RESUMEN
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 .5×106 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 ×107 CFU/mL,1 .5 ×108 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 .5×108 and 1 .5 ×107 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)×105 CFU/mL,(0.50 ±0.38)×105 CFU/mL,(1 .73 ±0.56)×105 CFU/mL,and (2.62±0.53)×105 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.