Thermal stability is essential for the survival and well-being of preterm neonates. This is achieved in neonatal incubators by raising the ambient temperature and humidity to sufficiently high levels. However, potentially pathogenic microorganisms also can thrive in such warm and humid environments. We therefore investigated whether the level of microbial contamination (i.e., the bacterial load) inside neonatal incubators can be predicted on the basis of their average temperature and relative humidity settings, paying special attention to local temperature differences. Swab samples were taken from the warmest and coldest spots found within Caleo incubators, and these were plated to determine the number of microbial CFU per location. In incubators with high average temperature (>34°C) and relative humidity (>60%) values, the level of microbial contamination was significantly higher at cold spots than at hot spots. This relates to the fact that the local equilibrium relative humidity at cold spots is sufficiently high to sustain microbial growth. The abundance of staphylococci, which are the main causative agents of late-onset sepsis in preterm neonates, was found to be elevated significantly in cold areas. These findings can be used to improve basic incubator hygiene.To increase the survival chances of premature infants, incubators have been developed which provide a thermoneutral environment. This environment must be defined in terms of temperature, humidity, convection, and surrounding radiant heat sources. The humidification of the incubators has helped in this respect, as the greatest heat loss by preterm neonates is due to evaporative transepidermal water loss. Increased relative humidity (RH) reduces the rate of evaporation and, as a consequence, not only reduces evaporative heat loss (4) but also helps to maintain the electrolyte and fluid balance of preterm neonates (7). Unfortunately, these conditions also increase the risk of microbial infection, because the moist and warm habitat created within an incubator is intrinsically ideal for microbial growth. A fine balance is sought between the thermal requirements of a newborn and the level of humidification and heating of the incubator. The highest levels of humidification and heating are used for the most immature infants with the lowest birth weights, as they have the most difficulty with maintaining their thermal stability (2, 8, 10). The humidification and heating levels are lowered slowly in the course of the first days and weeks after birth as the neonates' weight and the maturity of their skin barrier increase.The availability of water is one of the most important factors for microbial growth. Water availability on surface-to-air interfaces is determined by the local equilibrium relative humidity (RH e ). Molds require RH e values of at least 70%, and RH e values need to be even higher (80 to 95%) to allow for the growth of yeasts, Gram-positive bacteria, and Gram-negative bacteria; the latter group of bacteria require the highest RH e values (9). Th...
Membrane filtration systems are widely applied for the production of clean drinking water. However, the accumulation of particles on synthetic membranes leads to fouling. Biological fouling (i.e., biofouling) of reverse osmosis and nanofiltration membranes is difficult to control by existing cleaning procedures. Improved strategies are therefore needed. The bacterial diversity on fouled membranes has been studied, especially to identify bacteria with specialized functions and to develop targeted approaches against these microbes. Previous studies have shown that Sphingomonadaceae are initial membrane colonizers that remain dominant while the biofilm develops. Here, we characterized 21 Sphingomonadaceae isolates, obtained from six different fouled membranes, to determine which physiological traits could contribute to colonization of membrane surfaces. Their growth conditions ranged from temperatures between 8 and 42 oC, salinity between 0.0 and 5.0% w/v NaCl, pH from 4 and 10, and all isolates were able to metabolize a wide range of substrates. The results presented here show that Sphingomonadaceae membrane isolates share many features that are uncommon for other members of the Sphingomonadaceae family: all membrane isolates are motile and their tolerance for different temperatures, salt concentrations, and pH is high. Although relative abundance is an indicator of fitness for a whole group, for the Sphingomonadaceae it does not reveal the specific physiological traits that are required for membrane colonization. This study, therefore, adds to more fundamental insights in membrane biofouling.
The novel liquid-infused membranes have been shown to mitigate membrane biofouling. Here, the long-term stability of these membrane have been tested and analyzed using bacterial growth curve models.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.