Multicenter Clinical Evaluation of the Automated Aries Bordetella Assay

Molecular methods offer superior sensitivity and specificity and reduce testing turnaround time from days to hours for detection of Bordetella pertussis and Bordetella parapertussis In this study, we evaluated the performance of the automated PCR-based Aries Bordetella Assay, which detects both B. pertussis and B. parapertussis directly from nasopharyngeal swab specimens. The limits of detection (LoDs) were 1,800 CFU·ml-1 for B. pertussis and 213 CFU·ml-1 for B. parapertussis The assay detected 16/18 unique B. pertussis/B. parapertussis strains. Of 71 potentially cross-reacting organisms, 5 generated false positives in 1/6 replicates; none of 6 additional Bordetella spp. were erroneously detected. Specimens were stable at 20 to 25°C for at least 10 h, at 4 to 8°C for 10 days, and at temperatures not exceeding -70°C for 6 months. Of 1,052 nasopharyngeal specimens from patients with suspected pertussis, 3.0% (n = 32) were B. pertussis positive and 0.2% (n = 2) were B. parapertussis positive. Combining these data with Aries Bordetella Assay data from 57 nasopharyngeal samples with previously confirmed B. pertussis or B. parapertussis data and with data from 50 contrived B. parapertussis samples, the proportions of positive and negative agreement of the respective Aries assays with the reference assays were 97.1% and 99.0% for B. pertussis and 100% and 99.7% for B. parapertussis The Aries Bordetella Assay provides accurate detection and distinction of B. pertussis and B. parapertussis infections within 2 h. (This study has been registered at ClinicalTrials.gov under registration no. NCT02862262.)

Smallpox: Residual Antibody after Vaccination

Of all the microorganisms and toxins, poxviruses (Orthopoxvirus) have the greatest potential for use by terrorists. These viruses can spread rapidly through the environment following initial infection. In 1980, the World Health Organization Eradication Program discontinued vaccination for smallpox and declared that the disease had been eliminated. With the threat of smallpox virus as a bioterrorism weapon, questions have been asked about the persistence of protection (as offered by antibodies) following vaccination with vaccinia virus vaccine. To address this, sera from 204 adults vaccinated as children were tested by enzyme immunoassay (EIA) for the presence of vaccinia virus antibody. Of the 204 individuals whose sera were examined for the presence of vaccinia antibody, 165 (80.9%) had been vaccinated once and 39 (19.1%) had been vaccinated at least twice. Of the 165 sera from individuals vaccinated once, 112 (67.9%) were positive. Of the 39 sera from individuals vaccinated more than once, 31 (79.5%) were positive. The presence of a vaccination scar at the time of blood collection was not determined. Fifty-six nonvaccinated individuals, under 30 years of age, were tested by EIA; four of these (7.1%) were positive for vaccinia virus antibody by EIA. Forty-four EIA-positive and 16 EIA-negative sera were also tested by serum neutralization (SN) as a comparison with the EIA test results; one serum (negative by EIA) was SN positive. No attempt was made to ascertain any demographics other than age (date of birth) and “remembered” times of vaccination

Multicenter Evaluation of Methods To Quantitate Human Immunodeficiency Virus Type 1 RNA in Seminal Plasma

We have evaluated two commercially available kits (AMPLICOR MONITOR [Roche] and NASBA HIV-1 QT or NucliSens HIV-1 QT [Organon Teknika]) and two noncommercial methods for the accurate quantitation of human immunodeficiency virus type 1 (HIV-1) RNA in seminal plasma. The same panels of coded specimens were tested on four separate occasions. Laboratories using the commercial assays employed silica beads to isolate HIV-1 RNA, which removed inhibitory factors sometimes found in seminal plasma. Sensitivities and specificities, respectively, for each assay were as follows: AMPLICOR MONITOR, 100 and 73%; NASBA HIV-1 QT, 84 and 100%; NucliSens HIV-1 QT, 99 and 98%; and noncommercial assays, 91 and 73%. When results from the laboratory that was inexperienced with the silica bead extraction method were excluded from the analysis, specificity for the Roche assay increased to 100%. The commercial assays demonstrated highly reproducible results, with intra-assay standard deviations (measured in log(10) RNA copies/milliliter of seminal plasma) ranging from 0.11 to 0.32; those of the noncommercial assays ranged from 0.12 to 0.75. Differences in mean estimated HIV-1 RNA concentrations were ≤0.67 log(10) and were greater at low viral loads. Suspension matrices that used blood plasma or seminal plasma did not make a difference in recovery of HIV-1 RNA, which suggested that blood plasma specimens can be used as external controls for seminal plasma assays. More variation in the HIV-1 RNA viral loads was observed in the seminal plasma values than in the blood plasma values when paired specimens from HIV-1-infected men were tested. Quantitation of HIV-1 RNA in seminal plasma can be reliably accomplished using two commercially available assays, and may be incorporated into the evaluations of HIV-1 seropositive men enrolled in clinical studies