Adaptation of salivary Lactobacillus strains to xylitol.
OBJECTIVE
Acid production from sugars is one of the virulence factors of cariogenic bacteria. To eliminate this factor, many authors have suggested using sugar substitutes like xylitol, which is not fermented by most oral bacteria. The aim of this work was to investigate whether oral strains of lactobacilli unable to utilise xylitol could become able to utilise this polyol.


METHODS
Twenty-eight oral strains and six ATCC strains of lactobacilli were tested. None was initially able to produce acids from xylitol. Media containing only xylitol was used in order to see if an adaptation was possible. The acid production from xylitol was measured by recording the pH variations of the culture medium. The acids produced were identified by HPLC.


RESULTS
After a 15-days culture, 10 strains produced acids. After a 40-days culture, 11 more strains produced acid. When acid production occurred, lactic, formic, acetic, propionic and butyric acids were the organic acids formed by all the strains.


CONCLUSIONS
Adaptation of oral strains of lactobacilli to xylitol can occur in vitro.
Badet
C
C
Laboratoire Odontologique de Recherche, UFR d'Odontologie, 16 cours de la Marne, 33082 Bordeaux Cedex, France. cecile.badet@odonto.u-bordeaux2.fr
Richard
B
B
Castaing-Debat
M
M
de Flaujac
P M
PM
Dorignac
G
G
D000222:Adaptation, Physiological / Q000502:physiology; D002264:Carboxylic Acids / Q000378:metabolism; D002648:Child; D003470:Culture Media; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007778:Lactobacillus / Q000378:metabolism*; D012463:Saliva / Q000382:microbiology*; D014993:Xylitol / Q000378:metabolism*
D002264:Carboxylic Acids; D003470:Culture Media; D014993:Xylitol