Yield of fungal and mycobacterial cultures for operative specimens in orthopedic procedures: A retrospective, observational cohort study.

Fungal and mycobacterial cultures are routinely sent on orthopedic operative specimens, but their impact on clinical care is not well established. Processing fungal and mycobacterial cultures is time and labor intensive, associated with significant healthcare costs, and may yield false-positive results due to contamination. The objective of this study was to determine the utility and diagnostic yield of fungal and mycobacterial cultures from orthopedic operative specimens. Patients undergoing surgery by the orthopedic or podiatry service that had operative specimens sent for fungal and mycobacterial cultures from January through December 2022 were included. Fungal and mycobacterial cultures were ordered on a total of 1109 operative specimens in 428 patients. A mean of 2 (standard deviation 1.3) specimens was collected per operative procedure. A microorganism was identified in 34 (3.1 %) of fungal cultures and in no mycobacterial cultures. Fungal microorganisms included yeast (89.7 %), mold (7.7 %) and dermatophytes (2.6 %). Results of the fungal cultures alone led to a change in management for 4 (0.9 %) patients. Results of the mycobacterial cultures did not lead to a change in management for any patient. The diagnostic yield of fungal and mycobacterial cultures on operative specimens in orthopedic and podiatry surgery is low and rarely results in a change in therapeutic management. Standardized approaches for targeted rather than routine use of these cultures should be developed to improve stewardship of laboratory resources.