Tag Archives: Bacteria

Shining a Light on Bacteria

One hundred and twenty years ago, in her ‘Notes on Nursing’, Florence Nightingale wrote about the benefits of allowing sunshine into a patient’s room.[1] Since then many studies have shown that exposure to ultraviolet light can inactivate many bacteria. However, the windows used in most buildings only allow visible light though and block a large percentage of ultraviolet light. Now, a team of researchers from the University of Oregon have analysed the effect the Sun has on bacteria found in dust particles.[2] By contaminating climate-controlled scale model rooms with a sample of dust combined from the homes of various volunteers, they looked at the effect different window glazes had on the bacteria present. They found that in rooms that had no light 12% of bacteria were viable, while this was only 6.8% in rooms exposed to daylight, and 6.1% in rooms that were exposed to ultraviolet light (and not visible light). Interestingly it was bacteria species that are associated with respiratory diseases that were mainly absent when exposed to daylight/UV light.

This study is only a starting point – the rooms created were experimental and only covered a small range of light dosages, and the impacts of daylight exposure on bacteria compared to other things, such as ventilation or humidity, is unclear. Designs of future schools, offices, hospitals, etc. may want to take into account the amount of daylight that can penetrate rooms.

— Peter Chilton, Research Fellow


  1. Nightingale F. Notes on Nursing. What it is, and what it is not. 1898.
  2. Fahimipoiur AK, Harmann EM, Siemens A, et al. Daylight exposure modulates bacterial communities associated with household dust. Microbiome. 2018; 6: 175.

Biological Underpinnings of Chronic Fatigue?

A recent synopsis in Nature describes a study showing that immune cells in patients with chronic fatigue behave differently in vitro to those in healthy controls.[1] This suggests that the disease is not psychosomatic, argues the synopsis. That is not just out of date thinking, it is long out of date – the inter-relationship between mind and body has been known for over a century. The article suggests that gut bacteria may differ in chronic fatigue syndrome. If this hypothesis is confirmed then maybe the condition originates somatically and affects the brain, not the other way around. We develop this idea further in the next exciting instalment of your news blog.

— Richard Lilford, CLAHRC WM Director


  1. Maxmen A. Biological underpinnings of chronic fatigue emerge. Nature. 2017; 543: 602.