697. The Gut Microbiome and Susceptibility to Vibrio cholerae Infection
Session: Oral Abstract Session: Microbiome
Friday, October 9, 2015: 8:30 AM
Room: 25--ABC
Background: Susceptibility to Vibrio cholerae infection is related to age, blood group O status, and pre-existing immunity, but these factors only partially explain who becomes infected after exposure to V. cholerae. Our aim was to evaluate the relationship between the gut microbiota and susceptibility to V. cholerae infection among household contacts of cholera patients.

Methods: We studied gut microbes from stool using 16S sequencing in 122 household contacts of index cases hospitalized with cholera. Clinical symptoms and serum immune responses to V. cholerae were evaluated for 30 days after the exposure. Twenty household contacts that were uninfected at the time of case hospitalization demonstrated evidence of infection during the follow-up period, and 29 contacts had no signs of infection during the follow up period. Measures of alpha and beta diversity were calculated using the QIIME (Quantitative Insights into Microbial Ecology) program using weighted Unifrac distance. With a supervised learning method we used feature selection to identify operational taxonomic units (OTUs) that were predictive of infection.

Results: Diversity measures were not significantly different between infected and uninfected contacts. Specific OTUs could predict V. cholerae infection with a receiver-operating characteristic (ROC) of 0.88, improving on a logistic regression model of previously identified clinical and immunologic factors predicting infection (age, baseline vibriocidal titer, and blood group O status) with an ROC 0.72. The presence of specific microbes, such as Paracoccus aminovorans and family Atopobium were associated with a higher risk of subsequent infection with V. cholerae, and Blautia obeum (recently known as Ruminococcus obeum) and bacteria from the family Christensenellaceae were associated with a lower risk of infection.

Conclusion: The gut microbial population present at the time of exposure to V. cholerae is predictive of subsequent infection. The biological interaction between specific bacterial groups and V. cholerae warrants further study.

Ana Weil, MD, MPH1, Firas Midani, MS2, Fahima Chowdhury, MBBS3, Ashraf Khan, MBBS3, Yasmin Begum, PhD3, Richelle Charles, MD1, Stephen B. Calderwood, MD, FIDSA1, Edward T. Ryan, MD, DTMH, FIDSA1, Jason Harris, MD, MPH, FIDSA1, Firdausi Qadri, PhD3, Lawrence David, PhD2 and Regina Larocque, MD, MPH, FIDSA1, (1)Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, (2)Genomic and Computational Biology, Duke University, Durham, NC, (3)Vaccine Science, International Center for Diarrheal Disease Research, Bangladesh, Dhaka, Bangladesh

Disclosures:

A. Weil, None

F. Midani, None

F. Chowdhury, None

A. Khan, None

Y. Begum, None

R. Charles, None

S. B. Calderwood, None

E. T. Ryan, None

J. Harris, None

F. Qadri, None

L. David, None

R. Larocque, None

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