Cigarettes May Contain Bacteria

Nov. 24, 2009 -- Cigarettes are massive germ factories that may expose users and passersby to a swarm of disease-causing bacteria, a study shows.

It's well known that cigarette smoke harbors hundreds of toxic chemicals that are bad for your health. But a University of Maryland environmental health researcher says that's not the only danger. DNA examination of four cigarette brands shows, for the first time, that cigarettes are "widely contaminated" with hundreds of different types of bacteria. In fact, there appears to be as many bacteria in cigarettes as there are chemicals.

"The commercially available cigarettes that we tested were chock full of bacteria, as we had hypothesized, but we didn't think we'd find so many that are infectious in humans," says researcher Amy R. Sapkota, an assistant professor in the University of Maryland's School of Public Health.

Sapkota and microbial ecologists at the Ecole Centrale de Lyon in France examined the bacteria content in four major cigarette brands: Camel, Kool Filter Kings, Lucky Strike Original Red, and Marlboro Red and found similar types of bacteria in each one.

Previous research has watched for bacterial growth in lab dishes containing small tobacco samples, but this study is the first to scrutinize a cigarette's bacterial genetic makeup.

The testing revealed that cigarettes contain a wide variety of bacteria that are linked to lung, blood, and food-borne-related infections. Among those present were:   

• Acinetobacter -- associated with certain blood and lung infections
• Bacillus -- some types are associated with anthrax and food poisoning
• Burkholderia -- some strains can cause respiratory infections
• Clostridium -- linked to food poisoning-related illnesses and lung infections
• Klebsiella -- associated with many kinds of lung, blood, and other infections
• Pseudomonas aeruginosa -- a specific type of bacteria that is responsible for 10% of hospital-acquired infections

"If these organisms can survive the smoking process -- and we believe they can -- then they could possibly go on to contribute to both infectious and chronic illnesses in both smokers and individuals who are exposed to environmental tobacco smoke," Sapkota says.

Although the public health implications of these findings are unclear at present, scientists plan to continue their research to determine if the bacteria can be implicated in tobacco-related diseases. A big question is whether or not cigarette-borne bacteria can survive the burning process and enter the lungs of smokers and grow. Some evidence suggests that some bacteria can spread this way. The bacteria may also be present on, or in, the filter.

The study findings appear online ahead of print in the journal Environmental Health Perspectives.