Infectious diseases are a major cause of death worldwide,\u00a0and\u00a0diagnosing bacterial infections\u00a0remains\u00a0a\u00a0challenge in medicine. And doing so reliably is more important than ever, given the increasing frequency of antibiotic resistance. Now, research published in\u00a0ACS Central Science\u00a0could help healthcare professionals non-invasively diagnose\u00a0bacterial infections,\u00a0using breath-based tests.\u00a0Initial experiments\u00a0demonstrated\u00a0the approach in animals with\u00a0pneumonia and infections\u00a0in\u00a0the bloodstream,\u00a0muscles\u00a0and bones.\u00a0<\/p>\n
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In designing this study, we were motivated by a developing trend in clinical practice, whereby patients and providers want answers right away that will inform treatment decisions. If a patient visits the Emergency Room or Acute Care clinic, we hope that he or she can be diagnosed with an acute bacterial infection as efficiently as possible.”\u00a0<\/p>\n
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David Wilson, corresponding author of the study<\/p>\n
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Doctors currently rely on blood tests, imaging,\u00a0cultures\u00a0and molecular diagnostics to\u00a0identify\u00a0the cause of infections,\u00a0but these\u00a0tools are limited because they are slow, non-specific\u00a0or expensive.\u00a0The start to a potential solution could be the\u00a0long-used breath test for\u00a0Helicobacter\u00a0pylori, a bacterium that causes a common stomach infection.\u00a0The\u00a0original\u00a0test\u00a0works when a\u00a0person\u00a0drinks a\u00a0liquid\u00a0containing\u00a0traceable\u00a0substances\u00a0metabolized\u00a0by\u00a0H. pylori.\u00a0Then\u00a0the person\u00a0exhales into a device that measures\u00a0labeled carbon dioxide in their breath,\u00a0indicating\u00a0the\u00a0infection\u00a0is present. Inspired by this\u00a0test, Wilson, Kiel Neumann, Marina L\u00f3pez-\u00c1lvarez\u00a0and colleagues set out to expand the\u00a0technology’s\u00a0capabilities\u00a0to detect a broader range of bacterial infections.\u00a0<\/p>\n
For their prototype, the team tested sugar and sugar alcohols tagged with carbon-13, a traceable form of carbon that bacteria\u00a0metabolize\u00a0but human cells\u00a0largely ignore. In lab experiments, the researchers\u00a0identified\u00a0several of these compounds that bacteria convert into carbon-13-labeled carbon dioxide. Then they analyzed the labeled gas using a simple technique called nondispersive infrared spectroscopy.\u00a0<\/p>\n
When mice with infections such as pneumonia and bone, muscle, or blood infections received intravenous injections of these tagged compounds, the animals’\u00a0breath quickly showed elevated levels of the labeled carbon dioxide.\u00a0Although\u00a0the breath testing protocol was not\u00a0optimized\u00a0in this study, the researchers say they typically saw elevated carbon-13-labeled breath signals in infected animals within the first 10 minutes of metabolite administration and breath sampling.\u00a0In contrast,\u00a0the\u00a0breath\u00a0of healthy mice\u00a0showed little to no carbon-13.\u00a0<\/p>\n
In one infection model for\u00a0E.\u00a0coli, the amount of labeled carbon dioxide in the breath decreased during antibiotic treatment as bacterial levels went down, suggesting the method could also be used to\u00a0monitor\u00a0how well treatments are working.\u00a0<\/p>\n
Because breath-test instruments are\u00a0portable\u00a0and\u00a0breath signals appear within minutes\u00a0after the\u00a0traceable carbon-13 is\u00a0administered, the test could potentially deliver results faster than\u00a0current\u00a0methods.\u00a0In addition, the sugar and sugar\u00a0alcohols\u00a0used are considered safe for humans,\u00a0and\u00a0the researchers say this approach could\u00a0eventually\u00a0become\u00a0a tool for diagnosing bacterial infections.\u00a0<\/p>\n
The authors acknowledge funding from the National Institutes\u00a0of Health and the Cystic Fibrosis Foundation.\u00a0<\/p>\n
The authors have filed a U.S. patent related to this work.<\/p>\n
Source:<\/p>\n
American Chemical Society<\/a><\/p>\n Journal reference:<\/p>\n