Department of Civil Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano, SA, Italy.
CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, Institut Jean Barriol, 15 Avenue du Charmois, 54500, Vandoeuvre-lès-Nancy, France.
Environ Sci Pollut Res Int. 2017 Jan;24(2):1871-1879. doi: 10.1007/s11356-016-7981-6. Epub 2016 Oct 31.
Salmonellosis is one of the most common causes of foodborne bacterial human disease worldwide, and the emergence of multidrug-resistant (MDR) strains of Salmonella enterica serovar Typhimurium (S. typhimurium) was associated to the incidence of invasive salmonellosis. The objective of the present work was to investigate the effects of the TiO photocatalysis process in terms of both bacteria inactivation and the emergence of mutants, on S. typhimurium TA102 water suspensions. The TiO photocatalysis was compared with a conventional disinfection process such as UV-C radiation. In spite of the faster bacterial inactivation obtained in UV-C disinfection experiments (45, 15, and 10 min for total inactivation for initial cell density 10, 10, and 10 CFU mL, respectively), photocatalytic disinfection (60, 30, and 15 min) was more energy efficient because of a lower energy requirement (2-20 mWs cm) compared to the UV-C disinfection process (5-30 mWs cm). During the photocatalytic experiments, the mutation frequency increased up to 1648-fold compared to background level for a 10 CFU mL initial bacterial density, and mutants were inactivated after 1-10-min treatment, depending on initial bacterial cell density. In UV-C disinfection experiments, the mutation frequency increased up to 2181-fold for a 10 CFU mL initial bacterial cell density, and UV-C doses in the range of 0.5-4.8 mWs cm were necessary to decrease mutation frequency. In conclusion, both disinfection processes were effective in the inactivation of S. typhimurium cells, and mutants released into the environment can be avoided if cells are effectively inactivated.
沙门氏菌病是全世界最常见的食源性细菌人类疾病之一，而多重耐药（MDR）鼠伤寒沙门氏菌（S. typhimurium）菌株的出现与侵袭性沙门氏菌病的发病率有关。本工作的目的是研究 TiO 光催化过程对沙门氏菌 TA102 水悬液的细菌失活和突变体出现的影响。将 TiO 光催化与传统消毒过程（如 UV-C 辐射）进行了比较。尽管在 UV-C 消毒实验中获得了更快的细菌失活（初始细胞密度为 10、10 和 10 CFU mL 时，总失活所需的时间分别为 45、15 和 10 min），但由于光催化消毒的能量需求较低（2-20 mWs cm），因此比 UV-C 消毒过程（5-30 mWs cm）更节能。在光催化实验中，与背景水平相比，初始细菌密度为 10 CFU mL 时的突变频率增加了 1648 倍，并且突变体在 1-10 min 处理后失活，这取决于初始细菌细胞密度。在 UV-C 消毒实验中，初始细菌细胞密度为 10 CFU mL 时，突变频率增加了 2181 倍，需要 0.5-4.8 mWs cm 的 UV-C 剂量才能降低突变频率。总之，两种消毒过程都能有效灭活 S. typhimurium 细胞，如果能有效灭活细胞，则可避免突变体释放到环境中。
