Comparative incidence of early and late bloodstream and respiratory tract co-infection in patients admitted to ICU with COVID-19 pneumonia versus Influenza A or B pneumonia versus no viral pneumonia: wales multicentre ICU cohort study.

OBJECTIVE: The aim is to characterise early and late respiratory and bloodstream co-infection in patients admitted to intensive care units (ICUs) with SARS-CoV-2-related acute hypoxemic respiratory failure (AHRF) needing respiratory support in seven ICUs within Wales, during the first wave of the COVID-19 pandemic. We compare the rate of positivity of different secondary pathogens and their antimicrobial sensitivity in three different patient groups: patients admitted to ICU with COVID-19 pneumonia, Influenza A or B pneumonia, and patients without viral pneumonia. DESIGN: Multicentre, retrospective, observational cohort study with rapid microbiology data from Public Health Wales, sharing of clinical and demographic data from seven participating ICUs. SETTING: Seven Welsh ICUs participated between 10 March and 31 July 2020. Clinical and demographic data for COVID-19 disease were shared by each participating centres, and microbiology data were extracted from a data repository within Public Health Wales. Comparative data were taken from a cohort of patients without viral pneumonia admitted to ICU during the same period as the COVID-19 cohort (referred to as no viral pneumonia or 'no viral' group), and to a retrospective non-matched cohort of consecutive patients with Influenza A or B admitted to ICUs from 20 November 2017. The comparative data for Influenza pneumonia and no viral pneumonia were taken from one of the seven participating ICUs. PARTICIPANTS: A total of 299 consecutive patients admitted to ICUs with COVID-19 pneumonia were compared with 173 and 48 patients admitted with no viral pneumonia or Influenza A or B pneumonia, respectively. MAIN OUTCOME MEASURES: Primary outcome was to calculate comparative incidence of early and late co-infection in patients admitted to ICU with COVID-19, Influenza A or B pneumonia and no viral pneumonia. Secondary outcome was to calculate the individual group of early and late co-infection rate on a per-patient and per-sample basis, with their antimicrobial susceptibility and thirdly to ascertain any statistical correlation between clinical and demographic variables with rate of acquiring co-infection following ICU admission. RESULTS: A total of 299 adults (median age 57, M/F 2:1) were included in the COVID-19 ICU cohort. The incidence of respiratory and bloodstream co-infection was 40.5% and 15.1%, respectively. Staphylococcus aureus was the predominant bacterial pathogen within the first 48 h. Gram-negative organisms from Enterobacterales group were predominantly seen after 48 h in COVID-19 cohort. Comparative no viral pneumonia cohort had lower rates of respiratory tract infection and bloodstream infection. The influenza cohort had similar rates respiratory tract infection and bloodstream infection. Mortality in all three groups was similar, and no clinical or demographic variables were found to increase the rate of co-infection and ICU mortality. CONCLUSIONS: Higher incidence of bacterial co-infection was found in COVID-19 cohort as compared to the no viral pneumonia cohort admitted to ICUs for respiratory support.

Analyzing the performance of biological versus conventional drinking water filtration under warm and cold water conditions: A pilot scale study.

Conventional filtration practices typically operate with a pre-chlorination step for the disinfection of harmful pathogens. Without pre-chlorination, biofilters will develop, which are capable of reducing the formation of disinfection by-products (DBPs) and can decrease bacterial regrowth in the distribution system. However, concerns, particularly in North America, still exist with the implementation of biofiltration and there is a lack of side-by-side comparisons with pre-chlorinated filters in literature. A pilot scale study comparing conventional and biological dual media anthracite/sand filters was conducted to assess their performance under warm (15-25 °C) and cold (0-5 °C) water conditions. The filters were operated under various backwash conditions, including the addition of air scour and extended terminal subfluidization wash (ETSW). The biofilter effluent exhibited significantly lower (p < 0.05) DBP formations under both temperature conditions, with trihalomethanes (TTHM) and haloacetic acids (HAA9) concentrations 33-35% and 36-46% lower than the conventional filters, respectively. There was no significant difference when it came to particle passage or turbidity during ripening for both filter types, however the conventional filter proved to be more vulnerable to changes in terms of particles between backwashes. The biofilter exhibited greater average headloss development by 8.8 cm and 4.5 cm under warm and cold water conditions, respectively. Biofilter headloss was found to be minimized by 18% when applying air scour and ETSW during backwash compared to water only, under warm temperature conditions.