Molecular and biochemical characterizations of human oral lactobacilli as putative probiotic candidates.
BACKGROUND
The objective of this study was to characterize the lactobacilli from the human oral cavity as a potential source of probiotic strains.


METHODS
Samples were collected from four different locations within the oral cavity: surface of healthy tooth, oral mucous membrane, surface of tooth decay and deep tooth decay. On the basis of morphological and biochemical properties eight categories were formed and 26 isolates were selected for further characterization. The isolates were determined as Lactobacillus sp. using primers specific for 16S rDNA. Sequencing of 16S rDNA genes and repetitive sequence-based polymerase chain reactions were used for determination to species and subspecies levels.


RESULTS
Predominant species were Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus salivarius and Lactobacillus paracasei subsp. paracasei, while Lactobacillus acidophilus, Lactobacillus cellobiosus, Lactobacillus delbrueckii subsp. lactis and Lactobacillus gasseri were also present. The isolates Lactobacillus salivarius BGHO1, Lactobacillus fermentum BGHO36 and BGHO64, Lactobacillus gasseri BGHO89 and Lactobacillus delbrueckii subsp. lactis BGHO99 exhibited antagonistic action on the growth of Staphylococcus aureus, Enterococcus faecalis, Micrococcus flavus, Salmonella enteritidis, Streptococcus pneumoniae and Streptococcus mutans, but not on growth of Candida albicans. Moreover, the isolates L. salivarius BGHO1 and L. gasseri BGHO89 were tolerant to low pH and high concentration of bile salts.


CONCLUSIONS
Taken together, these findings imply that L. salivarius BGHO1 and L. gasseri BGHO89 might be subjects for additional investigation as potential probiotic strains.
Strahinic
I
I
Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Serbia.
Busarcevic
M
M
Pavlica
D
D
Milasin
J
J
Golic
N
N
Topisirovic
L
L
D000328:Adult; D000898:Antibiosis; D015373:Bacterial Typing Techniques; D004269:DNA, Bacterial / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis; D003731:Dental Caries / Q000382:microbiology*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007778:Lactobacillus / Q000737:chemistry / Q000145:classification* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009055:Mouth / Q000382:microbiology*; D019936:Probiotics; D012091:Repetitive Sequences, Nucleic Acid; D017422:Sequence Analysis, DNA
D004269:DNA, Bacterial; D004275:DNA, Ribosomal