Effects of Lactobacillus rhamnosus GG on saliva-derived microcosms.
OBJECTIVE
The probiotic strain Lactobacillus rhamnosus GG (LGG) is shown to hamper the presence of mutans streptococci in saliva and may have positive effects on oral health. We investigated the effects of LGG on the cariogenic potential and microbial composition of saliva-derived microcosms.


METHODS
Single and dual species biofilms of LGG and Streptococcus mutans, and saliva-derived microcosms with or without LGG were grown in an Active Attachment Biofilm model. The microcosms were grown on bovine dentin/enamel discs in the presence or absence of sucrose (suc+/suc-). The presence of LGG was determined by multiplex ligation-dependent probe amplification (MLPA) and real-time PCR. Mutans streptococci (MS) and total viable counts, pH of the spent medium, capacity of lactate formation and integrated mineral loss in dentin was assessed. MLPA was used for identification and relative quantification of 20 oral microorganisms in the microcosms. Principal Component Analysis was applied to MLPA data.


RESULTS
LGG inhibited the growth of S. mutans in dual species biofilms and did not affect the pH. LGG established in saliva-derived microcosms and reduced MS counts significantly, but did not affect pH or dentin demineralization. Simultaneous growth of the microcosms with LGG under heavy cariogenic conditions (suc+) introduced a compositional shift in the microbial community. The CFU, real-time PCR and MLPA data correlated significantly.


CONCLUSIONS
We conclude that LGG established into and inhibited the growth of MS in complex saliva-derived biofilms, but this had no significant effect on cariogenic potential of the microcosms. This suggests that other microorganisms besides MS were responsible for increased cariogenicity of sucrose-exposed biofilms.
Academic Centre for Dentistry Amsterdam, Division of Conservative and Preventive Dentistry, Department of Cariology, Endodontology, Pedodontology & Oral Microbiology, University of Amsterdam and VU University Amsterdam, The Netherlands.
Lien Chi
LC
Pham
Michel A
MA
Hoogenkamp
Rob A M
RA
Exterkate
Zewdu
Z
Terefework
Johannes J
JJ
de Soet
Jacob M
JM
ten Cate
Wim
W
Crielaard
Egija
E
Zaura
D000818:Animals; D018441:Biofilms; D002417:Cattle; D015169:Colony Count, Microbial; D006801:Humans; D052201:Lacticaseibacillus rhamnosus; D021141:Nucleic Acid Amplification Techniques; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012463:Saliva / Q000382:microbiology*