Ultraviolet irradiation and the mechanisms underlying its inactivation of infectious agents

Abstract

We review the principles of ultraviolet (UV) irradiation, the inactivation of infectious agents by UV, and current applications for the control of microorganisms. In particular, wavelengths between 200 and 280 nm (germicidal UV) affect the double-bond stability of adjacent carbon atoms in molecules including pyrimidines, purines and flavin. Thus, UV inactivation of microorganisms results from the formation of dimers in RNA (uracil and cytosine) and DNA (thymine and cytosine). The classic application of UV irradiation is the inactivation of microorganisms in biological safety cabinets. In the food-processing industry, germicidal UV irradiation has shown potential for the surface disinfection of fresh-cut fruit and vegetables. UV treatment of water (potable and wastewater) is increasingly common because the process is effective against a wide range of microorganisms, overdose is not possible, chemical residues or by-products are avoided, and water quality is unaffected. UV has been used to reduce the concentration of airborne microorganisms in limited studies, but the technology will require further development if it is to gain wider application. For bioaerosols, the primary technical challenge is delivery of sufficient UV irradiation to large volumes of air, but the absence of UV inactivation constants for airborne pathogens under a range of environmental conditions (temperature, relative humidity) further compounds the problem.

Dual UV irradiation-based metal oxide nanoparticles for enhanced antimicrobial activity in <em>Escherichia coli</em> and M13 bacteriophage

“…1,2 Under UV irradiation, they also target microorganisms and enhance the antimicrobial activities as disinfection agents in a purification system. 4,5 Thus, the combination of UV and MO nanoparticles can be applied for a future disinfection system. [9][10][11] Adsorption function of MO nanoparticles to microorganisms can induce the disruption of bio-membranes and massive leakage of cell contents, due to their surface characteristics and physicochemical properties.…”

Subcellular mechanism of Escherichia coli inactivation during electrochemical disinfection with boron-doped diamond anode: A comparative study of three electrolytes

“…Apart from the cell membrane and the enzymes, the cell death could also be induced by damage in the DNA. Typically, in UV disinfection, bacterial inactivation mainly results from the formation of dimers in DNA (thymine and cytosine) and RNA (uracil and cytosine) (Cutler and Zimmerman, 2011). However, with regard to electrochemical disinfection, especially with BDD anode, the investigations concerning the subcellular inactivation mechanisms were extremely limited.…”

Polioviruses and other Enteroviruses

“…Virus inactivation by UV is dependent on interaction between high-energy photons and nucleic acids within viral particles that form pyrimidine dimers, other photoproducts, tertiary structural changes, and at high doses (>1,000 mW • s/cm 2 ) may also affect the capsid protein and generate RNA-protein linkages (Cutler and Zimmerman, 2011;Hijnen et al, 2006;Kurosaki et al, 2003;Nuanualsuwan and Cliver, 2003b;Okoh et al, 2010). UV inactivation appears to be effective against all pathogenic organisms although susceptibility of different EVs varied (Hijnen et al, 2006)).…”

“…In contrast to chlorination, large amounts of DBPs are not formed (Ngwenya et al, 2013) and overdose is not possible (Cutler and Zimmerman, 2011). Inactivation of enteric viruses with UV appears more efficient than with chlorine compounds (Blatchley et al, 2007;Hijnen et al, 2006).…”