Surface Contamination of Reusable Respirators and Face Shields During Care of Critically Ill COVID-19 Patients.

BACKGROUND: With the emergence of SARS-CoV-2, healthcare workers (HCW) have relied on reusable personal protective equipment (PPE), including respirators and face shields (FSs). The effectiveness of decontamination procedures outside experimental settings is unclear. We examined the prevalence of surface contamination on reusable PPE used by HCWs at a hospital incorporating daily centralized decontamination and post-use wiping by sampling for common pathogens. METHOD: Samples were collected from HCWs' CleanSpace Halo respirator face masks (FMs) and FSs at the start of shift, immediately after use, and after cleaning with disinfecting wipes. Samples were analyzed for pathogens using the Applied Biosystems™ TaqPath™ COVID-19 Combo Kit and ThermoFisher TaqMan Array Card. Patient charts were reviewed for clinical correlation. FINDINGS: Of the 89 samples, 51 from FMs and 38 from FSs, none tested positive for SARS-CoV-2, despite 58 being obtained from PPE used in the care of patients with COVID-19, many with recent aerosol-generating procedures. Four samples tested positive (4.5%) for Staphylococcus aureus, two each from FMs and FSs. FMs that tested positive were not worn concurrently with FSs that tested positive. The FM and FS samples testing positive were worn in the care of patients without diagnosed S. aureus infection. No FMs tested positive following wipe-based disinfection, but both positive FS samples were found after disinfection wiping. CONCLUSION/APPLICATION TO PRACTICE: Contamination of reusable PPE appears uncommon, especially with SARS-CoV-2, when regular decontamination programs are in place. The rare presence of S. aureus highlights the importance of doffing procedures and hand hygiene by HCW to prevent surface contamination.

Tolerability, user acceptance and preference for a novel reusable respirator among health care workers.

BACKGROUND: The CleanSpace Technology Halo respirator combines a clear face mask and a powered air supply, without belts or hoses. Although providing higher protection than other respirators used in health care, user acceptance of this device has not been assessed with validated tools. METHODS: We surveyed healthcare workers (HCWs) within a US medical system using Halo respirators in 2021. Subjects completed 3 surveys over 8 weeks, which included the Respirator Comfort, Wearing Experience, and Function Instrument (R-COMFI), a validated tool to assess respirator tolerability. The survey included additional questions about user acceptability and respirator preference. Responses were evaluated for change over time and for significant predictors. RESULTS: Of 113 HCWs who completed the initial survey (29% response rate), mean ± SD R-COMFI score was 9.1± 5.1, (scale 0-47, lower = more tolerable) and did not change over time (P = .42). Fewer years in healthcare significantly predicted better R-COMFI score (P = .01). Many users preferred Halo in both usual care (45%-52%) and care of patients with COVID-19 (60%-64%). DISCUSSION: Halo respirators received favorable tolerability scores by HCWs, who often preferred them, especially during care of patients with COVID-19. CONCLUSIONS: Given demand for respirator use in health care, the innovative design provides higher protection than other respirators with a favorable user experience.

New mode of liquid chromatography separation: A new mode of separation using multi-charged ions in the mobile phase for high-performance liquid chromatography.

In liquid chromatography, several types of separation modes are known. Here, we are going to describe a new mode of retention and consecutively, a separation mechanism that to our knowledge was not identified as such before. We named this mode: Bridge Ion Separation Technique. This separation mode is possible when a double-charged ionic modifier of the mobile phase forms a dynamic bridge between an identically charged stationary phase and analyte. This phenomenon was observed in the water-reduced mobile phase and it is universal for both anions and cations as long as the column has the same charge as the analytes. This retention mechanism is observed with any number of charged functional groups in the analyte molecule but is more profound when the number of charges in the analyte molecule is increased.

Marine Bacteria under Low-Intensity Radioactive Exposure: Model Experiments.

Radioactive contaminants create problems all over world, involving marine ecosystems, with their ecological importance increasing in the future. The review focuses on bioeffects of a series of alpha and beta emitting radioisotopes (americium-241, uranium-(235 + 238), thorium-232, and tritium) and gamma radiation. Low-intensity exposures are under special consideration. Great attention has been paid to luminous marine bacteria as representatives of marine microorganisms and a conventional bioassay system. This bioassay uses bacterial bioluminescence intensity as the main testing physiological parameter; currently, it is widely applied due to its simplicity and sensitivity. Dependences of the bacterial luminescence response on the exposure time and irradiation intensity were reviewed, and applicability of hormetic or threshold models was discussed. A number of aspects of molecular intracellular processes under exposure to low-intensity radiation were analyzed: (a) changes in the rates of enzymatic processes in bacteria with the bioluminescent system of coupled enzymatic reactions of NADH:FMN-oxidoreductase and bacterial luciferase taken as an example; (b) consumption of an intracellular reducer, NADH; (c) active role of reactive oxygen species; (d) repairing of the DNA damage. The results presented confirm the function of humic substances as natural radioprotectors.

Development of Cellular and Enzymatic Bioluminescent Assay Systems to Study Low-Dose Effects of Thorium.

Thorium is one of the most widespread radioactive elements in natural ecosystems, along with uranium, it is the most important source of nuclear energy. However, the effects of thorium on living organisms have not been thoroughly studied. Marine luminescent bacteria and their enzymes are optimal bioassays for studying low-dose thorium exposures. Luminescent bioassays provide a quantitative measure of toxicity and are characterized by high rates, sensitivity, and simplicity. It is known that the metabolic activity of bacteria is associated with the production of reactive oxygen species (ROS). We studied the effects of thorium-232 (10-11-10-3 M) on Photobacterium phosphoreum and bacterial enzymatic reactions; kinetics of bacterial bioluminescence and ROS content were investigated in both systems. Bioluminescence activation was revealed under low-dose exposures (<0.1 Gy) and discussed in terms of "radiation hormesis". The activation was accompanied by an intensification of the oxidation of a low-molecular reducer, NADH, during the enzymatic processes. Negative correlations were found between the intensity of bioluminescence and the content of ROS in bacteria and enzyme systems; an active role of ROS in the low-dose activation by thorium was discussed. The results contribute to radioecological potential of bioluminescence techniques adapted to study low-intensity radioactive exposures.

Humic Substances Mitigate the Impact of Tritium on Luminous Marine Bacteria. Involvement of Reactive Oxygen Species.

The paper studies the combined effects of beta-emitting radionuclide tritium and Humic Substances (HS) on the marine unicellular microorganism-luminous bacteria-under conditions of low-dose radiation exposures (<0.04 Gy). Tritium was used as a component of tritiated water. Bacterial luminescence intensity was considered as a tested physiological parameter. The bioluminescence response of the marine bacteria to tritium corresponded to the "hormesis" model: it included stages of bioluminescence inhibition and activation, as well as the absence of the effect. HS were shown to decrease the inhibition and activation effects of tritium, similar to those of americium-241, alpha-emitting radionuclide, studied earlier. Correlations between the bioluminescence intensity and the content of Reactive Oxygen Species (ROS) were found in the radioactive bacterial suspensions. The results demonstrate an important role of HS in natural processes in the regions of low radioactive contamination: HS can mitigate radiotoxic effects and adaptive response of microorganisms to low-dose radioactive exposures. The involvement of ROS in these processes was demonstrated.

Definitive Wound Closure Techniques in Fournier's Gangrene.

Necrotizing soft tissue infection of the perineum, or Fournier's gangrene (FG), is a morbid and mortal diagnosis. Despite the severity of FG, the optimal definitive wound closure strategy is unknown, as are long-term wound outcomes. A retrospective review was performed over a 3-year period at a single trauma center. Patients were managed according to our institutional approach focusing on primary wound closure and secondary intention healing in residual wounds. Overall 168 patients were included. Complete primary wound closure was accomplished in 39.9 per cent of patients. Patients undergoing primary wound closure were primarily male (89.6 vs 64.4%, P < 0.001), had lower mean sequential organ failure assessment (SOFA) scores (1.70 ± 2.30 vs 2.98 ± 3.36, P = 0.004), more often had perineum-limited FG (67.2 vs 42.6%, P = 0.003), and required fewer debridements (2.40 vs 2.79, P = 0.02). On logistic regression, predictors of primary closure included gender (odds ratio 4.643, 95% confidence interval 1.885-11.437, P = 0.001) and SOFA score (odds ratio 0.834, 95% confidence interval 0.727-0.957, P = 0.01). Wound healing rates increased over time, to an 82.1 per cent wound healing rate without further intervention at greater than six months of follow-up. Wounds healed with secondary intention ranged from 70 to 9520 cm3 and primary closure ranged from 126 to 6912 cm3, whereas wounds requiring skin grafts ranged from 405 to 16,170 cm3. Complete primary wound closure is often achievable in FG patients. Using this standardized approach to FG wound management, even large wounds and wounds undergoing secondary intention healing will often close with long-term wound care and do not require flap creation or early skin grafting.

Less is more? Antibiotic duration and outcomes in Fournier's gangrene.

BACKGROUND: Antibiotic management of Fournier's gangrene (FG) is without evidence-based guidelines and is based on expert opinion. The effect of duration of antibiotic therapy on outcomes in FG is unknown. METHODS: A retrospective review was performed of FG patients from 2012 to 2015 at a single institution. Patients were managed by our institutional practice of complete primary wound closure as possible, with antibiotic duration according to physician judgment. Patients were stratified into multiple durations of antibiotic administration. RESULTS: Overall, 168 patients with FG were included. When examining multiple stratifications of antibiotic therapy of 7 days or less, 8 days to 10 days, 11 days to 14 days, or 15 days or more of antibiotics, there was no significant difference in mortality (p = 0.11), primary closure (p = 0.75), surgical site infection (SSI) (p = 0.52), or Clostridium difficile infection (p = 0.63). There were no cases of recurrent FG in any antibiotic stratification. Mortality was not increased (p = 1.00) and ability to achieve primary closure was not decreased (p = 0.08) with initial antibiotic therapy exclusive of cultured organisms. CONCLUSION: Shorter antibiotic courses for patients in whom source control is obtained and initial antibiotic selection exclusive of many resistant organisms were not associated with worse outcomes in FG. LEVEL OF EVIDENCE: Therapeutic, level IV.