内置物表面培养在骨折内固定术后感染致病菌中的检出效能初探

Efficacy of implant surface culture in identification of microorganisms for fracture device-related infection: a preliminary analysis

目的:评估一种内置物表面培养方式在骨折内固定术后感染致病菌中的检出效能。方法:前瞻性筛选自2020年11月至2023年1月期间就诊于南方医科大学南方医院骨科-创伤骨科、诊断为骨折内固定术后感染、根据临床诊疗原则需取出内置物的患者。将所有患者术中取出的内置物于无菌环境下采用生理盐水冲洗2遍后,表面浇筑薄层胰酪大豆胨琼脂培养基,随后置于37℃含5%CO 2的细菌培养箱,每天观察内置物表面及周围变化,必要时再次加注培养基避免其干涸凝固,培养2周,对于出现的菌落予无菌咽拭子采集3个独立菌落送检验科进行鉴定;将鉴定结果与传统术中多点取材进行培养的结果进行比较分析。结果:共纳入75例患者,其中男56例,女19例;年龄(46.2±15.4)岁;最常见的感染部位是胫骨(37例),最常见的内置物类型是钢板螺钉(59例);内置物表面细菌阳性率为86.7%(65/75),显著高于传统术中多点取材培养的52.0%(39/75),差异有统计学意义(P<0.001);传统培养阴性的80.5%(29/36)采用内置物表面培养可获得阳性结果;传统培养阳性而采用内置物表面培养获得阴性结果的患者3例;36例患者两种方式的培养结果均为阳性,35例患者两种方式的结果一致,一致率为97.2%(35/36);内置物表面培养方法的培养时间[1(1,2)d]显著短于传统培养方式[3(3,4)d],差异有统计学意义(P<0.001);65例内置物表面培养的阳性患者中,59例为单一菌种感染,最常见的致病菌为金黄色葡萄球菌(29例)。结论:内置物表面培养致病菌的方法具有一定的优势:阳性率高,培养时间短,可作为传统培养方法的一种有效补充。

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%CO2.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.