Prevalence of Opportunistic Pathogens and Diversity of Microbial Communities in the Water System of a Pulmonary Hospital / 生物医学与环境科学（英文）

Objective@#Our objective was to investigate the occurrence of opportunistic pathogens and characterize the bacterial community structures in the water system of a pulmonary hospital.@*Methods@#The water samples were collected from automatic and manual faucets in the consulting room, treatment room, dressing room, respiratory ward, and other non-medical rooms in three buildings of the hospital. Quantitative polymerase chain reaction was used to quantify the load of several waterborne opportunistic pathogens and related microorganisms, including spp., spp., and . Illumina sequencing targeting 16S rRNA genes was performed to profile bacterial communities.@*Results@#The occurrence rates of spp., spp., and were 100%, 100%, and 76%, respectively in all samples. Higher occurrence rates of were observed in the outpatient service building (building 1, 91.7%) and respiration department and wards (building 2, 80%) than in the office building (building 3), where no was found. were more abundant in automatic faucets (average 2.21 × 10 gene copies/L) than in manual faucets (average 1.03 × 10 gene copies/mL) ( < 0.01). , , , , , and were the dominant bacterial phyla. Disinfectant residuals, nitrate, and temperature were found to be the key environmental factors driving microbial community structure shifts in water systems.@*Conclusion@#This study revealed a high level of colonization of water faucets by opportunistic pathogens and provided insight into the characteristics of microbial communities in a hospital water system and approaches to reduce risks of microbial contamination.

Reductive dechlorination of p-chlorophenol by nanoscale iron / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate reductive dechlorination of 4-chlorophenol (4-CP) by nanoscale Fe0 under different conditions.</p><p><b>METHODS</b>Nanoscale Fe0 was synthesized by using reductive method. 4-CP and its intermediate products were analyzed by HPLC. Chlorine ion was quantified with DX-100 ion chromatograph. Nano-iron particles were observed under a FEI Quanta 200 FEG environmental scanning electron microscope (ESEM).</p><p><b>RESULTS</b>The size of the particles was in the range of 10-100 nm. The nano-iron particles could reduce 4-CP effectively. The initial concentration of 4-CP increased with the decrease of the relative degradation rate, whereas the reduced amount of 4-CP increased. Temperature could influence both the dechlorination rate and the reaction pathway. Moreover, the stability and durability of nanoscale Fe0 was evaluated through batch studies over extended periods of time.</p><p><b>CONCLUSION</b>The nanoscale Fe0 can be used for sustainable treatment of contaminants in groundwater.</p>