ESBLs Produced in Biofilm of Bacteria / 中华医院感染学杂志

ABSTRACT

OBJECTIVE To evaluate the mechanism that bacteria growing in biofilm(BF) always resist to antimicrobial agents,and to provide the theoretical basis for selecting antimicrobial agents in clinic. METHODS Model of Klebsiella pneumoniae and Escherichia coli bacterial biofilm was built up with the modified flat-board method and identified with the AgNO_3 staining and confocal scanning laser microscopy.We used imipenem to induce the ESBLs production of BF bacteria.ESBLs production was performed by the standard disk diffusion method. RESULTS The isolation rate of ESBLs producing strains in Klebsiella and E.coli planktonically was 20.0% and 22.5%,respectively.The isolation rate of ESBLs producing strains in Klebsiella biofilm and E.coli was 42.5% and 47.5%,respectively.The isolation rate of ESBLs producing strains in above two biofilms and(E.coli) biofilm being induced by imipenem was 65.0% and 70.0%,respectively.The isolation rate of groups A_1 and B_1,groups B_1 and C_1,groups A_2 and B_2,groups B_2 and C_2 was different from each other significantly with the statistic method of ?~2 test. CONCLUSIONS One of the main reasons that Klebsiella and E.coli resist to antibiotics is the synergetic effect of BF and ESBLs.