The Main Pathway Transmission And Genetics Studies On Drug-resistant Genes Of NICU Klebsiella Pneumoniae

Objectives To analyze the homology of Klebsiella pneumoniae(KP),which isolated form infected patients and colonized in the neurological intensive care unit(NICU)environment,to analyze isolated KP strains' main drug-resistant genes characteristics of chromosomes and plasmids and discuss the relationship between the characteristics with clinical antimicrobial susceptibility,and to identify the main transmission characteristics in ward environment and the genetic trend of clinical drug resistance,so we can set up NICU environmental disinfection projects and provide the basis for prevention and control of KP infection in clinical.Methods 1 Monitoring the status of infection and types of pathogenic bacteria of patients in the NICU of a grade A tertiary hospital from January 2015 to October 2016,and the KP which isolated from clinical patients specimen were selected.2 Monitoring the microbiological distribution in the air both general environment,the patients-infected environment and the bed units which resided the infected patients,and the KP which isolated from monitoring specimen were selected.3 Embedding the chromosomes DNA of all KP isolated strains in gel block,and then digested by restriction enzyme Xba I,so we can analyze the homology of isolated KP strains by pulsed-field gel electrophoresis.100% similarity belongs to the same clone strain,and ?80% similarity belongs to the same popular clone system.4 The chromosomes and plasmids DNA of all KP isolated strains were extracted by boiling method and plasmid small extraction kit,respectively.Then using the chromosomes and plasmids DNA as template to detecte the ?-lactam,aminoglycosides and quinolone-resistant genes carried in all KP isolated strains by polymerase chain reaction,respectively.5 K-B disk method was used to detect the phenotype of clinical resistance and the phenotype of ESBL was defined.Results 1 There were 574 patients hospitalized during the study period,in which 395 patients were infected and 362 patients were made to do the etiology inspection.A total of 208 pathogens were detected,in which non-duplicate KP from infected patients were 54 strains(25.96%),heading the list.And the followings were Pseudomonas aeruginosa(21.15%)and Staphylococcus aureus(10.10%),and the mainly type of specimens was sputum.2 During the period from January 2015 to December 2016,the Monitoring result of the air both general environment and the patients-infected environment in NICU showed that Gram-positive cocci and Gram-positive bacillus were accounted for the dominant position,followed with fungi and a small amount of Gram negative bacillus.A total of 9 KP strains were detected from NICU ward environmental monitoring specimen,in which 1 KP strain was detected from the conventional ward environment,4 KP strains were detected from the ambient air environment monitoring specimens of different infected patients and 4 KP strains were detected from the bed unit environment of different infected patients.3 Of the 63 KP strains detected in this study,61 strains were successfully typed and divided into 49 pattern.The same clone pattern involved more than one strains had 10 groups with 100% similarity.The same popular clone system clone involved more than one strains had 18 groups with ?80% similarity.More than 73% were the same popular clone system KP strains which could be found homologous relationships with ?80% similarity,and over 35% were the same pattern with 100% similarity.4 The SHV resistance gene topped the list in chromosomes and plasmids DNA of all KP strains,followed by qnr and CTX-M genes.There was no significantdifference in the types of gene carried by chromosomes and plasmids,but the number of resistance genes carried by plasmids DNA was more than chromosomes DNA.The main resistance genes carried by chromosomes were SHV,CTX-M-2,qnr B,qnr S,and the main resistance genes carried by chromosomes were SHV,CTX-M-2,qnr B,qnr S,acc(6')-Ib-cr.5 All of 63 non-duplicate KP were detected within two years,in which 48 KP strains detected from infected patients and 9 KP strains detected from environmental monitoring specimens were ESBLs(-),which were resistant to ampicillin(100.00%)and piperacillin(91.07%),but highly sensitive to other antibiotics.The remaining 7 ESBL(+)KP are all multidrug resistance strains,some strains can also exhibit resistance to 5-21 kinds of antibacterial agents,simultaneously.Conclusions KP is the main pathogen that causes infection in patients with neurocritical diseases,which can survive and colonization in NICU ward environment and the patients' bed unit environment,such as pillows,quilts,bedstand,etc.Thus becoming an occult source of infection leads to the transmission of nosocomial infection.The ?-lactams resistance gene SHV was carried by KP chromosomes DNA,which is associated with the main genetic basis of KP produced ampicillin and piperacillin resistant.The KPC,CTXM-9,TEM gene of ?-lactams,rmt B gene of aminoglycosides and qnr A,acc(6')-Ib-cr gene of quinolones were associated with genetic clonal spread of ESBL-producing isolates,the SHV,CTX-M-2,KPC,TEM,IMP,CTX-M-9 of ?-lactams,rmt D,npm A of aminoglycosides and qnr B,qnr S,acc(6')-Ib-cr gene of quinolones could also associated with horizontal transmission by plasmids.The vertical transfer of chromosomes and the horizontal transfer of plasmids are important ways to induce multi-drug resistance of KP infection.Therefore,effective disinfection protocols for KP in ward environment are important measures to prevent and control the emergence and spread of clinical drug resistance.