Multi-center evaluation of Cepheid Xpert® Xpress SARS-CoV-2/Flu/RSV molecular point-of-care test.

Background: SARS-CoV-2 is taking a huge toll on society while influenza and RSV detection are also becoming more important. These viruses pose a high burden on health care. Rapid and accurate diagnostics for these pathogens are important for swift triage in the hospital. Fast molecular point of care test (mPOCT) assays for these pathogens can prove an alternative. Here a multi-center evaluation of the Xpert® Xpress SARS-CoV-2/Flu/RSV assay is reported. Study design: The Xpert® Xpress SARS-CoV-2/Flu/RSV assay was compared to three reference assays at three Dutch medical microbiology laboratories. An external quality assessment panel consisting of 16 specimens containing SARS-CoV-2, influenza viruses, RSV or human seasonal coronaviruses, or a combination thereof were used. Clinical specimens containing SARS-CoV-2 (n = 57), influenza viruses (n = 21) or RSV (n = 12), at a wide range of relevant concentrations were used. One laboratory also tested zoonotic avian and swine influenza viruses, and eight relevant SARS-CoV-2 variants. Results: The Xpert® Xpress SARS-CoV-2/Flu/RSV assay showed equal performance compared to the reference assays. All SARS-CoV-2 variants of interest and variants of concern were accurately detected. Human seasonal coronaviruses were not detected. All four circulating seasonal influenza virus subtypes/lineages and both RSV types were accurately detected as well as a set of recent zoonotic avian and swine influenza viruses. The clinical specimens showed 98.2% concordance using this assay. Conclusion: The Xpert® Xpress SARS-CoV-2/Flu/RSV assay is a good alternative for accurate detection for SARS-CoV-2, influenza type A virus, influenza type B virus and RSV types A and B detection in a short timeframe.

Cervical cancer risk profiling: molecular biomarkers predicting the outcome of hrHPV infection.

INTRODUCTION: Cervical cancer affects half a million women worldwide annually. Given the association between high-risk human papillomavirus (hrHPV) infection and carcinogenesis, hrHPV DNA testing became an essential diagnostic tool. However, hrHPV alone does not cause the disease, and, most importantly, many cervical lesions regress to normal in a year because of the host immune system. Hence, the low specificity of hrHPV DNA tests and their inability to predict the outcome of infections have triggered a further search for biomarkers. AREAS COVERED: We evaluated the latest viral and cellular biomarkers validated for clinical use as primary screening or triage for cervical cancer and assessed their promise for prevention as well as potential use in the future. The literature search focused on effective biomarkers for different stages of the disease, aiming to determine their significance in predicting the outcome of hrHPV infections. EXPERT OPINION: Biomarkers such as p16/Ki-67, hrHPV genotyping, hrHPV transcriptional status, and methylation patterns have demonstrated promising results. Their eventual implementation in the screening programs may support the prompt diagnosis of hrHPV infection and its progression to cancer. These biomarkers will help in making clinical management decisions on time, thus, saving the lives of hrHPV-infected women, particularly in developing countries.

Multi-center evaluation of cepheid xpert® xpress SARS-CoV-2 point-of-care test during the SARS-CoV-2 pandemic.

BACKGROUND: With the outbreak of SARS-CoV-2, rapid diagnostics are paramount to contain the current pandemic. The routinely used realtime RT-PCR is sensitive, specific and able to process large batches of samples. However, turnaround time is long and in cases where fast obtained results are critical, molecular point of care tests (POCT) can be an alternative. Here we report on a multicenter evaluation of the Cepheid Xpert Xpress SARS-CoV-2 point-of-care test. STUDY DESIGN: The Xpert Xpress SARS-CoV-2 assay was evaluated against the routine in-house real-time RT-PCR assays in three medical microbiology laboratories in The Netherlands. A sensitivity and specificity panel was tested consisting of a dilution series of SARS-CoV-2 and ten samples containing SARS-CoV-2 and a range of other seasonal respiratory viruses. Additionally, 58 samples of patients positive for SARS-CoV-2 with different viral loads and 30 tested negative samples in all three Dutch laboratories using an in-house RT-PCR, were evaluated using Cepheids Xpert Xpress SARS-CoV-2 cartridges. RESULTS: Xpert Xpress SARS-CoV-2 point of care test showed equal performance compared to routine in-house testing with a limit of detection (LOD) of 8.26 copies/mL. Other seasonal respiratory viruses were not detected. In clinical samples Xpert Xpress SARS-CoV-2 reaches an agreement of 100 % compared to all in-house RT-PCRs CONCLUSION: Cepheids GeneXpert Xpert Xpress SARS-CoV-2 is a valuable addition for laboratories in situations where rapid and accurate diagnostics are of the essence.

Evaluation of p16/Ki-67 dual-stained cytology as triage test for high-risk human papillomavirus-positive women.

The aim of this study was to evaluate the clinical utility of p16/Ki-67 dual staining, for the identification of CIN in high-risk HPV-positive women from a non-responder screening cohort. P16/Ki-67 dual staining, Pap cytology, and HPV16/18 genotyping were performed on physician-taken liquid-based samples from 495 women who tested high-risk HPV positive on self-sampled material (PROHTECT-3B study). Different triage strategies involving p16/Ki-67 dual staining were evaluated for sensitivity, specificity, and predictive value for ≥CIN2 and ≥CIN3, and compared to Pap cytology with a threshold of atypical cells of undetermined significance. Centrally revised histology or an adjusted endpoint with combined high-risk HPV negative and cytology negative follow-up at 6 months was used as gold standard. Pap cytology (threshold atypical cells of undetermined significance) triage of high-risk HPV-positive samples showed a sensitivity of 93% (95% confidence interval: 85-98) with a specificity of 49% (95% confidence interval: 41-56) for ≥CIN3. Three triage strategies with p16/Ki-67 showed a significantly increased specificity with similar sensitivity. P16/Ki-67 triage of all high-risk HPV-positive samples had a sensitivity of 92% (95% confidence interval: 84-97) and a specificity of 61% (95% confidence interval: 54-69) for ≥CIN3. Applying p16/Ki-67 triage to only high-risk HPV-positive women with low-grade Pap cytology showed a similar sensitivity of 92% (95% confidence interval: 84-97), with a specificity for ≥CIN3 of 64% (95% confidence interval: 56-71). For high-risk HPV-positive women with low-grade and normal Pap cytology, triage with p16/Ki-67 showed a sensitivity of 96% (95% confidence interval: 89-99), and a specificity of 58% (95% confidence interval: 50-65). HPV16/18 genotyping combined with Pap cytology showed a sensitivity and specificity for ≥CIN3 similar to Pap cytology with an atypical cells of undetermined significance threshold. Because the quality of Pap cytology worldwide varies, and differences in sensitivity and specificity are limited between the three selected strategies, p16/Ki-67 triage of all high-risk HPV-positive samples would be the most reliable strategy in triage of high-risk HPV-positive women with an increased specificity and similar sensitivity compared with Pap cytology triage.

Triage of high-risk HPV positive women in cervical cancer screening.

INTRODUCTION: High-risk human papillomavirus (hrHPV) testing is expected to replace cytology as primary screening method for cervical cancer screening in an increasing number of countries. The high sensitivity of hrHPV testing is combined with a limited specificity which makes triaging of hrHPV positive women necessary. As an ideal triage method does not yet exist, an optimal triage strategy for hrHPV positive women based on current knowledge should be obtained. The aim of this article is to present an overview of available options for triage of hrHPV positive women, with their strengths and limitations and possible future opportunities. AREAS COVERED: Current knowledge on morphological biomarkers, molecular biomarkers and combined triage strategies will be discussed to give an overview of the state-of-the-art on triaging hrHPV positive women. The literature search was limited to studies on triage strategies for hrHPV positive women. Expert commentary: Experience with morphology-based biomarkers makes these a valuable triage method. However, they lack the ability of differentiating productive from transforming infections. Molecular biomarkers are objective, highly reproducible, can be used in high throughput testing, and show promising results. With more extensive knowledge on these molecular markers, cervical cancer screening may transform to a full molecular screening in the future.

Evaluation of the discriminatory power of pulsed-field gel electrophoresis and PCR fingerprinting for epidemiologic typing of Candida species.

OBJECTIVE: To evaluate the discriminatory power of genotyping methods (PCR fingerprinting and pulsed-field gel electrophoresis) validated for Candida albicans in other Candida species. METHODS: Molecular typing methods are increasingly being applied for studies where the interpretation of data essentially relies on the typing results rather than epidemiologic data. In this situation, the discriminatory power (ability to identify differences among epidemiologically unrelated strains) of the typing method is important in allowing one to draw valid conclusions. By applying PCR fingerprinting, electrophoretic karyotyping, and restriction fragment endonuclease analysis using standard restriction enzymes and primers proven to be useful in previous studies, we evaluated whether the use of multiple genotyping methods is sufficient to delineate known unrelated strains among seven Candida species. RESULTS: All three methods identified individual genotypes for each of the seven Candida species studied. However, optimal strain delineation required the combined use of all three typing methods and was observed only within the small number of C. albicans and C. tropicalis isolates tested in this study. CONCLUSION: Typing assays that are able to delineate a certain Candida species may not be used blindly for other species of that genus. Regarding the limited number of strains tested, further validation of the discriminative power of genotyping methods (including in C. tropicalis) should be done.