Search

Objectives To determine the risk of SARS-CoV-2 transmission by aerosols, to provide evidence on the rational use of masks, and to discuss additional measures important for the protection of healthcare workers from COVID-19. Methods Literature review and expert opinion. Short conclusion SARS-CoV-2, the pathogen causing COVID-19, is considered to be transmitted via droplets rather than aerosols, but droplets with strong directional airflow support may spread further than 2 m. High rates of COVID-19 infections in healthcare-workers (HCWs) have been reported from several countries. Respirators such as filtering face piece (FFP) 2 masks were designed to protect HCWs, while surgical masks were originally intended to protect patients (e.g., during surgery). Nevertheless, high quality standard surgical masks (type II/IIR according to European Norm EN 14683) appear to be as effective as FFP2 masks in preventing droplet-associated viral infections of HCWs as reported from influenza or SARS. So far, no head-to-head trials with these masks have been published for COVID-19. Neither mask type completely prevents transmission, which may be due to inappropriate handling and alternative transmission pathways. Therefore, compliance with a bundle of infection control measures including thorough hand hygiene is key. During high-risk procedures, both droplets and aerosols may be produced, reason why respirators are indicated for these interventions.

Additional file 1. Figure S1. Swiss map with the included ICU sites. Figure S2. Flowchart of the included blood culture episodes during the study after exclusion of episodes identified outside ICU, among children under 16 years of age or from patients abroad. Figure S3. Correlations of the ICU occupation due to all patients with blood culture contaminations incidence (A), ICU-BSI incidence (B) and percentage of blood culture contaminations (C). Figure S4. Weekly count of blood culture episodes reported to ANRESIS over the period 01.01.2018 ���31.05.2021. Figure S5. Confirmatory analysis on secular trends of blood culture for the intermediate and second pandemic period using a Poisson regression model.

Background Evidence about the impact of the pandemic of COVID-19 on the incidence rates of blood cultures contaminations and bloodstream infections in intensive care units (ICUs) remains scant. The objective of this study was to investigate the nationwide epidemiology of positive blood cultures drawn in ICUs during the first two pandemic waves of COVID-19 in Switzerland. Methods We analyzed data on positive blood cultures among ICU patients, prospectively collected through a nationwide surveillance system (ANRESIS), from March 30, 2020, to May 31, 2021, a 14-month timeframe that included a first wave of COVID-19, which affected the French and Italian-speaking regions, an interim period (summer 2020) and a second wave that affected the entire country. We used the number of ICU patient-days provided by the Swiss Federal Office of Public Health as denominator to calculate incidence rates of blood culture contaminations and bloodstream infections (ICU-BSI). Incidence rate ratios comparing the interim period with the second wave were determined by segmented Poisson regression models. Results A total of 1099 blood culture contaminations and 1616 ICU-BSIs were identified in 52 ICUs during the study. Overall, more episodes of blood culture contaminations and ICU-BSI were observed during the pandemic waves, compared to the interim period. The proportions of blood culture contaminations and ICU-BSI were positively associated with the ICU occupancy rate, which was higher during the COVID-19 waves. During the more representative second wave (versus interim period), we observed an increased incidence of blood culture contaminations (IRR 1.57, 95% CI 1.16–2.12) and ICU-BSI (IRR 1.20, 95% CI 1.03–1.39). Conclusions An increase in blood culture contaminations and ICU-BSIs was observed during the second COVID-19 pandemic wave, especially in months when the ICU burden of COVID-19 patients was high. Supplementary Information The online version contains supplementary material available at 10.1186/s13054-021-03814-z.

Background The World Health Organization (WHO) recommends administration of surgical antimicrobial prophylaxis (SAP) in cesarean section prior to incision to prevent surgical site infections (SSI). This study aimed to determine whether SAP administration following cord clamping confers an increased SSI risk to the mother. Methods Study design: Cohort. Setting: 75 participating Swiss hospitals, from 2009 to 2018. Participants: A total of 55,901 patients were analyzed. Main outcome measures: We assessed the association between SAP administration relative to incision and clamping and the SSI rate, using generalized linear multilevel models, adjusted for patient characteristics, procedural variables, and health-care system factors. Results SAP was administered before incision in 26′405 patients (47.2%) and after clamping in 29,496 patients (52.8%). Overall 846 SSIs were documented, of which 379 (1.6% [95% CI, 1.4–1.8%]) occurred before incision and 449 (1.7% [1.5–1.9%]) after clamping (p = 0.759). The adjusted odds ratio for SAP administration after clamping was not significantly associated with an increased SSI rate (1.14, 95% CI 0.96–1.36; p = 0.144) when compared to before incision. Supplementary and subgroup analyses supported these main results. Conclusions This study did not confirm an increased SSI risk for the mother in cesarean section if SAP is given after umbilical cord clamping compared to before incision.

Afternoon aortic valve replacement surgery may provide perioperative myocardial protection and improve patient outcomes compared with morning surgery. The results of our large observational study based on Swiss cardiac surgical site infection surveillance data suggest that the current evidence is insufficient to generally promote afternoon cardiac surgeries.

Journal of Hospital Infection, 104 (2)

OBJECTIVES Our goal was to determine the optimal timing and choice of surgical antimicrobial prophylaxis (SAP) in patients having cardiac surgery. METHODS The setting was the Swiss surgical site infection (SSI) national surveillance system with a follow-up rate of >94%. Participants were patients from 14 hospitals who had cardiac surgery from 2009 to 2017 with clean wounds, SAP with cefuroxime, cefazolin or a vancomycin/cefuroxime combination and timing of SAP within 120 min before the incision. Exposures were SAP timing and agents; the main outcome was the incidence of SSI. We fitted generalized additive and mixed-effects generalized linear models to describe effects predicting SSIs. RESULTS A total of 21 007 patients were enrolled with an SSI incidence of 5.5%. Administration of SAP within 30 min before the incision was significantly associated with decreased deep/organ space SSI [adjusted odds ratio (OR) 0.73, 95% confidence interval (CI) 0.54-0.98; P = 0.035] compared to administration of SAP 60-120 min before the incision. Cefazolin (adjusted OR 0.64, 95% CI 0.49-0.84; P = 0.001) but not vancomycin/cefuroxime combination (adjusted OR 1.05, 95% CI 0.82-1.34; P = 0.689) was significantly associated with a lower risk of overall SSI compared to cefuroxime alone. Nevertheless, there were no statistically significant differences between the SAP agents and the risk of deep/organ space SSI. CONCLUSIONS The results from this large prospective study provide substantial arguments that administration of SAP close to the time of the incision is more effective than earlier administration before cardiac surgery, making compliance with SAP administration easier. The choice of SAP appears to play a significant role in the prevention of all SSIs, even after adjusting for confounding variables.

Additional file 1: Table S1. Overview of environmental sampling. Sampling was performed with premoistened (0,9% NaCl) sterile swabs, direct plating of contrast agents (200 μl per sample) and direct wiping of plant material on plates. Plates were incubated at 35 °C in CO2 enriched atmosphere for 6 days. MALDI-TOF MS was used for bacterial identification. Table S2. Overview of eight isolates described in this study. The genome datasets are available in the European Nucleotide Archive repository, under Project number PRJEB34002 [ https://www.ebi.ac.uk/ena/data/view/PRJEB34002 ]. Table S3. Peak list generated from visual examination of MALDI-TOF spectra of the Isolates A-H. Presence (1) or absence (0) of peaks is indicated at the m/z positions. Potentially double-ionized peaks are indicated with an asterisk (*); numbers in bold indicate peaks with a signal-to-noise ratio > 10. Table S4. Results of digital DNA:DNA hybridization for isolates F, H, G and B performed against all known Agrobacterium genomospecies. A dDDH value over 70 ( http://ggdc.dsmz.de/; Formula 2) or ANI value over 95% ( http://enve-omics.ce.gatech.edu/ani/ ) indicates the same species. Table S5. Comparison of MALDI-TOF MS spectra with a database generated on the base of putatively ascribed ribosomal protein masses extracted from genomic data. G = genomospecies. Figure S1. Timeline of clinical, microbiological, environmental, and treatment features of the two Index cases (Cluster I). Figure S2. Representative differentiating mass to charge (m/z) peaks. The m/z peak 7882 (*) is present in isolates C (pink), D (violet), E (light green), F (dark green) and H (orange) – the peak at 7924 m/z (**) is present in isolates A (light blue) and B (dark blue). Both peaks are absent in isolate G (red). Four spectra were recorded for each isolate A-H. Figure S3. (A) Disposable contrast reservoir with the rubber seal (#) in resting position. The potential contaminable zone lies behind the rubber seal (★). (B) The contrast reservoir is filled with contrast media by pushing (1) the rubber-sealed plunger (*) and pulling it (2) back to resting position. (C) The reservoir is inserted in the injector device system and ready to use. Figure S4. Model highlighting the potentially contaminable area of the reservoir behind the rubber seal (★), for visualization a fluorescent solution was used (A: resting position, B: rubber seal pushed in, C: rubber seal back in resting position). Figure S5. Principal component analysis: Four spectra were recorded for each isolate A-H. Two-dimensional plot of the first two principal components indicating the two clusters I (isolates A and B) and II (isolates C, D, E and F) and the “unrelated” isolates G and H. Figure S6. PFGE based typing of isolates A-H. The scale indicates the degree of similarity (%) as calculated by dice correlation analysis.

a) Supplementary Methods (Microbiome); b) Supplementary References; c) Additional file 1: Figures S1 & S2. (DOCX 47 kb)

OBJECTIVES Our objective was to systematically study the influence of length of hospital stay on bacterial resistance in relevant respiratory tract isolates. METHODS Using prospective epidemiological data from the National Swiss Antibiotic Resistance Surveillance System, susceptibility testing results of respiratory isolates retrospectively retrieved from patients hospitalized between 2008-2014 were compiled. Generalized additive models were used to illustrate resistance rates relative to hospitalization duration and to adjust for co-variables. RESULTS 19,622 isolates of six relevant and predominant species were included. Resistance patterns for the predominant species showed a species and antibiotic resistance specific profile in function of hospitalization duration: The oxacillin resistance profile in Staphylococcus aureus isolates was constantly increasing (monophasic). The pattern of resistance to cefepime in Pseudomonas aeruginosa was biphasic with a decreasing resistance rate for the first five days of hospitalization and an increase for days 6-30. A different biphasic pattern occurred in Escherichia coli regarding amoxicillin-clavulanic acid resistance: odds/day increased for the first seven days of hospitalization and then remained stable for days 8-30. In the adjusted models epidemiological characteristics such as age, ward type, hospital type, and linguistic region were identified as relevant co-variables for the resistance rates. The contribution of these confounders was specific to the individual species/antibiotic resistance models. CONCLUSIONS Resistance rates do not follow a dichotomic pattern (early vs. late nosocomial) as suggested by current hospital-acquired pneumonia treatment guidelines. Duration of hospitalization rather appears to have a more complex and non-linear relationship with bacterial resistance in hospital-acquired pneumonia, also depending on host/environmental factors.

Table S1. Microorganism distribution of positive catheter tip culture and sBSI in the ICU. (DOCX 16 kb)

Knowledge Sharing in Infection Prevention in Routine and Outbreak Situations: A Survey of the Society for Healthcare Epidemiology of America Research Network . (DOCX 81 kb)

CD4 T cells promote innate and adaptive immune responses, but how vaccine-elicited CD4 T cells contribute to immune protection remains unclear. Here we evaluated whether induction of virus-specific CD4 T cells by vaccination would protect mice against infection with chronic lymphocytic choriomeningitis virus (LCMV). Immunization with vaccines that selectively induced CD4 T cell responses resulted in catastrophic inflammation and mortality following challenge with a persistent strain of LCMV. Immunopathology required antigen-specific CD4 T cells and was associated with a cytokine storm, generalized inflammation, and multi-organ system failure. Virus-specific CD8 T cells or antibodies abrogated the pathology. These data demonstrate that vaccine-elicited CD4 T cells in the absence of effective antiviral immune responses can trigger lethal immunopathology.