By Don Rauf
Although their makers may tout them as a healthier alternative to smoking, e-cigarettes have potential harmful effects — including increasing the strength of deadly bacteria in the body.
E-cigarettes heat a liquid containing tobacco to produce a vapor rather than smoke. Tobacco users have increasingly turned to “vaping” as a smoking alternative. Compared to regular cigarettes, e-cigarettes are supposedly safer and not prohibited in as many locations.
Recent research, however, has found that e-cigarettes may contain cancer-causing substances. And in a new lab study, e-cigarette vapor appears to boost the virulence of medication-resistant and potentially life-threatening bacteria, such as MRSA.
Laura E. Crotty Alexander, MD, a researcher with the VA San Diego Healthcare System (VASDHS) and an assistant professor of medicine in pulmonary and critical care at the University of California, San Diego (UCSD), and her colleagues investigated how e-cigarette vapor affects live methicillin-resistant Staphylococcus aureus (MRSA) and human epithelial cells, which line most internal organs and are the major tissues of glands.
Resistant to the antibiotics commonly used to treat ordinary staph infections, MRSA often colonizes the cells in the nasopharynx — the upper part of the throat behind the nose. E-cigarette users are constantly exposing these cells to vapors.
After Dr. Crotty Alexander and her team cultivated a strain of MRSA in a culture that contained vapor concentrations equal to those created by common inhalers, they evaluated factors that can make MRSA stronger.
These factors included growth rate, surface charge, susceptibility to reactive oxygen species (a variety of molecules and free radicals derived from molecular oxygen), hydrophobicity (a characteristic of repelling or not combining with water) and biofilm formation (when communities of microorganisms attached to a surface).
In particular, investigators noted that the vapors from e-cigarettes resulted in changes in surface charge and biofilm formation that made the MRSA less vulnerable to killing by human cells and antibiotics.
The authors also underscored that cigarette smoke appeared to make MRSA even stronger than e-cigarette vapor. Cigarette smoke caused greater changes in the factors that make MRSA more virulent.
In a mouse study, the survival rate of MRSA was three times greater in lungs exposed to e-cigarette vapors and four times greater in lungs exposed to cigarette smoke compared to lungs not exposed to either vapors or smoke.
"As health care professionals, we are always being asked by patients, ‘Would this be better for me?’” Dr. Crotty Alexander said in a press release. "In the case of smoking e-cigarettes, I hated not having an answer. While the answer isn't black and white, our study suggests a response: even if e-cigarettes may not be as bad as tobacco, they still have measurable detrimental effects on health."
The study was presented in May at the 2014 American Thoracic Society International Conference.