连续消毒中大肠杆菌O157:H7对消毒剂抗力变化与DNA关系的研究

STUDY ON RELATION BETWEEN CHANGES IN RESISTANCE OF Escherichia coli O157∶H7 TO DISINFECTANTS DURING CONTINUOUS DISINFECTION AND DNA

为了解50代连续消毒中大肠杆菌O157:H7对4种消毒剂抗力的变化以及抗力与染色体DNA的关系,用4种消毒剂连续消毒大肠杆菌O157:H750代,用XbaⅠ酶切试验菌染色体DNA,对比消毒前后试验菌对4种消毒剂的抗力及染色体DNA的变化。结果,连续消毒50代后,试验菌对二氯异氰尿酸钠、碘伏、季铵盐的抗力增加,细菌染色体DNAXbaⅠPFGE酶切图谱均发生一定的改变;试验菌对洗必泰的抗力不变,细菌染色体DNAXbaⅠPFGE酶切图谱不变。结论,细菌染色体上携带有抵抗二氯异氰尿酸钠、碘伏、季铵盐的抗力的基因,连续消毒会使试验菌对此3种消毒剂的抗力增加,抗力增加的原因可能与细菌染色体DNA结构的改变相关。

In order to know the changes of resistance of Escherichia coli O157∶H7 to 4 kinds of disinfectants during continuous disinfection for 50 generations and the relation between resistance and chromosome DNA, 4 kinds of disinfectants were used to disinfect continuously E. coli O157∶H7 for 50 generations, Xba Ⅰ cleavage was used to test chromosome DNA of the test bacteria and the resistance of the test bacteria to 4 kinds of disinfectants and the changes of chromosome DNA before and after disinfection were compared. Results: After continuous disinfection for 50 generations, the resistance of the test bacteria to sodium dichloroisocyanurate, iodophor and quaternary ammonium salt increased and the Xba Ⅰ PFGE cleavage map of the bacterial chromosome DNA presented certain changes. The resistance of the test bacteria to chlorhexidine did not change and the Xba Ⅰ PFGE cleavage map of the bacterial chromosome DNA also did not change. Conclusions: The bacterial chromosomes carry genes of resistance to sodium dichloroisocyanurate, iodophor and quaternary ammonium salts. Continuous disinfection would cause increase in resistance of the test bacteria to these 3 disinfectants and the cause of increase in resistance may be related to the change in structure of bacterial chromosome DNA.