Efficacy of implant surface culture in identification of microorganisms for fracture device-related infection: a preliminary analysis / 中华创伤骨科杂志

ABSTRACT

Objective:To evaluate the efficacy of implant surface culture in identification of pathogens for fracture device-related infection.Methods:A prospective study was conducted to include the eligible patients who were diagnosed with infection after fracture fixation and needed surgical removal of the implants according to treatment principles at Division of Orthopaedics and Traumatology, Department of Orthopaedics and Traumatology, Nanfang Hospital from November 2020 to January 2023. With informed consent, after rinsing with aseptic normal saline twice, their implants were gently covered with a thin layer of tryptone soy agar medium. Thereafter, the implants were incubated at 37 ℃ with 5% CO 2. Changes on the surface and in the surroundings of the implants were observed every day for consecutive 2 weeks to avoid drying up by supplementing the medium when necessary. Once pathogen colonies formed, samples were collected at 3 independent sites using sterile swabs for laboratory identification. Comparisons were made between the samples from implant surface culture and the intraoperative multisite samples from conventional culture. Results:Included were a total of 75 patients [56 males and 19 females with an age of (46.2±15.4) years]. The most common infection site was the tibia (37 cases), and the most common type of implants was plate and screw (59 cases). The positive rate of implant surface culture was significantly higher than that of conventional culture (86.7% vs. 52.0%, P<0.001). 80.5% (29/36) of the negative patients detected by the conventional culture obtained positive results by the implant surface culture; three of the positive patients detected by the conventional culture obtained negative results by the implant surface culture. The culture results were positive by both culture methods in 36 patients, and consistent by both culture methods in 35 patients, yielding a consistent rate of 97.2% (35/36). The time for implant surface culture was significantly shorter than that for conventional culture [1 (1, 2) d versus 3 (3, 4) d] ( P<0.001). Of the 65 positive patients by the implant surface culture, 59 were detected with monomicrobial infection, with Staphylococcus aureus on the top (29 cases). Conclusion:As the implant surface culture, a novel method, may be superior to the conventional culture in a significantly higher positive rate and a shorter culture time, it may be used as an effective adjunct to the conventional culture in identification of pathogens for fracture device-related infection.