一株肺炎克雷伯菌的分离鉴定及生物学特性分析

Isolation, identification and biological characteristics analysis of a strain of Klebsiella pneumoniae

摘要:

【背景】肺炎克雷伯菌是一种人兽共患机会致病菌，可引起多种动物感染且防治难度大。【目的】调查某犀牛驯养场病原菌存在情况。【方法】对随机采集到的6份犀牛粪便进行细菌分离鉴定、耐药情况及相关耐药基因、毒力基因筛查、小鼠致病性试验。【结果】分离到一株肺炎克雷伯菌，分离率为16.67%。分离株对强力霉素、多黏菌素B、杆菌肽等6种抗生素耐药，且携带有五大类共6种耐药基因。检出kfuBC、fimH、ureA、uge、wabG和wcaG这6种毒力基因。在致病性试验中接种浓度为1×10¹⁰ CFU/mL时小鼠死亡率高达80%，死亡小鼠肝脏、肺脏和小肠组织有不同程度的病变。【结论】该犀牛驯养场分离到的肺炎克雷伯菌耐药情况严重，耐药基因与耐药表型的复合率低，耐药机制复杂；毒力基因携带情况与致病性试验结果较符合，研究数据可为驯养场防治该菌的潜在感染提供参考。

Abstract:

[Background] Klebsiella pneumoniae is a zoonotic opportunistic pathogen, which can cause infections in many animals and is difficult to be controlled. [Objective] To investigate the existence of pathogenic bacteria in a rhinoceros domestication farm. [Methods] Bacteria isolation and identification, drug resistance and drug resistance genes, virulence gene screening, and pathogenicity test in mice were performed on six samples of rhinoceros feces randomly collected. [Results] One Klebsiella pneumoniae strain was isolated, with the isolation rate of 16.67%. The isolate was resistant to six antibiotics, including doxycycline, polymyxin B and bacitracin, and carried six resistance genes and six virulence genes (kfuBC, fimH, ureA, uge, wabG, and wcaG). In the pathogenicity test, the strain suspension of 1×10¹⁰ CFU/mL led to a mortality rate as high as 80% in mice and lesions appeared in the liver, lung, and small intestine tissues of dead mice. [Conclusion] The K. pneumoniae strain isolated from the rhinoceros domestication farm had strong drug resistance, a low combination rate of drug resistance gene and drug resistance phenotype, and a complex drug resistance mechanism. The results of virulence gene prediction were in good agreement with the results of pathogenicity test. The data could provide reference for the prevention and control of K. pneumoniae infection in domestication farms.