P332 Evaluation of the efficacy of fumigation practices on the mycological flora in the Orthopedic Operation theatre environment of a tertiary care hospital

POSTER SESSION 3, SEPTEMBER 23, 2022, 12:30 PM - 1:30 PM: OBJECTIVES: To determine the pre and post-fumigation prevalence of fungi in the Orthopedic Operation Theatre of a tertiary care hospital and characterization of fungal isolates. METHOD: This is a prospective environmental, analytical study conducted from July 2021 to January 2022. Pre- and post-fumigation samples were taken from Ultra and Modular OT of Orthopedic department every week by passive methods of air sampling using Gravity sedimentation method (1/1/1 scheme) on SDA and also by surface sampling using swabs. The fungal load of air was measured by calculating the number of CFU per cubic meter (CFU/m3) of air by Omeliansky formula. Fumigation of OT was done with a complex formulation of stabilized hydrogen peroxide 11% w/v with silver nitrate solution 0.01% (Baccishield®). All surface samples were inoculated on SDA with chloramphenicol and all plates were incubated at 22°C and 37°C. The isolates were identified by using standard mycological procedures. Statistical analysis was done using a T-test. RESULTS: Out of 19 surface sampling, fumigation was found to be 100% effective only on 3 occasions (15.79%) in Ultra OT and on 7 occasions (36.84%) in Modular OT. In air sampling ≥50% reduction was found in only 4 samplings (21.05%) in Ultra OT and 10 samplings (52.63%) in Modular OT. The counts were much more than the WHO OT permissible limits. A total of 16 species of fungi were isolated belonging to 11 genera. The most common isolate was Aspergillus niger, followed by sterile hyalohyphomycetes, A. flavus, Cladosporium spp., Curvularia spp., Bipolaris spicifera, A. fumigatus, etc. in both Ultra and Modular OT. Additionally, Exophiala spp. and Fonsecaea spp. were isolated in Ultra OT. The concentrations of fungi in Ultra OT before and after fumigation were in the range 22.11-58.97 CFU/m3 and 7.37-51.59 CFU/m3, respectively. Whereas, in Modular OT, the range was 14.74-36.86 CFU/m3 and 7.37-29.48 CFU/m3, respectively. Percentage reduction of fungi following fumigation with Baccishield varied from 0% to 75% both in Ultra OT and Modular OT. The statistically correlated P-value from pre- and post-fungal concentrations in Ultra and Modular OT were found to be .002 and .0002 respectively which was found significant by T-test, albeit ineffective as per standards. CONCLUSION: In corroboration with our findings, Baccishield has been reported to be less effective even by other researchers. Hence, this needs to be replaced by more effective fumigants. The ineffectiveness of fumigation in Ultra OT was most probably due to the lack of HEPA filters and not strictly following up of aseptic protocols. In Modular OT improper maintenance of ACs and lack of periodic cleaning up of HEPA filters may be contributing factors. Hence, implementing more stringent, frequent, and comprehensive disinfection and cleaning procedures, educating and motivating the health care personnel can help to improve the air quality of OTs that may aid in reducing post-operative infections.