• International Journal of Oral Biology
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• 제40권1호
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• pp.41-50
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• 2015

The aim of this study was to identify bacteria isolated from the oral cavities and to determine their antimicrobial susceptibility against eight antibiotics. The bacterial strains were obtained from the Korean Collection for Oral Microbiology (KCOM). The bacteria were identified by comparing 16S rDNA sequences at the species level. The data showed that 77 bacterial strains were predominantly identified as streptococci (49.4%) and staphylococci (14.3%). Minimum inhibitory concentrations (MIC) were determined using a broth dilution assay to test the sensitivity of the bacterial strains. The MIC values of the oral bacterial strains against antibiotics were different. Streptococci were sensitive to clindamycin, cefuroxime axetil, and vancomycin, and they were resistant to tetracycline. Staphylococci also were sensitive to clindamycin, cefuroxime axetil, and vancomycin, and they were resistant to penicillin antibiotics. Gramnegative bacterial strains were sensitive to tetracycline and were resistant to clindamycin. These results suggest that the antimicrobial susceptibility test is necessary in deciding the prescription for antibiotics, to prevent the misuse or abuse of antibiotics.

• International Journal of Oral Biology
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• 제38권4호
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• pp.181-188
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• 2013

The presence of distinct bacterial species is found to be dependent on age, diet, and disease. We compared the detection rate of several oral bacterial strains in a cohort of 36 subjects including healthy volunteers, periodontal patients, and oral cancer patients. Gargling samples were obtained from these subjects from which DNA was then extracted. Specific primers for 29 bacterial species were used for PCR detection. In the oral cancer patients, Capnocytophaga ochracea, Gemella morbillorum, and Streptococcus salivarius were detected more frequently compared with the healthy volunteers and periodontitis patients. Fusobacterium nucleatum/ polymorphym and Prevotella nigrescens were significantly less prevalent in oral cancer patients than the other groups. In periodontitis patients, Porphyromonas gingivalis and Treponema denticola were more frequently found compared with the healthy volunteers. In the healthy volunteer group, Peptostreptococcus anaerobius was more frequently found than the other groups. The detection rate of several oral bacterial species was thus found to differ between healthy volunteers, periodontitis patients and oral cancer patients.

• Journal of Korean Biological Nursing Science
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• 제17권2호
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• pp.97-103
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• 2015

Purpose: The aim of the study was to identify effects of oral care protocol on bacterial floras of the oral cavity and oral health status of intubated patients in an intensive care unit. Methods: The participants were 60 intubated patients who were recruited from an intensive care unit of a university hospital from Dec. 28, 2010 to Mar. 25, 2011. The participants were randomly assigned into 3 groups of 20 patients according to the application time of oral care (1-minute oral care, 2-minute oral care, and 3-minute oral care groups). The numbers of bacterial flora colonies in the oral cavity was assessed before and after the oral care. Oral health status was assessed using a Korean version of the Oral Assessment Guide developed by Elier et al. originally. Results: The numbers of bacterial flora colonies were less after oral care than those before the care, but there was no significant differences among the 3 groups after the care. Oral health status was better after the oral care than it was before the care, but there was also no significant differences among the 3 groups. Conclusion: If well-trained nurses perform oral care for 1 minute using a chlorhexidine swab on intubated patients, the numbers of bacterial flora colonies will be reduced and healthy oral status will be maintained.

• International Journal of Oral Biology
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• 제40권4호
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• pp.189-196
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• 2015

Minimal inhibitory concentration (MIC) is the lowest antibiotic concentration that inhibits the visible growth of bacteria. Sub-minimal inhibitory concentration (Sub-MIC) is defined as the concentration of an antimicrobial agent that does not have an effect on bacterial growth but can alter bacterial biochemistry, thus reducing bacterial virulence. Many studies have confirmed that sub-MICs of antibiotics can inhibit bacterial virulence factors. However, most studies were focused on Gram-negative bacteria, while few studies on the effect of sub-MICs of antibiotics on Gram-positive bacteria. In this study, we examined the influence of sub-MICs of doxycycline, tetracycline, penicillin and amoxicillin on biofilm formation and coaggregation of Streptococcus gordonii, Streptococcus mutans, Actinomyces naeslundii, and Actinomyces odontolyticus. In this study, incubation with sub-MIC of antibiotics had no effect on the biofilm formation of S. gordonii and A. naeslundii. However, S. mutans showed increased biofilm formation after incubation with sub-MIC amoxicillin and penicillin. Also, the biofilm formation of A. odontolyticus was increased after incubating with sub-MIC penicillin. Coaggregation of A. naeslundii with S. gordonii and A. odontolyticus was diminished by sub-MIC amoxicillin. These observations indicated that sub-MICs of antibiotics could affect variable virulence properties such as biofilm formation and coaggregation in Gram-positive oral bacteria.

• 한국치위생학회지
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• 제24권2호
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• pp.131-139
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• 2024

Objectives: Oral bacterial samples included subgingival, supragingival, and saliva plaques. As the diversity and number of microorganisms deffer depending on the area of the oral cavity and the method used, an appropriate and reliable collection method is important. The present study investigated oral bacterial sampling methods. Methods: Supragingival dental plaque was collected from the buccal and lingual tooth surfaces of study participants using sterilized cotton swabs. Plaques were collected from the subgingival area using a sterilized curette. Bacterial genomic DNA was extracted using MagNA Pure 96 DNA and Viral NA low-volume kits. Real-time polymerase chain reaction (PCR) was performed using the PowerCheck^TM Periodontitis Pathogens Multiplex Real-time PCR kit. Results: Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Fusobacterium nucleatum of the orange complex were not observed in the subgingival biofilms of all study participants. For Porphyromonas. gingivalis, a significant correlation was observed between supragingival, subgingival, and total tooth surface biofilms. Compared to the supragingival and subgingival biofilmss, total tooth surface biofilm exhibited the highest bacterial count when the inswabbing method was used. Conclusions: Based on these findings, the supragingival swab method is recommended for oral bacterial research.

• International Journal of Oral Biology
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• 제38권2호
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• pp.81-85
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• 2013

There are estimated to be about 700 species of bacteria in the oral cavity. Based on epidemiological investigations, some of these strains have been proposed as the pathogens responsible for oral diseases such as dental caries, gingivitis and periodontitis. Since electrolyzed hydrogen-rich water has been shown to have beneficial effects on human immunity, its use has increased. In our study, the antibacterial activity of hydrogen-rich water for oralagainst bacteria associated with oral disease was evaluated. The bacterial strains Streptococcus mutans, Fusobacterium nucleatum, Porphyromonas gingivalis and Tannerella forsythia were cultured in specific growth medium. S. mutans, F. nucleatum and P. gingivalis were soaked to thein both hydrogen water and tap water for 30 sec and then inoculated onto mitis-salivarius agar and brain heart infusion agar including supplemented withvitamin K and hemin, respectively. The numbers of bacterial colonies were then measured after cultivation for 48 hours. In the case of T. forsythia, which does not grow well on agar plates, inoculations into modified new oral spirochete (NOS) broth were performed and growth curve analysis was undertaken every day with a spectrophotometer. Hydrogen water showed antibacterial activity against all four bacterial strains in comparison with tap-water. We conclude from this that hydrogen water may have a positive impact on oral hygiene by helping to remove cariogenic bacteria and periodontopathogens.

• Journal of Oral Medicine and Pain
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• 제33권2호
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• pp.159-166
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• 2008

이상적인 구강항균제로는 구강환경 내에서 정상 세균총보다는 치아우식증의 원인균주 및 치주염이나 구취 유발세균에 대한 선택적인 항균력이 우수하면서도 인체 및 환경독성이 낮은 물질이 요구된다. 이러한 요구사항을 충족시킬 수 있는 천연항균제 개발을 위해 천연물질인 Hamamelis virginiana의 추출물을 이용한 연구를 하였다. 최근 식물 추출물이나 정유(essential oil)의 항균 효과를 관찰하는 연구가 활발히 이루어지면서 치아우식증이나 구취 및 치주질환을 예방하거나 진행을 억제하는 목적으로 사용할 수 있는 천연 항균제 후보 물질들이 속속 보고 되고 있으며, Hamamelis virginiana가 여기에 속한다. Hamamelis virginiana는 치주질환을 야기하는 세균을 포함하는 여러 세균 종, 즉 Porphyromonas gingivalis, Fusobacterium nucleatum, Capnocytophaga gingivalis, Veilonella parvula, Eikenella corrodens, Peprostreptococcus micros, Actinomyces odontolyticus 등에 대해 항균 효과가 있는 것으로 보고 되었고, 이 실험에서는 구강감염질환에 중요한 Streptoccoccus mutans, Haemophylus actinomycetemcomitans, Klebsiella pneumoniae에 대한 항균 효과를 연구함으로써 이러한 Hamamelis virginiana의 항균 효과를 이용하여 구강위생용품 등 치과영역 임상에 이용할 수 있는지에 대한 연구를 하였다. 본 실험에서는 Hamamelis virginiana의 항균 효과를 보기 위해서 Hamamelis virginiana 알콜 추출액을 처리하여 종이 원판 항생제 감수성 검사, 최소발육저지농도 그리고 최소살균농도를 결정하는 연구를 한 결과, 모든 실험 병원균주에 대해 항균성을 나타내었다. 본 연구 결과로 미루어 볼 때, Hamamelis virginiana의 항균력은 구강 감염질환에 중요한 Streptoccoccus mutans, Haemophylus actinomycetemcomitans, Klebsiella pneumoniae 모두에게 유효하게 작용하며, Hamamelis virginiana의 직접적인 살균작용까지도 확인되었다. 따라서 천연물질인 Hamamelis virginiana를 이용하여 구강질환을 일으키는 병원균에 대한 직접적인 항균작용을 기대할 수 있는 항균제 개발이 가능할 것으로 보인다.

• Journal of Periodontal and Implant Science
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• 제44권6호
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• pp.266-273
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• 2014

Purpose: We previously reported that human serum significantly reduces the invasion of various oral bacterial species into gingival epithelial cells in vitro. The aims of the present study were to characterize the serum component(s) responsible for the inhibition of bacterial invasion of epithelial cells and to examine their effect on periodontitis induced in mice. Methods: Immortalized human gingival epithelial (HOK-16B) cells were infected with various 5- (and 6-) carboxy-fluorescein diacetate succinimidyl ester-labeled oral bacteria, including Fusobacterium nucleatum, Provetella intermedia, Porphyromonas gingivalis, and Treponiema denticola, in the absence or presence of three major serum components (human serum albumin [HSA], pooled human IgG [phIgG] and ${\alpha}1$-antitrypsin). Bacterial adhesion and invasion were determined by flow cytometry. The levels of intracellular reactive oxygen species (ROS) and activation of small GTPases were examined. Experimental periodontitis was induced by oral inoculation of P. gingivalis and T. denticola in Balb/c mice. Results: HSA and phIgG, but not ${\alpha}1$-antitrypsin, efficiently inhibited the invasion of various oral bacterial species into HOK-16B cells. HSA but not phIgG decreased the adhesion of F. nucleatum onto host cells and the levels of intracellular ROS in HOK-16B cells. N-acetyl-cysteine (NAC), a ROS scavenger, decreased both the levels of intracellular ROS and invasion of F. nucleatum into HOK-16B cells, confirming the role of ROS in bacterial invasion. Infection with F. nucleatum activated Rac1, a regulator of actin cytoskeleton dynamics. Not only HSA and NAC but also phIgG decreased the F. nucleatum-induced activation of Rac1. Furthermore, both HSA plus phIgG and NAC significantly reduced the alveolar bone loss in the experimental periodontitis induced by P. gingivalis and T. denticola in mice. Conclusions: NAC and the serum components HSA and phIgG, which inhibit bacterial invasion of oral epithelial cells in vitro, can successfully prevent experimental periodontitis.

• The Journal of Advanced Prosthodontics
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• 제14권5호
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• pp.273-284
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• 2022

PURPOSE. Computer-aided design and manufacturing (CAD-CAM) of implant abutments has been shown to result in surface contamination from site-specific milling and fabrication processes. If not removed, these contaminants can have a potentially adverse effect and may trigger inflammatory responses of the peri-implant tissues. The aim of the present study was to evaluate the bacterial disinfection and cleaning efficacy of ultrasonic reprocessing in approved disinfectants to reduce the microbial load of CAD-CAM abutments. MATERIALS AND METHODS. Four different types of custom implant abutments (total N = 32) with eight specimens in each test group (type I to IV) were CAD-CAM manufactured. In two separate contamination experiments, specimens were contaminated with heparinized sheep blood alone and with heparinized sheep blood and the test bacterium Enterococcus faecium. Abutments in the test group were processed according to a three-stage ultrasonic protocol and assessed qualitatively and quantitatively by determination of residual protein. Ultrasonicated specimens contaminated with sheep blood and E. faecium were additionally eluted and the dilutions were incubated on agar plates for seven days. The determined bacterial counts were expressed as colony-forming units (CFU). RESULTS. Ultrasonic reprocessing resulted in a substantial decrease in residual bacterial protein to less than 80 ㎍ and a reduction in microbiota of more than 7 log levels of CFU for all abutment types, exceeding the effect required for disinfection. CONCLUSION. A three-stage ultrasonic cleaning and disinfection protocol results in effective bacterial decontamination. The procedure is reproducible and complies with the standardized reprocessing and disinfection specifications for one- or two-piece CAD-CAM implant abutments.

• International Journal of Oral Biology
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• 제37권4호
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• pp.197-201
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• 2012

LIVE/DEAD$^{(R)}$ BacLight$^{TM}$ and alamarBlue$^{(R)}$ are fluorescent materials used for the enumeration of live and dead bacteria. LIVE/DEAD$^{(R)}$ BacLight$^{TM}$ is generally used for confocal microscopy applications to differentiate live from dead bacteria in a biofilm or planktonic state. AlamarBlue$^{(R)}$ has also been used widely to assay live and dead bacteria in a planktonic state. Whilst these materials are successfully utilized in experiments to discriminate live from dead bacteria for several species of bacteria, the application of these techniques to oral bacteria is limited to the use of LIVE/DEAD$^{(R)}$ BacLight$^{TM}$ in biofilm studies. In our present study, we assessed whether these two methods could enumerate live and dead oral bacterial species in a planktonic state. We tested the reagents on Streptococcus mutans, Streptococcus sobrinus, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans and Enterococcus faecalis and found that only LIVE/DEAD$^{(R)}$ BacLight$^{TM}$ could differentiate live from dead cells for all five of these oral strains. AlamarBlue$^{(R)}$ was not effective in this regard for P. gingivalis or A. actinomycetemcomitans. In addition, the differentiation of live and dead bacterial cells by alamarBlue$^{(R)}$ could not be performed for concentrations lower than $2{\times}10^6$ cells/ml. Our data thus indicate that LIVE/DEAD$^{(R)}$ BacLight$^{TM}$ is a more effective reagent for this analysis.