Impact of Water Exposure and Temperature Changes on Skin Barrier Function

The frequency of hand hygiene has increased due to the COVID-19 pandemic, but there is little evidence regarding the impact of water exposure and temperature on skin. The aim of this study is to evaluate the effect of water exposure and temperature on skin barrier function in healthy individuals. A prospective observational study was conducted. Temperature, pH, transepidermal water loss (TEWL), erythema and stratum corneum hydration (SCH) were measured objectively before and after hot- and cold-water exposure and TempTest® (Microcaya TempTest, Bilbao, Spain) contact. Fifty healthy volunteers were enrolled. Hot-water exposure increased TEWL (25.75 vs. 58.58 g·h−1·m−2), pH (6.33 vs. 6.65) and erythema (249.45 vs. 286.34 AU). Cold-water immersion increased TEWL (25.75 vs. 34.96 g·h−1·m−2) and pH (6.33 vs. 6.62). TEWL (7.99 vs. 9.98 g·h−1·m−2) and erythema (209.07 vs. 227.79 AU) increased after being in contact with the hot region (44 °C) of the TempTest. No significant differences were found after contact with the cold region (4 °C) of the TempTest. In conclusion, long and continuous water exposure damages skin barrier function, with hot water being even more harmful. It would be advisable to use cold or lukewarm water for handwashing and avoid hot water. Knowing the proper temperature for hand washing might be an important measure to prevent flares in patients with previous inflammatory skin diseases on their hands.

Drowning Risk Analysis Comparing Surf Bather Subgroups

The study assessed the utility of risk analysis for advancing knowledge on drowning risk factors. The setting was unintentional drowning of surf bathers in Australia. Bathers reported earlier exposure to selected risk factors (swimming ability, wave height associated with rip currents and surf bathing experience) and were observed for water exposure (in minutes). These data were then assembled in mathematical models. The analysis forecast relative drowning risk pertaining to risk markers representing selected surf bather subgroups (gender, age and water activity). Contextualized through previous study findings, comparison of results with a gold standard obtained from mortality data generated new surf bather drowning hypotheses suitable for future testing by rigorous analytical epidemiologic designs. The hypotheses were: (1) The male to female comparative surf bather drowning rate is explained primarily by differences in crude water exposure; (2) the association of cardio-vascular medical conditions with surf bather drowning is stronger for older surf bathers compared to younger surf bathers; and (3) other risk contributors to surf bather drowning are: Poorly calibrated perception of bathing ability (overconfidence) and use of alcohol. Nonetheless, drowning rates appear generally consistent with time exposure to water. The study findings may also support drowning prevention strategies targeting risk marker subgroups.

Watercraft Decontamination Practices to Reduce the Viability of Aquatic Invasive Species Implicated in Overland Transport.

Recreational boating activities enable aquatic invasive species (AIS) dispersal among disconnected lakes, as invertebrates and plants caught on or contained within watercraft and equipment used in invaded waterbodies can survive overland transport. Resource management agencies worldwide recommend decontaminating watercraft and equipment using high water pressure, rinsing with hot water, or air-drying for up to seven days to inhibit this mode of secondary spread. There is a lack of studies on the efficacy of these methods under realistic conditions and considering feasibility for recreational boaters. Hence, we conducted experiments addressing this knowledge gap using AIS present in Ontario, namely zebra mussels (Dreissena polymorpha), banded mystery snails (Viviparus georgianus), spiny waterfleas (Bythotrephes cederstroemi), Eurasian watermilfoil (Myriophyllum spicatum), Carolina fanwort (Cabomba caroliniana), and European frogbit (Hydrocharis morsus-ranae). Washing at high pressures of 900-1200 psi removed the most biological material (90%) from surfaces. Brief (<10s) exposure to water at ≥60°C caused nearly 100% mortality among all species tested, except snails. Acclimation to temperatures from 15°C to 30°C before hot water exposure had little effect on the minimum temperature required for no survival. Air-drying durations producing complete mortality were ≥60h for zebra mussels and spiny waterfleas, and ≥6 days among plants, whereas survival remained high among snails after a week of air-drying. Hot water exposure followed by air-drying was more effective than either method separately against all species tested, reducing either the minimum water temperature or air-drying duration necessary. These findings can inform best management strategies against AIS spread.

1269. Infection, Clinical Syndromes and Antimicrobial Resistance by Aeromonas species: 13-Year Experience with an Emerging Pathogen at a Tertiary Care Center

Background Aeromonas spp. are emerging pathogens that cause a wide breadth of clinical syndromes, ranging from acute gastroenteritis to skin and soft tissue infections, sepsis, and “flesh-eating” necrotizing fasciitis. Aeromonads have been associated with natural disasters and have predominance in estuarine ecosystems, generating a negative impact on the fishing industry and aquaculture, as well as morbidity and mortality in human populations at risk. Antimicrobial resistance patterns differ by geographic locations worldwide, and studies to guide the therapy in the era of multidrug resistance are lacking in the US. Methods A retrospective case series was designed to chart review all adult subjects who had culture proven Aeromonas spp. infections during the period 2008-2020. Demographic data, water exposure, clinical syndromes on presentation, origin (community-acquired vs. nosocomial) and severity of infection, antibiograms, empirical antibiotics, time-to-appropriate therapy, and treatment outcomes were collected. Results Eighty-two subjects were included in the analysis. Demographic and clinical data is summarized in Table 1. Near 20% individuals had water exposure, including 53% of those with traumatic wound infections. Skin and soft tissue infection (including traumatic and surgical wound infections) was the most frequent clinical syndrome (51.2%). Sepsis was present on admission in 33% inpatients. Appropriate antibiotics were instituted in a median of 2 days (IQR=1-5), and the most prescribed empiric agents were piperacillin-tazobactam (48%) and meropenem (13.3%). Most isolates were susceptible to cefepime (70/71, 98.6%), levofloxacin (72/78, 92.3%) and TMP-SMX (69/78, 88.5%). Resistance to meropenem was reported in 18/31 isolates (58.1%) after 2015. Treatment failure was identified in 32.3% cases. Most cases (55%) were encountered during the months of spring and summer, which have warmer temperatures and seasonal heavy rains. Tropical storms caused significant flooding in the Galveston Bay area and Southeast Texas during the summer of 2015, which interestingly coincides with the high number of cases. However, following Hurricane Ike in 2008 or Hurricane Harvey in 2017, the number of cases did not significantly increase. Conclusion Aeromonads are emerging pathogens that cause mainly intraabdominal and skin and soft tissue infections. Their incidence is seasonal (55% cases in spring and summer) and it is associated with water exposure in more than half of those with traumatic wound infections. In subjects with specific risk factors, the use of carbapenem-sparing strategies, such as 3rd or 4th generation cephalosporins, fluoroquinolones or TMP-SMX, may improve outcomes. Disclosures All Authors: No reported disclosures

Aquaculture Reuse Water, Genetic Line, and Vaccination Affect Rainbow Trout (Oncorhynchus mykiss) Disease Susceptibility and Infection Dynamics

Infectious hematopoietic necrosis virus (IHNV) and Flavobacterium psychrophilum are major pathogens of farmed rainbow trout. Improved control strategies are desired but the influence of on-farm environmental factors that lead to disease outbreaks remain poorly understood. Water reuse is an important environmental factor affecting disease. Prior studies have established a replicated outdoor-tank system capable of varying the exposure to reuse water by controlling water flow from commercial trout production raceways. The goal of this research was to evaluate the effect of constant or pulsed reuse water exposure on survival, pathogen prevalence, and pathogen load. Herein, we compared two commercial lines of rainbow trout, Clear Springs Food (CSF) and Troutex (Tx) that were either vaccinated against IHNV with a DNA vaccine or sham vaccinated. Over a 27-day experimental period in constant reuse water, all fish from both lines and treatments, died while mortality in control fish in spring water was &lt;1%. Water reuse exposure, genetic line, vaccination, and the interaction between genetic line and water exposure affected survival (P&lt;0.05). Compared to all other water sources, fish exposed to constant reuse water had 46- to 710-fold greater risk of death (P&lt;0.0001). Tx fish had a 2.7-fold greater risk of death compared to CSF fish in constant reuse water (P ≤ 0.001), while risk of death did not differ in spring water (P=0.98). Sham-vaccinated fish had 2.1-fold greater risk of death compared to vaccinated fish (P=0.02). Both IHNV prevalence and load were lower in vaccinated fish compared to sham-vaccinated fish, and unexpectedly, F. psychrophilum load associated with fin/gill tissues from live-sampled fish was lower in vaccinated fish compared to sham-vaccinated fish. As a result, up to forty-five percent of unvaccinated fish were naturally co-infected with F. psychrophilum and IHNV and the coinfected fish exhibited the highest IHNV loads. Under laboratory challenge conditions, co-infection with F. psychrophilum and IHNV overwhelmed IHNV vaccine-induced protection. In summary, we demonstrate that exposure to reuse water or multi-pathogen challenge can initiate complex disease dynamics that can overwhelm both vaccination and host genetic resistance.