MSACL 2019 EU Abstract

Developing a New Diagnostic Tool for Small Intestinal Bacterial Overgrowth following Upper-Gastrointestinal Surgery

LS Hage (1), KV Savva (1), I Belluomo (2), PR Boshier (3), PA Gummett (4), GB Hanna (5), CJ Peters (6)
Imperial College London

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Lory Hage (Presenter) Imperial College London >> POSTER (PDF)

Presenter Bio: I am currently a master (MRes) student in Biomedical Research at Imperial College London, in the department of Cancer and Surgery. My first MRes project focused on the development of a new, more efficient diagnostic tool for SIBO in upper-gastrointestinal post-operative patients.

Upon completion of my second year of BSc in Biomedical Sciences in Paris V Descartes, I have enrolled in an exchange year at Imperial College London. Appreciating the english culture and its education system, I decided to pursue my studies in London.
I am particularly interested in clinical research and am aiming for a MD/PhD dual program.

Relevant Financial Disclosures (within past 24 months) No relevant financial relationship(s) to disclose. Conflict mitigation NOT REQUIRED.

Introduction: Nowadays, surgical treatments for oesophageal and gastric cancer, as well as morbid obesity, are increasingly common and have improved patient life expectancy. However, upper gastro-intestinal (GI) post-operative patients frequently experience a long-term decline of quality of life, manifested by symptoms that have often been associated with small intestinal bacterial overgrowth (SIBO); an increase or change of bacterial population in the gut. The current diagnostic tool used in clinic, hydrogen breath test (HBT), measures the change of concentration of hydrogen in the breath after ingestion of glucose. However, this test has a limited specificity. To alleviate this gap, the quantification of certain volatile organic compounds (VOCs) in the breath can be used to identify SIBO.

Objectives: The primary aim of this study was to identify significant VOCs found in the breath of upper-GI post-operative patients correlated with SIBO, to ultimately develop a new diagnostic tool based on the breath profiles of patients.

Methods: Breath samples were collected from 30 patients who had undergone upper-GI surgeries using Nalophan bags and analysed by selected ion flow tube mass spectrometry (SIFT-MS). This online quantification instrument has the ability to immediately calculate the concentration of the trace gas compounds present in breath by using its in-built library. A glucose HBT test was conducted in all patients in accordance to the NHS guidelines together with breath test. 11 targeted VOCs were compared between HBT positive and negative patients using mixed model statistics.
Results: This study has shown that three VOCs, acetone (p-value 0.030), heptanone (p-value 0.012) and butanoic acid (p-value 0.013), were significantly different between SIBO positive and negative patients and, could potentially be used to correctly identify SIBO. These compounds were found to be the product of bacterial fermentation of carbohydrates into fatty acids, indicating a link between SIBO and associated metabolic pathways. Moreover, our data highlighted the lack of clinical characterisation of SIBO and the symptomatic variability seen between post-operative patients.

Conclusion: To conclude, SIBO is a serious clinical concern among post-operative patients. In fact, the prevalence of SIBO determined in our study was quite high (66.7%), often contributing to the decline of quality of life after surgery. In order to improve prompt treatment, breath tests using VOCs seem to be a promising, efficient and non-invasive method of diagnosis.