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The BD Max CT/GC/TV (MAX) assay is a true multiplex assay for simultaneous detection of chlamydia (CT), gonorrhea (GC), and trichomonas (TV). We evaluated assay performance for women using endocervical and vaginal swabs as well as urine specimens. A total of 1,143 women were tested for CT, GC, and TV and, subsequently, another 847 (1,990 total women) for CT and GC only, with positivity rates for CT, GC, and TV of 7.1%, 2.3%, and 13.5%, respectively. In men, the performance for CT and GC was determined using only urine specimens. TV performance was not assessed in male urine samples. Among men, 181/830 (21.8%) and 108/840 (12.9%) chlamydia and gonorrhea infections, respectively, were identified. Comparator assays included BD ProbeTec Chlamydia trachomatis Q x (CTQ)/ Neisseria gonorrhoeae Q x (GCQ), Hologic Aptima Combo 2 (AC2) and Aptima TV (ATV), trichomonas microscopy, and culture. MAX CT sensitivity was 99.3% (95% confidence interval [CI], 96.1% to 99.9%), 95.7% (90.8% to 98.0%), 91.5% (85.8% to 95.1%), and 96.1% (92.2% to 98.1%) for vaginal swabs, endocervical swabs, female urine samples, and male urine samples, respectively. MAX GC sensitivity was 95.5% (84.9% to 98.7%), 95.5% (84.9% to 98.7%), 95.7% (85.5% to 99.8%), and 99.1% (94.9% to 99.8%) in the same order. MAX TV sensitivity was 96.1% (91.7% to 98.2%) for vaginal swabs, 93.4% (88.3% to 96.4%) for endocervical swabs, and 92.9% (87.8% to 96.0%) for female urine samples. Specificity for all organisms across all sample types was ≥98.6%. Performance estimates for the MAX assays were consistent with estimates calculated for the comparator assays (all P values were >0.1). The availability of a CT/GC/TV multiplexed assay on a benchtop instrument with a broad menu has the potential to facilitate local sexually transmitted infection (STI) testing at smaller laboratories and may encourage expanded screening for these highly prevalent infections.

This study evaluated the performance of the BD ProbeTec Chlamydia trachomatis Q (CTQ) Amplified DNA Assay on the BD Viper System with XTR Technology in a multicenter study.Specimens were collected at 7 geographically diverse clinical sites from 1538 women and men attending sexually transmitted disease, family planning, and obstetrics and gynecology clinics. There were 1465 evaluable participants, 993 women and 472 men. CTQ assay results from female endocervical, self-collected vaginal, male urethral swab specimens, and male and female neat (unpreserved) urine specimens as well as those obtained using the Urine Preservative Transport (UPT) tube for the CTQ assay were compared with patient-infected status (PIS). PIS was determined based on the combined results from Aptima Combo 2 and BD ProbeTec ET CT Amplified DNA Assay.The sensitivity versus PIS for endocervical, vaginal, and both female urine samples was 91.3%, 96.5%, and 93.0%, respectively. The specificity for the same specimen types was 98.3%, 99.2%, and 99.4% (urine neat) and 99.2% (UPT), respectively. The sensitivity versus PIS for male urethral swabs and both male neat and UPT urine were 92.1% and 98%, respectively, with specificities of 98.4%, 99.2%, and 98.1%, respectively.The CTQ assay demonstrated performance characteristics comparable with other commercially available nucleic acid-based tests such as Aptima Combo 2 and BD ProbeTec ET CT-Amplified DNA assay. Vaginal swabs and male urine specimens, the sample types recommended by the Centers for Disease Control for chlamydia screening, both performed at least as well as other sample types evaluated.

Background Detection of antigen in BAL is useful for diagnosis of histoplasmosis. The MVista Histoplasma antigen enzyme immunoassay has been modified to permit quantification. The purpose of this study is to compare the sensitivity of the quantitative antigen detection assay with cytopathology and culture of BAL specimens. Methods BAL from patients with histoplasmosis who were evaluated at the Indiana University Medical Center and controls without histoplasmosis were studied. BAL fluid was tested in the quantitative Histoplasma antigen assay. Results Antigen was detected in the BAL in 93.5% of patients with histoplasmosis, 80% with blastomycosis, and 0% of controls with nonfungal infections. Antigen was detected in the urine of 79% and serum in 65% of patients with histoplasmosis. Cytopathology was positive in 48% and culture in 48% of patients with histoplasmosis, and 40% and 60% of patients with blastomycosis, respectively. Serology was positive in 65%. Combining BAL antigen detection and BAL cytopathology, both methods for rapid diagnosis, the sensitivity was 96.8% in histoplasmosis and 80% in blastomycosis. Conclusions Detection of antigen in BAL complements antigen detection in serum and urine as an objective diagnostic test for histoplasmosis.

The first U.S. multicenter clinical trial to assess the performance of the Cepheid Xpert MRSA assay (Xpert MRSA) was conducted. The assay is a qualitative test designed for the rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) directly from nares swabs. This novel test combines integrated nucleic acid extraction and automated real-time PCR for the detection of a MRSA-specific signature sequence. A total of 1,077 nares specimens were collected from seven geographically distinct health care sites across the United States with prevalence rates ranging from 5.2% to 44%. Nares specimens were tested by (i) the Xpert MRSA assay, (ii) direct culture on CHROMagar MRSA medium (direct CM culture), and (iii) broth-enriched culture (Trypticase soy broth with 6.5% sodium chloride) followed by plating onto CHROMagar MRSA medium (broth-enriched CM culture). When direct CM culture was designated the reference method, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the Xpert MRSA assay were 94.3%, 93.2%, 73.0%, and 98.8%, respectively. When broth-enriched CM culture was used as the reference method, the clinical sensitivity, specificity, PPV, and NPV of the Xpert MRSA assay were 86.3%, 94.9%, 80.5%, and 96.6%, respectively. The BD GeneOhm MRSA (BDGO) assay was performed as a comparative molecular method. No statistical performance differences were observed between the Xpert MRSA and BDGO assays when they were compared to culture methods. From this large-scale, multicenter clinical comparison, we conclude that the Xpert MRSA assay is a simple, rapid, and accurate method for performing active surveillance for MRSA in a variety of health care populations.

A multicenter preclinical evaluation was conducted to evaluate the performance of two Cepheid Xpert assays for detection of methicillin-resistant Staphylococcus aureus (MRSA) and S. aureus . Sensitivity was 97.1% and 98.3% for MRSA in wound and blood culture specimens, respectively. Sensitivity was 100% for S. aureus from both specimen types.

SummaryAntigen detection is a useful adjunct for the diagnosis of histoplasmosis. The purpose of this study was to evaluate antigen detection in bronchoalveolar lavage (BAL) fluid using an improved second-generation Histoplasma antigen assay. Antigen was detected in 16 of 19 (84%) cases of histoplasmosis and 5 of 6 (83.3%) blastomycosis cases using the second-generation assay vs. 13 of 19 (68%) and 4 of 6 (66.7%), respectively, in the original assay. Ten-fold concentration permitted detection of antigen in an additional case of histoplasmosis and another with blastomycosis, for an overall sensitivity of 23 of 25 (92.0%). Specificity was 98.2% in both assays in controls with other pulmonary infections. These findings support the diagnostic utility of the second-generation assay in patients with pulmonary histoplasmosis and blastomycosis.

OBJECTIVE: To compare the Affirm VPIII Microbial Identification Test for detection and identification of Candida species, Gardnerella vaginalis and Trichomonas vaginalis to clinical and microscopic criteria commonly used to diagnose vaginitis. METHODS: Women that were symptomatic for vaginitis/vaginosis and asymptomatic women being seen for routine obstetric or gynecological care were included in this study. Women treated with antibiotics or antifungals within one week or women who had douched within 24 hours were excluded. Two vaginal swab specimens were simultaneously obtained from each patient, one swab was placed in sterile physiological saline for immediate microscopic wet mount examination and KOH testing. The other swab was placed in the Affirm collection tube for Affirm VPIII testing based on previously demonstrated methods. RESULTS: The Affirm assay was significantly more likely to identify Gardnerella and Candida than wet mount. 190 (45%) were positive for Gardnerella by Affirm compared to 58 (14%) by wet mount; 45 (11%) were positive for Candida by Affirm compared to 31 (7%) by wet mount; and 30 (7%) were positive for Trichomonas by Affirm compared to 23 (5%) by wet mount. Symptomatic women were significantly more likely to be positive by Affirm only (23% vs. 10%), wet mount only (3% vs. 2%) or Affirm and wet mount (15% vs. 1%). Asymptomatic women were significantly more likely to be negative for Affirm and wet mount (43% vs. 5%). CONCLUSIONS: The Affirm VPIII test is a more sensitive diagnostic test for detection and identification of symptomatic vaginitis/vaginosis than conventional clinical examination and wet mount testing.

Trichomonas vaginalis is the most prevalent nonviral sexually transmitted infection worldwide, and improved diagnostic methods are critical for controlling this pathogen. Diagnostic assays that can be used in conjunction with routine chlamydia/gonorrhea nucleic acid-based screening are likely to have the most impact on disease control. Here we describe the performance of the new BD T. vaginalis Q x (TVQ) amplified DNA assay, which can be performed on the automated BD Viper system. We focus on data from vaginal swab samples, since this is the specimen type routinely used for traditional trichomonas testing and the recommended specimen type for chlamydia/gonorrhea screening. Vaginal swabs were obtained from women attending sexually transmitted disease or family planning clinics at 7 sites. Patient-collected vaginal swabs were tested by the TVQ assay, and the Aptima T. vaginalis (ATV) assay was performed using clinician-collected vaginal swabs. Additional clinician-collected vaginal swabs were used for the wet mount and culture methods. Analyses included comparisons versus the patient infection status (PIS) defined by positive results with the wet mount method or culture, direct comparisons assessed with κ scores, and latent class analysis (LCA) as an unbiased estimator of test accuracy. Data from 838 women, 116 of whom were infected with T. vaginalis , were analyzed. The TVQ assay sensitivity and specificity estimates based on the PIS were 98.3% and 99.0%, respectively. The TVQ assay was similar to the ATV assay (κ = 0.938) in direct analysis. LCA estimated the TVQ sensitivity and specificity as 98.3 and 99.6%, respectively. The TVQ assay performed well using self-collected vaginal swabs, the optimal sample type, as recommended by the CDC for chlamydia/gonorrhea screening among women.

Chemiluminescent DNA probes (AccuProbe, species specific; and FlashTrack, bacterial generic) were used to determine oxacillin resistance in Staphylococcus aureus . Ribosomal RNA was measured at designated intervals in the presence and absence of antibiotic. A total of 48 (AccuProbe assay) and 24 (FlashTrack) S. aureus isolates with known oxacillin susceptibility patterns were inoculated into Bactec 6A bottles both with and without 4 μg/ml oxacillin and incubated at 35°C for 4 h. Aliquots were removed at 0 and 4 h, and pellets of bacteria were obtained via selective centrifugation. Probe assay counts (relative light units, RLUs) were performed. Of 21 oxacillin-resistant S. aureus (ORSA) strains, 20 showed a >5-fold RLU increase during the incubation period (AccuProbe assay): 25 of 27 oxacillin-susceptible strains demonstrated a ⩽4-fold increase. AccuProbe test sensitivity and specificity were 95% and 92%, respectively. With the generic FlashTrack probe assay, all nine ORSA isolates showed a ⩾4-to 10-fold increase in RLUs, and all 15 oxacillin-susceptible strains showed a ⩽4-fold increase in RLUs during the 4-h incubation. The FlashTrack test sensitivity and specificity were both 100%. Probe assays were completed within 5 h. This study suggests that rapid and reliable determination of oxacillin resistance in S. aureus clinical isolates can be accomplished using commercially available DNA probes.

The objective of this study was to measure the performance of the Affirm Ambient Temperature Transport System (ATTS) over time and to estimate the length of time the system can preserve a vaginal specimen containing the three common organisms causing vaginitis: Trichomonas vaginalis , Candida species, and Gardnerella vaginalis (one of the causative agents of bacterial vaginosis). Women with symptoms of vaginitis presenting to one of three clinical centers were evaluated over a 4- to 8-week period. Four simultaneously obtained swabs were collected and tested by the Affirm VPIII assay at time zero with and without a preservative reagent, at 24 h with reagent, and at either 48 or 72 h with reagent. For each of the three organisms, Trichomonas , Gardnerella , and Candida , positivity at each time point was evaluated and compared to that at reference time zero with and without the ATTS. A total of 940 specimens were obtained from the three clinical sites. Eight hundred three were positive for one or more of the three organisms. Gardnerella had the highest overall positive rate (62%), followed by Candida with 18% and Trichomonas at 9%. The percent sensitivity versus control for Trichomonas ranged from 100% at time zero with and without reagent to 91% by 72 h. Gardnerella and Candida sensitivity remained at 100% for each time period. The Affirm VPIII ATTS system performed within 10% of the control swab (no transport reagent) at all four time points (0, 24, 48, and 72 h) for Trichomonas , Gardnerella , and Candida .