Effects of estradiol and progesterone on Bacteroides melaninogenicus and Bacteroides gingivalis

Abstract

Bacteroides melaninogenicus subsp. intermedius increases in the subgingival microflora during pregnancy. These studies evaluated direct interactions between hormonal steroids and oral Bacteroides species. Resting cell suspensions of pure cultures of plaque organisms were incubated anaerobically with [14C]estradiol and [14C]progesterone. Uptake of labeled compound per microgram of bacterial protein was determined by thin-layer chromatography and liquid scintillation counting. B. melaninogenicus subsp. intermedius and B. melaninogenicus subsp. melaninogenicus took up 2.6 x 10(-4) to 5.4 x 10(-4) mumol of estradiol or progesterone per microgram of cell protein. Minimal steroid uptake was observed with B. gingivalis and five other organisms. Uptake of steroids by B. melaninogenicus subsp. intermedius was temperature dependent and resulted in a labeled product as detected on thin-layer chromatography. Growth curves indicated that intermedius and melaninogenicus subspecies of B. melaninogenicus but not B. gingivalis could substitute progesterone or estradiol for vitamin K, an essential growth factor. Growth of B. melaninogenicus subsp. intermedius in steroids was concentration dependent. Addition of fumarate to resting cells of B. melaninogenicus subspecies as well as B. gingivalis increased steroid uptake by 70 to 500% and resulted in the gas-liquid chromatographic detection of succinate. Cultures given fumarate alone or steroids alone produced no succinate. Steroids appeared to directly interact with the fumarate reductase system and foster the growth of B. melaninogenicus subsp. intermedius. This interaction may be of ecological significance.

Studies on the physiology and ecology of black-pigmented Gram-negative anaerobes which may be important in disease development

“…melaninogenica and Pr. intermedia, but not P. gingivalis can substitute estradiol and progesterone for their vitamin K requirement [24]. The uptake of these compounds is also influenced by addition of fumarate, suggesting a role for steroids in the electron transport system of these species.…”

Changes in subgingival microbiota during puberty A 4-year longitudinal study

“…Microorganisms of the dental plaque may also react specifically to increased availability of hormones in oral fluids. Such effects have been described, e.g., estradiol may be utilized by Bacteroides spp, (Kornman & Loesche 1982) and may substitute for menadione, an important growth factor for black-pigmenting Bacteroides (BPB) (Gibbons & Macdonald 1960). Gram-negative anaerobic bacteria including BPB are frequently found in diseased periodontal sites (Slots 1982, Zambon et al 1981, Dzink et al 1985 and species of this group of organisms are considered to be an important part of the presumptive pathogenic flora.…”

Factors influencing the susceptibility to gingivitis during childhood—a review

“…A similar increase in the number of B. intermedius has been reported in pregnant women and in women taking oral contraceptives [44,45]. It has been suggested that sex hormones may act as growth factors for Bacteroides species [46]. In many studies, black-pigmented Bacteroides species have been associated with periodontal disease [471.…”