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J Van Houte

Publications and source records attributed to J Van Houte.

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Role of sucrose in colonization of Streptococcus mutans in conventional Sprague-Dawley rats.

The role of sucrose in the colonization of S mutans strain 6715 in conventional Sprague-Dawley rats was studied. A diet with 56% sucrose favored the oral colonization of the test strain compared to diets with 56% glucose or fructose or to laboratory chow as determined by recoveries from extracted teeth ground in tissue grinders. S mutans strain 6715 cells became well established in all rats fed a high sucrose diet with cell inoculums ranging from 10(8) to the lowest effective dose of 10(5) CFU once orally administered; in rats on nonsucrose diets, inoculation with even the highest dose only infrequently resulted in the establishment of S mutans strain 6715. Sucrose- and glucose- grown cells appeared to behave similarly. Colonization of S mutans strain 6715 occurred in all rats fed diets with a sucrose content ranging from 56 to as low as 1%. The establishment of S mutans strain 6715 on the teeth of rats fed diets with a sucrose concentration of 0.1 or 0.01% was impaired and comparable to the diet containing 56% glucose. In rats fed a high glucose diet, uniform establishment and persistence of the test strain occurred after frequent inoculations with about 5 X 10(8) CFU. The colonization under these conditions appeared to be independent of the intestinal canal as a bacterial cell source. These data suggest the possibility that S mutans can establish itself in the human mouth in the absence of dietary sucrose. In rats fed a high glucose diet and inoculated with 10(7) CFU or less, the cells gradually disappeared from the teeth; in contrast, the test strain implanted well in rats fed the sucrose favors firmer attachment of initially weakly attached cells via in situ new glucan synthesis. S mutans strain 6715 also appeared to have some affinity for teeth in the absence of dietary sucrose that may be of ecological significance. Once firmly established in rats fed a high sucrose diet, S mutans strain 6715 maintained itself in high numbers on the teeth after a switch to a high glucose diet during a 14-week period.

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Studies of the mechanism of sucrose-associated colonization of Streptococcus mutans on teeth of conventional rats.

The mechanism of the colonization of S mutans strain 6715 on teeth in the presence of sucrose has been investigated using conventional Sprague-Dawley rats. Experiments were performed using rats fed diets with 56% sucrose or 56% glucose; oral inoculations with sucrose-grown, extracellular glucan-coated cells and glucose-grown, uncoated cells; and teeth treated with dextran 2000 via its incorportation in the diet, or teeth left untreated. In all instances, sucrose was required for satisfactory colonization of the test strain. Preformed extracellular glucan, whether associated with the bacterial cell or with the tooth surface, did not facilitate bacterial colonization when compared with cells or teeth devoid of extracellular glucan under the conditions used. The evidence suggests that glucan-mediated attachment of S mutans strain 6715 in the presence of sucrose involves an initial phase in which the cells are relatively weakly associated with the tooth surface and a subsequent phase during which firmer attachment occurs via new glucan synthesis.

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