The role of salivary factors in persistent oral carriage of Candida in humans.
BACKGROUND
Candida albicans is a commensal oral yeast in approximately one-third to one-half of the healthy population. To date, there are no studies investigating the multiple anti-candidal salivary constituents of healthy individuals with either nil or, consistent oral yeast carriage.


OBJECTIVE
To compare the composition and anti-candidal activity in stimulated whole saliva of healthy 'consistent' oral Candida carriers with Candida-free individuals.


METHODS
A sub-sample of 22 consistent, Candida-free individuals and 10 consistent Candida carriers were recruited from a 12 months screening study investigating oral Candida carriage in 97 healthy patients treated by fixed orthodontic appliances. Unstimulated and stimulated saliva samples were collected. The following salivary attributes were measured using standard methodology: the flow rate, pH, lysozyme, lactoferrin and IgA concentration and, the degree of inhibition of blastoconidial growth and blastospore germination.


RESULTS
Saliva from the Candida-free individuals showed 20.2% higher inhibition of blastoconidial growth (p < 0.05) of a reference strain of Candida albicans. No significant differences between the other salivary attributes of the two groups were found.


CONCLUSIONS
The fact that saliva of Candida-free individuals significantly inhibited the blastoconidial growth more than Candida-carriers (p < 0.05) suggests that saliva may play a role in modulating oral candidal populations in health. Further studies, with a larger cohort are needed to confirm these findings and determine the factors that confer enhanced salivary anti-candidal activity.
Hibino
Kyoko
K
Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China.
Samaranayake
Lakshman P
LP
Hägg
Urban
U
Wong
Ricky W K
RW
Lee
Wilson
W
D000293:Adolescent; D000935:Antifungal Agents / Q000032:analysis / Q000494:pharmacology; D002175:Candida / Q000187:drug effects / Q000254:growth & development / Q000302:isolation & purification*; D002176:Candida albicans / Q000187:drug effects; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007071:Immunoglobulin A, Secretory / Q000032:analysis; D007781:Lactoferrin / Q000032:analysis; D008297:Male; D009113:Muramidase / Q000032:analysis; D012463:Saliva / Q000737:chemistry / Q000382:microbiology* / Q000502:physiology; D012636:Secretory Rate / Q000502:physiology; D013172:Spores, Fungal / Q000187:drug effects / Q000254:growth & development; D055815:Young Adult
D000935:Antifungal Agents; D007071:Immunoglobulin A, Secretory; D009113:Muramidase; D007781:Lactoferrin