| ObjectiveTo investigate the distribution and resistance characteristics of Klebsiella pneumoniae carbapenemase-2(KPC-2)producing Klebsiella pneumoniae(K.pneumoniae)in nanjing drum tower hospital from 2012 to 2014,To analyze the molecular epidemiological characteristics,virulence genes and serotype characteristics of K.pneumoniae isolates producing KPC-2 in our hospital.Methods1.A total of 86 non-replicate and consecutive K.pneumoniae isolates were collected from our hospital from January,2012 to December,2014.To retrospectively investigate the distribution and resistance characteristics of 72 KPC-2 producing K.pneumoniae isolates,which phenotype and genotype were determined by Carba NP Confirmatory test and DNA sequencing.2.A total of 72 KPC-2 producing K.pneumoniae were analyzed for the prevalence of extended-spectrum β-lactamase(ESBLs),plasmid-mediated quinolone resistance genes(PMQRs),exogenously acquired 16S rRNA methyltransferase(16S-RMTase),and plasmid-mediated AmpC enzyme(pAmpCs)by PCR and DNA sequencing.The sequence types(STs)of the carbapenemase producers were analyzed by multi-locus sequence typing(MLST).And Pulsed-field gel electrophoresis(PFGE)was performed to investigate the genetic relationship of KPC-2 producing strains.3.86 carbapenem-non-susceptible K.pneumoniae isolates and 97 carbapenem-susceptible K.pneumoniae isolates were collected from our hospital,and the homology between these isolates was analyzed by PFGE.Then,9 virulence genes,including allS,rmpA,mrkD,kfuBC,cf29a,fimH,uge,wabG and ureA,and 6 serotypes such as K1,K2,K5,K54,K57 and K20 in these isolates were detected by PCR,and their differences between K.pneumoniae isolates producing KPC-2 and not were compared.Results1.The number of strains isolated in 2012 was 13,2013 was 40.The isolate rate of2014 was decrease through Strengthening the hand hygiene.Among them,48.6%(35/72)were isolated from sputum,18.1%(13/72)from blood,12.7%(9/72)from urine.Moreover the distribution of the ward are mainly composed of ICU department was 27.8%,followed by emergency room and neurosurgery.The susceptibility testing results showed that the drug resistance rate of Klebsiella pneumonia isolates exhibited to β-lactams is 100%.The resistance rate of quinolone,aminoglycoside and compound sulfamethoxazole are really high.2.The genes blaCTX-M,blaSHV,blaTEM-1,blaDHA-1,rmtB,armA,oqxA,oqxB,and qnrB were present in 38.9%,37.5%,62.5%,2.8%,34.7%,1.4%,81.9%,76.4%and 8.3%,respectively.MLST analysis revealed 10 different STs.The most dominant ST was ST11(80.6%),followed by ST15(8.3%).PFGE patterns of the KPC-2 producing K.pneumoniae isolates exhibited clonal dissemination of ST11 and ST15 clones as well as a genetic diversity of the remaining strains.3.PFGE showed that 72 isolates producing KPC-2 disseminated from 30 strain clones and 111 non-producing KPC-2 from 96 strain clones according to the cut offf value of 80%of resemblance.The positive rate of allS in K.pneumoniae isolates non-producing KPC-2(21.9%)was significantly higher than that in K.pneumoniae isolates producing KPC-2(3.3%,P<0.05).There was no significant difference in the distribution of serotypes K1,K2 and K54 between K.pneumoniae isolates producing KPC-2 and not(P>0.05),and the other three serotypes were not detected in these isolates.Conclusion1.In our hospital clinical KPC-2-KP mainly come from the sputum and separate from ICU.The drug resistance was serious.2.The intra-and inter-hospital cross-transmission of KPC-2-producing K.pneumoniae ST11 co-carrying oqxAB and rmtB in our hospital strongly suggested that rapid identification of colonized or infected patients and screening of carriers is quite necessary to prevent a scenario of endemicity.3.Virulence gene allS is less common in K.pneumoniae isolates producing KPC-2,and most of these isolates belong to non-highly virulent clones.However,surveillance and infection control measures should be used for these highly resistant strains. |
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