A Fully Automated Multiplex Assay for Diagnosis of Lyme Disease with High Specificity and Improved Early Sensitivity.

Lyme borreliosis is a tick-borne disease caused by the Borrelia burgdorferisensu lato complex. Bio-Rad Laboratories has developed a fully automated multiplex bead-based assay for the detection of IgM and IgG antibodies to B. burgdorferi The BioPlex 2200 Lyme Total assay exhibits an improved rate of seropositivity in patients with early Lyme infection. Asymptomatic subjects from endemic and nonendemic origins demonstrated a seroreactivity rate of approximately 4% that was similar to other commercial assays evaluated in this study. Coupled to this result was the observation that the Lyme Total assay retained a high first-tier specificity of 96% while demonstrating a relatively high sensitivity of 91% among a well-characterized CDC Premarketing Lyme serum panel. The Lyme Total assay also performs well under a modified two-tier algorithm (sensitivity, 84.4 to 88.9%; specificity, 98.4 to 99.5%). Furthermore, the new assay is able to readily detect early Lyme infection in patient samples from outside North America.

Environmental monitoring for biological threat agents using the autonomous pathogen detection system with multiplexed polymerase chain reaction.

We have developed and field-tested a now operational civilian biodefense capability that continuously monitors the air in high-risk locations for biological threat agents. This stand-alone instrument, called the Autonomous Pathogen Detection System (APDS), collects and selectively concentrates particles from the air into liquid samples and analyzes the samples using multiplexed PCR amplification coupled with microsphere array detection. During laboratory testing, we evaluated the APDS instrument's response to Bacillus anthracis and Yersinia pestis by spiking the liquid sample stream with viable spores and cells, bead-beaten lysates, and purified DNA extracts. APDS results were also compared to a manual real-time PCR method. Field data acquired during 74 days of continuous operation at a mass-transit subway station are presented to demonstrate the specificity and reliability of the APDS. The U.S. Department of Homeland Security recently selected the APDS reported herein as the first autonomous detector component of their BioWatch antiterrorism program. This sophisticated field-deployed surveillance capability now generates actionable data in one-tenth the time of manual filter collection and analysis.

Linked linear amplification for simultaneous analysis of the two most common hemochromatosis mutations.

BACKGROUND: Two mutations in HFE, G845A (amino acid substitution C282Y) and C187G (H63D), are associated with hereditary hemochromatosis. We developed and validated a novel method, linked linear amplification (LLA), for detection of these two mutations. METHODS: Two segments of HFE were amplified by a multiplex LLA reaction that generated biotinylated LLA products. Aliquots of the multiplex LLA reaction were captured in microwells by hybridization to immobilized allele-specific oligonucleotides (ASOs). One wild-type and one mutant ASO represented the DNA sequence at each of the two mutation sites. Hybridization was detected by a streptavidin-horseradish peroxidase-based colorimetric method. Genotypes obtained by LLA and PCR-restriction fragment length polymorphism (PCR-RFLP) methods for 320 individuals were compared. RESULTS: The amplified samples included the following genotypes as determined by PCR-RFLP: wild-type 282 and 63 codons (n = 105), C282Y homozygous mutant (n = 54), C282Y heterozygous (n = 52), H63D homozygous mutant (n = 17), H63D heterozygous (n = 59), and compound H63D and C282Y heterozygous mutant (n = 33). There was complete concordance between the results obtained by LLA and those obtained by PCR-RFLP analysis. The presence of another HFE mutation, A193T (encoding S65C), did not interfere with genotyping at codon 63. CONCLUSIONS: LLA provides a reliable method to detect the common mutations in HFE that cause hereditary hemochromatosis.