The following article by Robert Matthews, Science Correspondent,
appeared in The Sunday Telegraph (Main Section) 14th September 1997, page 17.
The fashion among dentists for "drilling and filling" with mercury amalgam in the Seventies may have spawned dangerous superbugs immune to antibiotics, say leading microbiologists. They are studying samples taken from thousands of patients to
discover the extent of the problem, and say mercury fillings may have to be discontinued if the threat is confirmed. The dental trend for drilling out decayed parts of teeth and filling them with mercury amalgam reached its peak in the late Seventies, with more than 32 million fillings being made in 1977.
With the advent of wide spread fluoridation, this has dropped at least 50 percent. Most concern over fillings has so far focused on the potential dangers from mercury poisoning, with some countries banning their use. Now a team led by Professor Robin Rowbury of University College, London believes that the fillings may have helped trigger antibiotic resistance in bacteria -- widely seen as one of the most serious threats facing modern medicine.
These so-called superbugs include streptococci, responsible for bacterial pneumonia and meningitis, some types of mycobacteria, which causes TB, and staphylococcus, a cause of lethal septic shock. Such superbugs have become immune to treatment using
many common antibiotics such as penicillin, and doctors fear it may only be a matter of time before all treatments fail against them.
The numbers of superbugs is rising, as bacteria pass on their antibiotic resistance to others. The link with dental fillings comes from the fact that genes giving bacteria antibiotic resistance are often on the same part of the bacterial genetic blueprint as those for resistance to lethal heavy metals -- including mercury.
As a result bacteria that survive the relatively high levels of mercury in the mouth are also likely to become resistant to antibiotics. Prof Rowbury said: "If there is an association between the use of mercury amalgams and antibiotic resistance, then the implications are enormous."
According to Prof Rowbury, one immediate effect would be that dentists would have fewer antibiotics capable of fighting mouth infections. But he said there could be more serious effects. "Some oral bacteria can have very serious effects, such as endocarditis, which affects the heart," he said. "The ingress of resistant bacteria into the gut may also result in the spread of antibiotic resistance to the normal gut microflora." So far, only animal studies of the link between fillings and antibiotic resistance have been carried out. Theses have, however, confirmed that more fillings increase the prevalence of antibiotic resistant bacteria.
Prof Rowbury and colleagues at the Eastman Dental Institute in London have begun the first human studies. "If an association between dental amalgam and antibiotic resistance in bacteria is established, then it may be necessary to prevent or limit
the use of dental amalgam. "We are now studying 6,000 isolates taken from patients over a wide range of ages whose mercury levels we know. What we plan to is to see if there is a link between those levels and both the antibiotic resistance and
virulence of bacteria in the isolates."
Photograph shows infant recieving a filling. Subtitle says:- "Open wide: microbiologists fear fillings may help trigger antibiotic resistance in bacteria - seen as one of the most serious threats facing modern medicine."
(The Sunday Telegraph is a National paper, one of the most respected in the United Kingdom)
Title: The dental amalgam mercury controversy--inorganic mercury and the CNS; genetic linkage of mercury and antibiotic resistances in intestinal bacteria.
Lorscheider FL; Vimy MJ; Summers AO; Zwiers H
Department of Medical Physiology, Faculty of Medicine, University of Calgary, Alberta, Canada.
Toxicology, 1995 Mar 31, 97:1-3, 19-22
Abstract: Mercury (Hg) vapor exposure from dental amalgam has been demonstrated to exceed the sum of all other exposure sources. Therefore the effects of inorganic Hg exposure upon cell function in the brain and in the intestinal bacteria have recently been examined. In rats we demonstrate that ADP-ribosylation of tubulin and actin brain proteins is markedly inhibited, and that ionic Hg can thus alter a neurochemical reaction involved with maintaining neuron membrane structure. In monkeys we show that Hg, specifically from amalgam, will enrich the intestinal flora with Hg-resistant bacterial species which in turn also become resistant to antibiotics.
Title: Antimicrobial and mercury resistance in aerobic gram-negative bacilli in fecal flora among persons with and without dental amalgam fillings.
Osterblad M; Leistevuo J; Leistevuo T; JŠrvinen H; Pyy L; Tenovuo J; Huovinen P.
Antimicrobial Research Laboratory, National Public Health Institute, Turku, Finland.
Abstract: Antimicrobial resistance is more widespread than can be accounted for as being a consequence of the selection pressure caused by the use of antibiotics alone. In this study, we tested the hypothesis that a high mercury content in feces might select for mercury-resistant bacteria and thus for antimicrobial resistance linked to mercury resistance. Three subject groups with different exposures to dental amalgam fillings were compared. None of the subjects had taken antimicrobial agents during the three preceding months or longer. The group exposed to dental amalgam (n = 92) had 13 times more mercury in feces than the group that had never been exposed to amalgam (n = 43) and the group whose amalgam fillings had been removed (n = 56). No significant differences in either mercury resistance or antibiotic resistance in the fecal aerobic gram-negative flora of these subject groups were seen. The following antimicrobial resistance frequencies were detected with a replica plating method: > or = 1% resistance was seen in 40% of the subjects for ampicillin, 14% of the subjects for cefuroxime, 6% of the subjects for nalidixic acid, 14% of the subjects for trimethoprim, 19% of the subjects for sulfamethoxazole, and 25% of the subjects for tetracycline. The amount of mercury in feces derived from amalgam was not selective for any resistance factors in aerobic gram-negative bacteria, but antimicrobial resistance was widespread even among healthy subjects with no recent exposure to antibiotics.
Title: Metal ion induced autoimmunity. [Review article]
Griem P, Gleichmann E
Current Opinion in Immunology 1995 7:831-838.
Abstract: Metal-induced autoimmunity is a well established but poorly understood phenomenon. Recent work has begun to elucidate the molecular interactions of metal ions with immune cells and self-proteins. Metal-induced presentation of cryptic self-peptides emerges as a possible mechanism for activation of 'metal-specific' T cells, challenging the hypothesis of a random polyclonal activation of T and B cells by metals. A preferential T-helper cell type 2 response is involved in metal ion induced systemic autoimmune disease.
Filling and Drilling 'breeds superbugs'