Framework supports microbiota assessment in cleanroom changing rooms

New analysis from a five-year environmental monitoring study could support improved microbial profiling, trending, and benchmarking in pharmaceutical cleanrooms.

The study involved recovery of microbiota from changing rooms and access corridors across cleanroom Grades D, C, and B in the UK.

In general, there are limitations of microbiota studies, Sandle noted. Yet their model overcomes this to a degree “through the use of general-purpose media (tryptone soya agar) and dual incubation”.

their model [partly overcomes limitations of microbiota studies] through the use of general-purpose media (tryptone soya agar) and dual incubation”

Study findings showed that all areas presented a dominance of Gram‑positive cocci, “especially Micrococcus, Kocuria, and coagulase‑negative Staphylococcus, consistent with human skin flora”.

While Grade D changing rooms had the highest overall bioburden and organism diversity, “opportunities for improvement in gowning, cleaning, and moisture control were identified” for personnel transitioning from Grade C into Grade B areas.

These outcomes illustrated different levels of microbial control, with the aseptic area being the most controlled. The study raised some concerns about the Grade C area.

Key study findings include:

• · Changing rooms contained more frequent isolation and greater diversity of contamination compared with the adjacent process areas
• · General contamination patterns were consistent with expected outcomes from a changing room environment
• · Microbial profile was dominated by coagulase-negative Staphylococcus spp., Micrococcus/Kocuria, and occasional Corynebacterium/Bacillus at low levels.

Additionally, assessment 1 (Grade D changing rooms interfacing with a general access Grade D corridor) showed that while the findings were “generally satisfactory”, they showed some recovery of Staphylococcus aureus.

Considering this, the author cautioned that “if trends were to alter, such as repeated S. aureus detections, this should trigger an investigation of gowning, exposed skin, mask fit and related areas”.

Furthermore, the assessment recovered a low level of Gram-negative rods. If this trend was to increase, the facility should audit the following areas:

• · floors after cleaning
• · mop storage
• · sinks/drains (if any)
• · PPE storage and trolleys.

The collected data highlights the value in microbial identification, and with sorting, trending and tracking such information. Notably, the methodology proposed in this study can be applied to different locations even if the resultant microbial profiles differ.

The paper was published in EJPPS.