• BioChip Journal
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• v.12 no.4
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• pp.287-293
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• 2018

Bacillus cereus can cause blood infections (i.e., sepsis). Its early detection is very important for treating patients. However, an antibody with high binding affinity to B. cereus is not currently available. Bacteriophage cell wall-binding domain (CBD) has strong and specific binding affinity to B. cereus. Here, we report the improvement in the sensitivity of an ATP bioluminescence assay for B. cereus detection using CBD-conjugated magnetic nanoparticles (CBD-MNPs). The assay was able to detect as few as 10 colony forming units (CFU) per mL and $10^3CFU\;per\;mL$ in buffer and blood. CBD-MNPs did not show any cross-reactivity with other microorganisms. These results demonstrate the feasibility of the ATP assay for the detection of B. cereus.

• Restorative Dentistry and Endodontics
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• v.46 no.4
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• pp.58.1-58.8
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• 2021

Objectives: This study addresses the effect of using nanoparticles (np) on the antimicrobial properties of bioactive glass (BAG) when used in intracanal medicaments against Enterococcus faecalis (E. faecalis) biofilms. Materials and Methods: E. faecalis biofilms, grown inside 90 root canals for 21 days, were randomly divided into 4 groups according to the antimicrobial regimen followed (n = 20; BAG-np, BAG, calcium hydroxide [CaOH], and saline). After 1 week, residual live bacteria were quantified in terms of colony-forming units (CFU), while dead bacteria were assessed with a confocal laser scanning microscope. Results: Although there was a statistically significant decrease in the mean CFU value among all groups, the nano-group performed the best. The highest percentage of dead bacteria was detected in the BAG-np group, with a significant difference from the BAG group. Conclusions: The reduction of particle size and use of a nano-form of BAG improved the antimicrobial properties of the intracanal treatment of E. faecalis biofilms

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.2
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• pp.149-157
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• 2022

The aim of this study was to evaluate the effects of erythrosine-mediated photodynamic therapy (PDT) on Streptococcus mutans biofilm recovery by counting its colony-forming units (CFUs) and via confocal laser scanning microscopy analysis at different time points following PDT. In PDT, photosensitizer was an erythrosine. S. mutans ATCC25175 biofilms were irradiated using an LED curing light. Chlorhexidine (CHX) was used as positive control. After each antimicrobial treatment, samples were cultured to allow biofilm recovery. Viability was measured by calculating the CFU counts after treatment and after every 3 hours for up to 24 hours. Immediately after treatment, the PDT and CHX groups showed equally significant decreases in S. mutans CFU counts compared to the negative control. After 12 hours of reculture, the PDT group showed no significant difference in the decrease in CFU count compared to the negative control, whereas the CHX group showed significantly lower CFU counts throughout the 24-hour period. Erythrosine-mediated PDT can effectively inhibit S. mutans biofilm formation. However, biofilm recovery occurred earlier in the CHX group after PDT. This study provides insights into the clinical effectiveness of PDT in preventing dental caries.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.19
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• pp.8171-8175
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• 2014

Background: To study the radioprotective effects of flavonoids from Rosa roxburghii Tratt (FRT). Materials and Methods: The radioprotective effects of FRT were investigated by examining cell viability, 30-day survival of mice and the number of colony-forming units in spleen (CFU-S) after total-body 60Co irradiation. Results: The survival rates of irradiated cells gradually increased with increasing concentrations of FRT. The survival rate was the highest at 87% with a concentration of $30{\mu}g/mL$. Pretreatment with FRT was needed to realize its radioprotective activity in mice at the dose of 60 mg/kg. With the increasing doses of 30 mg/kg, 60 mg/kg and 120 mg/kg, the numbers of CFU-S increased, and were significantly different compared with the control group. Conclusions: Pretreatment with FRT prior to irradiation resulted in significantly higher cell survival at 24 h after 5 Gy radiation, increased 30-day survival in mice after exposure to a potentially lethal dose of 8 Gy, and resulted in a higher number of CFU-S in mice after exposure to a dose of 6 Gy. These results collectively indicate that FRT is an effective radioprotective agent.

• Journal of Microbiology and Biotechnology
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• v.22 no.9
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• pp.1296-1300
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• 2012

The feasibility of using Deinococcus showing strong resistance to both desiccation and ionizing radiation as a dose indicator of gamma radiation exposure was evaluated. Three Deinococcus strains having different levels of radiation resistance, Deinococcus radiodurans (DRD), Deinococcus radiopugnans (DRP), and the DRD pprI mutant (DRM), were selected to develop an appropriate dose indicator for a broad range of exposures. DRD, DRP, and DRM cultures with different numbers of cells [${\sim}10^7$ to $10^3$ colony forming units (CFU)/$100{\mu}l$] were lyophilized and subjected to various doses of gamma radiation to determine a critical dose that inhibited bacterial growth completely. Finally, a combination of DRD at ${\sim}10^7$ and ${\sim}10^6$ CFU, DRP at ${\sim}10^5$ CFU, and DRM at ${\sim}10^4$ CFU successfully indicated exposure to 5, 10, 20, and 30 kGy of gamma radiation, respectively. This study shows the possibility of developing a qualitative indicator of radiation exposure using Deinococcus.

• International Journal of Oral Biology
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• v.40 no.3
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• pp.143-146
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• 2015

The purpose of this study was to compare the effect of different methods of hand washing by counting the number of bacteria on the hand surface. Eighteen clinicians were chosen and divided into three groups, consisting of six clinicians each. Culturing of the right raw palms of all individuals was performed. Individuals in the control group washed hands for 5 seconds with antimicrobial soap. Group 1 washed their hands for 10 seconds with antimicrobial soap. Group 2 washed with an instant alcohol-based hand sanitizer. After the respective washes, re-culturing of the right raw palm was done for each member of all groups. The colony-forming units (CFU) were calculated at each time point, and the reduction rate of CFU among the three groups were statistically evaluated using student t-test. All groups showed a significant decrease in CFU, according to the time applied (P<0.01). In addition, the reduction rate of CFU between the groups were statistically evaluated with ANOVA (P<0.01). It showed statistically difference between the control group and group 1, control group and group 2. The present study confirmed that the hand washing method with antimicrobial soap for 10 seconds and hand sanitizer, including alcohol, were excellent for decreasing the number of bacteria on the hand surface.

• Journal of Food Hygiene and Safety
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• v.29 no.1
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• pp.16-20
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• 2014

The prevalence of Bacillus cereus was determined in salad and Kimbab obtained from commercial retailers. Among the 100 salad samples analyzed, 54 samples were negative for B. cereus, whereas the bacterial count was < 10 colony forming units (CFU)/g in 8 samples, < 100 CFU/g in 25 samples, < 1,000 CFU/g in 11 samples, and > 1,000 CFU/g in 2 samples. The mean (standard deviation) was 1.18 log CFU/g (${\pm}0.71$ log CFU/g). In Kimbab, B. cereus was isolated from 20 samples; the mean bacterial count was 1.01 log CFU/g (${\pm}0.71$ log CFU/g). On the basis of the monitoring data, a statistical sampling plan was determined with the NEW sampleplan program (ICMSF), which was used as an analytical tool. To identify the most suitable sampling plan, the microbial limits (m, M) and the maximum allowable number of sample units yielding unsatisfactory test results (c) were varied, but the number of samples units, n = 5, was fixed. Sampling plans showing an acceptable probability (Pa) over 0.95 were considered suitable. Two plans (A and B) were finally suggested. Parameters for plan A are n = 5, c = 0, m = 1,000, and M = 10,000 and for plan B are n = 5, c = 2, m = 100, and M = 1,000. Interestingly, the latter plan was identical to the microbial sampling plan used in New Zealand. Thus, it was concluded that the suggested plan can be used as a sampling plan that is in line with international standards.

• Journal of Genetic Medicine
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• v.7 no.2
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• pp.138-144
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• 2010

Purpose: Endothelial progenitor cells (EPCs), which mediates neovascularization of uterine endometrium may be involved in the neovascularization in the utero-placental circulation. Low numbers of endothelial progenitor colony-forming unit (CFU) in culture are predictive biomarker of vascular disease. The aim of the present study was to evaluate whether the number of CFU in preeclampsia differed from that in normal pregnancy. Materials and Methods: Women with singleton normal (n=26) or preeclamptic (n=20) pregnancies were studied during the third trimester. The number of EPCs was quantified by CFU methodology. Plasma levels of angiogenic factors, vascular endothelial growth factor (VEGF), soluble fms-like tyrosine kinase-1 (sFlt-1), and placental growth factor (PlGF) were determined by enzyme-linked immunoassay. Results: CFU numbers were significantly decreased in the preeclamptic patients compared with the controls (median, 3; range 1-12 vs. 31; 3-81 CFU/well, P<0.001). A majority of the cells comprising individual colonies were positive for endothelial characteristics (Ulex europaeus lectin staining and acetylated low-density lipoprotein uptake). Plasma levels of the sFlt-1 were highly elevated (P<0.001) in patient with preeclampsia compared to controls, whereas PlGF were highly reduced (P=0.004), but these factors did not associate with CFU numbers. Conclusion: Our results suggest that reduced numbers of CFU obtained from maternal peripheral blood may contribute to the development of preeclampsia.

• Journal of dental hygiene science
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• v.14 no.1
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• pp.1-6
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• 2014

The purpose of this study was to investigate the killing effect of Candida albicans on hairless mouse-2 (HRM-2) mouse tissues. We tested the effectiveness of a non-thermal atmospheric pressure plasma in killing C. albicans strains. The viability of C. albicans was determined by counting the colony forming units (CFU), after non-thermal atmospheric pressure plasma treatment. When non-thermal atmospheric pressure plasma was repeatedly treated on mouse skin which inoculated with C. albicans. The C. albicans cells were planted on skin tissue, and then the infected mouse tissue was exposed to non-thermal atmospheric pressure plasma for 0 sec, 60 sec, 180 sec and 300 sec. The death rate of C. albicans was increased in dependent with treatment times. The three times of non-thermal atmospheric pressure plasma at the interval of 10 minutes significantly showed the 6 log CFU/ml reduction of death rate on HRM-2 mouse tissues. Thus, non-thermal atmospheric pressure plasma could be used for the disinfection of C. albicans on oral surface.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.2
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• pp.405-421
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• 1997

The main purpose of this study was to evaluate the acid resistance and antimicrobial effect of fluoride-laser combined application. Recently extracted third molars were used. $5{\times}3mm$ of the buccal and lingual specimens were exposed and incipient artificial carious lesions were formed by keeping them in the artificial cariogenic solution for 5 days. They were divided into five groups and treated with fluoride and laser according to the predetermined regimen. The acid resistance was compared between groups by chemical quantitative analysis of the calcium and phosphorous released into the test solution after single or combined application of fluoride and laser. The antimicrobial effect of each group was analyzed by counting the number of colony forming units after microbial incubation. The results from the present study can be summarized as follows; 1. Experimental groups showed lower values in calcium and phosphorous contents as well as in $CFU/m{\ell}$(colony forming units) than control group. Combined application groups showed lower values than single application groups. 2. Acid resistance and antimicrobial effect by fluoride and laser treatment were confirmed in this study. 3. Based upon the above-mentioned results of this study, it can be assumed that the use of laser-fluoride combined application may provide the child and adolescent patient population with antimicrobial effect as well as acid resistance. Further studies using various materials and experimental conditions are being encouraged.