Comparison of Nucleic Acid Amplification Assays with BD Affirm VPIII for Diagnosis of Vaginitis in Symptomatic Women

A commercially available, nonamplified, nucleic acid probe-based test system (BD Affirm VPIII) was compared with nucleic acid amplification (NAA)-based assays for determining the etiology of vaginitis in a cohort of 323 symptomatic women. First, a semiquantitative, multiplexed PCR assay (BV-PCR) and the Affirm VPIII Gardnerellavaginalis test were compared with a unified bacterial-vaginosis (BV) reference standard incorporating both Nugent Gram stain scores and Amsel clinical criteria. In the evaluable population of 305 patients, BV-PCR was 96.9% (191/197) sensitive and 92.6% specific (100/108) for BV, while Affirm VPIII was 90.1% sensitive (179/197) and 67.6% specific (73/108). Second, a multiplexed PCR assay detecting Candida albicans and Candida glabrata (CAN-PCR) was compared with the Affirm VPIII Candida test using a reference standard for vulvovaginal candidiasis (VVC) of yeast culture plus exclusion of alternate vaginitis etiologies. In the population evaluated (n = 102), CAN-PCR was 97.7% sensitive (42/43) and 93.2% specific (55/59) and Affirm VP III was 58.1% sensitive (25/43) and 100% specific (59/59) for VVC. Finally, the results of a commercial NAA test (GenProbe Aptima Trichomonas vaginalis assay; ATV) for T. vaginalis were compared with the Affirm VPIII Trichomonas vaginalis test. In the absence of an independent reference standard for trichomonal vaginitis (TV), a positive result in either assay was deemed to represent true infection. In the evaluable cohort of 388 patients, the sensitivity of ATV was 98.1% (53/54) versus 46.3% (25/54) for Affirm VPIII. The diagnostic accuracy of the combined NAA-based test construct was approximately 20 to 25% higher than that of the Affirm VPIII when modeled in populations with various prevalences of infectious vaginitis.     

ESwab as an Optional Collection Device for Use with the Affirm VPIII Microbial Test System

The ESwab collection device was compared to the collection swab provided as part of the Affirm VPIII microbial identification test kit for testing vaginal specimens with the Affirm test system. There was excellent agreement between the two sampling devices for Candida spp., Gardnerella vaginalis, and Trichomonas vaginalis.     

Comparison of serological tests for detection of antibodies to infectious laryngotracheitis virus

Four serological tests i.e. ELISA, serum neutralisation (SN), fluorescent antibody (FA), and agar gel immunodiffusion (AGID) were compared for sensitivity using several criteria, for detection and titration of infectious laryngotracheitis (ILT) virus antibodies in chicken sera. In the ELISA test, sera were tested in parallel on virus positive and negative control antigens with results expressed as positive-negative difference. Non-specific binding was not a problem in this test. SN tests were performed in microtitre plates using chick embryo liver cells, while sera for FA tests were titrated on multispot slides on which were fixed ILT virus-infected chick embryo liver cell cultures. The AGID test was the standard test still widely used for serological diagnosis of ILT. The four tests were compared using (1) sera from experimentally inoculated birds bled regularly at intervals from 4 to 35 days post-inoculation, (2) convalescent sera from a natural outbreak of ILT, and (3) serial dilutions of an ILT positive serum. In all experiments the ELISA test was of slightly greater sensitivity than SN and was comparable to the FA test. In the experimentally infected birds ELISA and FA test detected sero-conversion in more birds at 7 days than SN. In tests with the serially diluted hyperimmune ILT serum, ELISA, FA and SN tests were comparable. SN however was the most useful test for quantification of ILT antibodies. ILT-SN titres in birds were never high, the highest titre recorded in experimental birds and in convalescent sera was 1/48. AGID was found to be less sensitive than ELISA, FA or SN test but was considered useful for detection of antibodies on a flock basis, since, with the convalescent sera AGID detected a significant proportion of positives.     

Comparison of tests for viable and infectious Cryptosporidium parvum oocysts

The purpose of this study was to compare different assays for viable Cryptosporidium parvum incubated in water at a temperature commonly found in the environment. C. parvum oocysts were stored in sterile water for 9 months at 15 degrees C. A sample was removed monthly and analyzed by five different assays to determine oocyst viability. Mouse infection and cell culture showed that C. parvum oocysts remained viable and infectious when stored for 7 months at this temperature. Fluorescence in situ hybridization (FISH) using probes directed to ribosomal RNA was also applied to these oocysts. The proportion of FISH-positive oocysts was 70-80% for the first 2 months of storage, decreased and remained nearly constant at 40-50% for 3-7 months, then decreased to 20% by 8 months, and to 0% by 9 months. Amylopectin content and mRNA for amyloglucosidase (CPAG), as measured by RT-PCR, decreased much more rapidly. By 3 months and for the remainder of the incubation period, amylopectin content was 20% of the original amount present in the oocysts. The CPAG RT-PCR signal at 3 months was 50% of that observed after 1 month storage, 20% at 4 months, and was not detected thereafter. Thus, results from cell culture and mouse infection assay exhibited the best agreement, the FISH assay showed modest agreement with these assays, and CPAG RT-PCR and the amylopectin assay displayed marginal agreement with the other three assays.     

Cytologic-histologic correlation of screening and diagnostic Papanicolaou tests

The Pap test (PT) is most commonly used as a screening test; however, it is often also used as a "diagnostic test," usually in patients of known or suspected lesions. As we have recently shown that the yield of atypical interpretations in diagnostic Pap tests (DPTs) is nearly five times greater than the yield for screening Pap tests (SPTs), we speculated that the PT might function differently when used in each population. The University of Virginia's cytologic-histologic correlation results for PTs, accessioned between 4 January 2003 and 11 December 2003, were reviewed. PTs were considered as SPTs or DPTs, depending on the billing codes used by referring physicians. Using the original diagnosis, results were compared for SPTs and DPTs using chi-square testing. There were 1,311 PTs (776 DPTs and 535 SPTs), which had histologic follow-up within a 7-mo period. Of SPTs interpreted as negative (242), 11 (4.5%) showed SIL or worse and 3 (1.2%) showed HSIL or worse on follow-up biopsy. Of SPTs interpreted as ASC (133), 59 (44.3%) showed SIL or worse and 16 (12.0%) showed HSIL or worse on follow-up biopsy. Of SPTs interpreted as LSIL (117), 65 (55.5%) showed SIL or worse and 17 (14.5%) showed HSIL or worse on follow-up biopsy. Of SPTs interpreted as HSIL (38), 31 (81.6%) showed SIL or worse and 23 (60.5%) showed HSIL or worse on follow-up biopsy. Of SPTs interpreted as glandular lesions (AGC, adenocarcinoma, etc.) (4), 3 (75%) showed HSIL or malignancy. Of DPTs interpreted as negative (261), 69 (26.4%) showed SIL or worse and 10 (3.8%) showed HSIL or worse on follow-up biopsy. Of DPTs interpreted as ASC (166), 75 (45.2%) showed SIL or worse and 22 (13.3%) showed HSIL or worse on follow-up biopsy. Of DPTs interpreted as LSIL (227), 146 (64.4%) showed SIL or worse and 31 (13.7%) showed HSIL or worse on follow-up biopsy. Of DPTs interpreted as HSIL (119), 105 (87.4%) showed SIL or worse and 84 (70.6%) showed HSIL or worse on follow-up biopsy. Of DPTs interpreted as glandular lesions (AGC, adenocarcinoma, etc.) (3), 3 (100%) showed HSIL or malignancy. Overall, DPTs were more likely than SPTs to show SIL or HSIL on follow-up biopsy (P < 0.01), and negative DPTs were more likely than negative SPTs to show SIL or HSIL on follow-up biopsy (P < 0.01, P = 0.01, respectively). Some of this may be a reflection of the increased percentage of LSIL and HSIL results for DPTs. Despite the difference in disease prevalence between women having SPTs and those having DPTs, the PT seems to function relatively the same in both scenarios, except in high risk women with negative DPTs.     

Possible role of enterotoxigenic Bacteroides fragilis in the etiology of infectious vaginitis

Vaginitis is a common gynecologic disorder. It is due to several causes, some even unknown. Bacteroides fragilis is the most important anaerobe in clinical bacteriology, some strains of this group are notable for being enterotoxigenic and they have been associated with intestinal and extraintestinal syndromes. They have recently been isolated from patients with vaginitis. The purpose of this study was to investigate a possible association of enterotoxigenic B. fragilis with infectious vaginitis. 265 samples of vaginal exudate were processed, 202 from symptomatic patients and 63 healthy women. The identification of the microorganisms was carried out by conventional methods. In 31.2% of symptomatic patients were identified: Gardnerella vaginalis, Mobiluncus, Candida albicans, Mycoplasma hominis, Ureaplasma urealyticum and Streptococcus agalactiae. B. fragilis was identified in 27 symptomatic patients and 5 healthy women. These strains were cultivated in liquid medium and incubated during 48 h at 36 degrees C in anaerobe chambers. Supernatant activity was assayed in HT-29 cells. Eighteen B. fragilis strains isolated from symptomatic patients were enterotoxigenic, because induced alterations in target cell morphology. It was not identified in healthy women (P < 0.05). 77.7% of enterotoxigenic B. fragilis strains were not associated with other specific pathogens. This fact suggests that enterotoxigenic B. fragilis could be a cause for vaginitis. The effect of enterotoxin on E-cadherin of vaginal epithelium could facilitate invasion and its possible pathogenic role in the vagina. This is the first report that associates enterotoxigenic Bacteroides fragilis as a possible cause of infectious vaginitis.     

Comparison of tests for detection of beta-lactamase-producing staphylococci

Penicillin resistance identification tests are important in veterinary medicine. Six enzyme assays and a PCR test were compared for the detection of beta-lactamase production or the beta-lactamase gene in 175 staphylococcal isolates. We conclude that the PCR test and two nitrocefin-based assays can be recommended for routine clinical use.     

Accuracy of herpes simplex virus detection in liquid-based (SurePath) Papanicolaou tests: a comparison with polymerase chain reaction

A review of our institution's Papanicolaou test records over an 11-yr period showed that liquid-based Papanicolaou tests (LBPTs) had a significantly higher frequency of diagnoses of Herpes simplex virus (HSV)-related cellular changes compared to conventional Papanicolaou smears (77/302,841, 0.026% vs. 56/376,173, 0.015%, P = 0.002). To investigate the accuracy of the diagnosis of HSV by LBPT, we performed conventional polymerase chain reaction (PCR) on the residual samples from 258 prospectively collected LBPT and real-time PCR using a different primer set on a subset of 40 LBPT. Conventional PCR was positive in 22 of 22 cases diagnosed of HSV, 1 of 2 cases diagnosed as suspicious for HSV, and none of 234 LBPT without a cytologic HSV diagnosis. Real-time PCR was positive in 8 of 8 cases diagnosed as HSV and none of the 32 controls. We conclude that LBPT allows an increased detection of HSV that is highly accurate.     

Comparison of three stool antigen tests for Helicobacter pylori detection

BACKGROUND: Active Helicobacter pylori infection can be diagnosed by invasive (biopsy based) or non-invasive methods, such as stool antigen testing. AIMS: To compare three stool antigen enzyme immunoassay kits--Premier Platinum Hp SA, FemtoLab Cnx, and Hp Ag--with biopsy based methods for the detection of H pylori in previously undiagnosed patients. METHODS: One hundred and eleven adults with dyspepsia referred for endoscopy provided a stool sample for testing and had biopsies taken. Patients were considered H pylori positive if two out of three invasive tests were positive or if culture alone was positive. RESULTS: The sensitivities and specificities of the Premier Platinum Hp SA, FemtoLab Cnx, and Hp Ag stool antigen kits when compared with biopsy based diagnosis were, 63.6%, 88.0%, and 56.0% and 92.6%, 97.6%, and 97.6%, respectively. CONCLUSIONS: FemtoLab Cnx may be considered as an alternative to urea breath testing in the initial diagnosis of patients with dyspepsia who do not require immediate endoscopy. Stool testing has the potential advantages of being simple to perform, relatively cheap, and samples can be submitted directly from primary care.     

Comparison of lymphocyte transformation and macrophage migration inhibition tests in the detection of beryllium hypersensitivity.

In seven patients with chronic beryllium disease (Be) the Be lymphocyte transformation test was positive in 100%, independent of steroid therapy, and was reproducible. The Be macrophage migration inhibition test was only positive in four of seven patients (57%) not on steroids, and was not reproducible. In 72 potentially exposed healthy beryllium workers the lymphocyte transformation test was negative in all subjects. The macrophage test was positive in four of 78 and again the results were not reproducible. The workers with positive results showed no differences in age, type or duration of employment from those with negative results and showed no evidence of disease. In addition, the macrophage test was positive in two of 45 non-exposed control subjects. We also confirmed the above advantages of the lymphocyte transformation technique by using tuberculin antigen (PPD). The PPD lymphocyte transformation test gave positive results in approximately 60% of healthy beryllium workers, but the PPD macrophage test was only positive in 7%. We conclude that the Be lymphocyte transformation test is the most sensitive and reproducible and advocate its use in the diagnosis of disease and in monitoring the health of potentially exposed workers.     

液相芯片技术与实时荧光定量PCR在检测儿童感染性腹泻病原体的比较

目的研究液相芯片检测儿童感染性腹泻病原体的效率,为感染性腹泻病的临床快速诊断提供依据。方法收集96例婴幼儿及儿童腹泻患者粪便样本,运用Luminex液相芯片进行检测,并与实时荧光定量PCR检测结果比较。结果液相芯片技术共检测出7种病原体,阳性检出率为65.63%(63/96),其中沙门氏菌的检出率最高,为50.00%(48/96);单病原感染的阳性率为39.58%(38/96),混合感染的阳性率为26.04%(25/96)。与实时荧光定量PCR相比,液相芯片检测腹泻病原体的敏感度和特异度分别为100.00%和71.74%,阴性预测值和阳性预测值分别为100.00%和79.37%(P<0.05)。结论与实时荧光定量PCR相比,液相芯片技术具有高通量、快速、可靠等特点,有利于感染性腹泻病原体的临床检测。