Sterilization of neoprene gloves used to preparations shielded enclosure and microbiological assessment in radiopharmacy

The preparation of radiopharmaceutical drugs is subject to the Good Preparation Practices (GPP) revised in 2023. Microbiological monitoring during implementation of this revision of the radiopharmacy unit revealed recurrent non-compliance of samples taken from gloves in shielded enclosure, classified as a class A controlled atmosphere zone (CAZ). A 3-point action plan was introduced: weekly sterilization, gloves’ regular disinfection in use, and identification of microorganisms present in positive samples.

This work aim is to carry out a comparative assessment of gloves’ microbiological monitoring and evaluate the impact of new hygiene practices.

The gloves initially disinfected by soaking in a detergent-disinfectant are now washed by thermal induction in a washer-disinfector and sterilized by steam at 134°C for 18 minutes, with a maximum of 15 cycles as recommended by the supplier, to meet sterile drug requirements. In addition, gloves are now disinfected every hour in use.
Gloves’ microbiological analyses (“contact” agars) based on sampling plan were carried out over a period of 7 months before and after new measures adoption. The microorganisms were identified by our environmental biology laboratory.

Before protocol application, 171 of 265 samples came back positive (64.5%), with an average of 2 CFU, and 5 samples with uncountable number colonies, compared with 110 out of 288 (38.2%) after new hygiene protocol application, with an average of 0.9 CFU and no uncountable samples. In decreasing order of frequency, bacteria identified were: Coagulase-negative Staphylococcus, Micrococcus sp. Corynebacterium sp. and Bacillus sp.

Since implementation of corrective measures, a significant reduction of positive samples and average CFU count less than 1 have been observed after 7 months. Glove sterilization protocol combined with reinforced biocleaning has enabled to achieve GPP’s objectives.
Bacteria identified are mainly skin commensals usually sensitive to the products used, with the exception of Bacillus sp. which is spore-forming and resistant to non-sporicidal detergent-disinfectant used daily. Bacteriological identifications made in class A demonstrate that colony counting is not enough in results analyze and the importance of adapting biocleaning products according to sampling.

See the poster