Sensitivity of oral bacteria to 254 nm ultraviolet light

Metzger, Zvi; Dotan, Miri; Better, Hadar; Abramovitz, Itzhak

doi:10.1111/j.1365-2591.2006.01191.x

Cited by 21 publications

(28 citation statements)

References 31 publications

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“…Interestingly, all the strains revealed UV resistance, since the fraction of each population killed by 254 nm irradiation was in the range of 0-5% at 60 J.m -2 , 60-70% at 80 J.m -2 , 95-98% at 100 J.m -2 and 99.5-99.9% at 120 J.m -2 . This is to be compared to the reported 100% killing of Lactobacillus brevis exposed to 254 nm UV light at 70 J.m -2 [47]. Competition experiments in mixed cultures revealed no imbalance in growth or survival between the σ H overproducing or σ H deficient and WT strains in MCD medium (Figure 5).…”

Section: Resultsmentioning

confidence: 57%

Alternative sigma factor σH activates competence gene expression in Lactobacillus sakei

2012

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BackgroundAlternative sigma factors trigger various adaptive responses. Lactobacillus sakei, a non-sporulating meat-borne bacterium, carries an alternative sigma factor seemingly orthologous to σH of Bacillus subtilis, best known for its contribution to the initiation of a large starvation response ultimately leading to sporulation. As the role of σH-like factors has been little studied in non-sporulating bacteria, we investigated the function of σH in L. sakei.ResultsTranscription of sigH coding for σH was hardly affected by entry into stationary phase in our laboratory conditions. Twenty-five genes potentially regulated by σH in L. sakei 23 K were revealed by genome-wide transcriptomic profiling of sigH overexpression and/or quantitative PCR analysis. More than half of them are involved in the synthesis of a DNA uptake machinery linked to genetic competence, and in DNA metabolism; however, σH overproduction did not allow detectable genetic transformation. σH was found to be conserved in the L. sakei species.ConclusionOur results are indicative of the existence of a genetic competence state activated by σH in L. sakei, and sustain the hypothesis that σH-like factors in non sporulating Firmicutes share this common function with the well-known ComX of naturally transformable streptococci.

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Section: Resultsmentioning

confidence: 57%

Alternative sigma factor σH activates competence gene expression in Lactobacillus sakei

2012

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“…The conclusion is that the application of UV light to eliminate endodontic pathogens may be possible. Nevertheless, its absorbance by outer layers of bacteria should be considered and the UV light dose adapted accordingly (13).…”

Section: S S U E 2 2 0 1mentioning

confidence: 99%

Application of ultraviolet light (UV) in dental medicdine

Panov¹,

Borisova-Papancheva²

2015

MedInform

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Ultraviolet (UV) light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, that is, in the range between 400 nm and 100 nm. Because of its ability to cause chemical reactions and excite fluorescence in materials, ultraviolet light has a huge number of useful applications in modern medicine, for diagnostic and therapeutic purposes. UV rays are the oldest method humans have used for decontamination; it is used for inactivating viruses, bacteria and fungi. In dental medicine, the diagnostic uses are concerned with the fluorescence of teeth with radiation exposures to small areas and doses no more than 5 J/cm2. A number of dental procedures involve the use of Ultraviolet radiation in the oral cavity.

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“…Photodynamic therapy (PDT) and ultraviolet disinfection both use light at a specified wavelength that is known to have antimicrobial properties (Metzger et al 2007, Chrepa et al 2014). The most current endodontic research is focusing on PDT as a potential adjunctive debridement technique.…”

Section: Advances In Irrigation and Disinfection Of The Root Canalmentioning

confidence: 99%

“…In a recent systematic review on PDT, Chrepa et al found that all 57 studies included in the review "showed positive effect of PDT in the reduction of microbial load in root canal treatment ranging from 91.3% -100%." The PDT is showing positive results in the eradication of bacteria from the canal space, but, this treatment does not come without disadvantages; such as tooth discoloration due to the photosensitizer and potential for wide range cytotoxicity (Chrepa et al 2010 (Metzger et al 2006 and).…”

Section: Advances In Irrigation and Disinfection Of The Root Canalmentioning

confidence: 99%

“…In a recent review, Holliday et al addresses the potential issues of UV light being absorbed through thin dentin and effecting the surrounding tissues, "with 100 µm of dentine (the thickness of a coat of a paint) allowing passage of only 1% of the UV light (<3 mJ/cm2), which is within EU safety limits" (Holliday et al 2014). However, further understanding into the depth of dentin penetration of UV light and potential cytotoxicity to surrounding tissues is still required to make this therapy safe for in vivo use (Metzger et al 2007).…”

Section: Advances In Irrigation and Disinfection Of The Root Canalmentioning

confidence: 99%

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Development of a new multi-species, in vitro model for root canal disinfection

Morio¹

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Bacterial disinfection of the root-canal system is the goal in achieving a successful root canal treatment. Currently, this is accomplished by mechanical and chemical debridement. However, limitations continue to exist with these processes and bacteria can still remain, resulting in potential failure of treatment. The aims of this study were to develop a stable, reproducible polymicrobial biofilm in human teeth and utilize this model to compare the bactericidal activity of the UV light disinfection to current root canal chemo-mechanical debridement techniques. We hypothesized that use of UV light at known bactericidal wavelengths were lethal to bacterial cells. Our pilot studies have revealed strong bactericidal capabilities of the UV light against four bacterial species which have been previously isolated in failed root canal procedures; Enterococcus facealis, Actinomyces viscosus, Porphyromonas gingivalis and Fusobacterium nucleatum. We then developed a novel stable reproducible human tooth multi-species biofilm model for UV light disinfection testing. Studies were conducted to evaluate the treatment effects of NaOCl only, UV only and NaOCl+UV. The data revealed strong evidence of initial treatment effect with NaOCl and NaOCl+UV for species A. viscosus and E. faecalis. At 72 hours incubation/immediate post-treatment of NaOCl and NaOCl+UV, treated groups demonstrated lower bacterial concentrations (CFU/ml) compared to 6 days incubation/72 hour post-treatment, indicating significant regrowth caused by the remaining bacteria, which is reflective of the etiology of post-treatment reinfection of the root canal. We believe that our polymicrobial colonization model system will provide a unique and valuable model system for our future studies. Moreover, more comprehensive treatment modalities can be assessed in our novel model system. iv

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Sensitivity of oral bacteria to 254 nm ultraviolet light

Abstract: The application of UV light to eliminate endodontic pathogens may be possible. Nevertheless, its absorbance by outer layers of bacteria should be considered and the UV light dose adapted accordingly.

Cited by 21 publications

References 31 publications

Alternative sigma factor σH activates competence gene expression in Lactobacillus sakei

Alternative sigma factor σH activates competence gene expression in Lactobacillus sakei

Application of ultraviolet light (UV) in dental medicdine

Development of a new multi-species, in vitro model for root canal disinfection

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