.
If you have questions about USP <797> environmental monitoring, Pace® is here to help. Contact us for a personal response.