Differences in expression of virulence genes amongst invasive and colonizing isolates of meticillin-resistant Staphylococcus aureus.

The prevalence of meticillin-resistant Staphylococcus aureus (MRSA) is an important global concern in healthcare due to potentially life-threatening infections and difficulties in treatment. The organism can colonize the mucosa, e.g. anterior nares or result in invasive infections, e.g. bloodstream infections, through the coordinated expression of extracellular and cell-bound virulence factors (Goerke et al., 2000; Novick et al., 1993). The transcription profiles of virulence genes vary in-vivo depending on the dynamic interaction between the host environment and the pathogen. Since the dynamic environment may be differentially altered in MRSA carriage compared to infection, the expression of S. aureus virulence genes may also vary. We previously found no significant correlation between the presence of 17 virulence genes and invasiveness of MRSA isolates (O'Donnell et al., 2008) and this non-association of specific genes or combinations of genes with invasive isolates is in agreement with other larger studies (Lindsay et al., 2006). The lack of a definitive correlation between invasive S. aureus strains and the carriage of virulence genes, suggests that the expression, rather than carriage of virulence determinants in-vivo, may mediate pathogenicity.</p

Vitamin D Deficiency and ARDS after SARS-CoV-2 Infection

Male gender, age over 40 years, cancer, diabetes mellitus, and chronic respiratory and cardiovascular disease have each been associated with increased severity of disease, including ARDS, after SARS-CoV-2 infection. We hypothesize that nutrition might also play a role. Vitamin D (25OHD) deficiency has previously been linked to a greater susceptibility to viral infection, ARDS, and pneumonia.3,4 Since 25OHD deficiency is both highly prevalent and easily treatable and the morbidity, mortality, and costs of SARS-CoV-2 related ARDS are great, we wanted to explore whether 25OHD levels might be associated with an increased risk of the development of ARDS due to SARS-CoV-2

Can e-learning improve the performance of undergraduate medical students in Clinical Microbiology examinations?

Background: Clinical Microbiology is a core subject in medical undergraduate curricula. However, students struggle to cover the content and clinically contextualise basic microbiology. Our aim was to evaluate student engagement with new e-learning material and to investigate the impact it had on examination performance in a Clinical Microbiology module.Methods: An online resource was designed to support didactic teaching in a Fundamentals of Clinical Microbiology module. One cohort of students had access to the online material (2017/2018 class) and the other did not (2016/2017 class). Each cohort sat the same multiple-choice question (MCQ) and short-note question (SNQ) examination papers and the impact of engagement with the online resource and examination performance was analysed.Results: Both groups were of the same academic standard prior to beginning the module. In the 2017/2018 cohort, 227/309 (73.5%) students had ≥80% engagement with the content. Students engaged most with the index of pathogens and pathogen focused clinical cases related to diverse genera and families of clinically important microorganisms. A statistically higher difference in the mean percentage grade in both the MCQ and SNQ examinations was seen for 2017/2018 compared to 2016/2017 cohort. For the MCQ examination, the 2017/2018 cohort were on average 5.57% (95% confidence interval (CI): 3.92 to 7.24%; P Conclusions: These findings suggest students engage with e-learning when studying and that such activities may help students perform better in assessments.</p

Hospital outcomes in patients hospitalized for COVID-19 pneumonia: the effect of SARS-CoV-2 vaccination and vitamin D status

SARS-CoV-2 vaccination promises to improve outcomes for patients with COVID-19 pneumonia (most notably those with advanced age and at high risk for severe disease). Here, we examine serum 25-Hydroxyvitamin D (25(OH)D) status and outcomes in both old (>70 years) and young vaccinated (n = 80) and unvaccinated (n = 91) subjects, who were hospitalized due to COVID-19 pneumonia in a single center (Connolly Hospital Dublin). Outcomes included ICU admission and mortality. Serum 25(OH)D levels were categorized as D30 (p = 0.036)) and mortality (OR: 24.81 (95% CI: 1.57-392.1) (p = 0.023)) in unvaccinated patients, even after adjustment for major confounders including age, sex, obesity and pre-existing diabetes mellitus. While mortality was consistently higher in all categories of patients over 70 years of age, the highest observed mortality rate of 50%, seen in patients over 70 years with a low vitamin D state (D30), appeared to be almost completely corrected by either vaccination, or having a higher vitamin D state, i.e., mortality was 14% for vaccinated patients over 70 years with D30 and 16% for unvaccinated patients over 70 years with a 25(OH)D level greater than 30 nmol/L. We observe that high mortality from COVID-19 pneumonia occurs in older patients, especially those who are unvaccinated or have a low vitamin D state. Recent vaccination or having a high vitamin D status are both associated with reduced mortality, although these effects do not fully mitigate the mortality risk associated with advanced age. </p

Vitamin D status and mortality from SARS CoV-2: a prospective study of unvaccinated Caucasian adults

COVID-19 and a low vitamin D state share common risk factors, which might explain why vitamin D deficiency has been linked with higher COVID-19 mortality. Moreover, measures of serum vitamin D may become lower during systemic inflammatory responses, further confounding the association via reverse causality. In this prospective study (recruited over 12 months), we examined whether the association between a low vitamin D state and in-hospital mortality due to SARS-CoV-2 pneumonia in unvaccinated subjects is explained by (i) the presence of shared risk factors (e.g., obesity, advanced age) or (ii) a reduction in serum 25(OH)D due to COVID-19 (i.e., reverse causality). In this cohort of 232 (mean age = 56 years) patients (all had SARS-CoV-2 diagnosed via PCR AND required supplemental oxygen therapy), we failed to find an association between serum vitamin D and levels of CRP, or other inflammatory markers. However, the hazard ratio for mortality for subjects over 70 years of age (13.2) and for subjects with a serum 25(OH)D level less than 30 nmol·L-1 (4.6) remained significantly elevated even after adjustment for gender, obesity and the presence of diabetes mellitus. Subjects 70 years had significantly higher mortality with a serum 25(OH)D less than 30 nmol·L-1 (11.8% and 55%), than with a serum 25(OH)D greater than 30 nmol·L-1 (2.2% and 25%). Unvaccinated Caucasian adults with a low vitamin D state have higher mortality due to SARS CoV-2 pneumonia, which is not explained by confounders and is not closely linked with elevated serum CRP. </p