HCAIs: The increasing need for airborne E.coli infection control

airborne E.coli Emerging evidence suggests that airborne transmission could account for up to a quarter of all cases of healthcare-associated infections1. These infections could range in their severity; with some examples being that of airborne E.coli.

Healthcare-associated infections (HCAIs) are a considerable public health issue. They result from contact with bacteria or viruses within the healthcare setting; for example, hospital wards & hospital waiting rooms. NHS England states that 300,000 people in England are affected by HCAIs of all kinds every year, leading to 9,000 deaths and a cost of £1bn to the NHS.

The World Health Organization notes that seven out of 100 hospital patients in Europe can expect to contract an HCAI. The elderly, children, those with compromised immunity and people with serious medical conditions are most at risk.

Urinary tract infections are the most common of the HCAIs, and Escherichia coli (E.coli) is the leading cause of these. It is therefore important to consider the transmission of airborne E.coli and take steps to prevent this risk.

In the healthcare setting, there is a high density of people that are either contagious or vulnerable through compromised immunity (or both), which creates conditions where infection can arise from airborne transmission or through direct or indirect contact. The bodily functions of an infected person can contaminate hands and surfaces, as well as emitting airborne particles which either settle or remain airborne, potentially travelling large distances from the source of infection. A person may become exposed either by touching a surface where airborne E.coli particles have settled or via inhalation - making a hospital's Airborne infection control an important aspect of managing airborne hygiene needs.

Infection prevention and control have been taken increasingly seriously in recent years2, although the focus has been primarily on hand hygiene and improving surface cleanliness, and often less on hospital air filtration and the potential for airborne transmission.

 

Evidence for Airborne E.Coli

E.coli is a bacterium found naturally in the intestines of humans and other animals. Many strains are harmless, but some produce toxins which can cause illness. The most common of these is E.coli 0157. Symptoms of E.coli 0157 ‘food poisoning’ infection include diarrhoea, vomiting and stomach cramps. While most cases resolve, the infection can lead to serious kidney disease, particularly in children and the elderly. E.coli toxic strains are also an increasingly important cause of bloodstream infections (BSIs), which can be fatal.

A report from The Health Foundation2 highlights the attention now being given to E.coli infection control, given the significant increase since mandatory surveillance came in in 2011. It is particularly concerning to learn that E.coli now accounts for 36% of BSIs.

Outbreaks of E.coli 0157 are not uncommon. A 2016 outbreak across England, Scotland and Wales affected 151 people. Two people died and 62 needed hospital care. It is known that E.coli is spread by eating contaminated food, drinking contaminated water or by contact with someone who is infected, but what about the need for airborne E.coli infection control?

The issue of airborne E.coli first came up in 2002, during the investigation of an outbreak at an agricultural show in Oregon3. Swabs from high up in the building proved positive, suggesting that the bacterium had, indeed, become airborne. The investigators noted that there had been similar outbreaks associated with dairy farms and county fairs in previous years and airborne transmission may have been significant in those also.  Recent research4 from the United States Department of Agriculture suggests that airborne E.coli 0157 can be carried up to 200 metres on the wind. The researchers sampled leafy green plants located 60, 120 and 180 metres from a site where cattle, which carry the bacterium, were being fed. While rates of transmission varied with the level of activity in the site and weather, on a dry and dusty day 92% of plants 180 meters from the cattle were infected. Healthcare environments are clearly different from agricultural settings but, given the closer proximity of sources of infection and those exposed, airborne E.coli infection control in hospital wards and waiting rooms could be an even greater priority.

More evidence of the risk of airborne E.coli comes from a study carried out in Mexico City5. Analysis of airborne and settled dust showed significant concentrations of many strains of the bacterium, several of them antibiotic resistant.

Clearly, more research is needed to define the airborne transmission of infection in the healthcare setting. The evidence suggests that airborne E.coli infection control is becoming more significant, and it may now be time to implement measures such as IQAir Air Filtration Units to ensure the air in healthcare environments is free from contamination.

 

References

1 Fernstrom A and Goldblatt M (2013). Aerobiology and its role in the transmission of infectious diseases. Journal of Pathogens http://dx.doi.org/10.1155/2013/4939602

2 The Health Foundation (2015). Infection prevention and control: lessons from acute care in England.

3 http://www.about-ecoli.com/ecoli_outbreaks/news/tests-suggest-e-coli-spread-through-air

4 Farming Online (2014). https://farming.co.uk/news/airborne-spread-of-e-coli-underestimated

5 Rosas I, Salinas E, Yela A et al (1997). Escherichia coli in settled dust and air samples collected in residential environments in Mexico City. Applied and Environmental Microbiology 63 (10); 4093–4095