Your breath can say more about you than the garlic from your last meal.

In fact, when you exhale, you emit volatile organic compounds (VOCs), or chemicals that appear as vapor at room temperature.

Many are innocuous, but others tell the story of what’s occurring below your skin’s surface.

Measuring these, or at least looking for specific byproducts of a bacterial infection, could be key to helping clinicians determine not only the cause of an infection but also the best way to treat it.

Researchers based at Zhejiang University in China are studying ways to pinpoint specific VOCs emitted by a bacteria responsible for common hospital-acquired infections.

Their goal is to one day develop a tool to help doctors differentiate between types of bacteria so they can prescribe the proper antibiotics to treat a particular infection.

Much like how specially trained dogs can smell hypoglycemia on the breath of someone with diabetes, these specialized tools gauge the contents of your breath, searching for telltale signs something is wrong.

Rapid diagnostic tools like this are a crucial step in helping preserve current antibiotics by being judicious with their use.

In other words, it will help doctors pair the right drugs for the right bugs, thus reducing chances of bacteria developing defenses.

A third of all antibiotic prescriptions in the United States, according to the U.S. Centers for Disease Control and Prevention (CDC), are unnecessary.

In fact, they do more harm than good by helping perpetuate antibiotic resistant bacteria, which are responsible for 2 million infections each year, 23,000 of which result in death.

The misuse of antibiotics in the face of this epidemic highlights the need for proper diagnosis.

And your breath — whether good or bad — may be able to tell your doctor something that could help.

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Bacteria on Your Breath

When organisms do their thing, they often leave unwanted or wanted byproducts, like how combining yeast and sugars creates alcohol and carbon dioxide.

Much like how a Breathalyzer can detect alcohol on your breath, researchers are trying to discover a way to detect the byproducts of a potentially deadly bacterial infection in your lungs.

Ventilator-associated pneumonia (VAP) is a type of hospital-acquired infection that can affect up to 42 percent of patients on a breathing machine. It’s fatal in more than one in 10 cases.

Diagnosing it currently requires an invasive procedure that increases a person’s risk of infection and has limitations to people with severe lung problems.

So researchers are looking for a better way.

In November, a study published in Nature found it was possible to distinguish patients in the intensive care unit with VAP based on a profile of only 12 VOCs. In other words, they found a way to determine if someone had a bacterial infection based simply off a breath test.

“Exhaled breath analysis is a promising, simple, safe, and noninvasive technique for the rapid diagnosis of VAP,” the study concluded.

That team said further studies were needed, including whether strain-specific VOC profiles can be found. That would help doctors pair antibiotics to their patients better.

“To confirm whether patients have a bacterial infection of the respiratory tract, doctors currently have to take a number of different samples — blood and sputum — and even chest X-rays in the case of pneumonia,” Kejing Ying, a research coordinator at Zhejiang University School of Medicine, said in a press release.

The Zhejiang team studied 60 ventilated patients and collected samples of their breath hoping to detect the bacteria Acinetobacter baumannii. Besides hospitals, the bacteria were a problem for soldiers injured while serving in Iraq and Afghanistan.

Their results, published in the Journal of Breath Research, showed their device could determine a bacterial infection, but it couldn’t quite pinpoint a signature unique to Acinetobacter baumannii.

The researchers found it’s not as simple to detect the bacteria’s signature in someone’s breath the same way they can find it in a petri dish.

“The challenge we face is that many VOCs are not unique to one pathogen,” Ting said.

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Stories Your Breath Can Tell

Besides bacteria and how many rounds you had at the bar, breath tests are being tested for the detection of diseases like asthma, COPD, cystic fibrosis, tuberculosis, and even cancer.

Researchers at the University of Louisville published findings of a new study that shows lung tumors produce detectible kinds of VOCs, specifically carbonyl compounds.

Their process of detecting these VOCs starts when a patient blows into a specialized balloon. The balloon is connected to a pump, which traps their breath with a microchip. The chip is sent to a lab, which is analyzed within hours.

All told, the process costs about $20 and is completely noninvasive.

"We hope that breath analysis will allow us to diagnose patients with primary or recurrent lung cancer long before they suffer from symptoms, when we have more options for treating them, giving them the best chance for a cure,” Dr. Erin M. Schumer, M.D., M.P.H., one of the lead researchers on the project, said in a statement.

The next step for their research is approval from the U.S. Food and Drug Administration (FDA).

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