乌鸦传媒

NEW ORLEANS -- Bacterial content of hookah tobacco products varies by manufacturer, and even by flavor, researchers reported here.

Both Shannon diversity and types of bacterial communities varied by flavor when comparing three flavors of hookah tobacco among two major manufacturers, Fumari and Al Fakher, reported Leena Malayil, a medical student at the University of Maryland, and colleagues, in a at the ASM Microbe meeting.

Malayil told 乌鸦传媒 that her group "knew there was bacteria" in the hookah tobacco, but wanted to see if the brand and manufacturer made a difference in terms of bacterial content.

The authors noted that use of non-cigarette products, particularly water pipes, such as hookah, has more than doubled among young adults in the past decade in the U.S. and they are considered a "healthier" alternative to cigarettes, despite studies that show the health risks of hookah are similar to cigarette smoking. They added that hookah users are also exposed to bacterial agents that could play an active role in the production of tobacco-specific N-nitrosamines, which are carcinogenic.

Malayil said that while other studies have examined the bacterial contents of water bowls and the mouthpieces of water pipes, they wanted to look at what was in the hookah tobacco itself.

"There are 100 chemicals in there, but no one has gone in too much to check," she said.

They chose the Fumari and Al Fakher, because they were the most common brands of hookah tobacco.

"Every hookah smoker would know these two brands -- it's like Marlboro for cigarettes," Malayil said.

Her group conducted a 14-day study where they analyzed three flavors from each brand: two apple, mint, and watermelon from Al Fakher and "white gummy bear," ambrosia, and mint chocolate chill from Fumari.

They compared the number of observed bacterial operational taxonomic units (OTUs) and the Shannon index, measuring the bacterial diversity of the flavors over time. They also conducted a beta-diversity analysis using the Bray-curtis distance to compare the bacterial communities of different flavors to each other.

Overall, the authors found that the dominant bacteria across all products was from the Pseudomonas, Bacillus and Paenibacillus genera. But the composition differed across varying flavors and brands. Fumari's ambrosia flavor had higher levels of Pseudomonas, while Al Fakher's watermelon flavor had higher levels of Paenibacillus. The Shannon index was also lower for the ambrosia flavor, indicating lower bacterial diversity. The beta-diversity analysis also found that ambrosia was distinct not only from the Al Fakher products, but from the other Fumari flavors.

The authors also conducted time-series experiments storing each flavor of hookah tobacco under three distinct conditions: pocket, refrigerator, and room and measured the abundance of Pseudomonas spp. on days 0, 5, 9 and 14. They found that all three Al-Fakher brands had a relatively low abundance of bacteria for most of the time period, but it greatly increased on day 14. The patterns were more variable for the Fumari brands.

Malayil said that the next step in this research would be to increase the sample to get more sequences and determine how many sequences are live bacteria.

"Imagine the effect not just on lung cancer patients, but even on someone with bronchitis," she said. "Maybe hookah manufacturers would have to warn about that and it would be one more reason to tell people to avoid smoking."

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