HG METABOLIZING BACTERIA IN SUBJECTS WITH DENTAL AMALGAM

对这两种细菌具有抵抗力并能够进行生化转化的细菌 无机和有机汞化合物广泛存在于许多 包括肠杆菌科在内的兼性细菌属， 葡萄球菌、链球菌和杆菌科(Summers，1986)。而当 工业污染可以解释这些基因座在中国的发生 水土种群(Barkay and Olson，1986；Barkay，1987；Nishimura 和Kamahai，1983；Trevors，1986；Summers等人，1978) 存在于人类的粪便菌群中(马歇尔等人，1981；Gilbert和 萨默斯，1988)更难理解。人们知道这一点已经有一段时间了 汞从牙科汞齐中释放出来，而且有相当大的 人类从尿液中排出汞的能力的变化(Clarkson et Al，1988)。最近，Hahn等人。(1989)和Vimy等人(正在印刷中) 已经证明，口腔和口腔中汞的大量负荷 牙科汞齐可导致胃肠道组织，因此，汞在 这样的修复可能会在正常菌群中选择抗药性细菌 嘴巴或肠道的。因为这些细菌通过化学方式转化汞 化合物，它们可能对汞的生物利用度有很大影响 从牙科汞合金中释放出来。 卡尔加里大学的Fritz Lorscheider博士和他的同事们 评估牙科银汞合金修复所产生的特定器官负担 (Hahn等，1989)，并计划在灵长类动物模型中进行类似的研究 以及对选定的人类受试者的调查。我提议，在合作中 与Lorscheider博士一起评估口腔汞抵抗的发生率 和他的动物和人类受试者的粪便微生物菌群，并相互关联 这种现象与银汞合金质量、体内汞负荷和汞的排泄率有关。 HG(按Lorscheiders组测量)。如果我们发现存在一个 高度耐药的微生物菌群与减少身体负担或 汞的排泄增加，未来的研究可以考虑实验 利用自然产生的抗汞质粒对菌群的改良 减少这种剧毒和致突变的金属在体内的积累。 或者，如果菌群中汞抵抗力的增加会增强身体 负担，这些微生物构成了额外的风险因素 使用牙科汞合金。

Bacteria resistant to and capable of biochemically transforming both inorganic and organic mercury compounds are widely found in many facultative, enbacterial genera including the enterobacteriaceae, staphylococci, streptococci, and bacillaceae (Summers, 1986). While industrial contamination can explain the occurrence of such genetic loci in water and soil populations (Barkay and Olson, 1986; Barkay, 1987; Nishimura and Kamahai, 1983; Trevors, 1986; Summers, et al., 1978) their frequent occurrence in the fecal flora of humans (Marshall et al, 1981; Gilbert and Summers, 1988) is harder to understand. It has been known for some time that Hg is released from dental amalgams and that there is considerable variation in the ability of humans to excrete this Hg in urine (Clarkson et al, 1988). Very recently, Hahn, et al. (1989) and Vimy et al (in press) have demonstrated that a substantial burden of Hg in oral and gastrointestinal tissues can result from dental amalgam Thus, the Hg in such restorations may select for resistant bacteria among the normal flora of either the mouth or bowel. Since these bacteria chemically transform Hg compounds, they could have a large influence on the bioavailability of Hg released from dental amalgam. Dr. Fritz Lorscheider and his colleagues at the University of Calgary have assessed the specific organ burden arising from dental amalgam restorations in sheep (Hahn et al, 1989) and plan similar studies in a primate model as well as a survey of selected human subjects. I propose, in collaboration with Dr. Lorscheider, to assess the incidence of Hg resistance in the oral and fecal microbial flora of his animal and human subjects and to correlate this phenomenon with amalgam mass, body burden of Hg, and excretion rate of Hg (as measured by Lorscheiders group). If we find that the presence of a highly resistant microbial flora correlates with reduced body burden or enhanced excretion of Hg, future studies could consider experimental amendment of the flora with naturally occurring Hg resistance plasmids to reduce body accumulation of this highly toxic and mutagenic metal. Alternatively, if increased Hg resistance in the flora enhances body burden, these micro-organisms constitute an additional risk-factor for the use of dental amalgam.