In the past studies have shown two common bacteria have short lifespans outside of the human body; but new research suggests they live for longer than we thought. 

The Streptococcus pneumoniae and Streptococcus pyogenes bacteria can cause "colds, ear infections, strep throat and more serious infections," and may be lingering on furniture, child toys, and other surfaces, a University of Buffalo news release reported.

"These findings should make us more cautious about bacteria in the environment since they change our ideas about how these particular bacteria are spread," senior author Anders Hakansson, PhD, assistant professor of microbiology and immunology in the UB School of Medicine and Biomedical Sciences, said in the news release. "This is the first paper to directly investigate that these bacteria can survive well on various surfaces, including hands, and potentially spread between individuals."

A research team found that  S. pneumonaie was present on four out of five stuffed toys hours after they had come in contact with a human; other surfaces such as cribs also contained the bacteria. 

The team suggested the bacteria could be so long-lived because they form structured communities called "biofilms."

"Bacterial colonization doesn't, by itself, cause infection but it's a necessary first step if an infection is going to become established in a human host," Hakansson said. "Children, the elderly and others with compromised immune systems are especially vulnerable to these infections."

Past studies have used lab-grown samples called broth-grown planktonic bacteria, and found the bacteria die rapidly on a non-living surface. 

"But we knew that this form of bacteria may not represent how they actually grow in the host," Hakansson said. "Since discovering that biofilms are key to the pathogenesis of S. pneumonaie, we wanted to find out how well biofilm bacteria survive outside the body."

The team found these biofilms could survive on hands, as well as surfaces such as toys, books, and furniture, even hours after they were well-cleaned. 

"Commonly handled objects that are contaminated with these biofilm bacteria could act as reservoirs of bacteria for hours, weeks or months, spreading potential infections to individuals who come in contact with them," Hakansson said.

"If it turns out that this type of spread is substantial, then the same protocols that are now used for preventing the spread of other bacteria, such as intestinal bacteria and viruses, which do persist on surfaces, will need to be implemented especially for people working with children and in health-care settings," he said.