Foul-smelling bacteria and fungi lingering in automobile air conditioners could pose health problems for people with allergies or weakened immune systems, researchers said Tuesday.

A study of air conditioner evaporators from 12 cars found many types of fungi and bacteria, researchers said. Owners of the vehicles complained of unpleasant odors.All of the air conditioners, from six manufacturers and three countries, had been used for less than two years.

Robert Simmons, a professor of biology at Georgia State University, said the growths could cause problems for people with weakened immune systems or who are allergic to the fungi. The research was presented at a conference of the American Society for Microbiology.

"Any kind of immunosuppressed person is more susceptible to this kind of a problem," Simmons said.