耐碳青霉烯类肺炎克雷伯菌对C57BL/6小鼠肺部菌群的扰动

Perturbation of carbapenem-resistant Klebsiella pneumoniae on the pulmonary flora of C57BL/6 mice

【背景】肺部菌群与宿主健康和呼吸道疾病密切相关,耐碳青霉烯类肺炎克雷伯菌(carbapenem-resistantKlebsiellapneumonia,CRKP)是临床常见的条件致病菌,感染后对肺部菌群的影响尚不清楚。【目的】探究耐碳青霉烯类肺炎克雷伯杆菌CRKP2对C57BL/6小鼠肺部菌群的扰动。【方法】将C57BL/6小鼠随机分为3组,分别用CRKP2、碳青霉烯类敏感肺炎克雷伯菌KP2044和无菌PBS溶液滴鼻,利用16Sr RNA基因的高通量测序技术分析肺部菌群结构。【结果】与健康小鼠相比,菌株KP2044和CRKP2感染后小鼠肺部菌群α多样性和β多样性均显著改变,变形菌门相对丰度显著增加,乳酸杆菌属相对丰度明显下降。与KP2044相比,CRKP2生物膜形成能力较弱,感染后小鼠死亡率较低,对肺部菌群的扰动较小。【结论】虽然肺炎克雷伯菌是条件致病菌,但高剂量耐碳青霉烯类肺炎克雷伯菌CRKP2仍对健康小鼠肺部菌群造成显著影响;尽管菌株CRKP2具有多重耐药性,但与菌株KP2044相比对肺部菌群的扰动较小,因此推测KP菌株感染对肺部菌群的扰动程度可能与菌株毒力有关。

[Background]Pulmonary flora is closely associated with host health and respiratory diseases.Carbapenem-resistant Klebsiella pneumoniae(CRKP)is a common opportunistic pathogen in clinical practice,while its impact on pulmonary flora after infection remains unclear.[Objective]To explore the perturbation of carbapenem-resistant K.pneumoniae CRKP2 on the pulmonary flora of C57BL/6 mice.[Methods]The C57BL/6 mice were randomly assigned into 3 groups which were intranasally inoculated with CRKP2,carbapenem-sensitive K.pneumoniae KP2044,and sterile PBS solution,respectively.The structure of pulmonary flora was analyzed via 16S rRNA high-throughput sequencing.[Results]Compared with those in healthy mice,the alpha diversity and beta diversity of the pulmonary flora in the mice after KP2044 and CRKP2 strain infection significantly changed.Specifically,the infection with strain CRKP2 and KP2044 significantly increased the relative abundance of Proteobacteria and decreased that of Lactobacillus.Compared with KP2044,CRKP2 showed decreased biofilm formation and caused low mortality of infected mice,which indicated that CRKP2 infection led to weaker alteration of pulmonary flora than KP2044 infection.[Conclusion]Although K.pneumoniae is an opportunistic pathogen,high-dose carbapenem-resistant K.pneumoniae CRKP2 significantly affects the pulmonary flora of healthy mice.Although stain CRKP2 has multi-drug resistance,it leads to lower disturbance on the pulmonary flora than strain KP2044.Therefore,we hypothesize that the degree of disturbance of the pulmonary flora by K.pneumoniae infection may be related to strain virulence.