Description:
Executive Summary
Infectious disease researchers at the University of Virginia have developed quantitative multiplex RT-PCR assays for the major viral, bacterial, protozoan and helminthes causes of infectious gastroenteritis.
Background
Infectious gastroenteritis, or the “stomach flu,” results in acute diarrhea, vomiting and abdominal pain. In the United States, an estimated 211–375 million episodes of diarrheal illness occur each year, resulting in 73 million physician consultations, 1.8 million hospitalizations and 3,100 deaths. The economic costs of infectious diarrheal diseases are considerable, and each year an estimated $6 billion is spent in the U.S. on medical care and lost productivity.
When diagnosing infectious gastroenteritis, conventional diagnostic methods — such as culture, biochemical tests, PCR and ELISA — can be laborious, expensive and insensitive. Additionally, although infection with multiple pathogens is common, existing diagnostic methods are typically ordered and performed for individual pathogens, such that these individual assays may routinely miss the diversity of infecting organisms.
About the Invention
The four multiplex RT-PCR panels listed below are capable of rapid, specific, sensitive and quantitative detection of the viral, bacterial and parasitic pathogens most commonly responsible for causing gasteroenteritis.
| Pathogen |
Sensitivity |
Specificity |
| Viruses |
|
|
| Norovirus GI |
100% |
94% |
| Norovirus GII |
95% |
100% |
| Rotavirus |
100% |
97% |
| Astrovirus |
100% |
100% |
| Sapovirus |
100% |
88% |
| Adenovirus |
100% |
100% |
| Bacteria |
|
|
| Aeromonas species |
89% |
87% |
| Campylobacter jejuni and coli |
92% |
92% |
| Salmonella species |
96% |
94% |
| Shigella species and EIEC |
94% |
93% |
| Vibrio cholera and parahaemolyticus |
92% |
96% |
| Yersinia species |
100% |
100% |
| Protozoa |
|
|
| Giardia intestinalis |
89% |
97% |
| Cryptosporidium spp. |
90% |
100% |
| Entamoeba histolytica |
86% |
98% |
| Helminth |
|
|
| Ancylostoma duodenale |
100% |
99% |
| Ascaris lumbricoides |
100% |
100% |
| Necator americanus |
90% |
95% |
| Strongyloides stercoralis |
100% |
97% |
The limit of detection of the multiplex RT-PCR-Luminex assay correlates to 102–104 viral copies/g of stool; 103-105 bacterial cfu/g of stool; 103 Giardia cysts, 102 Cryptosporidium oocysts and 101 E. histolytica trophozoites/200mg stool; and 10−4, 10−6, 10−6 and 10−4 dilutions of confirmed samples, respectively, of Ancylostoma, Ascaris, Necator,and Strongyloides.
Advantages
This technology offers the following advantages over existing technologies:
- Simultaneously identifies and quantifies infections by multiple pathogens
- Allows assay directly from fecal samples
- Offers comparable reliability to the gold standard assay
- Completes testing in under six hours
Resources
For more information, please see the following inventor publications:
- J Clin Virol. “Multiplex reverse transcription PCR Luminex assay for detection and quantitation of viral agents of gastroenteritis.” 2011 Apr;50(4):308-13. (Available online.)
- Am J Trop Med Hyg. “High throughput multiplex PCR and probe-based detection with Luminex beads for seven intestinal parasites.” 2011 Feb;84(2):332-7. (Available online.)
