Senior author Anders Hakansson at the University at Buffalo's School of Medicine and Biomedical Sciences and colleagues found Streptococcus pneumoniae and Streptococcus pyogenes persist on surfaces for far longer than appreciated.
The findings suggest additional precautions might be necessary to prevent infections, especially in settings such as schools, day care centers and hospitals.
"These findings should make us more cautious about bacteria in the environment since they change our ideas about how these particular bacteria are spread," Hakansson said in a statement. "This is the first paper to directly investigate that these bacteria can survive well on various surfaces, including hands, and potentially spread between individuals."
S. pneumoniae, a leading cause of ear infections in children and morbidity and mortality from respiratory tract infections in children and the elderly, is widespread in day care centers and a common cause of hospital infections, Hakansson said. S. pyogenes commonly causes strep throat and skin infections in school children but also can cause serious infection in adults.
The UB researchers found in a day care center, 4-of-5 stuffed toys tested positive for S. pneumonaie and several surfaces, such as cribs, tested positive for S. pyogenes, even after being cleaned.
"In all of these cases, we found that these pathogens could survive for long periods outside a human host," Hakansson said.
But, the scientific literature maintains people become infected only by breathing in infected droplets expelled through coughing or sneezing by infected individuals, he said.
"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 concluded.