P-368. Long-range Air Dispersal as An Important Source of Environmental Contamination in <i>Candida auris</i> Clustering: Possible Infection Control Implication

Abstract Background Long-range air dispersal of Candida auris has recently been described. Contact precautions alone may not be sufficient to target this mode of transmission. Hence, we study the factors affecting the extent of environmental contamination including air grilles in sporadic C. auris hospitalized patients, and in outbreak settings. Study flow chart Methods Outbreaks and sporadic C. auris cases involving two local hospitals from March to October 2023 were retrospectively analysed. C. auris screening was performed for patients with defined risk factors or regular surveillance as per hospital policy. Environmental samples were taken from high-touch surfaces and air grilles from patients’ environment. Correlation between scale of C. auris clustering and extent of environmental contamination was analysed. Outbreaks with positive environmental sampling Results A total of 170 new C. auris patients were identified, including 65 patients from nine outbreaks and 105 sporadic cases. Environmental screening was performed in eight outbreaks and 46 sporadic isolated cases (Fig 1). Environmental contamination rate of the outbreak group was significantly higher than the sporadic group (15.1% vs 2.5%, P&amp;lt; 0.05). Among outbreak groups, longer median duration of outbreak (34 [27-45] vs 7 [7-12] days, p&amp;lt; 0.05), and more patients’ involvement (9 [6-10] vs 5 [4-7], p=0.05) were associated with higher environmental contamination rate (Table 1). Ward contamination was more frequently detected in sporadic patients with longer duration of stay, though it was not statistically significant (30.8% vs 10%, p=0.09). Air grille samples had a significantly higher contamination rate than high-touch surfaces in both outbreak (41.4% vs 16.7%, p&amp;lt; 0.05) and isolated group (19.7% vs 6.7%, p&amp;lt; 0.05). Outbreaks with negative environmental sampling Conclusion Prolonged and sizeable C. auris clustering was associated with more extensive environmental contamination, particularly air grilles. Long-range air dispersal, as evidenced by air grille contamination, is a possible risk factor for propagation in outbreaks. Contact precautions together with physical segregation to limit air dispersal is recommended. Decontamination of air grille is necessary to prevent further spread. The role of air grille surveillance as a surrogate marker of ward contamination is worthy of further investigation. Disclosures All Authors: No reported disclosures