People with the germiest mouths are the most likely to have heart attacks, U.S. researchers reported on Wednesday.

A study that compared heart attack victims to healthy volunteers found the heart patients had higher numbers of bacteria in their mouths, the researchers said.

Their findings add to a growing body of evidence linking oral hygiene with overall health.

Oelisoa Andriankaja and colleagues at the University at Buffalo in New York were trying to find if any particular species of bacteria might be causing heart attacks.

Their tests on 386 men and women who had suffered heart attacks and 840 people free of heart trouble showed two types — Tannerella forsynthesis and Prevotella intermedia — were more common among the heart attack patients.

But more striking, the people who had the most bacteria of all types in their mouths were the most likely to have had heart attacks, they told a meeting of the International Association of Dental Research in Miami.

"The message here is that even though some specific periodontal pathogens have been found to be associated with an increased risk of coronary heart disease, the total bacterial pathogenic burden is more important than the type of bacteria," Andriankaja, now at the University of Puerto Rico, said in a statement.

"In other words, the total number of 'bugs' is more important than one single organism."

Doctors are not sure how bacteria may be linked with heart attacks but several studies have shown associations between gum disease and heart disease. Bacteria may set off general inflammation that in turn causes blood to clot.