JUL 30, 2019 4:16 PM PDT

Cigarette Smoke can Increase the Pathogenicity of Microbes

WRITTEN BY: Carmen Leitch

Strains of methicillin resistant Staphylococcus aureus - MRSA - can become more resistant to antibiotics when exposed to cigarette smoke, researchers have found. Some strains of S. aureus microbes are harmless while others like MRSA are far more dangerous. S. aureus bacteria are found in anywhere from thirty to sixty percent of people worldwide. It wasn’t true of every strain tested, but cigarette smoke caused some of the infectious strains to become more invasive and persistent. The findings have been published in Scientific Reports.

"Smoking is the leading cause of preventable death worldwide, and cigarette smoke has over 4,800 compounds within it. We wanted to study S. aureus because it's so common in humans and it can cause a range of diseases, so we wanted to see what happened when we exposed it to smoke,” explained the lead study author Dr. Maisem Laabei of the University of Bath's Department of Biology & Biochemistry.

In this work, the international research team selected six clinically relevant reference strains of MRSA known to cause a variety of disorders including pneumonia and skin infections. The genetically diverse group of microbial strains were then exposed to cigarette smoke. They didn’t all have the same reaction, but some became more resistant to the antibacterial effect of rifampicin, and were more persistent and invasive.

Cigarette smoke is thought to be an environmental stressor that triggers an emergency response in S. aureus cells; the mutation rate in the DNA of the microbes increases, raising the likelihood that a persister that can resist antibiotics will be created.

Cigarette smoke accelerates the emergence of antibiotic resistant Small Colony Variants (SCVs) in the human pathogen, Staphylococcus aureus. Left panel shows normal wild-type S aureus; Right panel shows gentamicin-resistant SCVs. / Credit: University of Bath

The research also connected this stress to the growth of tough populations of cells called Small Colony Variants (SCVs), which previous work has linked with chronic infections in smokers. Other studies have also suggested that the increased incidence of infection in smokers was attributable to immune system impairment caused by cigarette smoke. This study indicates that the smoke is also impacting microbes in a way that raises the chance of dangerous infection.

"These Small Colony Variants are highly adhesive, invasive and persistent. They can sit around for a long time, are difficult to kick out, and are linked to chronic infections. We hope that our work provides another reason for people not to smoke and for current smokers to quit," added Laabei.

"We expected some effects but we didn't anticipate smoke would affect drug-resistance to this degree. We recognize that exposure in a lab is different to inhaled smoke over a long time, but it seems reasonable to hypothesize, based on our research and others' that stressful conditions imposed by smoking induce responses in microbial cells leading to adaptation to harsh conditions, with the net effect of increasing virulence and/or potential for infection," added Laabei.

Next, the investigators want to see whether air pollution is having a similar effect on bacteria living in our nasal passages.


Sources: AAAS/Eurekalert! via University of Bath, Scientific Reports

About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
JUL 07, 2020
Cell & Molecular Biology
Anticancer Compound Found in Marine Bacteria
JUL 07, 2020
Anticancer Compound Found in Marine Bacteria
Bacteria live in symbiosis with many animals in the world. These tiny single-celled creatures often play crucial roles i ...
JUL 12, 2020
Microbiology
Our Flu Response Is Influenced by Previous Exposures
JUL 12, 2020
Our Flu Response Is Influenced by Previous Exposures
The flu is caused by a respiratory virus, which evolves from year to year. Three kinds of influenza viruses infect human ...
JUL 15, 2020
Microbiology
A Common Drug Could Help Reduce the Risk of COVID-19 Infections
JUL 15, 2020
A Common Drug Could Help Reduce the Risk of COVID-19 Infections
Heparin is a very common drug that's been approved as an anticoagulant since 1992. Researchers have now found that the m ...
AUG 02, 2020
Microbiology
Examining the Existence of Organelles in Bacteria
AUG 02, 2020
Examining the Existence of Organelles in Bacteria
Cells can be grouped into two general categories: prokaryotic, which make up microbes like bacteria and archaea, or euka ...
SEP 02, 2020
Immunology
Alarmins: The Immune "Gold" in Breast Milk
SEP 02, 2020
Alarmins: The Immune "Gold" in Breast Milk
We know that infants fed with breast milk develop more robust immune systems as a result of factors that support the nat ...
SEP 11, 2020
Chemistry & Physics
Indigenous fermentation processes require complex chemical reactions
SEP 11, 2020
Indigenous fermentation processes require complex chemical reactions
A study published in the Nature journal Scientific Reports uncovers the complex chemical processes behind aborigina ...
Loading Comments...