| ObjectivesPeriodically,new disease-associated variants of the human pathogen Neisseria meningitides(Nm) arise.In order to determine the epidemic clonel complex of Nm isolated from patients in Guangdong province between 1965 and 2006,and understand the antigenic diversity of antigen genes encording the outer membrane proteins(OMPs),the genotyping was carried out by using multilocus sequence typing(MLST) and the character of genes encoding OMPs was analyzed by DNA sequencing.Methods66 Nm isolated from patients in Guangdong province between 1965 and 2006 were recovered and identificated.7 housekeeping genes were sequenced then BLAST with the sequence in PubMLST database to produce a strain allelic profile.Each allelic profile was assigned as a sequence type(ST).The genetic evolution relationship was analyzed on-line by using the online software PHYLIR The epidemic clonel complex of isolates was determined according to the polymorphism of housekeeping genes.To understand the molecular character of OMPs,the typing for variable regions of of genes porA and porB which encode OMPs were performed by using DNA sequencing and online BLAST with those in the database.Results1.Totally 66 isolates were subtyped to 3 serogroups,they were 51 serogroup A strains,10 serogroup B strains and 4 serogroup C strains.One strain could not be serogrouped.The results of serogrouping were matched with those of past in generally.2.The polymorphism of housekeeping genes abcZ and adk of Nm isolated in Guangdong province between 1965 and 2006 was at a rather low level,and that of housekeeping genes aroE,fumC,and gdh was at a middle level,while that of housekeeping genes pdhC and pgm was at a rather high level.3.The Nm isolated from patients in Guangdong could be classified into 8 clone complexes,which were ST-5,ST-l,ST-4821,ST-11,ST-41/44,ST-3789,ST-254 and ST-8,with the percentage of 62.1%,15.2%,7.6%,6.1%,3%,3%,1.5%,1.5%, respectively.40 isolates of 51 serogroup A Nm and 1 strain which was unable to be serogrouped were belonged to ST-5 clone complex.The other 10 isolates of serogroup A Nm isolates belonged to ST-1 clone complex,and 1 isolate belonged to ST-254 clone complex.Of the 10 serogroup B Nm isolates,4 isolates belonged to ST-11 clone complex,2 isolates belonged to ST-41/44 clone complex,2 isolates belonged to ST-3789 clone complex,1 isolate belonged to ST-4821 clone complex,and 1 isolate belonged to ST-8 clone complex.All the 4 serogroup C Nm isolates belonged to ST-4821 clone complex.4.ST-5 clone complex was responsible for the pandemic of epidemic meningitis in 1967.It has been prevailing from then on,only except the period 1977-1984.ST-1 clone complex was responsible for the pandemic of epidemic meningitis in 1977 and had been epidemic ST from 1977 to 1984.The year before and after 1988,the high invasive clone complexes ST-11 and ST-41/44 appeared,and along with the ST-254,and ST-8 clone complexes.After the year 2000,the high invasive clone complex ST-4821 appeared,and also along with ST-1,ST-11,and ST-3789 clone complexes,besides the persistent circulating of clone complex ST-5.5.The type 20 is the mainly type of VR1 with geneporA which encoding OMP1, with the percentage of 63.6%.The type 5 accounted a percentage of 10.6%.The other 5 types of porA VR1 was 7,5-2,7-2,2,and 12-6.And they all accounted a percentage of less than 10%.However,the type 9 was the main type of VR2 with gene porA,and it accounted a percentage of 51.5%,while that of type 10 was 13.6%,and the percentage with type 2-48 was 10.6%.The other 7 types were 2-2,2,14-4,16-75, 2-31,4-1,and 14-9.And they all accounted a percentage of less than 10%as well.6.The two main types of VR1 with gene porB which encoding OMP2/3,were type 4 and type 9.This two types accounted percentage of 43.9%and 30.3% respectively.The percentage with type 6 was 10.6%.The other 3 types(type14,1,and 3) all accounted a percentage of less than 10%.The main type of VR4 with gene porB was type 7,it accounted a very high percentage of 86.4%;The other 4 types,9, 11,1,and 10,all accounted a percentage of less than 10%.The main type of VR5 with gene porB was type 11,whose percentage was 66.7%;The type 15 accounted a percentage of 10.6%;The other 4 types,18,20,21,1 and 19,all accounted a percentage of less than 10%;And there was no VR5 in genes porB with 2 isolates. There were only two types of VR6 with gene porB among all 66 isolates.The type 10, accounting a percentage of 60.61%,was the predominate type.And the other isolates had no the VR.All isolates had no VR7 except 3 isolates.Only one isolate had VR8 in gene porB.Conclutions1.The polymorphism of housekeeping genes abcZ and adk with the Nm isolates in Guangdong province between 1965 and 2006 was at a rather low level,and that of housekeeping genes aroE,fumC,and gdh was at a middle level,while was similar with the other Nm isolates belonged to homologous clone complex.And that of housekeeping genes pdhC and pgm was at a rather high level,whose variation were higher than Nm isolates in PubMLST database.This means the appearance of new isolates.2.The Nm isolates from patients in Guangdong between 1965 and 2006 couled be classified to 8 clone complexes,which were ST-5,ST-1,ST-4821,ST-11,ST-41/44, ST-3789,ST-254 and ST-8.The ST-5 clone complex was the predominant one.The significant relation between serogroup and clone complex can not be found.3.ST-5 clone complex was predominated before the year 2000.And there had been more and more other clone complexes such as ST-1,ST-41/44,ST-3789,ST-254 and ST-8,and also the high pathogenicity clone complexes ST-4821 and ST-11 in recent years,which means the trend of multielement.So it is necessary to enhance the surveillance with pathogens of epidemic meningitis especially those of hyperinvasive clone.4.The VRs ofgeneporA and porB encording OMPs of Nm isolates were stable, and could not be observed the high level of polymorphism.And this was beneficial for the developing and enacting of vaccinum.
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