• Journal of dental hygiene science
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• v.23 no.4
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• pp.343-350
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• 2023

Background: Digital panoramic dental X-ray equipment (PDX) is frequently used by patients and dental workers for diagnosis and examination in dental institutions; however, infection control has not been properly implemented. Therefore, in this study, we aimed to systematically review the potential risk of cross-infection in the dental environment by investigating the contamination level of general aerobic bacteria and Staphylococcus aureus, which are important in hospital infections, in PDX areas that people mainly contact. Methods: This survey was conducted from March to May 2023 and covered one general hospital, three dental hospitals, and nine dental clinics equipped with PDX. Bacteria samples were collected from the left-handle, right-handle, forehead support, and head side support as the patient's contact areas, as well as the X-ray exposure switch and left-click mouse button as the dental hygienist's contact areas of the PDX. The collected bacteria were spread on Petrifilm, and colonies formed after 48 hours of culture were counted. Results: General aerobic bacteria and S. aureus were detected in all areas investigated. Significant differences in bacterial counts between different regions of the PDX were observed in both groups (p<0.001). The detection rates of general aerobic bacteria (p<0.001) and S. aureus (p<0.001) were significantly higher in the contact areas of patients than those of dental hygienists. A positive correlation was observed between the forehead and the temple region in terms of general aerobic bacteria and S. aureus detection (r=1) (p<0.01). Conclusion: Taken together, the presence of many bacteria, including S. aureus, detected in PDX indicates that PDX has a potential cross-infection risk. Our results therefore highlight the need for the development of appropriate disinfection protocols for reusable medical devices such as PDX and periodic infection prevention training for hospital-related workers, including dental hygienists.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.2
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• pp.101-109
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• 2006

The objective of this study is to provide fundamental data for pertinent management of indoor air quality through investigating the size-based characteristics of bioaerosol distributed in the general hospital. Measurement sites are main lobby, ICU, ward and laboratory and total five times were sampled with six-stage cascade impactor. Based on the result of this study, concentrations of airborne bacteria and fungi were the highest in main lobby as followed by an order of ward, ICU and laboratory. Concentrations of airborne bacteria was generally higher than those of airborne fungi and the ratio of indoor and outdoor concentration of both exceeded 1.0 in all the measurement sites of the general hospital. The predominant genera of airborne bacteria identified in the general hospital were Staphylococcus spp.(50%), Micrococcus spp.(15-20%), Corynebacterium spp.(5-20%), and Bacillus spp.(5-15%). On the other hand, the predominant genera of airborne fungi identified in the general hospital were Cladosporium spp.(30%), Penicillium spp.(20-25%), Aspergillus spp.(15-20%), and Alternaria spp.(10-20%). In regard to size distribution of bioaerosol, the detection rate was generally highest on 5 stage($1.1-2.1{\mu}m$) for airborne bacteria and on 1 stage(>$7.0{\mu}m$) for airborne fungi. Cleanliness of facilities in the general hospital and condition of HVAC system should be monitored regularly to prevent indoor air contamination by airborne microorganisms.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.15-18
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• 2007

This study investigated disinfection effect by general water purifier and water purifier with UV light disinfection. The results are as follows : (i) The general bacteria existed plentifully in a storage tank before treatment (ii) Water treated in water purifier did not meet the water treatment regulation standard since the presence of bacteria, whereas with UV light application the regulation standard is totally satisfied. (iii) Photocatalytic disinfection process with UV light in the presence of $TiO_2$ more effectively killed general bacteria than UV light only.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.18 no.1
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• pp.11-19
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• 2008

Mean levels of airborne bacteria, airborne fungi, temperature, relative humidity and carbon dioxide in total 69 general offices were $426({\pm}83)\;cfu/m^3$, $234({\pm}125)\;cfu/m^3$, $25.9({\pm}1.3)\;^{\circ}C$, $57.7({\pm}8.6)\;%$, $422({\pm}38)\;ppm$, respectively. The I/O ratio of airborne bacteria and fungi was over 1 and there was no significant difference among temperature, relative humidity and carbon dioxide in total 69 general offices. In construction period, a concentration of airborne bacteria and fungi was significantly highest in general offices constructed under one year and over three years since construction, respectively (p<0.05). The concentration of airborne fungi in general offices located at basement was significantly higher than those located at ground (p<0.05). No significant difference of airborne bacteria and fungi in general offices was found regardless of installation of HVAC system (p>0.05). The dominant bacterial genera identified in general offices was Staphylococcus, followed by Micrococcus, Bacillus, and Corynebacterium while usarium, Penicillium, Aspergillus, Alternaria, Rhizopus and Mucor were identified as dominant fungal genera in general offices.

• Journal of Korean society of Dental Hygiene
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• v.20 no.5
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• pp.743-752
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• 2020

Objectives: The objectives of this study were to investigate the distribution and level of periodontopathic bacteria with the general characteristics and oral health condition of the elderly. Methods: A total of 335 elderly individuals aged 65 years or older who lived in Ganghwa-gun, Incheon, were included in the study. Oral examination, investigation through a questionnaire, and collection of saliva were carried out. The collected saliva was analyzed for the distribution and levels of bacteria (red and orange complex bacteria) by real-time polymerase chain reaction. Statistical analyses were performed using chi-square test, t-test, one-way analysis of variance, and Pearson's correlation coefficient with SAS statistical software version 9.4. Results: Among the general characteristics, there were significant differences in the distribution of Porphyromonas gingivalis, Treponema denticola, and Parvimonas micra depending on sex, age, and dental visits (p<0.05). The number of remaining teeth and denture use were related to the distribution of periodontopathic bacteria, except T. denticola (p<0.05). Additionally, periodontitis was related to the distribution of P. gingivalis (p<0.05). As the number of remaining teeth increased, the copy number of red and orange complex bacteria also increased (p<0.05). Those individuals who did not use dentures and had periodontal disease had more periodontopathic bacteria (p<0.05). Conclusions: The distribution and copy number of periodontopathic bacteria in the elderly were more related to oral health condition than to general characteristics. In particular, the distribution and copy number of periodontopathic bacteria were higher in subjects with multiple remaining teeth, no dentures, and periodontal disease.

• Journal of Environmental Health Sciences
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• v.9 no.2
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• pp.1-10
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• 1983

The purpose of this study was to analyze general ingredient of bean cured on the market and to examine its exposure to bacterial contamination. For this study, 17 samples (each 9 samples for general bean curd, soft bean curd, and uncurdled bean curd) were randomly collected from nine areas in Seoul from the beginning of April, 1983 to the beginning of June, 1983. The result of ingredient analysis of moisture, ash, and protein of bean curd was compared with the standard set by the Ministry of Health & Social Affairs. In order to find out exposure of bean curd on the market to bacterial contamination, total biological bacteria and coliform group were examined. Experimental results were shown as follows 1) Results of ingredient analysis of moisture, ash, and protein of general bean curd showed that total samples in both moisture and protein met the standard set by the Ministry of Health & Social Affairs but 44.4% of the samples in ash was below the above standard, indicating average 82.0%, 0.9% and 9.6% in moisture, ash, and protein order. 2) Experimental results of moisture, ash, and protein of soft bean curd demonstrated 90.2%, 0.5% and 4.3% respectively total samples in both moisture and protein satisfied the self-criteria set by the Soft Food Co-operative Association of Seoul City but 11.1% of the samples in ash didn't meet the self-criteria. 3) Total samples of uncurdled bean curd satisfied the self-criteria set by the above association, indicating average 92.0%, 0.4%, and 3.5% in moisture, ash, and protein order. 4) Total biological bacteria and coliform group detected in general bean curd showed that more than 10$^5$/g in total biological bacteria accounted for 88.8% of the samples and that 10$^4$/g or more in coliform group accounted for 77.7% of the samples. The result proves that general bean curd has been exposured to a severe bacterial contamination. 5) Result of total biological bacteria and coliform group detected in such packed bean curd as uncurdled bean curd and soft bean curd showed that 61.6% of the samples exceeded 10$^6$/g in total biological bacteria and 27.7% of the samples exceeded 10$^3$/g in coliform group. 6) According to the change with time and temperatures in total biological bacteria and coliform group of general bean curd, general bean curd began to decay around 72 hours at 4$\circ$C and around 48 hours at 23$\circ$C and around 24 hours at 37$\circ$C and, at that time, total biological bacteria approached 10$^6$/g while coliform group did 10$^6$/g. The result indicates that temperature has a great effect on bacteria counts and decay.

• Applied Biological Chemistry
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• v.34 no.2
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• pp.130-133
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• 1991

The distribution of acid producing bacteria and general bacteria in 23 samples of Korean traditional Meju loaves was investigated and the strains isolated from the samples identified. The acid producing bacteria occurred more in outer part than inner part and anaerobic acid producing bacteria showed higher tendency of occurrence compared with the aerobes in each part. The average number of nonhalophilic and halotolerant bacteria belonging to aerobes were counted as $24{\times}10^6$ and $33{\times}10^5$ and the average number of those belonging to anaerobes $10{\times}10^7$ and $58{\times}10^5$ cells/g, respectively. The general bacteria isolated more in outer part than inner part and its average number was $62{\times}10^7$ cells/g. In the isolates, 2 aerobic acid producing strains were identified as Micrococcus spp., 3 anaerobic acid producing strains as Streptococcus sp., Pediococcus sp. and Lactobacillus sp., and 2 strains of aerobic general bacteria as Bacillus spp.

• Journal of Oral Medicine and Pain
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• v.23 no.2
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• pp.109-117
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• 1998

Fixed orthodontic appliances for the treatment of malocclusion has iatrogenic side effect such as demineralization of enamel, gingivitix and gingival hyperplasia. The purpose of this study is to longitudinally investigate the salivary microorganisms and immunoglobulin A after delivery of fixed orthodontic appliances for 10 months. Eight orthodontic patients were included in this study and the author has investigated the numbers of general bacteria, Streptococcus mutans Staphylococcus aureus and concentration of immunoglobulin A from unstimulated whole saliva. The author examined these parameters at prebracketing, 1 month after, 4 months after, 7 months after and 10 months after delivery of fixed orthodontic appliances. The obtained results were as follows : There were significant increases in the number of salivary general bacteria, Streptococcus mutans and Staphylococcus aureus after delivery of fixed orthodontic appliances The numbers of general bacteria were significantly increased at 1 month after (p<005), 4 months after (p<0.05), 7 months after (p<0.01), compared with prebracketing. However it showed no difference at 10 month after compared with 7 months after bracketing. The Numbers of Staphylococcus aureus were significantly increased at 1 month after (p<0.05), 4 months after(p<0.01), 7 month(p<0.01), compared with prebracketing. However it showed decreasing pattern at 10 months after compared with 7 months after bracketing. There was no significant difference in the concentration of immunoglobulin A after delivery of fixed orthodontic appliances.

• Journal of Food Hygiene and Safety
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• v.14 no.4
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• pp.433-435
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• 1999

The number of viable microorganism in drinking water was monitored according to storage temperature and storage period. The number of general bacteria in underground water was 10$^2$~10$^{5}$ CFU/ml and that of coliform group was decreased after 7days. The number of general bacteria in bottle water was increased until 7days but decreased after that day. Coliform group in bottle water were detected only 1 sample. The number of general bacteria in purified water was 10$^3$~10$^4$CFU/ml and 10$^2$~10$^4$CFU/m1 at 8$^{\circ}C$ and $25^{\circ}C$, respectively. Coliform group were not detected in purified water.

• Korean Journal of Microbiology
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• v.12 no.4
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• pp.153-158
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• 1974

Around and in the area of Wolgot-Muon, Gimpo-Gun, Kyunggi province, I examined total bacteria, general Pseudomonas spp., fluorescent Pseudomonas spp., in soil layers and also in different kinds of soil of respective diseased, uncultivated, and healthy areas, and found the followings. 1. In the diseased and uncultivated areas, the content of moisture and silt was greater than in the healthy area. 2. Contrary to the above, the healthy area contained a greater amount of inorganic elements such as $P_2O_5$, K, Ca and of soil particle such as Cs and Fs. The degree of pH and content of Mg were even in three types of soils. 3. Total bacteria were found in abundance in the healthy soil. It was observed that in all types of areas, bacteria reside in abundance in the rhizosphere, i.e., 10-15 cm layers and that the closer the surface, the greater the numbers of the bacteria. 4. General Pseudomonas spp. were also found to the greater in number on the surface of the soil, especially so in the rhizosphere, with the numbers decreasing as the soil layers increase. Numbers of this bacteria in all types of area were nearly uniform. 5. A great number of fluorescent Pseudomonas spp. were found in the diseased area, especially so in the rhizosphere.