Lateral flow assay for detecting colonization by Streptococcus agalactiae

DESCRIPTION (provided by applicant): Streptococcus agalactiae, a.k.a. group B streptococcus (GBS), is one of the leading causes of morbidity, and mortality among newborns. We propose to develop a molecular assay for GBS using our proprietary helicase depe ndent amplification (HDA), and a lateral flow strip embedded in a device that encloses the reaction vessel to prevent contamination of the laboratory by amplicons. HDA is similar to the polymerase chain reaction (PCR) in that it uses two primers to exponen tially amplify nucleic acids. Like PCR, HDA assays can use a competitive internal control; i.e., a template DNA of known concentration spiked into the raw sample that can be amplified by the same primers as the analyte, but detected separately. Unlike PCR, HDA is entirely isothermal, and thus does not require costly thermocyclers. In fact we routinely use water baths to perform assays. The objectives for Phase I are to: 1) Validate the sensitivity and specificity of the assay with a panel of DNA samples fro m near neighbor strains, as well as strains commonly found in the sampling sites. 2) Evaluate the performance of the filtration sample preparation method proposed in the body with clinical specimens from Dr. Gary Procop, University of Miami Medical Center (UMMC). 3) Develop a clinical plan and a pre-IDE for review by the Food and Drug Administration (FDA) for a multi-site clinical study to seek regulatory clearance for sale of the assay for human diagnostics. The milestone for this Phase I is to deliver a p re-IDE to FDA. Comments from FDA will be used to design a clinical study during Phase II. We believe our proposed assay system can obtained the moderate degree of complexity designation from the FDA. Indeed, to obtain such a designation, a system manufactu rer must obtain a score of 12 of less when answering 7 questions covering: user knowledge, user training, reagent preparation, operational steps, testing materials, troubleshooting, and result interpretation. The answer to these 7 questions can receive a s core of 1 or 3. We estimate our proposed system could get a score of 11. Considering our assay system will not require costly instrumentation and plastic disposables, we believe we can offer a useful alternative to the Xpert GBS(tm), if we can obtain FDA c learance for our test. Support from NIAID is essential to reaching this goal. PUBLIC HEALTH RELEVANCE: Group B streptococcus (GBS) infection of newborns usually takes place in the birth canal and can lead to sepsis, pneumonia, and meningitis. GBS infecti on of neonates is estimated to cost roughly 300 million in additional healthcare costs. The current standard of care is to screen all women at 35 to 37 weeks of gestation, and to eradicate GBS in colonized women. Despite this aggressive approach, invasi ve early-onset disease incidence has only declined by 34% in the US. Risk factors for early-onset invasive GBS in the newborns are: rupture of membranes more than 18 h before delivery, a febrile mother during labor, preterm delivery, and a history of GBS d isease in a previous delivery. Current practice it to prescribe prophylactic antibiotics to mothers with the aforementioned risk profile, even in the absence of evidence of colonization by GBS. Premature rupture of membranes (PROM) occurs in approximately one third of preterm births and it increases the potential for perinatal infection because of its association with brief latency between membrane rupture, and delivery. Preterm pregnancies only represent 7% to 11% of births, but account for 32% to 38% of e arly-onset GBS disease because the mother was not tested prior to labor. CDC estimates that there are 500,000 pre-term births, and 143,000 births from mothers that received no pre-natal care in the United States. When culture is performed at the time of de livery, it seldom provides a sufficiently rapid turnaround time to influence the decision of whether or not to initiate antimicrobial therapy. A rapid test is