Powerful salmonella strains could be prevented after researchers detect stealthy, 'hypervirulent' salmonella strains.

Credit: Rocky Mountain Laboratories

Michael Mahan and Douglas Heithoff, researchers from the University of California, US, recently documented findings in a paper titled ‘Intraspecies Variation in the Emergence of Hyperinfectious Bacterial Strains in Nature,’ emphasising the potential for these sometimes fatal strains of salmonella to be detected, and therefore eradicated.

Salmonella is one of the most common causes of infection, hospitalisation, and death due to foodborne illness. The researchers looked to address this problem by looking for the dangerous strains present in salmonella, finding  hypervirulent strains that present a potential risk to food safety and the livestock industry.

An international team of scientists  conducted a global search for hypervirulent salmonella strains. They were found among isolates derived from livestock, and rendered current vaccines obsolete. The severe strains were compared to the fifth gear of a car, acting much like a Trojan Horse by exposing their weapons only after initiating infection.

The findings required new techniques, after previous efforts failed to find hypervirulent strains owing to the fact that bacteria behaves much like their less-virulent cousins after environmental exposure. Professor Mahan  explained: "The trick was to assess their virulence during infection – before they switch back to a less-virulent state in the lab.”

Knowing what to look for is half the battle when it comes to detecting and discriminating more harmful strains. The strategy is aided by a special medium utilised by the researchers that forces the bacteria to reveal their weapons in the laboratory. The researchers will now look for ways to rapidly detect the strains, using the data to design of therapeutics to combat them.

As hypervirulent strains pose a potential risk to human and animal health, mitigation efforts warrant researchers' careful attention. "Now that we have identified the problem –– and potential solutions –– we just need to get to work," Heithoff concluded.