Cigarettes are "widely contaminated（污染）" with bacteria（细菌）, including some known to cause disease in people, concludes a new international study conducted by a University of Maryland environmental health researcher and microbial（微生物的） ecologists at the Ecole Centrale de Lyon in France. The research team describes the study as the first to show that "cigarettes themselves could be the direct source of exposure to a wide array of potentially pathogenic（致病的） microbes among smokers¹ and other people exposed to secondhand smoke." Still, the researchers caution that the public health implications（含意，启示） are unclear and urge further research.

"We were quite surprised to identify such a wide variety of human bacterial² pathogens（病原体） in these products," says lead researcher Amy R. Sapkota, an assistant professor in the University of Maryland's School of Public Health. http://www.sph.umd.edu/miaeh/people/index.cfm

"The commercially-available cigarettes that we tested were chock full（塞满了的） of bacteria, as we had hypothesized（假设，假定）, but we didn't think we'd find so many that are infectious（传染的） in humans, explains Sapkota, who holds a joint³ appointment with the University's Maryland Institute for Applied⁴ Environmental Health and the Department of Epidemiology and Biostatistics.

"If these organisms（生物体，有机体） can survive the smoking process—and we believe they can—then they could possibly go on to contribute to both infectious and chronic⁵ illnesses in both smokers and individuals who are exposed to environmental tobacco smoke," Sapkota adds. "So it's critical that we learn more about the bacterial content of cigarettes, which are used by more than a billion people worldwide."

The study will appear in an upcoming edition of the journal Environmental Health Perspectives and the pre-copyedited manuscript has been posted online: http://www.ehponline.org/members/2009/0901201/0901201.pdf