简介：Klebsiellapneumoniae(K.pneumoniae)isoneofthemaingram-negativebacilliinclini-calpractice.NosocomialinfectionscausedbyK.pneumoniaeproducingextended-spectrumβ-lactama-ses(ESBLs)areverydifficulttotreat.ThispaperinvestigatedtheresistantcharacteristicsofK.pneu-moniaeproducingESBLsandtheiraminoglycoside-modifyingenzymegeneexpressionsincludingN-acetyhransferasesandO-adenyhransfemses.BacteriaidentificationandESBLsconfirmatorytestswereperformedbyPhoenix~(TM)-100system.Andminimuminhibitoryconcentrations(MICs)ofgentamicin,amikacin,kanamycin,tobramycin,netilmicinandneomycinin53K.pneumoniaeisolateswerede-tectedbyagardilution.Inaddition,sixaminoglycoside-modifyingenzymegeneswereamplifiedbypolymerasechainreaction(PCR)andverifiedbyDNAsequencer.Itwasfoundthatimipenemandmeropenemagainst120K.pneumoniaeisolatesproducedpowerfulantimicrobialactivities.Theresis-tantratesofgentamicinandamikacinwere55.0%and46.7%,respectively.Exceptneomycin,MIC_(50)andMIC_(90)ofgentamicin,amikacin,kanamycin,tobramycinandnetilmicinin53K.pneumoni-aewereall>128μg/ml,andtheresistantrateswere83.0%,52.3%,75.5%,81.1%and69.8%,respectively.However,neomycinwasonly39.6%.Inaddition,fivemodifyingenzymegenes,includingaac(3)-Ⅰ,aac(3)-Ⅱ,aac(6')-Ⅰb,ant(3″)-Ⅰ,ant(2″)-Ⅰgenes,werefoundin53isoahesexceptaac(6')-Ⅱ,andtheirpositiverateswere11.3%,67.9%,47.2%,1.9%and39.6%,respectively.Itwasalsoconfirmedbynucleotidesequenceanalysisthattheaboveresistantgenessharednearly100%identitieswithGenBankpublishedgenes.TheresultsobtainedinthepresentstudyindicatedthatK.pneumoniaeproducingESBLsstrainsarerapidlyspreadinginourhospital,andtheirresistancetoaminoglycosidesmaybeassociatedwithaminoglycoside-modifyingenz-ymegeneexpressions.

简介：Objective:ToconfirmwhetherMycoplasmapneumoniae(MP)arepresentinreproductivetractofSTDpatientsinChina.Methods:ApplicationofnestedPCR(nPCR)andDNAsequencingtotestsamplesofurethral/vaginalswabswithMPcultureconfirmationofseveralnPCRpositivepatients.Results:74of786STDpatientswerepositiveforMPbynPCR,witharateof9.4%.Ofthe484malepatients,10.5%werepositive,andamongthe302femalepatients,7.6%werepositive.Therewasnosignificantdifferencebetweenthem(P>0.05).Of12casesofMPpositivesamplesbynPCR,4caseswerefirstgenerationculture-positive,andoneofthempassedtothenextgenerationsuccessfully.DNAsequencingwasperformedonthenPCRproductofoneswabsampleandoneMPcultureisolation.ThedeterminedsequencewasidenticaltothetypicalMPstrain.Conclusion:InChina,MParepresentinreproductivetractofbothmaleandfemaleSTDnatients.

简介：ObjectivesTodetectionofchlamydiapneumoniae(Cpn)DNAinthecirculatingmononuclearcellfractionsofcoronaryheartdiseaseandtoinvestigatetheassociationbetweeninfectionwithchlamydiapneumoniaeandcoronaryheartdisease(CHD)andprospectivelywhetherblood-basednestedpolymerasechainreaction(nPCR)isusefulinidentifyingCpninfection.MethodsTheperipheralbloodmononuclearcell(PBMC)CpnDNAwasexaminedusingnPCRtechniqueandconfirmedbyelectrophoresisin150patientswithCHD.Select55patientswithclinicalsuspectedCHDbutangiographyresultarenormalascontrolgroup(CG).Thenweconductedaprospective,randomized,double-blind,placebo-controlledstudyof6monthsofazithromycinandplacebotreatmentinCHDgroup.PatientswithCpnDNApositivewerethenrandomizedtoreceiveazithromycinorplacebo.Aftertreatmentbloodsamplewerecollectedforrepeatedmeasurement.ResultsChlamydiapneumoniaeDNAwasdetectedin49(32.7%)of150personswithCHDandin1(1.8%)of55personswithcontrolgroup,oddsratio26.2,95%confidenceinterva13.52-194.98.ThepositivityratesofnPCRinCHDgroupswerehigherthanthoseincontrolgroup.16cases(29.1%)inlatentcoronaryheartdiseases(LCHD)group,19cases(39.6%)inunstableangina(UAP)group,and14cases(29.9%)inacutemyocardialinfarction(AMI)groupwereCpnpositivebynPCR.TherewerenosignificantdifferenceamonginAMIUAPandLCHDgroup.ThereweresignificiantdifferenceinCpnDNAnegativeratesaftertheazithromycinandtheplacebotreatment.ConclusionsChlamydiapneumoniaeispresentinPBMCofasignificantproportionofpersonswithCHD.Thepotentialroleofchlamydiapneumoniaeincoronaryatherosclerosismaythereforebemorerelatedtoaccelerationofdiseaseorsystemiceffectsbypersistentinfectionthantosuddeninitiationofprogressivecoronaryarterydiseasebyacuteinfection.ThedetectionofCpnDNAinPBMCwithnPCRmaybeofgreatvalueforidentifyingCpncarriersandfo

简介：AbstractImportance:Hypervirulent variants of Klebsiella pneumoniae (hvKp) are capable of causing life-threatening pyogenic liver abscesses (PLAs), but hvKp caused PLAs was seldom reported in pediatric populations. Hence, there is an urgent need to raise our awareness of this phenomenon in pediatric populations.Objective:This study aimed to report the clinical characteristics of hvKp that caused fatal PLA complicated by bacteremia in an adolescent and further identify the microbiological and genomic features of the causative strain.Methods:A 14-year-old boy with diabetes mellitus was admitted to our hospital with a diagnosis of PLA complicated by bacteremia. A hypermucoviscous hvKp strain, KPN_19-106, was isolated from the drainage fluid present within the liver abscess cavity and blood. The hypermucoviscosity phenotype of the causative strain was determined by string test. Its virulence was measured using serum resistance assay and Galleria mellonella larvae-killing assay. Antimicrobial susceptibility was determined by broth microdilution method. Genetic information was obtained by whole-genome sequencing and bioinformatics analysis.Results:KPN_19-106 belonged to sequence type 380 and serotype K2 and exhibited stronger serum resistance and higher in vivo lethality than the well-characterized hvKp NTUH-K2044 strain. Although KPN_19-106 is susceptible to most antibiotics, no sign of improvement was observed during treatment with such drugs. Whole-genome sequencing revealed that the isolate had integrated multiple mobile genetic elements related to virulence.Interpretation:Antibiotic-susceptible hvKp can cause fatal PLA complicated by bacteremia in adolescents, with no improvement during antimicrobial therapy. The causative strain in this case had integrated multiple virulence genes and thus exhibited higher virulence both in vitro and in vivo when compared with NTUH-K2044.

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简介：Toclonethegenecodingtheimmunodominantregioninthechlamydialprotease-likeactivityfactor(CPAF)fromChlamydophilapneumoniae,toanalyzeimmunocompetenceoftheexpressedprotein,andtoevaluateitsvalueinserodiagnosis,theCPAFimmunodominantregiongenewasamplified,ligatedintoapGEX6p-2vector,andthentheexpressedrecombinantproteinwaspurifiedwithglutathioneS-transferase(GST)agarosegelFFafterrenaturation,thenidentifiedbySDS-PAGEandWesternblot.AnewindirectELISAwasdevelopedwiththepurifiedproteinascoatingantigen.TheimmunogenicityoftherecombinantproteinwasevaluatedbyimmunizationtoNewZealandrabbits,anditsimmunoreactivitywasanalyzedbyreactingwithanti-C,pneumoniaeantibody.300clinicalserasampleswererespectivelyde-tectedbymicroimmunofluorescence(MIF)asreferencemethodandtheindirectELISA,andthediffer-encebetweenthetwomethodswasanalyzed.Cross-reactivityagainstChlamydiatrachomatiswasinvesti-gatedwiththeindirectELISAtodetectanti-C,trachomatispositiveantisera.Theresultsindicatedthata51.3kDarecombinantproteinwasobtained.Westernblotassayprovedthattherecombinantproteincouldmerelyspecificallyreactwithhumananti-C.pneumoniaeantisera.ThetitersofthespecificIgGan-tibodiesintheimmunizedNewZealandrabbitswereabove1:16000.Anti-C.pneumoniaeIgGpositiveandnegativereferencesereweredetectedwiththeindirectELISA,andtheconcordancerateofnegativeandpositiveresultswereboth100%(40/40).ThesensitivityandspecificityoftheindirectELISAincomparisonwithMIFwere93.8%(45/48)and100%(252/252)separatelybydetecting300clinicalserasamples,andtheconcordanceratebetweenthetwomethodswas99.0%.NocrossreactionagainstC.trachomatiswasfoundwiththeindirectELISAtodetectanti-C,trachomatispositiveantisera.Incon-clusion,thepreparedrecombinantproteinoftheCPAFimmunodominantregionshowsexcellentimmuno-competenceandcanbeusedtodevelopanewindirect

简介：AbstractBackground:Carbapenemase-producing Klebsiella pneumoniae (CP-Kp) poses distinct clinical challenges due to extensively drug resistant (XDR) phenotype, and sequence type (ST) 11 is the most dominant blaKPC-2-bearing CP-Kp clone in China. The purpose of this current retrospective study was to explore the genetic factors associated with the success of XDR CP-Kp ST11 strains circulated in the intensive care unit (ICU) of a Chinese tertiary hospital.Methods:Six ST11 XDR CP-Kp strains were identified between May and December 2014 and validated by minimum inhibitory concentration examination, polymerase chain reaction, and pyrosequencing. The six ST11 XDR CP-Kp, as well as three multi-drug resistant (MDR) and four susceptible strains, were sequenced using single-molecule real-time method. Comprehensively structural and functional analysis based on comparative genomics was performed to identify genomic characteristics of the XDR ST11 CP-Kp strains.Results:We found that ST11 XDR blaKPC-2-bearing CP-Kp strains isolated from inpatients spread in the ICU of the hospital. Functionally, genes associated with information storage and processing of the ST11 XDR CP-Kp strains were more abundant than those of MDR and susceptible strains, especially genes correlative with mobile genetic elements (MGEs) such as transposons and prophages. Structurally, eleven large-scale genetic regions taken for the unique genome in these ST11 XDR CP-Kp strains were identified as MGEs including transposons, integrons, prophages, genomic islands, and integrative and conjugative elements. Three of them were located on plasmids and eight on chromosomes; five of them were with antimicrobial resistance genes and eight with adaptation associated genes. Notably, a new blaKPC-2-bearing ΔΔTn1721-blaKPC-2 transposon, probably transposed and truncated from ΔTn1721-blaKPC-2 by IS903D and ISKpn8, was identified in all six ST11 XDR CP-Kp strains.Conclusion:Our findings suggested that together with clonal spread, MGEs identified uniquely in the ST11 XDR CP-Kp strains might contribute to their formidable adaptability, which facilitated their widespread dissemination in hospital.

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