Changes in salivary microbiota increase volatile sulfur compounds production in healthy male subjects with academic-related chronic stress.
OBJECTIVE
To investigate the associations among salivary bacteria, oral emanations of volatile sulfur compounds, and academic-related chronic stress in healthy male subjects.


METHODS
Seventy-eight healthy male undergraduate dental students were classified as stressed or not by evaluation of burnout, a syndrome attributed to academic-related chronic stress. This evaluation was carried out using the Maslach Burnout Inventory-Student Survey questionnaire. Oral emanations of hydrogen sulfide, methyl mercaptan, and dimethyl sulfide were measured using an Oral Chroma™ portable gas chromatograph. The amounts in saliva of total bacteria and seven bacteria associated with halitosis were quantified by qPCR. The in vitro production of H2S by S. moorei and/or F. nucleatum was also measured with the Oral Chroma™ instrument.


RESULTS
The stressed students group showed increased oral emanations of hydrogen sulfide and dimethyl sulfide, together with higher salivary Solobacterium moorei levels (p < 0.05, Mann Whitney test). There were moderate positive correlations between the following pairs of variables: Fusobacterium nucleatum and S. moorei; F. nucleatum and hydrogen sulfide; Tannerella forsythia and F. nucleatum; T. forsythia and S. moorei. These correlations only occurred for the stressed group (p < 0.05, Spearman correlation). The in vitro experiment demonstrated that S. moorei increased H2S production by F. nucleatum (p < 0.05, ANOVA and Tukey's test).


CONCLUSIONS
The increased amount of S. moorei in saliva, and its coexistence with F. nucleatum and T. forsythia, seemed to be responsible for increased oral hydrogen sulfide in the healthy male stressed subjects.
Department of Physiological Sciences, Piracicaba Dental School, University of Campinas-UNICAMP, Piracicaba, SP, Brazil.
Bruno Dias
http://orcid.org/0000-0002-5964-8245
BD
Nani
Department of Physiological Sciences, Piracicaba Dental School, University of Campinas-UNICAMP, Piracicaba, SP, Brazil.
Patricia Oliveira de
PO
Lima
Department of Physiological Sciences, Piracicaba Dental School, University of Campinas-UNICAMP, Piracicaba, SP, Brazil.
Fernanda Klein
FK
Marcondes
Department of Physiological Sciences, Piracicaba Dental School, University of Campinas-UNICAMP, Piracicaba, SP, Brazil.
Francisco Carlos
FC
Groppo
Department of Basic Health/Applied Psychology, Federal University of Juiz de Fora (UFJF), Governador Valadares, MG, Brazil.
Gustavo Sattolo
GS
Rolim
Department of Physiological Sciences, Piracicaba Dental School, University of Campinas-UNICAMP, Piracicaba, SP, Brazil.
Antonio Bento Alves de
AB
Moraes
Department of Physiological Sciences, Piracicaba Dental School, University of Campinas-UNICAMP, Piracicaba, SP, Brazil.
Karina
K
Cogo-Müller
Department of Physiological Sciences, Piracicaba Dental School, University of Campinas-UNICAMP, Piracicaba, SP, Brazil.
Michelle
M
Franz-Montan
D000293:Adolescent; D001419:Bacteria / Q000378:metabolism; D006209:Halitosis / Q000382:microbiology; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D012463:Saliva / Q000382:microbiology*; D013315:Stress, Psychological / Q000382:microbiology*; D013334:Students / Q000523:psychology*; D013457:Sulfur Compounds / Q000737:chemistry* / Q000378:metabolism*; D014835:Volatilization; D055815:Young Adult
D013457:Sulfur Compounds