Study On Disinfectant Resistance And Mutant Selection Prevention Of Multidrug-Resistant Organism In Health Care-Associated Infections Surveillance Focus On

Objective To conduct the quantitative suspension bactericidal tests,the minimum inhibitory concentration(MIC)test,the minimum bactericidal concentration(MBC)test,the mutant prevention concentration(MPC)detection and major disinfectant resistance genes against six kinds of multiple drug-resistant bacterial in health care-associated infections.Study on the carrying status,distribution frequency and main combination of sex genes,evaluate the killing ability of four common chemical disinfectants,explore the resistance changes of these six multi-drug resistant bacteria to four disinfectants and the range of mutation selection window.Provide data for optimizing disinfectant applications in healthcare facilities and limiting selective proliferation of resistant mutant strains.Methods(1)Using a suspension quantitative bactericidal test to evaluate the killing ability of didecyl dimethyl ammonium bromide(represented as a quaternary ammonium disinfectant),digluconate chlorhexidine(represented as a biguanide disinfectant),Povidone iodine(represented as an iodine-containing disinfectant)and trichloroisocyanuric acid(represented as a chlorine disinfectant)against carbapenem-resistant Escherichia coli(CREco),carbapenem-resistant Klebsiella pneumoniae(CRKpn),methicillin-resistant Staphylococcus aureus(MRSA),carbapenem-resistant Acinetobacter baumannii complex(CRAba),carbapenem-resistant Pseudomonas aeruginosa(CRPae)and vancomycin-resistant enterococcus(VRE).(2)Establishing MIC,MBC,and MPC testing models of CREco,CRKpn,MRSA,CRAba,CRPae and VRE for didecyl dimethyl ammonium bromide,digluconate chlorhexidine,povidone iodine and trichloroisocyanuric acid for Analysis of their resistance characteristics and mutation selection window range(MSW).(3)To explore the relationship between resistance gene and resistance phenotype by studying the carrying status,distribution frequency and main combination of 281 strains of multi-drug resistant disinfectant resistance genes qacA/B,qacC/D,qacE and qacE△1.Result All the quality control strains and 281 health care-related infections in the trial were monitored for multi-drug resistant bacteria.At the recommended concentration and duration of action of the four disinfectants,the killing logarithm was≥ 5.00 and the killing rate was 100%.The MIC90 values of CRPae and CRKpn are close to the recommended concentrations of chlorine disinfectants.MRSA carries a qacA/B rate of 46.0%(23/50),VRE carries a qacA/B rate of 22.6%(7/31);qacE gene and its attenuating variant qac EA1 are widely distributed in multi-drug resistant Gram-negative bacilli.The strain carrying the qacE gene/qacE△1 gene in CREco collected in this experiment reached 74.0%(37/50);the strain carrying the qacE gene/qacE△1 gene in CRKpn was 58.0%(29/50);The strain carrying the qacE/qacEAl gene in CRPae was 84.0%(42/50),in 100%(43/50)of CRAba.The disinfectant resistance gene combination qacE△1+sugE(c)had the highest frequency,of which CRPae had a simultaneous carrying rate of 20.0%and CREco had a simultaneous carrying rate of up to 58.0%.Conclusion The conventional suspension quantitative bactericidal test reflects the killing effect of disinfectant on the quality control strain at the concentration used,and does not target clinical isolates and multi-drug resistant strains.Only from the perspective of verification of the microbial killing effect specified in the disinfection technical specification,regardless of whether there is a selection of drug resistance mutations,as long as the product specification recommendations and medical institution disinfection technical specifications are strictly followed,the four disinfectants are multiple The killing effect of resistant bacteria is also positive.The suspension quantitative bactericidal test could not supervise the proliferation of the strain with the first mutation,but MIC、MBC and MPC test could do this.To avoid bacterial resistance mutation selection,MSW must be turned off.MSW can be turned off by keeping the disinfectant concentration above the MPC,so that the possibility of bacterial resistance mutations is almost non-existent.It is of great significance for the infection control of medical and health care institutions to understand pathogenic bacterias,especially those related to medical and health care,and focus on monitoring the tolerance of multi-drug resistant bacteria to disinfectants,so as to apply disinfectants rationally and minimize the tolerance of bacteria to disinfectants in the disinfection work of medical and health care institutions.