Prevalence of new variants of Chlamydia trachomatis escaping detection by the Aptima Combo 2 assay, England, June to August 2019

At the end of April 2019, Public Health England (PHE) was alerted, via an international Epidemic Intelligence System-Sexually Transmitted Infections (EPIS-STI) post from Finland, of false-negative Chlamydia trachomatis (CT) test results using the Aptima Combo 2 (AC2) assay (Hologic Inc., San Diego, California, United States (US)), a nucleic acid amplification test (NAAT) for CT (target: 23S rRNA) and Neisseria gonorrhoeae (GC) (target: 16S rRNA). Discrepant results between the AC2 assay and the Aptima Chlamydia trachomatis assay (ACT) (target: 16S rRNA) were reported to have occurred primarily in specimens that had AC2 relative light units (RLU) from 20 to 84 [1]. These false-negative AC2 results [2,3] were attributed to a C1515T mutation in the CT 23S rRNA gene. In early June 2019, Hologic Inc. issued a Field Safety Notice (FSN) to AC2-using laboratories, recommending ACT reflex retesting of AC2 CT-negative with RLU ≥ 15, CT-equivocal, or GC-equivocal/-positive (if CT-negative/equivocal) specimens to ensure detection of the Finnish new variant CT strain (F-nvCT) [3]. A European Centre for Disease Prevention and Control (ECDC) rapid risk assessment recommended countries estimate the spread of F-nvCT to inform the need for patient recall and retesting [4]. Here we report results from an investigation coordinated by a multiagency incident management team (IMT) to ascertain the prevalence of new variants of Chlamydia trachomatis escaping detection by the Aptima Combo 2 assay in England

Role of Surface Area, Primary Particle Size, and Crystal Phase on Titanium Dioxide Nanoparticle Dispersion Properties

Characterizing nanoparticle dispersions and understanding the effect of parameters that alter dispersion properties are important for both environmental applications and toxicity investigations. The role of particle surface area, primary particle size, and crystal phase on TiO2 nanoparticle dispersion properties is reported. Hydrodynamic size, zeta potential, and isoelectric point (IEP) of ten laboratory synthesized TiO2 samples, and one commercial Degussa TiO2 sample (P25) dispersed in different solutions were characterized. Solution ionic strength and pH affect titania dispersion properties. The effect of monovalent (NaCl) and divalent (MgCl2) inert electrolytes on dispersion properties was quantified through their contribution to ionic strength. Increasing titania particle surface area resulted in a decrease in solution pH. At fixed pH, increasing the particle surface area enhanced the collision frequency between particles and led to a higher degree of agglomeration. In addition to the synthesis method, TiO2 isoelectric point was found to be dependent on particle size. As anatase TiO2 primary particle size increased from 6 nm to 104 nm, its IEP decreased from 6.0 to 3.8 that also results in changes in dispersion zeta potential and hydrodynamic size. In contrast to particle size, TiO2 nanoparticle IEP was found to be insensitive to particle crystal structure

What Do Diagnoses of Pelvic Inflammatory Disease in Specialist Sexual Health Services in England Tell Us About Chlamydia Control?

BACKGROUND Pelvic inflammatory disease (PID) is an outcome measure for the evaluation of chlamydia screening programs. We explore PID diagnoses in specialist sexual health services (SSHSs) in England to inform the evaluation of the National Chlamydia Screening Programme, which was implemented nationally in 2008. METHODS We conducted descriptive analyses using data on diagnoses of PID-with and without Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC)-by age and year of birth, in SSHSs between 2009 and 2019 from the GUMCAD STI Surveillance System database. Rates were calculated per 100 000 females residing in England. RESULTS CT screening activity peaked in 2010. The rates of all PID diagnoses decreased between 2009 and 2019 by 39%. CT-associated PID (CT-PID) declined by 58%, and nonspecific PID declined by 37%. GC-PID increased by 34%. CT-PID decreased across all age groups with the highest observed decline, 71%, in 15- to 19-year-olds. A dose-response relationship was observed between CT-PID rates and screening, with rates lowest in those with the greatest exposure to screening. CONCLUSIONS There was a marked decline in diagnoses of CT-PID, and nonspecific PID, at SSHSs after the introduction of widespread chlamydia screening, whereas GC-PID diagnoses increased. This ecological trend was broadly consistent with what we would have expected to see if widespread screening reduced the incidence of chlamydia-associated PID (and of nonspecific PID), as has been observed in randomized controlled trials of screening

Managing plant biosecurity in the Pacific region

The island nations of the Pacific are scattered across a vast expanse of ocean and face many unique plant biosecurity challenges. This talk will focus on biosecurity as it relates to traditional crops such as banana, coconut, sweet potato and taro, and highlight specific case studies to demonstrate difficulties with containing and controlling pests and pathogens in this region. Some of the most serious pests and pathogens such as the coconut rhinoceros beetle and banana bunchy top virus date back 100 years to the period of European colonization but are still proving difficult to control, with new spread pathways still being uncovered. There are other emerging pests and pathogens such as the coconut and banana wilt-associated phytoplasmas, which are likely indigenous to the region but for reasons that are unclear, are increasing in importance. Lessons that have been learnt from these case studies will be discussed and recommendations for the future put forward. Australia has a vested interest in ensuring a strong biosecurity system in this region as it represents a major entry point for pests and pathogens that could affect our northern Australian agricultural industries