Is it necessary to change instruments between sampling sites when taking multiple tissue specimens in musculoskeletal...

Introduction Surgical debridement of orthopaedic infections allows biopsy for microbiology and facilitates successful treatment. It is recommended that biopsy instruments are changed when taking multiple samples. This study compared assessed cross-contamination between biopsy sites when using same instruments to take tissue samples from multiple sites. Materials and methods During the surgical debridement, we defined five sampling sites and marked them with diathermy. Two sampling techniques were performed on same patient to minimise any potential bias arising from the type of host and the severity of infection. First, fresh instruments were used for each biopsy site. Titleond, the instruments used in the first sampling site were reused to take samples from the remaining sites. By comparing the microbiology results of the samples taken by each technique for each site we determined cross-contamination with microorganisms. Results Fifteen patients with foot and ankle infections (mean age 56 years) were included. Ten patients were diabetic and five had neuropathies. Cross-contamination between sampling sites occurred in eight cases when the same instruments were used to take biopsies (P = 0.002, Fisher's exact test). One or more microorganisms were involved in cross-contamination and the latter always occurred between two consecutive sites rather than sites that were further apart. Conclusion It is important to use fresh instruments for each biopsy site when taking multiple samples in musculoskeletal infection as cross-contamination might occur otherwise and affect microbiological studies.