BACKGROUND The exosporium of the anthrax-causing Bacillus anthracis endospores display a tetrasaccharide composed of three rhamnose residues and an unusual sugar termed anthrose. Anthrose is a proposed potential target for immunotherapy and for specific detection of B. anthracis. Although originally thought to be ubiquitous in B. anthracis, previous work identified an anthrose negative strain from a West African lineage isolated from cattle that could represent a vaccine escape mutant. These strains carry genes required for expression of the anthrose operon but premature stop codons resulting from an 8-bp insertion in BAS3320 (an amino-transferase) and a C/T substitution at position 892 of the BAS3321 (a glycosyltransferase) gene prevent anthrose expression. Various other single nucleotide polymorphisms (SNPs) have been identified throughout the operon and could be the basis for detection of anthrose-deficient strains. RESULTS In this study, we evaluated rhAmp genotypic assays based on SNPs at positions 892 and 1352 of BAS3321 for detection and differentiation of anthrose negative (Ant-) West African strains. Discrimination of anthrose negative West African isolates was achieved with as low as 100 fg of DNA, whereas consistent genotyping of Sterne necessitated at least 1 pg of DNA. CONCLUSIONS Screening of a global panel of B. anthracis isolates showed anthrose-expressing alleles are prevalent worldwide whereas the anthrose-deficient phenotype is to date limited to West Africa. Our work also revealed a third, previously unreported anthrose genotype in which the operon is altogether missing from a Polish B. anthracis isolate.

中文翻译：

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核苷酸多态性测定法用于鉴定西非炭疽芽孢杆菌：一种缺乏炭疽病的血统。

背景技术引起炭疽的炭疽芽孢杆菌内生孢子的孢子囊显示出由三个鼠李糖残基和一种称为蔗糖的不寻常糖组成的四糖。炭疽病是免疫疗法和炭疽芽孢杆菌特异性检测的潜在潜在靶标。尽管最初被认为是在炭疽杆菌中普遍存在的，但是先前的工作从分离自牛的西非谱系中鉴定出了一种炭疽阴性菌株，该菌株可以代表疫苗逃逸突变体。这些菌株携带表达炭疽操纵子所需的基因，但由于BAS3320中插入了8 bp（氨基转移酶）和BAS3321基因（糖基转移酶）892处的C / T取代而导致的过早终止密码子阻止了炭疽表达。 。整个操纵子中还发现了其他各种单核苷酸多态性（SNP），它们可能是检测无蔗糖菌株的基础。结果在这项研究中，我们评估了基于BAS3321 892和1352位置SNP的rhAmp基因型分析，用于检测和区分炭疽阴性（Ant-）西非菌株。低至100 fg的DNA即可鉴定出炭疽病阴性的西非分离株，而Sterne的一致基因分型至少需要1 pg的DNA。结论对全球炭疽芽孢杆菌分离物的筛选显示，表达炭疽的等位基因在世界范围内普遍存在，而缺乏炭疽的表型迄今为止仅限于西非。我们的工作还揭示了第三点