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Disinfection
Published in Paul N. Cheremisinoff, Handbook of Water and Wastewater Treatment Technology, 2019
Generally, pathogenic bacteria are best suited to their environment inside a warm-blooded host animal and usually do not multiply and are readily killed by disinfecting chemicals. There are some exceptions, however, and total pathogen die-off should never be taken for granted. Spore-producing pathogens can resist chemical disinfection, and although they are not direct human-water-borne microorganisms, they should be noted. Bacillus anthracis: The anthrax pathogen is picked up by animals and transmitted to humans.Clostridium tetani: These spores introduced to bathers via deep wounds could conceivably cause tetanus (lockjaw).Clostridium botulinum: Produces botulism toxin (the most powerful poison known). These spores will not affect human beings directly but uncooked foods sealed in spore-laden water can be deadly.Some of the waterborne bacterial diseases areCholera: The most serious waterborne disease with potentially fatal results can be spread via polluted water. The organism Vibrio cholerae can persist for weeks in very turbid waters. Turbidity also protects it from some disinfectants.Salmonellosis: There are several hundred species of the genus Salmonella known to attack humans. Their effects range in severity from typhoid fever to the common acute intestinal upsets (food, ptomaine, poisoning). The source is direct or indirect fecal contamination from practically any warm-blooded animal.Shigellosis: This is the most common waterborne cause of acute diarrhea in the United States. There are many genus types, with Shigella dysenteriae being the most serious cause of dysentery. The malady known as “Montezuma’s revenge” or “turista” is caused by regional variants of Escherichia coli. It is harmless to natives but often affects visitors.Tuberculosis: This is a lung disease commonly thought to be spread through the air, but it also can be transmitted via swimming in or drinking contaminated water.
Fish waste capped and colloidal nanosilver and its valorization as natural zeolite conjugates for application in aquaculture
Published in Journal of Dispersion Science and Technology, 2023
Kangkana Das, Kishore Kumar Krishnani, Ajay Kumar Upadhyay, Satya Prakash Shukla, Kurcheti Pani Prasad, Puja Chakraborty, Biplab Sarkar
Krishnani et al.[45] have reported antimicrobial activity of silver-ion-exchanged zeolite against E. coli, Vibrio harveyi, V. cholerae, and V. parahaemolyticus in liquid medium and agar well diffusion assays. However, they have not used silver nanoparticles. Sinha et al.,[47] reported the biological synthesis of silver nanoparticles by using freshwater green alga Pithophora oedogonia (Mont.) Wittrock and their antibacterial activity by disk diffusion method with the result of the maximum zone of inhibition shown against Pseudomonas aeruginosa (17.2 mm) followed by E. coli (16.8 mm). Firdhouse and Lalitha[48] have reported the synthesis of silver nanoparticles using the leaf extract of Abutilon indicum exhibiting highly potent antibacterial activity on certain microbes such as S. aureus, B. subtilis, A. hydrophila, S. typhi, and E. coli. Jo et al.[49] have reported the surface independent antibacterial coating strategy based on the fusion of MAP (Mussel adhesive proteins) derived from marine mussels to a silver-binding peptide, which can synthesize silver nanoparticles having broad antibacterial activity against Gram negative bacteria E. coli, Salmonella enterica subspecies enterica serotype Typhimurium and Shigella dysenteriae and the Gram + ve bacteria Staphylococcus aureus.
Evaluation of antioxidation, regulation of glycolipid metabolism and potential as food additives of exopolysaccharide from Sporidiobolus pararoseus PFY-Z1
Published in Preparative Biochemistry & Biotechnology, 2023
Di Xue, Fangyi Pei, Henan Liu, Zhenyan Liu, Yuchao Liu, Lei Qin, Yinzhuo Xie, Changli Wang
The antibacterial activities of pathogenic bacteria (Bacillus subtilis CICC 10275, Streptococcus pyogenes CICC 10373, Staphylococcus aureus CICC 10384, Escherichia coli CICC 10389, Klebsiella Pneumoniae CICC 10870, Bacillus cereus CICC 21261, Salmonella infantis CICC 21482, Salmonella enteritidis CICC 21513, Proteus mirabilis CICC 21516, Vibrio parahemolyticus CICC 21617, Pseudomonas aeruginosa CICC 21636, Rhodococcus equi CICC 22955, Enterococcus faecalis CICC 23658, and Shigella dysenteriae CICC 23829) of SPZ were determined using the Oxford cup method. The SPZ solution (2 mg/mL) was added to the well, which was incubated at 30 °C for 24 h; we then measured the diameter of the inhibition zone.[25,33,34]
PVCS/GO nanocomposites: investigation of thermophysical, mechanical and antimicrobial properties
Published in Journal of Sulfur Chemistry, 2022
Milad Sheydaei, Vahid Pouraman, Ebrahim Alinia-Ahandani, Shabnam Shahbazi-Ganjgah
To sum up, we dechlorinated the PVC and successfully added 35.6 wt.% of sulfur to the structure. The presence of S-S bonds in the structure due to their weak and flexibility, as well as preventing the crystallization of any of the PVCs attached to them, reduced the mechanical properties. But, the presence of sulfur in the structure due to its lipophilic nature can penetrate the mitochondrial inner membrane and thereby create antibacterial properties. The basis of sulfur function is through contact action, respiratory inhibition, and the formation of chelating complexes with cellular lipid moieties. Hence, the results showed that PVCS is more effective against gram-positive bacteria than gram-negative, which is related to their different cell-wall structures. On other hand, the presence of GO in the structure improved the mechanical, thermophysical, and antimicrobial properties. Thermophysical results showed that the GO content increases the Tg up to 3°C and the Tm up to 16.5°C. The antimicrobial results showed that the content of 0.3% and 0.5% of GO caused the inhibition zone in Escherichia coli and Shigella dysenteriae, as well as improved the inhibition zone and killing in gram-positive bacteria. Also, the results showed that the content of 0.5% of GO significantly increases the mechanical properties. In general, it can be said that the PVCS and its nanocomposites have the potential to be used in environments with high population densities such as hospitals, bus stations, and subways for seats, flooring, wall coverings, and counters.