A new international study conducted by centers in both the USA and France shows that cigarettes are "widely contaminated" with bacteria, including some known to cause disease in people. This work was done by researchers at the University of Maryland as well as 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 microbes among smokers and other people exposed to secondhand smoke." Their study will appear in an upcoming edition of the journal Environmental Health Perspectives and the manuscript has been posted online.
Lead researcher Amy R. Sapkota, an assistant professor at UMD (Maryland) says, "We were quite surprised to identify such a wide variety of human bacterial pathogens in these products. 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," explains Sapkota, who holds a joint appointment with the University's Maryland Institute for Applied Environmental Health and the department of epidemiology and biostatistics.
"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 adds. Obviously scientists feel they need to learn more about the bacterial content of cigarettes, because these products are still used by more than a billion people worldwide.
Among the study's findings and conclusions:
* Commercially available cigarettes show a broad array of bacterial diversity, ranging from soil microorganisms to potential human pathogens;
* This is the first study to provide evidence that the numbers of microorganisms in a cigarette may be as "vast as the number of chemical constituents;"
* Hundreds of bacterial species were present in each cigarette, and additional testing is likely to increase that number significantly;
* No significant variability in bacterial diversity was observed across the four different cigarette brands examined: Camel; Kool Filter Kings; Lucky Strike Original Red; and Marlboro Red;
* Bacteria of medical significance to humans were identified in all of the tested cigarettes and included Acinetobacter (associated with lung and blood infections); Bacillus (some varieties associated with food borne illnesses and anthrax); Burkholderia (some forms responsible for respiratory infections); Clostridium(associated with foodborne illnesses and lung infections); Klebsiella (associated with a variety of lung, blood and other infections); and Pseudomonas aeruginosa (an organism that causes 10 percent of all hospital-acquired infections in the United States).
This research might account for the fact that the respiratory tracts of smokers are characterized by higher levels of bacterial pathogens.