Analysis Of Drug Resistance Phenotype And Homology Of Carbapenem-Resistant Klebsiella Pneumoniae In Our Hospital

Objective:This study through analysis of the resistance phenotype an-d homology of Carbapenem-resistant Klebsiella pneumoniae（CRKP）in our hospital wants to reveal the resistance phenotype of CRKP and the genetic relationship among strains.To provide referen-ce basis for the development of corresponding infection preven-tion and control measures in the department of nosocomial inf-ection,and to guide the clinical application of antibiotics from the perspective of drug resistance.Methods:Collected 176 strains of Klebsiella pneumoniae（KPn）in our hospital（Chengde Central Hospital）from January 2018 to Decemb-er 2020.They were sent to the microorganism laboratory for culture,identification and purification.Among the 176 KPn stra-ins,there were 76 CRKP strains and 100 Carbapenem-sensitive Klebsiella pneumoniae strains（CSKP）.Collected the information of 176 KPn patients,including:age,length of hospital stay,sp-ecimen type,clinical department,etc.The m CIM combined with e CIM was used to analyze the resistance phenotype.The homol-ogy was analyzed by MALDI-TOF MS.The results of CRKP w-ere imported into WHONET5.6 software for statistical analysis of bacterial resistance rate.SPSS26.0 software was used to ana-lyze the date.The differences of age and length of stay betw-een patients with CRKP and CSKP were compared.If the distr-ibution is normal and the difference is expressed by x±s,and compared by independent sample t-test.If the distribution is n-ot normal and the difference was expressed by M(P₂₅,P₇₅),and compared by nonparametric test.The drug resistance rate an-d detection rate of the strains were compared byχ²-test.The difference was statistically significant with P<0.05.Results:1.Clinical distribution of departments、specimen types、detection rate and patients,condition1.1 The distribution of 76 CRKP strains in the main departments were intensive care unit（27.5%）,neurosurgery（22.4%）、respiratory（14.5%）and respiratory（14..5%）.76 CRKP strains were isolated from sputum（72.4%）,urine（13.2%）,whole blood（9.2%）and throat swab（3.9%）.1.2 Compared with the detection rates of CRKP in our hospital from2016-2019,the difference was statistically significant（P<0.05）.Compared with the detection rate of CARSS in the same period,the difference between2016 and 2018 was statistically significant（P<0.05）.There was no significant difference in 2019（P>0.05）.1.3 The ages（years）of patients infected with CRKP and CSKP w-ere respectively 70.75±13.23、52.99±17.27.The length of hospital stay（days）are respectively 33.00（20.00,67.25）、12.50（8.25,17.00）.There was a statistically significant difference between the two groups of patients i-n the comparison of age and length of stay（P<0.05）.2.CRKP resistanceThe WHONET5.6 software was used to statistically analyze the dru-g susceptibility results of CRKP strains from 2018 to 2020.The resista-nce rates of CRKP to cefoperazone/sulbactam,piperacillin/tazobactam,c-eftazidime,cefepime,imipenem,meropenem,ciprofloxacin,levofloxacin,amikacin,gentamicin,compound trimethoprim and tigecycline were no si-gnificant difference（P>0.05）.The drug resistance rate to piperacillin,ce-ftriaxone,andaztreonam had always been 100%.The resistance rate of CRKP in our hospital to tigecycline,compound trimethoprim,amikacin and gentamicin islow（<35.6%）,lowest rate of resistance to tigecycline.Compared with CHINET of the same year,the resistance rate of CRKP to tigecycline,compound trimethoprim,amikacin,and gentamicin from2018 to 2020 is lower than the national average.3.Analysis of resistance phenotype of CRKPThere were 59 strains（77.6%）producing metallo-β-lactamases.There were 14 strains（18.4%）of serine carbapenemase-producing strains.The rewere 3 strains（4.0%）that do not produce carbapenemase.There was no statistically significant difference in the detection rate of non-carbape-nemase and serine carbapenemase from 2018 to 2020（P>0.05）.The di-fference in the detection rate of metalβ-lactamase is statistically signifi-cant（P>0.05）.4.Homology analysis of MALDI-TOF MS4.1 All 76 strains of CRKP were identified as Klebsiella pneumoniae by MALDI-TOF MS,and the identification accuracy was more than 99.9%.The mass spectrum results of each strain were imported into SARAMIS database for strain cluster analysis,and the result tree showed that the relative value of homology was above 75%.There were 5 stains with relative homology value between 75%-80%,53 strains with relative homology value between80%-85%,18 strains with relative homology value between 85%-90%,mainly distributed in respiratory,neurosurgery and intensive care medicine.4.2 The mass spectrum results of 27 CRKP strains detected from July to December 2020 were imported into the SARAMIS database for cluster analysis,and the result tree showed that the relative value of homology was above 80%.There were 18 stains with relative homology value between80%-85%,9 strains with relative homology value between 85%-90%,mainly distributed in neurosurgery,respiratory and intensive care medicine.Conclusion:1.Patients infected with CRKP are related to the patient,s age and length of hospital stay.The age of patients infected with CRKP is older than that of CSKP.After patients infected with CRKP,the length of hos-pital stay is significantly prolonged.2.The CRKP strains were mainly distributed in intensive care medicine,neurosurgery and respiratory in our hospital;The specimens were mainly derived from sputum,urine and whole blood.3.CRKP in our hospital mainly produces metalβ-lactamase（77.6%）.4.The relative homology value of the CRKP strains in our hospital was between 75%-90%.In the second half of 2020,the relative value of CRKP homology was between 80%-90%,and the homology is relatively high.