Genetic biomarker for deadly pathogen identified

New York: Researchers have discovered several genetic biomarkers that can accurately identify hypervirulent Klebsiella pneumoniae, a pathogen that infects healthy people and can cause blindness in one day and flesh-eating infections, brain abscesses and death.

Hypervirulent K. pneumoniae, which is also resistant to all antibiotics, is a rare but increasingly common strain of K. pneumoniae.

There is no accurate method for distinguishing between the hypervirulent strain from the classical strain of K. pneumoniae, which is most often seen in the Western hemisphere, is less virulent and usually causes infections in hospital settings.

In a study published in the Journal of Clinical Microbiology, the researchers detailed a few biomarkers that can identify hypervirulent K. pneumoniae.

“Presently, there is no commercially available test to accurately distinguish classical and hypervirulent strains,” said Thomas Russo, Professor at Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo in New York.

“This research provides a clear roadmap as to how a company can develop such a test for use in clinical laboratories. It’s sorely needed,” Russo added.

Russo and his co-authors knew that the hypervirulence of K. pneumoniae is largely due to genes located on a large virulence plasmid, DNA that is independent from the chromosome.

They hypothesised that some of these genes, including those producing iron-acqusition molecules called siderophores, might be good biomarkers and this proved to be the case, according to the study.

The researchers also found that higher concentrations of siderophores predicted hypervirulence. They then validated the identified biomarkers in a mouse infection model.

“The advantage of identifying these genetic biomarkers is that they can be developed into rapid nucleic acid tests, and if approved by the Food and Drug Administration (FDA), would then provide clinicians with an accurate method to quickly determine if a patient is suffering from an infection due to the classical or hypervirulent strain,” Russo explained.

He added that such a test will not only benefit patients and possibly save lives, but will also prove critical in learning more about hypervirulent K. pneumoniae.

“For example, we don’t know the frequency of infection by hypervirulent K. pneumoniae in different parts of the world,” he said.