Tobacco Smoke Makes Oral Bacteria More Resilient



The mouth is home to more than 700 different bacteria species. Tobacco smoke, though, promotes the colonization and fortification of harmful species like Porphyromonas gingivalis. The immune system, then, has a much harder time fighting them off as biofilms begin to develop.

“Once a pathogen establishes itself within a biofilm, it can be difficult to eradicate as biofilms provide a physical barrier against the host immune response,” said David A. Scott, PhD, a researcher at the University of Louisville School of Dentistry.

The chemicals in tobacco smoke stress the oral environment and alter the expression of multiple genes and proteins in the bacteria there, promoting colonization and immune evasion. Biofilms then form, comprising complex, interacting multispecies structures.

Biofilms can form on surfaces like plastics, rocks, and metals as well as on host surfaces like teeth, heart valves, and mucosal layers. Dental plaque is a biofilm that can lead to gingivitis, chronic periodontitis, and other severe oral diseases.

“Furthermore, biofilms allow for the transfer of genetic material among the bacterial community, and this can lead to antibiotic resistance and the propagation of other virulence factors that promote infection,” Scott said.

In addition to P gingivalis, pathogens including Staphylococcus aureus, Streptococcus mutans, Klebsiella pneumonia, and Pseudomonas aeruginosa form biofilms after being affected by the components in tobacco smoke.

“Many studies have investigated biofilms using a single species, but more relevant multispecies models are emerging,” Scott said. “Novel treatments for biofilm-induced diseases also are being investigated, but we have a long way to go.”

These treatments include antimicrobial surfaces for medical devices, therapeutics that specifically target the adhesive interactions between early colonizers and later colonizing pathogenic species, and small-molecule antimicrobials that, unlike antibiotics, can penetrate biofilms.

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