Performance qualification of the Kiro Isolator^® robotic system through decontamination challenge testing

Introduction
The opening of a digestive oncology day unit at Rennes University Hospital has led to an estimated 30% increase in the annual production volume of chemotherapy preparations. To accommodate this rise while ensuring microbiological control of the preparations, the cytotoxic reconstitution unit acquired a Kiro Isolator^® robot, installed in a Grade D controlled atmosphere environment. The aim of this study is to describe the development and validation of a decontamination challenge protocol for this robotic isolator.

Materials and methods
Protocol development was based on a cross-analysis of applicable regulatory frameworks and a risk-zone mapping conducted in collaboration with the manufacturer, identifying the areas within the enclosure least favourable to vaporised hydrogen peroxide (vH₂O₂) penetration. Decontamination challenge testing was selected as the qualification method for the vH₂O₂ bio-decontamination cycle. Loading scenarios were defined for each of the three modules processed simultaneously by the vH₂O₂ cycle, incorporating maximum load configurations and areas of unfavourable diffusion. Cycle efficacy is assessed using two complementary biological challenge approaches. Biological indicators (BIs) consisting of Geobacillus stearothermophilus spores (initial load: 10⁶ CFU) on stainless steel carriers are positioned according to the critical-zone mapping and incubated for 7 days at 57.5 ± 2.5°C in TSB broth. The robotic arm joints, as mobile zones of complex geometry particularly unfavourable to vH₂O₂ penetration, are subject to a specific challenge by surface inoculation (10⁶ CFU), followed by post-decontamination swab sampling and microbiological culture. Positive and negative controls are included in each series.

Results
Cross-analysis of the regulatory frameworks and risk scenarios enabled the formalisation of a decontamination challenge protocol tailored to the specific features of the Kiro Isolator^®. The mapping defined BI placement points and swab sampling sites, including transfer hatches, enclosure corners, and areas shadowed by the robotic arms. Results are expected to demonstrate a 6log reduction in spore load across all BIs and the absence of microbiological growth at swab sites, thereby validating decontamination efficacy across all three modules of the isolator.

Discussion and Conclusion
The development of a decontamination challenge protocol represents an essential prerequisite for the performance qualification of a robotic isolator. This work, currently being implemented, conditions the performance qualification of the Kiro Isolator^® within our unit under worst-case conditions.