Yunpeng Cui,1 Qiwei Wang,1 Chuan Mi,1 Bing Wang,1 Yuanxing Pan,1 Yunfei Lin,1 Rui He,2 Liying Sun,3 Bo Zheng,4 Xuedong Shi1 

1Department of Orthopaedics, Peking University First Hospital, Beijing, People’s Republic of China; 2Department of Plastic Surgery and Burn, Peking University First Hospital, Beijing, People’s Republic of China; 3Department of Clinical Laboratory, Peking University First Hospital, Beijing, People’s Republic of China; 4Department of Clinical Pharmacology, Peking University First Hospital, Beijing, People’s Republic of China

Correspondence: Xuedong Shi, Department of Orthopedic, Peking University First Hospital, Beijing, People’s Republic of China, Email pku_ortho@163.com

Background: This retrospective cohort study explores a practical approach to acquiring pathogenic microorganisms in patients with bone and joint infections.
Methods: From Aug 2018 to Mar 2022, 68 consecutive patients (87 cultures) with bone and joint infection were recruited in this study. All cultures followed the Peking University First Hospital Procedure of Culturing Pathogenic microorganisms for bone and joint infection. Tissue samples were obtained through fluoroscopy-guided biopsy or open debridement. Tissue samples were divided into manual homogenization (MH), manual mixture (MM), and pathological examination. The baseline, antibiotic exposure, laboratory, surgical, and microbial data were reviewed. Independent sample T-test, Mann–Whitney U-test, and Chi-square test were used to detect the difference between patients who received different processing measures.
Results: The average age was 55.8± 2.4 years old. Thirty-nine patients were male. The total positive culture rate of the manual homogenization group was 80.5% (70/87). Thirty-five patients had mixed infections with more than one microorganism cultured. Staphylococci accounted for 60.23% of all microorganisms. Staphylococcus aureus (18.2%) and Staphylococcus epidermidis (15.9%) were the two most common bacteria cultured in this study. Patients with positive culture in the manual mixture group had significantly higher WBC (p = 0.006), NE% (p = 0.024), ESR (p = 0.003), CRP (p = 0.020) and IL6 (0.050) compared to patients with negative culture. After tissue homogenization, only ESR is still statistically different. Patients without SIRS had a low positive culture rate (59.4%). Tissue homogenization could significantly increase the positive culture rate of patients without SIRS. Pre-culture antibiotic exposure was not an independent risk factor for culture results.
Conclusion: Peking University First Hospital Procedure for Culturing Pathogenic microorganisms for Bone and Joint Infections was a practical approach for obtaining pathogenic microorganisms.

Keywords: bone and joint infection, systemic inflammatory response syndrome, antibiotic, tissue homogenization