腹腔引流液结核硬脂酸棒杆菌的鉴定与耐药性分析

Identification of Corynebacterium tuberculostearicumstrain isolated from abdominal drainage fluid and analysis of drug resistance

目的对宫外孕术后患者腹腔引流液中分离到的一株棒杆菌属进行鉴定与耐药分析,为临床鉴定及用药提供依据。方法利用形态、触酶试验初步进行细菌鉴定,最终通过基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)明确其种属。采用纸片扩散法检测抗菌药物的最低抑菌浓度(MIC)和抑菌圈直径。结果分离出棒杆菌属1株,MALDI-TOF MS分析显示为结核硬脂酸棒杆菌,药物敏感试验显示,其对万古霉素、利奈唑胺、亚胺培南、阿莫西林、阿莫西林/克拉维酸、头孢曲松、头孢吡肟和头孢他啶均敏感,对其余抗菌药物均耐药。结论结核硬脂酸棒杆菌的一般实验室鉴定非常困难,常需MALDI-TOF MS或16SrRNA基因测序,并且存在多药耐药现象,体外试验敏感的药物临床治疗可能无效,治疗应以万古霉素和利奈唑胺为首选。

OBJECTIVE To identify one strain of Corynebacterium tuberculostearicumisolated from the abdominal drainage fluid of an ectopic pregnancy patient after surgery and analyze the drug resistance so as to provide guidance for clinical identification and use of antibiotics.METHODS The preliminary bacterial identification was carried out by means of morphology,catalase test,and the species was finally determined through the matrix assisted laser desorption Ionization time of flight mass spectrometry（MALDI-TOF MS）.The minimum inhibitory concentrations（MICs）of antibiotics and inhibition zone diameters were detected with the use of disk diffusion method.RESULTS One strain of gram-positive Corynebacterium was isolated,and the MALDI-TOF MS showed that it was C.tuberculostearicum.The drug susceptibility testing indicated that the strain was in vitro susceptible to vancomycin,linezolid,imipenem,amoxicillin,amoxicillin-clavulanic acid,ceftriaxone,cefepime,and ceftazidime and that it was resistant to the rest of antibiotics.CONCLUSIONIt is very difficult to identify the C.tuberculostearicumin common laboratory and is necessary to conduct the MALDI-TOF MS or 16 SrRNA gene sequencing.The strain shows multidrug-resistant.The in vitro sensitive antibiotics may be ineffective for the clinical treatment;vancomycin and linezolid are preferred for the treatment.