秀丽隐杆线虫-泛耐药肺炎克雷伯菌感染模型的建立

Establishment of an infection model using Caenorhabditis elegans-extensively drug-resistant Klebsiella pneumoniae

目的建立泛耐药肺炎克雷伯菌(XDRKP)感染秀丽隐杆线虫感染模型。方法在液体条件下,利用临床分离的XDRKP菌株感染秀丽隐杆线虫,观察线虫存活及体内细菌数量变化情况。结果线虫感染XDRKP后活动明显迟缓,不同浓度的XDRKP对线虫的致死情况不同。log-rank检验显示,1.5×106 CFU/mL XDRKP组与E.coli OP_(50)对照组的生存曲线差异无统计学意义(χ2=0.08,P>0.05);1.5×107、1.5×108 CFU/mL组与E.coli OP_(50)对照组的生存曲线差异均有统计学(χ2值分别为229.37、275.98,均P<0.001),1.5×108与1.5×107 CFU/mL XDRKP组线虫的生存率低于对照组。实验获得上清悬液,经细菌纯培养后进行细菌鉴定和药敏测试,证实为XDRKP。XDRKP感染线虫4、6、12、24 h后,线虫体内细菌总量分别为(0.28±0.02)×105、(0.50±0.38)×105、(1.73±0.56)×105、(2.62±0.53)×105 CFU/mL,不同时间线虫体内细菌总数存在统计学差异(F=1 363.39,P<0.001)。结论成功建立了秀丽隐杆线虫-XDRKP感染模型。

Objective To establish an infection model using Caenorhabditis elegans （C.elegans）-extensively drug-resistant Klebsiella pneumoniae （XDRKP）system.Methods Clinically isolated XDRKP strains were used to infect C.elegans in the liquid killing assay,the nematode survival and the number of bacteria in C.elegans digestive tract was observed.Results C.elegans was significantly retarded after being infected by XDRKP,different concentra-tions of XDRKP led to different patterns of the worm death.Log-rank test showed that survival curves of C. elegans infected with 1 .5×10^6 CFU/mL of XDRKP and E.coli OP50 （control）were not significantly different （χ2 =0.08,P 〉0.05）;survival curves of C.elegans infected with 1 .5 ×10^7 CFU/mL,1 .5 ×10^8 CFU/mL of XDRKP and E.coli OP50 were significantly different（χ2 =229.37,275.98,respectively,both P 〈0.001）.The survival rates of 1 .5×10^8 and 1 .5 ×10^7 CFU/mL XDRKP groups were both lower than that of the control group.Supernatant suspension obtained from test was performed bacterial culture,identification and antimicrobial susceptibility testing, XDRKP was determined.After being infected with XDRKP 4,6,12,and 24 hours,the total number of bacteria in C.elegans were（0.28±0.02）×10^5 CFU/mL,（0.50 ±0.38）×10^5 CFU/mL,（1 .73 ±0.56）×10^5 CFU/mL,and （2.62±0.53）×10^5 CFU/mL,respectively,the number of bacteria in C.elegans digestive tract was significantly different at different time points （F =1 363.39,P 〈0.001）.Conclusion The infection model of C.elegans-XDRKP is established successfully.