NEW YORK (360Dx) – Specific Technologies announced late last month a collaboration with infectious disease diagnostic nonprofit FIND to advance the firm's rapid blood infection testing system for use in low-resource settings, a move that Specific called a big step forward in the development of its technology.
Current approaches for diagnosing sepsis are labor-intensive and require significant laboratory resources, which make them problematic in general, but especially so for use in areas without the resources of western medical labs, Specific Technologies CEO Paul Rhodes said in an interview this week.
Specific set out several years ago to develop a quicker and simpler methodology for diagnosing blood infections, based on detection of volatile metabolites, in signatures that sensitively and specifically distinguish different species and strains.
The result, called SpecID, combines pathogen detection with species identification in standard culture tubes, taking what can be a highly manual, two-day process and translating it into a single labor-free instrument that the company says delivers comparable results within 12 hours.
The company's approach relies on low-cost, disposable printed sensor arrays, Rhodes explained.
"These have colorimetric indicators [73 of them] and each has a different pattern of chemical affinities to different volatiles, which are small molecules, not proteins, but molecules that are released that you can smell in the air, for example," Rhodes said.
In a blood culture tube, or a petri dish, the sensor array allows detection of specific patterns of volatiles released that correspond to a particular organism.
In a proof-of-principle paper published in 2014 in the Journal of Clinical Microbiology, researchers demonstrated that the SpecID method could discriminate between highly similar strains of Staphylococcus aureus, indicating that the metabolomic fingerprints the company detects are not just species-specific but can be strain-specific as well.
More recently, the company published a study in the journal Analyst showing that its colorimetric sensor array could detect the presence of microorganisms not only in blood culture tubes, but also in petri dishes, and continue to do so faster than current methods.
Finally, Specific has a paper that is in press to appear this year in PLOS One in which investigators from the Cleveland Clinic showed that SpecID could also detect yeast infections in blood culture, and ID species faster than current methods.
Under the new collaboration with FIND, the company plans to work on adapting its current technology more specifically to the low-resource setting, as well as developing a plan to manufacture and validate a final version of the SpecID instrument.
Rhodes said more specifically that Specific will undergo a six-month project to add additional organisms that are endemic to low- and middle-income countries to the library of bacterial and fungal organisms it can already detect.
Though he couldn't share details of the financial aspects of the partnership with FIND, Rhodes said that Specific anticipates that this initial support will be one of several awards enabling the company to develop a robust, commercially viable solution for the markets that FIND serves.
He added that Specific plans to share next steps and discuss other ways the collaboration might expand in March.
In addition to its new relationship with FIND, Specific also announced this week that it had won new funding — $2.9 million from the National Institutes of Health — to support research to push its technology beyond diagnosis and speciation — to also include antibiotic susceptibility testing.
The company calls this adaptation SpeciFAST. Though Specific hasn't published on it yet, Rhodes said that it is based on the same technology that underlies its ability to detect blood infections and determine what species or strain is causing them.
Just as signatures of volatile metabolites can specifically distinguish the presence of an infection and the organism causing it, they can also indicate whether the infection is responding to an antibiotic challenge.
"It is a vital last step," Rhodes said, "determining what antibiotic to use."
"If you know its E coli, for example, you might want to use ampicillin or other drugs that are applicable for gram-negative bacteria, but E coli are now developing resistance to ampicillin so you really have to do antibiotic susceptibility testing to be sure."
SpeciFAST begins right after the 12-hour period in which the company's SpecID process identifies the presence of a bacterial infection and the nature of the infecting organism.
"We take some of that sample, dilute it with growth medium, and put it back in [an] incubator, but in a 96-well array, where each [well] has a different amount of a variety of antibiotics," Rhodes said.
"We found that in two and a half hours, we have very robust signature of what antibiotic will work and at what concentration, and it looks like volatile emission is a faster way to read this out than anything else that has been announced as far as we know," he added.
Specific is not the only company hoping to advance rapid sepsis test platforms that can supplant or enhance commonly used culture methods. Genomic and other molecular technologies are also being investigated heavily, most promisingly for diagnosis directly from blood samples without culture — by firms like T2 Biosystems, Roche, and recent startup Qvella, among others.
According to Rhodes, while molecular detection methods can identify infecting organisms, they don't necessarily fit as neatly into standard workflows, or have potential to combine detection, speciation, and antibiotic resistance analysis at as low a cost as Specific believes it can achieve with SpecID.
"People who do PCR or even whole genome-based assessment of pathogens will tell you that to choose the antibiotic to treat patients you can't rely on that. You still have to test antibiotic susceptibility directly because there can always be SNPs in a gene that can have effects that are unknown that can change the antibiotic susceptibility," he said.
Moreover, the cost of goods to run blood culture bottles is around $12 per patient, so molecular platforms that might have exponentially higher costs are going to be a hard sell, especially for developing world settings, he added.
"We check all those boxes in a way that, at least as far as I am aware, is unique," Rhodes said.