Association of enterotoxigenic Bacteroides fragilis infection with inflammatory diarrhea.
BACKGROUND
Diarrheal illnesses remain a leading cause of morbidity and mortality globally, with increasing recognition of long-term sequelae, including postinfectious irritable bowel syndrome and growth faltering, as well as cognitive deficits in children. Identification of specific etiologic agents is often lacking. In vitro and in vivo data suggest that enterotoxigenic Bacteroides fragilis (ETBF) may contribute to the burden of colonic inflammatory diarrheal disease. The study goal was to investigate the pathogenesis of ETBF diarrheal illnesses.


METHODS
We performed an observational study of children and adults with acute diarrheal illnesses in Dhaka, Bangladesh, from January 2004 through November 2005, to define the clinical presentation, intestinal inflammatory responses, and systemic and intestinal antibody responses to ETBF. Other enteric pathogens were also evaluated.


RESULTS
ETBF was identified to cause a clinical syndrome with marked abdominal pain and nonfebrile inflammatory diarrhea in both children (age, >1 year) and adults. Fecal leukocytes, lactoferrin, and proinflammatory cytokines (interleukin 8, tumor necrosis factor-alpha)-as well as B. fragilis toxin systemic antitoxin responses-increased rapidly in ETBF-infected patients. Evidence of intestinal inflammation often persisted for at least 3 weeks, despite antibiotic therapy.


CONCLUSIONS
ETBF infection is a newly recognized cause of inflammatory diarrhea in children and adults. Future studies are needed to evaluate the role of ETBF in persistent colonic inflammation and other morbid sequelae of acute diarrheal disease.
Sears
Cynthia L
CL
Division of Infectious Diseases and Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, USA. csears@jhmi.edu
Islam
Salequl
S
Saha
Amit
A
Arjumand
Maleka
M
Alam
Nur Haque
NH
Faruque
A S G
AS
Salam
M A
MA
Shin
Jai
J
Hecht
David
D
Weintraub
Andrej
A
Sack
R Bradley
RB
Qadri
Firdausi
F
D000293:Adolescent; D000328:Adult; D001427:Bacterial Toxins; D001442:Bacteroides Infections / Q000382:microbiology*; D001441:Bacteroides fragilis / Q000302:isolation & purification; D002648:Child; D002675:Child, Preschool; D004403:Dysentery / Q000382:microbiology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007223:Infant; D008666:Metalloendopeptidases; D016133:Polymerase Chain Reaction
D001427:Bacterial Toxins; C405031:Bacteroides fragilis toxin; D008666:Metalloendopeptidases