Possible association of Bifidobacterium and Lactobacillus in the gut microbiota of patients with major depressive disorder.
Bifidobacterium and Lactobacillus in the gut have been suggested to have a beneficial effect on stress response and depressive disorder. We examined whether these bacterial counts are reduced in patients with major depressive disorder (MDD) than in healthy controls.



Bifidobacterium and Lactobacillus counts in fecal samples were estimated in 43 patients and 57 controls using bacterial rRNA-targeted reverse transcription-quantitative polymerase chain reaction



The patients had significantly lower Bifidobacterium counts (P=0.012) and tended to have lower Lactobacillus counts (P=0.067) than the controls. Individuals whose bacterial counts below the optimal cut-off point (9.53 and 6.49log10 cells/g for Bifidobacterium and Lactobacillus, respectively) were significantly more common in the patients than in the controls for both bacteria (Bifidobacterium: odds ratio 3.23, 95% confidence interval [CI] 1.38-7.54, P=0.010; Lactobacillus: 2.57, 95% CI 1.14-5.78, P=0.027). Using the same cut-off points, we observed an association between the bacterial counts and Irritable bowel syndrome. Frequency of fermented milk consumption was associated with higher Bifidobacterium counts in the patients.



The findings should be interpreted with caution since effects of gender and diet were not fully taken into account in the analysis.



Our results provide direct evidence, for the first time, that individuals with lower Bifidobacterium and/or Lactobacillus counts are more common in patients with MDD compared to controls. Our findings provide new insight into the pathophysiology of MDD and will enhance future research on the use of pro- and prebiotics in the treatment of MDD.
Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
Emiko
E
Aizawa
Yakult Central Institute, Tokyo, Japan.
Hirokazu
H
Tsuji
Yakult Central Institute, Tokyo, Japan.
Takashi
T
Asahara
Yakult Central Institute, Tokyo, Japan.
Takuya
T
Takahashi
Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
Toshiya
T
Teraishi
Department of Psychiatry, National Center of Neurology and Psychiatry Hospital, Tokyo, Japan.
Sumiko
S
Yoshida
Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
Miho
M
Ota
Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
Norie
N
Koga
Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
Kotaro
K
Hattori
Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan. Electronic address: hkunugi@ncnp.go.jp.
Hiroshi
H
Kunugi
D000328:Adult; D001644:Bifidobacterium / Q000302:isolation & purification*; D016022:Case-Control Studies; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D005260:Female; D000069196:Gastrointestinal Microbiome / Q000502:physiology*; D041981:Gastrointestinal Tract / Q000382:microbiology; D006801:Humans; D007778:Lactobacillus / Q000302:isolation & purification*; D008297:Male
Bifidobacterium; Distress; Gut microbiota; Irritable bowel syndrome; Lactobacillus; Major depressive disorder