In the journal Cancer, Biology & Therapy, study leader Erle Robertson, PhD, professor and vice chair of otorhinolaryngology at the university's Perelman School of Medicine, and colleagues applied the test - called PathoChip - to tissue samples of a patient with relapsed acute myelogenous leukemia (AML).
The patient - a middle-aged man - had undergone chemotherapy for the cancer, a treatment that is well known to weaken the immune system, increasing susceptibility to infection. As a result, he developed an unknown fungal infection.
Such incidents are not uncommon; according to the Centers for Disease Control and Prevention (CDC), each year, around 60,000 cancer patients in the US are hospitalized as result of low white blood cell counts, and around 1 in 14 of these patients die.
It goes without saying that rapid identification of the cause of infection is key to fast and effective treatment for these patients. But this is where a major problem lies; there are certain pathogens for which, at present, doctors lack efficient identification techniques.
One of these pathogens is a rare fungus known as Rhizomucor, which is a cause of the hard-to-treat fungal infection zygomycosis in humans. Such fungal species can take a very long time to culture in the lab, and some cannot be cultured at all, making patient diagnosis challenging.
However, in their study, Robertson and colleagues reveal how they used PathoChip to identify a species of Rhizomucor as the cause of their study subject's "unknown" fungal infection.
PathoChip detected cause of fungal infection in little over 24 hours
The researchers describe the PathoChip as a microarray technology that is capable of testing human tissue for the possible presence of thousands of pathogens.
The technology contains 60,000 probes that simultaneously test for all known viruses, as well as a variety of bacteria, fungi, helminths (parasitic worms) and protozoa.
"We've run many tests to see if we could identify pathogens in the lab, just to see if the PathoChip has efficacy in identifying a variety of organisms, and we were able to identify all infectious agents tested," Robertson said. "But this was the first time we actually looked directly at a patient sample to identify a pathogenic agent."
By using the PathoChip to test preserved tissue samples from the AML patient, the researchers were able to identify one of the two species of Rhizomucor as the cause of the patient's fungal infection in just over 24 hours.
Commenting on the results, the authors say:
"This report highlights the value of PathoChip as a diagnostic tool to identify microorganisms to the species level, especially for those difficult to identify in most clinical laboratories.
It will also help clinicians to obtain a critical snapshot of the infection profile of a patient to plan treatment strategies."
PathoChip 'complementary to next-generation sequencing'
The researchers note that there are other methods - such as next-generation sequencing - that are capable of identifying unknown pathogens, but there are limitations of such technologies.
For example, Robertson says that in the case of next-generation sequencing, there needs to be a high level of nucleic acids in tissue samples in order for pathogens to be identified, and analyzing tissue using such a method is more time-consuming.
"We think this technology [the PathoChip] is complementary to next-generation sequencing in some ways, and even more finely tuned, because we have a much higher sensitivity in detecting agents or individual organisms present in any kind of sample, whether it's abiotic or biotic," says Robertson. "We can identify agents in soil, for example, in plant tissue, in animal tissue, or human tissue."
While the PathoChip holds promise for clinical use, the team says many more studies are required before it can reach that stage. "This will take a great deal more research to eventually lead to approval for frontline clinical use in hospitals," adds Robertson.
Last September, a study reported by Medical News Today revealed the development of a new test called ViroCap, which researchers say can detect almost any virus.