Excess dietary manganese promotes staph heart infection

September 21, 2017

Too much dietary manganese—an essential trace mineral found in leafy green vegetables, fruits and nuts—promotes infection of the heart by the bacterium Staphylococcus aureus ("staph").

The findings, reported this week in the journal Cell Host & Microbe, add to the evidence that diet modifies risk for . The discovery also suggests that people who have excess levels of tissue manganese, including those who consume dietary supplements with high concentrations of the metal, may be at increased risk for of the heart.

"The human body does a wonderful job of regulating nutrient levels, and a traditional Western diet has plenty of minerals in it. The idea of super-dosing nutrients needs to be given careful consideration," said Eric Skaar, Ph.D., MPH, Ernest W. Goodpasture Professor of Pathology and senior author of the current study.

Skaar and his colleagues studied the impact of dietary manganese on staph infection in a mouse model. Most of the mice that consumed a high manganese diet—about three times more manganese than normal—died after infection with staph. The investigators discovered that the animals on the high manganese diet were particularly susceptible to staph infection of the heart, which was a surprise, said Skaar, who is also professor of Pathology, Microbiology and Immunology and director of the Vanderbilt Institute for Infection, Immunology and Inflammation.

"We know very little about how manganese is moved around and regulated. It's a mystery why high manganese affects staph infection of a single organ," he said.

The researchers found that excess manganese inactivates a key line of defense against pathogens: the innate immune system's reactive oxygen burst. Normally, in response to staph, "neutrophils pour into the site of infection and blast the bacteria with reactive oxygen species," Skaar explained. The excess manganese counters this blast.

"It's striking that a single dietary change can inactivate one of the most powerful branches of innate immune defense and lead to ," Skaar said.

The protein calprotectin—another line of defense—usually acts as a "sponge" to mop up manganese and other metals. Keeping nutrients away from pathogens is known as "nutritional immunity." For reasons that are not clear, however, calprotectin is completely ineffective in the high manganese hearts, Skaar said.

Staph is the leading cause of bacterial endocarditis (infection of the inner lining of the heart chamber and heart valves) and the second most frequent cause of bloodstream infections.

Interestingly, some populations of people have both increased risk for staph infections, particularly endocarditis, and higher than normal levels of tissue manganese, Skaar noted. These populations include intravenous drug users, patients with chronic liver disease and patients on long-term intravenous diets.

In ongoing studies, Skaar and his colleagues are working to understand how manganese is transported and regulated in vertebrates and why the is particularly susceptible to fatal staph infections when levels are high. They are also exploring the impact of other nutrient minerals and vitamins on infection.

Explore further: Investigators use light to kill microbial 'vampires'

More information: Cell Host & Microbe (2017). DOI: 10.1016/j.chom.2017.08.009

Related Stories

Investigators use light to kill microbial 'vampires'

August 1, 2017
On July 24 Vanderbilt scientist Eric Skaar, Ph.D., MPH, summarized his group's latest paper in a tweet: "If S. aureus is going to drink our blood like a vampire, let's kill it with sunlight."

Staph 'gangs' share nutrients during infection, study finds

October 16, 2014
Antibiotic-resistant bacteria can share resources to cause chronic infections, Vanderbilt University investigators have discovered. Like the individual members of a gang who might be relatively harmless alone, they turn deadly ...

Excess dietary zinc worsens C. diff infection

September 26, 2016
Too much dietary zinc increases susceptibility to infection by Clostridium difficile – "C. diff" – the most common cause of hospital-acquired infections.

Vanderbilt studies outline new model for staph bone infections

August 1, 2013
Osteomyelitis, a debilitating bone infection most frequently caused by Staphylococcus aureus ("staph") bacteria, is particularly challenging to treat.

Recommended for you

Amber-tinted glasses may provide relief for insomnia

December 15, 2017
How do you unwind before bedtime? If your answer involves Facebook and Netflix, you are actively reducing your chance of a good night's sleep. And you are not alone: 90 percent of Americans use light-emitting electronic devices, ...

Warning labels can help reduce soda consumption and obesity, new study suggests

December 15, 2017
Labels that warn people about the risks of drinking soda and other sugar-sweetened beverages can lower obesity and overweight prevalence, suggests a new Johns Hopkins Bloomberg School of Public Health study.

Office work can be a pain in the neck

December 15, 2017
Neck pain is a common condition among office workers, but regular workplace exercises can prevent and reduce it, a University of Queensland study has found.

Regular takeaways linked to kids' heart disease and diabetes risk factors

December 14, 2017
Kids who regularly eat take-away meals may be boosting their risk factors for heart disease and diabetes, suggests research published online in the Archives of Disease in Childhood.

Simulation model finds Cure Violence program and targeted policing curb urban violence

December 14, 2017
When communities and police work together to deter urban violence, they can achieve better outcomes with fewer resources than when each works in isolation, a simulation model created by researchers at the UC Davis Violence ...

Your pets can't put your aging on 'paws'

December 14, 2017
(HealthDay)—In a finding that's sure to ruffle some fur and feathers, scientists report that having a pet doesn't fend off age-related declines in physical or mental health.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.