Self-collected swabs of the urinary meatus diagnose more Chlamydia trachomatis and Neisseria gonorrhoeae infections than first catch urine from men.

OBJECTIVES: To compare first catch urine (FCU) and self-collected urinary meatal swabs for the detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) using the APTIMA Combo 2 assay. METHODS: A total of 511 young men from a high risk street youth clinic were studied. Group A (n=293) collected a FCU and a meatal APTIMA swab followed by Group B (n=218) who collected a FCU and two meatal samples using an APTIMA swab and a flocked swab. Order of sample collection was alternated. Individuals in Group B rated collection as easy, difficult or neither, then expressed a preference for sampling and swab type. All subjects performed meatal self-collection in the presence of a study monitor. RESULTS: The combined CT prevalence was 7.8% and 2.7% for NG where 80% of the men were without symptoms. Meatal swabbing identified 35 cases of CT and 14 cases of NG compared to 33 and 11 for FCU. Flocked and APTIMA swabs were equally effective in detecting more cases. The majority of men found self-collection of meatal swabs and urine to be easy. Although 63% preferred urine sampling, 60% of those who preferred swabbing selected the flocked swab. CONCLUSIONS: Collection of meatal swabs could serve as an alternative to urethral swabbing and FCU for the detection of CT and NG.

Comparison of dacron and nylon-flocked self-collected vaginal swabs and urine for the detection of Trichomonas vaginalis using analyte-specific reagents in a transcription-mediated amplification assay.

OBJECTIVES: To compare self-collected vaginal swab (SCVS) types and first-catch urine (FCU) to diagnose Trichomonas vaginalis using analyte-specific reagents designed to be used in a transcription-mediated amplification assay. METHODS: A total of 241 women (group A) collected a FCU and a SCVS using a dacron swab (APTIMA collection kit). A second group of 289 women (group B) collected two SCVS using one dacron swab and one nylon-flocked swab. RESULTS: Of 75 young women (street youth) determined to be infected with T vaginalis only seven reported symptoms of vaginal discharge or irritation. Using a cutoff of 50,000 relative light units, the sensitivity and specificity was 97.2% and 97.6%, respectively for dacron SCVS compared with 41.7% and 100% for FCU in group A; 92.3% and 98.8% for dacron SCVS and 92.3% and 99.2% for flocked-nylon SCVS in group B. The assay tested 96 samples in 6 h. CONCLUSIONS: Dacron and nylon-flocked SCVS performed equally well and significantly better than FCU using analyte-specific reagents in the APTIMA transcription-mediated amplification assay. Either swab type could be used for self-collection.

Comparative evaluation of AMPLICOR HPV PCR and Linear Array assays on SurePath liquid-based Pap samples for the detection of high-risk HPV genotypes.

BACKGROUND: Persistent cervical infection with high-risk [HR] HPV is a causative factor for cancer. Liquid-based [L-Pap] Pap samples are convenient for HPV testing and SurePath samples have been least studied. Most HPV tests have multiple step protocols and testing laboratories experience large volumes of samples. OBJECTIVES: Using SurePath L-Pap residual samples the objectives were as follows: [1] to test the performance of AMP-HPV and LA-HPV. [2] To perform an agreement study between two laboratories for the AMP-HPV test and [3] to compare agreement of results between AMP-HPV and LA-HPV and HC2. STUDY DESIGN: Samples from 657 women were tested for Pap cytology then assayed for HR-HPV using AMP-HPV and LA-HPV tests. AMP-HPV performance was compared between 2 laboratories and agreement studies were conducted between AMP-HPV, LA-HPV and HC2. RESULTS: HR-HPV genotypes were associated with L-Pap readings as follows: HSIL 92% [23/25], LSIL 73.6% [162/220], ASCUS 70.4% [131/186], normal 31.9% [72/226]. More women less than 30 were infected with HR-HPV and multiple genotypes regardless of the L-Pap reading. AMP-HPV and LA-HPV testing had an overall raw agreement with each other of 84.2% [Kappa 0.66] and each had agreement of 94% with HC2 testing of 133 samples [Kappa 0.86/0.87]. AMP-HPV agreement between two laboratories was better at 93% [Kappa 0.84] compared to 76.1% [Kappa 0.40] when extraction was standardized. CONCLUSION: It is feasible to perform AMP-HPV and LA-HPV on SurePath samples to detect HR-HPV genotypes. HC2, AMP-HPV and LA-HPV showed strong agreement. The extraction component of the AMP-HPV assay needs careful attention to yield consistent results.

The peptidoglycan-binding protein FimV promotes assembly of the Pseudomonas aeruginosa type IV pilus secretin.

The Pseudomonas aeruginosa inner membrane protein FimV is among several proteins of unknown function required for type IV pilus-mediated twitching motility, arising from extension and retraction of pili from their site of assembly in the inner membrane. The pili transit the periplasm and peptidoglycan (PG) layer, ultimately exiting the cell through the PilQ secretin. Although fimV mutants are nonmotile, they are susceptible to killing by pilus-specific bacteriophage, a hallmark of retractable surface pili. Here we show that levels of recoverable surface pili were markedly decreased in fimV pilT retraction-deficient mutants compared with levels in the pilT control, demonstrating that FimV acts at the level of pilus assembly. Levels of inner membrane assembly subcomplex proteins PilM/N/O/P were decreased in fimV mutants, but supplementation of these components in trans did not restore pilus assembly or motility. Loss of FimV dramatically reduced the levels of the PilQ secretin multimer through which pili exit the cell, in part due to decreased levels of PilQ monomers, while PilF pilotin levels were unchanged. Expression of pilQ in trans in the wild type or fimV mutants increased total PilQ monomer levels but did not alter secretin multimer levels or motility. PG pulldown assays showed that the N terminus of FimV bound PG in a LysM motif-dependent manner, and a mutant with an in-frame chromosomal deletion of the LysM motif had reduced motility, secretin levels, and surface piliation. Together, our data show that FimV's role in pilus assembly is to promote secretin formation and that this function depends upon its PG-binding domain.

Validation of the APTIMA Combo 2 assay for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae in SurePath liquid-based pap test samples taken with different collection devices.

Mocked samples of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) diluted in SurePath liquid-based Pap (L-Pap) fluid were detected by the APTIMA Combo 2 assay to end points 10-fold greater than dilutions in specimen transport media. Pooled L-Pap clinical specimens yielded CT-positive results after storage at room temperature for 10 days. Based on an infected patient standard for comparison, cervical swabs, urine, and SurePath L-Pap test samples collected with a SurePath cervical broom or ThinPrep cytobrush from 520 women then tested by APTIMA Combo 2 assay, detected 25 (4.8%) with CT, 5 (1.0%) with (GC), and 3 (0.6%) with both. Percent sensitivities (80-84), specificities (99.8-100), positive (99.5-100) and negative (99.2-99) predictive values of SurePath L-Pap for CT were validated as similar to those reported in a previously published multicenter trial. All values for GC were 100%. One collection device was not significantly better than the other.

Comparison of the RIDASCREEN norovirus enzyme immunoassay to IDEIA NLV GI/GII by testing stools also assayed by RT-PCR and electron microscopy.

RIDASCREEN norovirus enzyme immunoassay (EIA) detected 80.3% of norovirus-infected feces samples compared to 60.6% by IDEIA NLV GI/GII from 228 patients with no false positives by either assay. RT-PCR and electron microscopy percent sensitivity and specificity were 98.5, 100 and 36.4 and 96.9, respectively.

High analytical sensitivity and low rates of inhibition may contribute to detection of Chlamydia trachomatis in significantly more women by the APTIMA Combo 2 assay.

The clinical sensitivity of nucleic acid amplification tests may be determined by analytical sensitivity and inhibitors in patient samples. We established endpoints for detection of propagated Chlamydia trachomatis L2 434, diluted according to swab and urine protocols for APTIMA Combo 2 (AC2), ProbeTec ET (PT), and Amplicor (AMP) assays. AC2 was 1,000-fold more sensitive than PT and 10-fold more sensitive than AMP on mock swab specimens. For urine, AC2 analytical sensitivity was 100-fold greater than those of the other assays. Spiking an aliquot of each clinical-trial sample from 298 women demonstrated inhibition rates in first-void urine (FVU), cervical swabs (CS), and vaginal swabs (VS) of 12.1%, 12.8%, and 10.4% for AMP; 27.2%, 2%, and 2%, for PT; and 0.3%, 1.7%, and 1.3% for AC2. Inhibition of our C. trachomatis spike and the PT or AMP amplification controls from the manufacturers showed less than 50% correlation. Using an infected-patient reference standard (a specimen positive in at least two tests or a single test positive in two of three samples) in AC2, the VS identified 68/69 (98.6%) infected women compared to CS (89.9%) or FVU (81.2%). Significantly fewer women were identified by PT (65.2%, 63.8%, and 66.7%) or AMP (65.2%, 59.4%, and 56.5%) with the three specimens. By individual specimen type, AC2 confirmed virtually all PT- and AMP-positive specimens, but rates of AC2 confirmation by AMP or PT ranged from 62.9 to 80.3%. The AC2 test identified significantly more women infected with C. trachomatis (P = 0.001). Vaginal swabs appear to be the specimen of choice for screening.