Bacteria Persists on Books, Toys and Cribs for Long Periods

How long can bacteria live outside the human body? Apparently it's far longer than you might first imagine. Scientists have discovered that Streptococcus pneumonia and Streptococcus pyogenes can persist on surfaces far longer than first thought. The findings suggest that additional precautions may be necessary when it comes to preventing infections.

S. pneumonia is a leading cause of ear infections in children and morbidity and mortality from respiratory tract infections in children and the elderly. It's widespread in daycare centers and is a common cause of hospital infections. In contrast, S. pyogenes commonly causes strep throat and skin infections in school children, but can also cause serious infection in adults.

In order to see whether these bacteria persisted outside the body, the researchers tested stuffed toys and other surfaces for the bacteria at a daycare center. In the end, they found that four out of five stuffed toys tested positive for S. pneumonaie. In addition, several surfaces, such as cribs, tested positive for S. pyrogenes even after being cleaned. What was more surprising was the fact that the testing was done just before the daycare center opened in the morning, which meant that it had been many hours since the last human contact.

"These findings should make us more cautious about bacteria in the environment since they change our ideas about how these particular bacteria are spread," said Ander Hakansson, one of the researchers, in a 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."

That's not to say that this bacterial colonization causes infection by itself. However, it is a necessary first step if an infection is going to become established in a human host. Because this bacteria can persist outside a host, it can linger and potentially be far more infectious than previously realized.

"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," said Hakansson in a news release. "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."

The findings are published in the journal Infection and Immunity.