ISLAMABAD: A New research suggested that air pollution may have an effect on human health by altering bacteria. It shows that black carbon, a major component of air pollution, dramatically changes how bacteria grow and form biofilms, which can affect their survival in the lining of airways and their resistance to antibiotics. The study - by researchers from the University of Leicester in the United Kingdom - is published in the journal Environmental Microbiology.

The team suggests that the work may have important implications for the treatment of infectious diseases, which are known to occur more frequently in places with high levels of air pollution.

First author Julie Morrissey, associate professor in microbial genetics, says that the findings show "that the bacteria which cause respiratory infections are affected by air pollution, possibly increasing the risk of infection and the effectiveness of antibiotic treatment of these illnesses."

However, as Prof. Morrissey and colleagues note, the effects of black carbon on bacteria, "organisms central to ecosystems in humans and in the natural environment, are poorly understood."

For their study, they investigated how black carbon affects bacteria living in the respiratory tract - that is, the nose, the throat, and the lungs.

The researchers found that black carbon alters the antibiotic tolerance of S. aureus biofilms and increased the ability of S. pneumoniae biofilms to resist penicillin, the front-line drug for treating bacterial pneumonia.

Biofilms form when bacteria cells stick to surfaces and form communities held together by a slimy, glue-like substance that they excrete and surround themselves with. These surfaces can include living tissue, such as of the heart and lungs. Once established, biofilms cause stubborn infections that are hard to treat and extremely resistant to antibiotics once they become chronic.

The researchers note that their findings show that "exposure to black carbon induces structural, compositional, and functional changes in the biofilms of both S. pneumoniae and S. aureus."

Finally, in tests on mice, they also found that black carbon causes S. pneumoniae to spread from the nose to the lower respiratory tract - a key step in the development of disease.

They conclude that their study "highlights that air pollution has a significant effect on bacteria that has been largely overlooked."

Prof. Julie Morrissey said that "Our research could initiate an entirely new understanding of how air pollution affects human health. It will lead to enhancement of research to understand how air pollution leads to severe respiratory problems and perturbs the environmental cycles essential for life."