Retrospective cohort study investigating extent of pertussis transmission during a boarding school outbreak, England, December 2017 to June 2018.

On 1 May 2018, a pertussis outbreak was declared and widespread vaccination recommended at an all-female secondary boarding school in southern England. We conducted a retrospective cohort study to determine the extent of pertussis transmission and identify risk factors in this semi-closed population. Of 504 students and staff assessed before post-exposure vaccination, 48% (n = 240) had evidence of pertussis. A sub-analysis of 409 students found that both residential dormitory (p = 0.05) and school year (p = 0.03) were associated with pertussis, with odds decreasing by 11% for each increase in school year (95% confidence interval: 0.7-20.2). Odds of pertussis were 1.7 times higher in those assumed to have received acellular vaccines for their primary course compared with those assumed to have received whole-cell vaccines (based on date of birth), although this difference was not significant (p = 0.12). Our findings support the need for timely, widespread vaccination following identification of cases among adolescents in a semi-closed United Kingdom (UK) setting and to review the evidence for the introduction of an adolescent pertussis booster to the UK routine vaccination programme.

Can a quantitative assessment of SARS-CoV-2 PCR predict degree of severity and outcomes in critical care patients with COVID-19?

Real-Time polymerase chain reaction (qPCR) is the gold standard diagnostic method for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Cycle threshold (Ct) is defined as the number of heating and cooling cycles required during the PCR process. Ct-values are inversely proportional to the amount of target nucleic acid in a sample. Our aim, in this retrospective study, was to determine the impact of serial SARS-CoV-2 qPCR Ct-values on: mortality, need for mechanical ventilation (MV) and development of acute kidney injury (AKI) in patients admitted to the intensive care unit (ICU) with COVID-19. Ct values were evaluated during the time points from pre-ICU admission to week 1, week 2 and week 3 during ICU stay; impact on mortality, need for MV and AKI was determined. There was a continuous increment in Ct-values over the ICU stay from 1st week through to 3rd week. Although not significant, lower ICU 1st week Ct-values were associated with Black ethnicity, increased need for MV and mortality. However, patients who had developed AKI at any stage of their illness had significantly lower Ct-values compared to those with normal renal function. When ICU 1st-week Ct-values are subcategorised as <20, 20-30 and >30 the 28-day survival probability was less for patients with Ct-values of <20. This report shows that the impact of Ct-values and outcomes, especially AKI, among patients at different time points prior to and during ICU stay, larger studies are required to confirm out findings.

Diagnostic accuracy of loop-mediated isothermal amplification coupled to nanopore sequencing (LamPORE) for the detection of SARS-CoV-2 infection at scale in symptomatic and asymptomatic populations.

OBJECTIVES: Rapid, high throughput diagnostics are a valuable tool, allowing the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in populations so as to identify and isolate people with asymptomatic and symptomatic infections. Reagent shortages and restricted access to high throughput testing solutions have limited the effectiveness of conventional assays such as quantitative RT-PCR (RT-qPCR), particularly throughout the first months of the coronavirus disease 2019 pandemic. We investigated the use of LamPORE, where loop-mediated isothermal amplification (LAMP) is coupled to nanopore sequencing technology, for the detection of SARS-CoV-2 in symptomatic and asymptomatic populations. METHODS: In an asymptomatic prospective cohort, for 3 weeks in September 2020, health-care workers across four sites (Birmingham, Southampton, Basingstoke and Manchester) self-swabbed with nasopharyngeal swabs weekly and supplied a saliva specimen daily. These samples were tested for SARS-CoV-2 RNA using the Oxford Nanopore LamPORE system and a reference RT-qPCR assay on extracted sample RNA. A second retrospective cohort of 848 patients with influenza-like illness from March 2020 to June 2020 were similarly tested from nasopharyngeal swabs. RESULTS: In the asymptomatic cohort a total of 1200 participants supplied 23 427 samples (3966 swab, 19 461 saliva) over a 3-week period. The incidence of SARS-CoV-2 detection using LamPORE was 0.95%. Diagnostic sensitivity and specificity of LamPORE was >99.5% (decreasing to approximately 98% when clustered estimation was used) in both swab and saliva asymptomatic samples when compared with the reference RT-qPCR test. In the retrospective symptomatic cohort, the incidence was 13.4% and the sensitivity and specificity were 100%. CONCLUSIONS: LamPORE is a highly accurate methodology for the detection of SARS-CoV-2 in both symptomatic and asymptomatic population settings and can be used as an alternative to RT-qPCR.

Multiple co-regulatory elements and IHF are necessary for the control of fimB expression in response to sialic acid and N-acetylglucosamine in Escherichia coli K-12.

Expression of the FimB recombinase, and hence the OFF-to-ON switching of type 1 fimbriation in Escherichia coli, is inhibited by sialic acid (Neu(5)Ac) and by GlcNAc. NanR (Neu(5)Ac-responsive) and NagC (GlcNAc-6P-responsive) activate fimB expression by binding to operators (O(NR) and O(NC1) respectively) located more than 600 bp upstream of the fimB promoter within the large (1.4 kb) nanC-fimB intergenic region. Here it is demonstrated that NagC binding to a second site (O(NC2)), located 212 bp closer to fimB, also controls fimB expression, and that integration host factor (IHF), which binds midway between O(NC1) and O(NC2), facilitates NagC binding to its two operator sites. In contrast, IHF does not enhance the ability of NanR to activate fimB expression in the wild-type background. Neither sequences up to 820 bp upstream of O(NR), nor those 270 bp downstream of O(NC2), are required for activation by NanR and NagC. However, placing the NanR, IHF and NagC binding sites closer to the fimB promoter enhances the ability of the regulators to activate fimB expression. These results support a refined model for how two potentially key indicators of host inflammation, Neu(5)Ac and GlcNAc, regulate type 1 fimbriation.