放射根瘤菌感染六例临床特点分析

Clinical and microbiological characteristics of Rhizobium radiobacter infections： six cases report and literature review

目的探讨放射根瘤菌感染患者的临床症状及体征，为预防与治疗放射根瘤菌感染提供依据。方法回顾性分析2008年5月至2009年7月福建医科大学附属第二医院收治的6例血培养放射根瘤菌阳性患者的临床症状及实验室检测结果，并结合相关文献进行复习。结果6例患者中男4例，女2例，年龄5—88岁。6例均发热，伴畏寒、寒战或疲乏感；血常规均示白细胞增高和（或）中性粒细胞比例升高。肺部感染5例，均有轻度咳嗽、咳痰，肺部可闻及湿性啰音，X线胸片或胸部CT可见斑片状阴影；另1例感染部位不明。6例均存在免疫受损的基础疾病包括恶性肿瘤、系统性红斑狼疮、肺结核、先天性心脏病、巨幼细胞性贫血及低白蛋白血症，5例有土壤密切接触史，4例曾应用广谱抗生素或免疫抑制剂。6株放射根瘤菌对第三代头孢菌素、头霉素类、碳青霉烯类、氟喹诺酮类、四环素及呋喃妥因均敏感，对青霉素类及青霉素类／β-内酰胺酶抑制剂复合物、第一代及第四代头孢菌素、单环类均耐药，对氨基糖苷类大部分药物敏感。6例患者均未出现继发性脏器损害，根据药敏结果用药后均好转出院。结论放射根瘤菌感染常见于有高危因素的患者，临床表现无特异性；放射根瘤菌对大多数抗菌药物敏感；经治疗后患者预后良好。

Objective To explore the clinical and microbiological characteristics of Rhizobium radiobacter infection, and therefore to provide information for the prevention and treatment of the disease. Methods The clinical and microbiological data were analyzed for patients proved to have Rhizobium radiobacter infection by blood culture obtained from May 2008 to July 2009 in the Second Affiliated Hospital of Fujian Medical University. Related literature were reviewed. Results There were 4 males and 2 females aging 5 -88 years old. All the patients suffered from fever and chillsor malaise, and had increased peripheral WBC or neutrophil count . The majority（5/6） of the infections was pneumonia, characterized by mild cough and expectoration, lung rales, patchy infiltrates on chest X-ray. All the patients had underlying diseases or were immunocompromised. Five of the 6 patients had close soil exposure. Four of the 6 patients received broad-spectrum antibiotics or immunosuppressive therapy. Antibacterial susceptibility testing showed that, all the isolates of Rhizobium radiobacter were susceptible to the third generation cephalosporins, cephamycins, Carbapenems, fluoroquinolones, tetracycline,nitrofurantoin and some of the aminoglycosides, but resistant to penicillins, penicillins/enzyme inhibitors, first and fourth generation cephalosporins, and helices 15-lactamase antibiotics. There were no complications, and all patients recovered uneventfully after treatment with antibiotics according to the susceptibility testing. Conclusions Rhizobium radiobacter infections often occur in patients with underlying risk factors. The clinical manifestations of Rhizobium radiobacter infection are nonspecific. Theorganism is sensitive to most antibiotics, and the clinical outcome is favorable.