Salmonella, a bacteria that causes vomiting, diarrhea, and stomach cramps, is most commonly found in unpasteurized milk or eggs and uncooked meat. Until now, it has been believed that after Campylobacter, the most common cause of gastroenteritis is Salmonella infection.
But here’s the surprise. A new study reveals that the second most common cause of intestinal infection lives in our tummy only.
Scientists from the University of New South Wales (UNSW) in Sydney have made a breakthrough by identifying that Aeromonas bacteria play a significant role in gastroenteritis cases.
Gastroenteritis, colloquially referred to as gastro, is an infectious ailment that arises due to the inflammation of the digestive tract. It is characterized by symptoms such as vomiting and diarrhea and is known to spread rapidly.
The research, spearheaded by Associate Professor Li Zhang of the School of Biotechnology and Biomolecular Sciences at UNSW, reveals astonishing insights regarding the varieties of intestinal bacteria, known as enteric bacteria, that are responsible for this illness.
Prior to this discovery, the general understanding was that Campylobacter was the primary bacterial culprit behind gastroenteritis, followed by Salmonella infections.
According to the author, these findings show “Aeromonas are the second most prevalent enteric bacterial pathogens across all age groups, and are in fact the most common enteric bacterial pathogens in children under 18 months.”
This research, which was made public on June 28 in the Microbiology Spectrum journal, could potentially revolutionize the procedure for diagnosing gastroenteritis, and pave the way for more specialized treatment options.
Zhang adds, “With further research, once we’re able to figure out the source of infection, we may eventually be equipped with the knowledge of how best to prevent Aeromonas infection.”
In reference to the pattern of infection, Zhang states, “Historically, Aeromonas species have been largely overlooked and understudied, but they are increasingly recognized as emerging enteric pathogens globally.”
The research collective, which also included doctoral candidate Christopher Yuwono, scrutinized data from 341,330 Australian gastroenteritis patients between 2015 and 2019.
They employed quantitative real-time PCR to examine fecal specimens from these patients in order to identify the presence of bacterial pathogens. Moreover, they categorized the specimens according to age to further comprehend the dynamics of gastroenteritis infection.
The analysis demonstrated an exclusive infection pattern that involved three separate peaks in infection rates corresponding to different age groups.
Zhang points out, “The occurrence of Aeromonas enteric infections was predominately observed in young children and individuals over 50 years old, suggesting a higher susceptibility to these infections during stages where the immune system tends to be weaker.”
Interestingly, there was also a surge in infections among individuals aged 20 to 29, which might be due to heightened exposure to the bacteria.
Zhang indicates, “These findings suggest that both human host and microbial factors contribute to the development of Aeromonas enteric infections.”
Regarding the diagnostic process, Zhang mentions that currently, diagnostic labs do not regularly screen for Aeromonas in stool samples from patients with gastroenteritis.
“But the high rate of Aeromonas infection discovered in our study, and significantly, how they are impacting different patient age groups, suggest that Aeromonas species should be included on the common enteric bacterial pathogen examination list.”
The team’s next objective is to pinpoint the Aeromonas species involved.
Zhang notes, “We already know of at least five different species of Aeromonas cause gastrointestinal infections in Australia. And we know that they have different virulent genes—with that some are more virulent than others. So if Aeromonas bacteria are identified to species level, it could lead to even more targeted treatment.”
Another hurdle is determining the origin of the pathogen. Zhang’s earlier studies showed that most Aeromonas infections in Australia were contracted locally, not through international travel.
Zhang concludes, “Future research is needed to identify the sources of Aeromonas infections in Australia, so that effective strategies can then be implemented to reduce these infections.”
Image Credit: Shutterstock