Optimization of microbiological sampling in a centralized anticancer drugs preparation unit

Introduction
The centralized anticancer drugs preparation unit (UPCA) is a controlled atmosphere area which is used for the production of sterile injections preparations for patients.
Regular monitoring of microbiological contamination is therefore essential, as it represents a major risk for patients.
The aim of this study was to analyze environmental microbiological non-conformities in sterile production areas in 2022.

Material and methods
The results of environmental surface and air sampling in UPCA over the course of the year were collected. Air samples were taken using an aerobiocollector, while surface samples were taken using contact agars within the UPCA, in 3 zones: the production zone (ZP) and the storage zone (ZS), both classified C, and the personal airlock, which is not classified but communicates with the ZS and ZP. Several items of information were collected: the date, the concerned zone, the number of colony-forming units (CFU), and the number of compliant and non-compliant (NC) samples.
A sample is compliant if the number of CFUs is below the regulatory action level. There is an intermediate threshold, known as the alert threshold, which enables corrective action to be taken. An analysis of NC results by zone and type of surface was carried out. The evolution of the number of NCs in 2022 was also evaluated.

Results
In 2022, 165 air samples and 1175 surface samples were taken. No significant air contamination was detected in the ZP or personal airlock areas. Air contamination was detected in the ZS, corresponding to a NC rate of 0.6%. 38 NC out of 1175 surface samples were identified, corresponding to an NC rate of 3%. These NCs were mainly observed in the personal airlock: 15 NCs out of 38, i.e. 39%. Both class A isolators showed contamination of gloves (4 NC), contamination of a sleeve (1NC) and contamination of the inner airlock door (1NC), representing a NC rate of 0.5%. Despite hygiene procedures, 8 of the 38 NCs were preceded by contamination at an intermediate threshold, i.e. 21% of cases where it is assumed that the contamination found was the result of several weeks old contamination.

Conclusion/Discussion
In 2022, the low contamination rates in UPCA enabled production to be maintained and made safe. In addition to initial team training, and the personal protective equipment used, hygiene awareness and more efficient bio cleaner analysis based on microbiological results would be necessary.
The research of the microbial ecology in collaboration with the microbiology laboratory is an area for improvement, which will enable us to identify the various sources of microbiological contamination.

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