Molecular Epidemiology Of Mycobacterium Tuberculosis Stains From Prison Populations In Tianjin,China

Objectives: Part?: To compare the difference of mycobacterium tuberculosis detection effect between Z-N staining method and Auramine O fluorescent staining method in microscopy of sputum smear.Part?: Because of overcrowding and poorly ventilated environments,the notification rate of tuberculosis is much higher in prisons worldwide when compared to the general populations and this situation pose serious challenges for TB control.In order to enrich our epidemiological data to guide the TB control program in Tianjin prisons,we evaluated the molecular epidemiology of circulating strains in prisons of Tianjin for clarifying the major genotype of Mycobacterium tuberculosis(MTB)and the mode of transmission.Methods: Part?: Two smears were prepared for the same site of 580 clinical sputum specimens.Two mears were followed with Z-N and fluorescent staining respectively.Compare with the difference of two methods including positive detection rate?the standard of positive classification and time of reading.At the same time,phosphate buffer was used to make 60 copies of smear negative control,Staining by Z-N and fluorescence respectively.The remaining sputum specimens were tested by automatic Mycobacterium detection / drug sensitivity system for liquid culture.Part?: The Beijing genotype of MTB was identified from the isolates through analyzing the deletion of RD207 and RD105.LSP of Beijing strains were determined based on the presence or absence of RD181,RD150 and RD142.The IS6110 insertion in NTF region was also analyzed for differentiating modern Beijing sublineage and ancient Beijing sublineage.Genotyping of all the MTB isolates using 15-VNTR loci.The copy number of tandem repeats for each VNTR loci was determined by Quantity One software.Bionumerics software was used to characterize phylogenetic relationship and cluster by UPGMA and MST.Results: Part?: 1.The positive detection rate using Z-N was 10.8%,that of fluorescent staining was 15.3%,the differences of two methods were considered significant significant(P<0.05).2.The results showed that there was no statistical difference between the two staining methods at each grade(P>0.05).Part?:1.Of the 124 clinical isolates,116(93.5%)were identified as Beijing genotype,which is predominate among the prisoners of Tianjin.2.Among these Beijing strains,96(77.6%)belonged to Beijing modern sublieage,which possessed IS6110 insertion in NTF region,20(22.4%)belonged to Beijing ancient sublineage,which had no IS6110 insertion in NTF region.3.Based on large sequence polymorphism(LSP),all 116 Beijing strains were further divided into four sublineages.7(6.9%)were RD181(+),and all these RD181(+)strains belonged to ancient Beijing genotype.RD181(-)/RD150(+)modern Beijing sublineage is prevalent in the prison of Tianjin,accounting for 81.9% of Beijing genotype stains.Only 1 stains with RD150 deletion was found in this study.All genome of the Beijing strains possessed RD142,indicating that there was no polymorphism for this sequence.4.Phylogenetic tree and Minimum spanning tree(MST),based on 15-VNTR genotyping,were performed using Bionumerics software.Of all the 124 isolates,93 isolates were distributed into 18 clusters.The biggest size of cluster contained 26 isolates,which belonged to RD181(-)/RD150(+)modern Beijing sublineage.The other 31 isolates were genotyping unique.MST analysis showed that all the MTB isolated were classified three complexes.Of all the 8 non-Beijing isolates,3 and 5 non-Beijing isolates were composed of complex ? and complex ? respectively,while all the Beijing genotype isolates were composed of complex ?.Conclusions: Part?: The positive detection rate of fluorescence staining was slightly higher than Z-N.It was proved that fluorescence staining is a fast and sensitive detection method,and it will provide important reference for the clinical diagnosis of tuberculous pleuritis.Part ? : Our study showed that the Beijing genotype of Mycobacterium tuberculosis is predominated in the prisons of Tianjin.According the LSP,there are at least four sublineages of Beijing genotype were prevalent in the prisons of Tianjin.However,the rates of incidence were quite difference among the Beijing sublineages,and the RD181(-)/RD150(+)Beijing modern sublineage displayed much higher prevalence when compared with others among the prisoners of Tianjin.Genotyping of MTB isolates showed that recent infection spreading by exogenous infection is the major transmission mode among the populations in the prisons of Tianjin,but the reactivation of latent TB emerging by endogenous infection can also be found.Our data showed the need for continuing surveillance of TB occurring among prison inmates in high TB burden regions like Tianjin.