| Objective:1.The sensitivity of carbapenem-resistant K.pneumoniae isolated from clinical patients in our hospital to common antibiotics was tested.The clinical features of infected patients were analyzed and the risk factors for infection were explored.2.To investigate the epidemiological characteristics of carbapenem-resistant K.pneumoniae and the cloning of carbapenem-resistant K.pneumoniae strains in ICU.3.To study the resistance mechanism of carbapenem-resistant K.pneumoniae resistant and capsular serotypes and virulence genes.Methods:1.We collected non-repeated CRKP 125 strains clinically isolated from January 2016 to March 2017 at the Second Affiliated Hospital of Nanchang University.VITEK-2 compact was used for identification and susceptibility testing.Consult the patient's clinical data,analyze the patient's age,gender,department,specimen type,basic disease,invasive operation,admission to the ICU ward,antibiotic exposure and prognosis before and after collection of specimens.2.The Modified Hodge and the Modified Carbapenem Inactivation Method(mCIM)tests were used to detect the carbapenemase phenotypes of the strains;the string test was used to detect the hypermucoviscosity phenotype of the CRKP strains.3.PCR detection of ?-lactam-type amines(carbapenease,ESBL,AmpC)and quinolone 19 resistance genes and 6 capsule serotypes and 17 virulence genes were amplified and some positive products were randomly selected two-way sequencing was performed to determine the genotype.4.Multi-site sequence analysis(MLST)performed an epidemiological survey of 125 CRKPs.Pulsed field gel electrophoresis(PFGE)was used to detect CRKP cloning in ICU isolates.Results:1.The resistance rate of CRKP to cephalosporin and carbapenem was 100.0%,the resistance rate to enzyme inhibitors and quinolones was more than 95.0%,and the resistance to aminoglycosides and tigecycline was the lowest(65.0%)..Of these,67 isolates were multi-drug resistant(MDR)strains and 58 isolates were pan-resistant(XDR)strains.2.Infected patients were mostly distributed in ICU wards,respiratory medicine,and neurosurgery,and mainly in elderly men;the specimens were the highest in the separation rate of sputum.3.Prior to the isolation of CRKP,120 patients were exposed to antibiotics,mainly carbapenems and enzyme inhibitors,and less frequently used tigecycline and aminoglycosides;110 patients had undergone invasive procedures.4.Carbapenemase phenotypic assays: The positive rate of the modified Hodge assay was 84.0%(105/125),and the positive rate of the modified carbapenemase inactivated(mCIM)phenotype test was 92.8%(116/125).5.Hypermucoviscosity phenotype: 12 out of 125 experimental strains(9.6%)were positive for the string test.6.PCR showed that all strains carried the carbapenemase gene,of which 92.8%(116/125)strains carried KPC-2,4.0%(5/125)carried NDM,3.2%(4/125)carried IMP-4,two strains expressed both carbapenemase genes KPC-2 and NDM-1 at the same isolates.Among the ? amidase genes,the highest detection rate of CTX-M gene was 113 strains(90.4%),followed by SHV respectively.Among 102 strains(81.6%)of genes,52 strains(41.6%)of TEM genes and 97 strains(77.6%)of quinolone genes were positive for qnrS.The detection rate of the strains carrying the four drug resistance genes was the highest,65/125(52.0%).),1 strain of CRKP carries 6 drug resistance genes.7.125 CRKPs were divided into 5 ST types by MLST,among which ST11 was predominant,accounting for 88.8%(111/125),ST890,ST485,and ST1308 were 4 and 2 ST86.46 strains were isolated from CRKPs in ICU wards.The ST type was ST11(44 strains)and ST86(2 strains).The PFGE results showed that the 46 strains were A-D type according to the 85% similarity.8.Virulence factor: Capsular serotypes were not detected in 125 strains.Among the virulence genes,the detection rates of entB,wabG,ybtA,ureA,ycf and fimH were the highest,all >90.0%.The rmpA gene was positive in 25 strains,accounting for 20.0%,and all of them expressed KPC-2 and SHV genes.Only one CRKP carrying the virulence gene of wcaG was detected,and no virulence genes of markD,ironB,vatD,magA,alls and aerobactin were detected.Conclusion:1.The resistance of CRKP strains to clinically used antibacterial drugs is very serious,and the resistance rate to aminoglycosides and tigecycline is relatively low.Exposure to antibiotics and invasive operations may be an important cause of epidemic transmission in strains.2.The main resistance mechanisms of CRKP strains are KPC,NDM and IMP-4 carbapenemases.Carrying expend-spectrum ?-lactams and quinolone-resistant genes are also important for multidrug resistance and even pan-drug resistance.mechanism.3.There were more virulence genes detected in CRKP strains,with the highest positive rates for entB,wabG,ybtA,ureA,ycf and fimH.4.ST11 is the main ST type of CRKP in this hospital.For the first time,a strain of ST485 CRKP carrying NDM-5 resistance gene was found in this region.The ICU ward is the main ward for cloning of CRKP strains. |
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