Liu Kang, Yang Zhi, Xie Weipeng, Wang Sicheng, Hu Shouye
The Second Clinical Medical College, Shaanxi University of Chinese Medicine, xianyang, shaanxi, china.
Department of Joint Surgery, Hong Hui Hospital, Xi' an Jiaotong University, Xi'an, shaanxi, China.
Medicine (Baltimore). 2024 Dec 27;103(52):e41174. doi: 10.1097/MD.0000000000041174.
Mycoplasma hominis is an opportunistic pathogen commonly found in the human genitourinary system. However, infections caused by Mycoplasma hominis following knee arthroplasty are relatively rare.
A 68-year-old male patient underwent bilateral total knee arthroplasty 2 years ago due to osteoarthritis. Over the past 3 months, he developed persistent swelling and pain in both knees, along with the formation of a mass in the left knee. The patient also has a history of type 2 diabetes and hypoalbuminemia.
Joint fluid samples from both knees were collected for metagenomic sequencing (mNGS), which detected Mycoplasma hominis infection. Histopathological examination confirmed chronic infection.
The patient underwent 1-stage revision surgery for the left knee, followed by intravenous doxycycline (100 mg, q12h) and intra-articular injections of vancomycin (0.5 g/d) and meropenem (0.5 g/d) for 2 weeks. Afterward, the patient was switched to oral rifampin (450 mg daily) and moxifloxacin (400 mg daily) for six weeks. Following improvement in the left knee symptoms, 1-stage revision surgery was performed on the right knee. The same antibiotic regimen was used postoperatively.
The patient experienced significant postoperative improvement, with marked pain relief and no signs of recurrent infection. The knee remained stable, and functional recovery was observed. To date, there have been no signs of infection recurrence during follow-up.
After joint arthroplasty, if a patient has persistent infection symptoms, does not respond to beta-lactam antibiotics, and has negative blood cultures, Mycoplasma infection should be considered. In this instance, the use of mNGS proved highly effective in diagnosing this atypical pathogen. The patient improved significantly after 1-stage revision surgery and targeted antibiotic therapy, though longer follow-up is needed to confirm long-term outcomes. Additionally, limited access to mNGS in some regions may delay diagnosis and treatment.
人型支原体是一种常见于人类泌尿生殖系统的机会致病菌。然而，人工膝关节置换术后由人型支原体引起的感染相对罕见。
一名68岁男性患者因骨关节炎于2年前接受了双侧全膝关节置换术。在过去3个月里，他双膝关节持续肿胀、疼痛，左膝还形成了一个肿块。该患者有2型糖尿病和低蛋白血症病史。
采集双膝关节液样本进行宏基因组测序（mNGS），检测出人型支原体感染。组织病理学检查证实为慢性感染。
患者接受了左膝一期翻修手术，随后静脉注射强力霉素（100毫克，每12小时一次）以及关节腔内注射万古霉素（0.5克/天）和美罗培南（0.5克/天），持续2周。之后，患者改用口服利福平（每日450毫克）和莫西沙星（每日400毫克），持续6周。左膝症状改善后，对右膝进行了一期翻修手术。术后使用相同的抗生素方案。
患者术后有显著改善，疼痛明显减轻，无感染复发迹象。膝关节保持稳定，观察到功能恢复。迄今为止，随访期间无感染复发迹象。
关节置换术后，如果患者有持续感染症状，对β-内酰胺类抗生素无反应且血培养阴性，应考虑支原体感染。在这种情况下，mNGS被证明在诊断这种非典型病原体方面非常有效。患者在一期翻修手术和针对性抗生素治疗后有显著改善，不过需要更长时间的随访来确认长期结果。此外，一些地区mNGS的获取受限可能会延迟诊断和治疗。
