Improving gastro treatment in residential care

Scientists at UNSW Sydney have made a breakthrough discovery that could better protect older people from gastroenteritis, an illness causing vomiting and diarrhoea.

A new study examined over 300,000 patient samples, identifying the bacterium Aeromonas as the second most prevalent pathogen associated with bacterial gastroenteritis.

Gastroenteritis, commonly known as gastro, is a contagious illness that leads to vomiting and diarrhoea due to infection and inflammation of the digestive system. 

It's estimated that roughly one in three aged care facilities in Australia experiences a gastro outbreak each year.

Associate Professor Li Zhang said the findings were especially relevant for older people who are more susceptible to severe complications due to a weakened immune system.

"This could ultimately lead to more targeted treatment," Professor Zhang said.

Older people face severe risks when infected with gastroenteritis, such as dehydration, which could lead to decreased kidney functioning. 

Gastro can also disrupt the balance of electrolytes in bodies, leading to muscle weakness, confusion, irregular heartbeat, and falls.

Combined with pre-existing chronic conditions such as diabetes, older people may experience more severe symptoms and interference with their medication.

"They have a higher susceptibility to these infections during stages where the immune system tends to be weaker," Professor Zhang said.

"The high rate of Aeromonas infection discovered in our study and its impact suggest that this species should be included on the common enteric bacterial pathogen examination list."

Gastro outbreaks in aged-care facilities can rapidly spread through the faecal-oral route, inhalation of aerosolised virus particles, or contact with contaminated surfaces or people.

Under the Public Health Act 1997, facilities must inform their local Public Health Unit (PHU) if they have two or more gastro cases among residents or staff within 24 hours.

In 2018, nearly 80 per cent of Australian aged-care homes had an infection control plan in place for gastroenteritis, including social distancing and frequent hand washing.

The most common forms are viral gastroenteritis, caused by noroviruses and rotaviruses, and bacterial gastroenteritis, caused by bacteria like salmonella and campylobacter. 

Viral outbreaks are characterised by vomiting in about 50 per cent of affected people and last for more than a week.

Bacterial outbreaks can cause more severe symptoms and may be linked to contaminated food. 

But the new study found that Aeromonas bacteria was actually the second most prevalent pathogen in cases of bacterial gastroenteritis.

Professor Zhang said the findings could influence how gastroenteritis is diagnosed and treated in the future, leading to more specific and effective treatments.

"We know of at least five different species of Aeromonas that cause gastrointestinal infections in Australia," she said.

"And we know they have different virulent genes – some are more virulent than others. 

"So if Aeromonas bacteria are identified to species level, it could lead to even more targeted treatment." 

Professor Zhang said more research was needed to better identify the source of the Aeromonas infection to develop effective prevention measures.

"Improved diagnostic processes and preventive measures tailored to older people are crucial to mitigate the risks associated with gastroenteritis."

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