【摘要】 【目的】分离鉴定1株牛源肺炎克雷伯菌，检测其耐药性与致病性，为该菌的致病机理研究及临床防治提供参考。【方法】采集牛鼻拭子样品，经分离培养、染色镜检、生化试验及16S rRNA分子鉴定菌株，同时开展耐药表型、耐药基因及毒力基因检测，通过小鼠致病性试验分析其致病性。【结果】分离菌株在LB培养基上呈圆形、凸起、灰白色菌落，革兰染色为阴性短杆菌。生化鉴定显示可发酵蔗糖、麦芽糖、葡萄糖及乳糖；甲基红和吲哚试验阴性，V-P试验阳性。基于16S rRNA基因序列分析，该菌与肺炎克雷伯菌A27782（登录号：CP181979.1）相似度为99.73%,系统发育分析显示二者处于同一分支，鉴定为肺炎克雷伯菌A1。药敏试验显示，菌株A1对氨苄西林、四环素、多黏菌素B耐药，对头孢曲松、氧氟沙星、左氧氟沙星高度敏感；分子检测携带bla_SHV、oqxA耐药基因及fimH、wabG毒力基因。小鼠致病性试验结果显示，高剂量组于接种后12 h内全部死亡，剖检见肺、脾出血，肝瘀血肿大，肠道黏膜充血肿胀，且病变组织中分离到该菌；低剂量组出现临床症状后自愈；对照组无异常。【结论】分离出1株具有多重耐药性和一定致病特性的肺炎克雷伯菌A1,该菌株的检出对临床抗感染治疗及公共卫生防控具有重要参考价值。更多还原

【Abstract】 [Objective] One strain of Klebsiella pneumoniae from bovine origin was isolated and identified, and its drug resistance and pathogenicity were detected, providing a reference basis for the study of the pathogenic mechanism and clinical prevention and treatment of this strain.[Methods] Bovine nasal swab samples were collected.Strains were identified through isolation and culture, staining and microscopic examination, biochemical tests, and 16S rRNA molecule identification.Drug resistance phenotypes, drug resistance genes, and virulence genes of the strains were detected.Meanwhile, pathogenicity was analyzed through mouse pathogenicity tests.[Results] The isolated strains formed round, raised, and grayish-white colonies on the LB medium. They were Gram-negative short bacilli. Biochemical identification showed that they could ferment sucrose, maltose, glucose, and lactose; the methyl red and indole tests were negative, and the V-P test was positive. Based on the analysis of the 16S rRNA gene sequence, this bacterium was 99.73% similar to Klebsiella pneumoniae A27782（accession number: CP181979.1）, and the phylogenetic analysis showed that they were in the same branch, and was identified as Klebsiella pneumoniae A1. The drug sensitivity test showed that strain A1 was resistant to ampicillin, tetracycline, and polymyxin B, and highly sensitive to ceftriaxone, ofloxacin, and levofloxacin; molecular detection carried the bla_SHV, oqxA resistance genes and fimH, wabG virulence genes. The mouse pathogenicity test results showed that the high-dose group all died within 12 hours after inoculation, and autopsy revealed hemorrhage in the lungs and spleen, congestion and enlargement of the liver, and congestion and swelling of the intestinal mucosa. The bacteria were isolated from the lesion tissues; the low-dose group showed clinical symptoms but recovered spontaneously; the control group showed no abnormalities.[Conclusion] One strain of Klebsiella pneumoniae A1 with multi-drug resistance and certain pathogenic characteristics was isolated in this experiment.The detection of this strain has reference value for clinical anti-infection treatment and public health prevention and control.更多还原