PhoB regulates the survival of Bacteroides fragilis in peritoneal abscesses.
In response to phosphate limitation, bacteria employ the Pho regulon, a specific regulatory network for phosphate acquisition. The two-component signal transduction system of PhoRB plays a crucial role in the induction of Pho regulon genes, leading to the adaptation to phosphate starvation. Herein, we identified the PhoRB system in Bacteroides fragilis, a commensal gut bacterium, and evaluated its role in gut colonization and survival in peritoneal abscesses. BF1575 and BF1576 encoded PhoR (sensor histidine kinase) and PhoB (response regulator) in the sequenced B. fragilis strain YCH46, respectively. Transcriptome analysis revealed that deletion of phoB affected the expression of 585 genes (more than 4-fold change) in B. fragilis, which included genes for stress response (chaperons and heat shock proteins), virulence (capsular polysaccharide biosynthesis) and phosphate metabolism. Deletion of phoB reduced the ability of the bacterium to persist in peritoneal abscesses induced by an intra-abdominal challenge of B. fragilis. Furthermore, PhoB was necessary for survival of this anaerobe in peritoneal abscesses but not for in vitro growth in rich media or in intestinal colonization. These results indicate that PhoB plays an important role in the survival of B. fragilis under stressful extraintestinal conditions.
Department of Immunology and Parasitology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan.
Shin
S
Wakimoto
Haruyuki
H
Nakayama-Imaohji
Minoru
M
Ichimura
Hidetoshi
H
Morita
Hideki
H
Hirakawa
Tetsuya
T
Hayashi
Koji
K
Yasutomo
Tomomi
T
Kuwahara
D018784:Abdominal Abscess / Q000382:microbiology*; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001442:Bacteroides Infections / Q000382:microbiology*; D001441:Bacteroides fragilis / Q000166:cytology / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D000071677:Histidine Kinase; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D050296:Microbial Viability; D010537:Peritoneum / Q000382:microbiology*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D018085:Regulon; D015398:Signal Transduction; D013312:Stress, Physiological
D001426:Bacterial Proteins; C061278:PhoB protein, Bacteria; D011494:Protein Kinases; D000071677:Histidine Kinase