During measles outbreaks, it is important to be able to rapidly distinguish between measles cases and vaccine reactions to avoid unnecessary outbreak response measures such as case isolation and contact investigations. We have developed a real-time reverse transcription-PCR (RT-PCR) method specific for genotype A measles virus (MeV) (MeVA RT-quantitative PCR [RT-qPCR]) that can identify measles vaccine strains rapidly, with high throughput, and without the need for sequencing to determine the genotype. We have evaluated the method independently in three measles reference laboratories using two platforms, the Roche LightCycler 480 system and the Applied Biosystems (ABI) 7500 real-time PCR system. In comparison to the standard real-time RT-PCR method, the MeVA RT-qPCR showed 99.5% specificity for genotype A and 94% sensitivity for both platforms. The new assay was able to detect RNA from five currently used vaccine strains, AIK-C, CAM-70, EdmonstonZagreb, Moraten, and Shanghai-191. The MeVA RT-qPCR assay has been used successfully for measles surveillance in reference laboratories, and it could be readily deployed to national and subnational laboratories on a wide scale.
We sought to confirm the results of 81 rectal specimens positive for Chlamydia trachomatis by the APTIMA Combo 2 assay among patients with concurrently collected negative genitourinary specimens. A total of 79 (97.5%) samples were confirmed by the APTIMA single target assay and/or sequencing of the C. trachomatis ompA gene.
Background: Persistent infection with a subset of human papillomavirus (HPV) genotypes can cause abnormal cytology and invasive cervical cancer. This study examines the circulating HPV genotype strains in a local population of the province of Alberta (a largely unvaccinated population) to establish baseline frequency of vaccine and non-vaccine genotypes causing abnormal cervical cytology. Method: Remnant liquid-based cytology specimens from the Alberta Cervical Cancer Screening Program (March 2014–January 2016) were examined. Only specimens from women who had a cytology grading of atypical squamous cells of undetermined significance or higher were included. HPV genotype was determined for all samples, and results were stratified by demographics and cytology results. Results: Forty-four unique HPV genotypes were identified from 4,794 samples. Of the 4,241 samples with a genotype identified, the most common genotypes were HPV 16, 18, 31, and 51, with 1,599 (37.7%), 441 (12.2%), 329 (7.8%), and 354 (8.4%), respectively. HPV9 vaccine genotypes made up 73.2% of these genotyped samples. Compared with specimens in which HPV9 vaccine genotypes were not detected, those with a genotype covered by the HPV9 vaccine were from younger women (33 y [interquartile range {IQR] 28 to 42] versus 40 y [IQR 32 to 51]; p < 0.00001). Conclusions: The baseline distribution of HPV genotypes in this largely unvaccinated population indicates that the HPV 9 vaccine provides good protection from high-risk HPV infections. Determining the frequency of genotypes causing abnormal cytology in this population post–vaccine implementation will be important to assess efficacy of vaccination and monitor for any potential genotype replacement.
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