Study On The Environmental Adaptability And Virulence Effect Of Multi-drug Resistant Acinetobacter Baumannii

Part I Study on environmental adaptability of Acinetobacter baumanniiObjective: To investigate the difference in growth rate,anti-drying ability,anti-ultraviolet killing capacity and serum scavenging capacity between multi-drug resistant Acinetobacter baumannii and susceptible strains,and to clinically manage and control multi-drug resistant Acinetobacter baumannii Provide theoretical support.Methods: The growth curves of strain-sensitive strains and multi-drug-resistant strains within 24 hours were determined by absorbance value method;the growth competition of strain-susceptible strains and multi-resistant strains was compared by in vitro competition experiments;The ability of resistant bacteria to resist drying;UV-sensitive method was used to determine the anti-ultraviolet radiation killing ability of susceptible strains and multi-drug-resistant strains;the killing ability of sensitive strains and multi-drug resistant strains was compared by the human serum killing test.Results: The growth curves of susceptible strains and multi-antibioticresistant strains were similar.The logarithmic phase was between 6 and 12 hours,and it was in a stable phase between 12 and 18 hours.It was already in a recession at 18 to 24 hours.However,many resistant bacteria were more sensitive.The bacterial decay is slower.In in vitro competition experiments,the growth curves of the susceptible and multi-antibiotic resistant strains were similar.When the two strains were mixed and cultured for 24 hours,the susceptible strains and multi-antibiotic resistant strains were 8.20 and 6.73 Log of CFU/mL,respectively.The bacterial liquid concentration was 1.43 Log of CFU/mL lower than that of sensitive bacteria,and the difference was statistically significant(CI=0.82,P<0.05).There was a certain difference between the tolerance of dry and susceptible strains,and the survival rate of the two strains decreased significantly in the dry environment over time.After 30 days of experimentation,the survival rate of susceptible strains and multidrug resistant strains decreased to 50.%,there was no difference between the two groups;on the 45 th and 60 th days,the number of sensitive bacteria was significantly less than that of multiple drug-resistant bacteria,and there was a difference between the two(P<0.05);on the 75 th day,the two bacteria were further However,there was a decrease in the number of multi-drug resistant bacteria,and the number of sensitive bacteria decreased drastically.There was a significant difference between the two(P < 0.001).The sensitive bacteria and multi-drug resistant bacteria all showed a certain degree of reduction after UV irradiation;at 15 min,the two bacteria survived less than 50%,but there was no difference in the amount of the two bacteria(P>0.05);at 30 minutes,they could be observed.The number of sensitive bacteria decreased significantly,and the survival was significantly less than that of multiple resistant bacteria(P<0.001).At the 45 th minute,the number of sensitive bacteria decreased drastically,which wassignificantly less than that of multiple resistant bacteria(P<0.001).At the 60 th minute,Sensitive bacteria were almost undetectable,while the number of multidrug resistant bacteria decreased slowly.There was a significant difference between the two(P < 0.001).Both susceptible strains and multidrug-resistant strains had anti-serum killing ability.The number of multi-drug resistant bacteria in normal human serum was significantly higher than that of susceptible strains(P < 0.001).In heat-treated inactivated serum,both survived.Good,no difference in comparison(P>0.05).CONCLUSIONS: The multi-drug resistance Acinetobacter baumannii significantly increased resistance to desiccation,anti-ultraviolet killing and anti-serum killing ability,and had stronger environmental adaptability in these environments;but when mixed with sensitive bacteria When growing,its growth competitiveness is weaker than that of susceptible bacteria.Part 2.In vitro virulence studies of Acinetobacter baumannii Objective: To explore the difference between biofilm formation ability and exercise capacity of multi-drug resistant Acinetobacter baumannii and susceptible strains,and to provide a theoretical basis for the prevention of multi-drug resistant Acinetobacter baumannii biofilm formation and spread of strains.Methods: The ability of biofilm formation of susceptible strains and multidrug resistant strains was determined by crystal violet staining.The exercise ability of sensitive strains and multidrug resistant strains was compared by means of limp exercise and swimming experiments.Results: The biofilm could be formed by susceptible strains and multidrug-resistant strains.It began to form on the first day.Both of them reached the maximum amount of biofilm on the third day.Among them,multiple drug-resistant strains had strong biofilm-forming ability.Biofilms were more than the sensitive bacteria at each time point(P<0.05).Both susceptible strains and multidrug-resistant strains can carry out clonic exercise.The mean values of the long diameter of the fungus halo were 1.21 cm and 1.16 cm,respectively,but there was no difference in the length and diameter of the two strains(P>0.05).Sensitive bacteria and multidrug resistant bacteria The swimming experiment was negative and its long axis was less than 10 mm.Conclusion: The multi-drug resistance of Acinetobacter baumannii has strong biofilm formation ability and it has the ability to exercise.