MBS is seeking a commercial partner to bring a stall side assay for the detection of Strep equi (Strangles) to market. MBS brings validated antibody reagents and years of R&D to the partnership. A review of data from a recent field trial of the antibodies in a lateral flow format makes a compelling case for the utility of the assay for the control of Strangles outbreaks

1. Maine Biotechnology Services, Inc.
2014
Streptococcus equi
“Strangles” Rapid
Stall Side Test
Release of Field Trial Data

2. Maine Biotechnology Services, Inc.
2014
Development of Stall Side Test
 Resulted from multi-directional collaborations
UMO, U-Kentucky, MBS, Diagnostic Innovations
 Address need for rapid identification of
Strangles (+) horses
Enabling Barn Manager to take appropriate
actions days before PCR results available.
 Follow up with confirmatory PCR expected.

3. Maine Biotechnology Services, Inc.
2014
Prototype Rapid Test Developed
 Sensitivity
 Quantitative PCR done on Strep equi culture
 Enabled assessment of sensitivity
 Artificial swabs with known bacterial counts
tested
 Limit of sensitivity ~ 50 CFU (colony forming
units) per strip
 Clinical target: 1000 organisms, as recommended
by Dr. John Timoney University of Kentucky

4. Maine Biotechnology Services, Inc.
2014
Sensitivity:

5. Maine Biotechnology Services, Inc.
2014
Prototype Rapid Test Developed
 Specificity
Bank of Strep equi and Strep zoo clinical
isolates provided by Dr. Causey
Isolates were tested and compared the signal
to the CF32 Strep equi reference strain at 16
cells per strip.

6. Maine Biotechnology Services, Inc.
2014
The data on clinical isolates
supports specificity for Strep
equi with no cross reactivity
to Strep zoo isolates.

7. Test against known CFU of Strep equi.
 UMO provided known concentrations of
Strep equi via the CFU metric
 Provided both bacteria in water and in
saline
 To evaluate possible effect of saline or water
nasal flushes
 Results show detection limit of 50-500
CFU
Limit of detection needed for clinical
application reported to be 1000 CFU
 Dr. John Timoney, University of Kentucky

10. Maine Biotechnology Services, Inc.
2014
Summary:
Specificity metrics show no cross reactivity to the Strep zoo ancestor of
Strep equi subsp. equi
Sensitivity as determined by
 Quantitative PCR
 CFU
 Indicates that the prototype can detect 50-100 CFU

11. Maine Biotechnology Services, Inc.
2014
Nasal Swabs taken from 10 healthy
horses.
 UMO performed nasal swabs (2 per horse) on
10 horses documented as healthy
 Prototype Strep equi test run to validate no cross
reactivity with equine nasal flora
 Negative swabs were spiked to assess
interference with nasal natural flora

12. Maine Biotechnology Services, Inc.
2014
Results
Diagnostic
Innovations

13. Maine Biotechnology Services, Inc.
2014
Summary
 Monoclonal antibodies to Strep equi
 Prototype rapid assay designed
 Strep equi CF32 reference strain Q-PCR
 Strep equi and zoo clinical isolates
specificity.
 Nasal swabs from healthy horses tested
 Spiked nasals swabs tested
 Ready to take the rapid test to the field.

14. Maine Biotechnology Services, Inc.
2014
Test Components
Diagnostic
Innovations

15. Maine Biotechnology Services, Inc.
2014
Clinical Trial, 23 horses in Maine
 December 2013, barn in Cumberland
Maine was stricken with a highly
contagious respiratory disease
 May have been started via purchase of a
yearling in Texas that showed signs of a
mild respiratory illness.
 Attending Veterinarian, Dr. Martha Smith

16. Maine Biotechnology Services, Inc.
2014
Clinical Trial:
Compare PCR to rapid stall side assay
 23 horses dual nasal swabs
1 sent to UC Davis for Quantitative PCR
1 run on Rapid Stall side assay
 Health histories during outbreak recorded.
 Random selection of samples also tested
for Streptococcus zooepidemicus.
 Ancestor of Streptococcus equi. subsp. equi

17. Maine Biotechnology Services, Inc.
2014
Diagnostic Test Metrics:
• Specificity
•refers to the cross reactivity profile of the test
• Sensitivity
•refers to the lowest detectable load of bacteria
• Positive Predictive Value (PPV)
•is the proportion of patients with positive results, who
are correctly diagnosed
• Negative Predictive Value (NPV)
•is the proportion of patients with negative results, who
are correctly diagnosed.

18. Maine Biotechnology Services, Inc.
2014
Results:
Disease + Disease - Total
Test + 5 (TP) 2 (FP) 7 (PPV Denominator)
Test - 0 (FN) 16 (TN) 16 (NPV Denominator)
5 18 23
Positive Predictive Value: TP / (TP + FP) x 100 = 72%
Negative Predictive Value: TN / (TN + FN) x 100 = 100%
Sensitivity: TP / (TP + FN ) x 100 = 100 %
Specificity : TN / (TN + FP) x 100 = 88%
Take away message from this small clinical trial is: The test may have false
positives, but it does not show the propensity for false negatives. It errs on
the side of safety for the barn managers with a 100% NPV and 100%
Sensitivity metric.
Both (–) Strep zoo

19. Maine Biotechnology Services, Inc.
2014
Questions for End User
 How might you incorporate this test in your
practice
 What rapid test attributes are most
important to you? (cost, ease of use, time,
et al..)
 Can you identify any weaknesses for the
commercialization of this test?
 Questions, concerns?