• Journal of Microbiology and Biotechnology
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• 제16권4호
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• pp.623-632
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• 2006

To find potential targets of novel antimicrobial agents, we identified essential genes of Staphylococcus aureus N315 by using comparative genomics and allele replacement mutagenesis. By comparing the genome of S. aureus N315 with those of Bacillus subtilis, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, and Streptococcus pneumoniae, a total of 481 candidate target genes with similar amino acid sequences with at least three other species by >40% sequence identity were selected. of 481 disrupted candidate genes, 122 genes were identified as essential genes for growth of S. aureus N315. Of these, 51 essential genes were those not identified in any bacterial species, and 24 genes encode proteins of unknown function. Seventeen genes were determined as non-essential although they were identified as essential genes in other strain of S. aureus and other species. We found no significant difference among essential genes between Streptococcus pneumoniae and S. aureus with regard to cellular function.

• Journal of Microbiology and Biotechnology
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• 제32권10호
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• pp.1253-1261
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• 2022

Staphylococcus aureus (S. aureus) infection causes dramatic harm to human health as well as to livestock development. As an important virulence factor, alpha-hemolysin (hla) is critical in the process of S. aureus infection. In this report, we found that bavachin, a natural flavonoid, not only efficiently inhibited the hemolytic activity of hla, but was also capable of inhibiting it on transcriptional and translational levels. Moreover, further data revealed that bavachin had no neutralizing activity on hla, which did not affect the formation of hla heptamers and exhibited no effects on the hla thermal stability. In vitro assays showed that bavachin was able to reduce the S. aureus-induced damage of A549 cells. Thus, bavachin repressed the lethality of pneumonia infection, lung bacterial load and lung tissue inflammation in mice, providing potent protection to mice models in vivo. Our results indicated that bavachin has the potential for development as a candidate hla inhibitor against S. aureus.

• Journal of Microbiology and Biotechnology
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• 제33권3호
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• pp.319-328
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• 2023

Malassezia and Staphylococcus are the most dominant genera in human skin microbiome. To explore the inter-kingdom interactions between the two genera, we examined the transcriptional changes in Malassezia and Staphylococcus species induced upon co-culturing. RNA-seq analyses revealed that genes encoding ribosomal proteins were upregulated, while those encoding aspartyl proteases were downregulated in M. restricta after co-culturing with Staphylococcus species. We identified MRET_3770 as a major secretory aspartyl protease coding gene in M. restricta through pepstatin-A affinity chromatography followed by mass spectrometry and found that the expression of MRET_3770 was significantly repressed upon co-culturing with Staphylococcus species or by incubation in media with reduced pH. Moreover, biofilm formation by Staphylococcus aureus was inhibited in the spent medium of M. restricta, suggesting that biomolecules secreted by M. restricta such as secretory aspartyl proteases may degrade the biofilm structure. We also examined the transcriptional changes in S. aureus co-cultured with M. restricta and found co-cultured S. aureus showed increased expression of genes encoding ribosomal proteins and downregulation of those involved in riboflavin metabolism. These transcriptome data of co-cultured fungal and bacterial species demonstrate a dynamic interplay between the two co-existing genera.

• 대한약침학회지
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• 제10권3호
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• pp.71-76
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• 2007

Objectives This experimental study was performed to investigate the continuous anti-bacterial potency of Coptidis rhizoma extract on cultivation of Staphylococcus species(S. aureus, S. epidermidis) that induce eye disease. Methods Minimal inhibitory concentration(MIC) was measured by dropping to $50{\mu}l$ diluted Coptidis rhizoma extract(100%, 10%, 1%, 0.1%) on S. aureus, S. epidermidis that were cultivated from 2 to 6 days. Anti-bacterial potency was measured by the size of inhibition zone with change of volume($20{\mu}l,\;30{\mu}l,\;40{\mu}l,\;50{\mu}l$). Results 1. Anti-bacterial potency of Coptidis rhizoma extract on S. aureus was appeared in 100%, 10% and was the same as anti-bacterial potency of 2 days and 6 days. Anti-bacterial potency with change of volume(100%) was increased in propotion to increase volume on all samples. Anti-bacterial potency with change of volume(10%) was increased in propotion to increase volume on all samples except $20{\mu}l$. Anti-bacterial potency of Coptidis rhizoma extract on S. aureus was appeared continuous. 2. Anti-bacterial potency of Coptidis rhizoma extract on S. epidermidis was appeared in 100%, 10% and was the same as anti-bacterial potency of 2 days and 6 days. Anti-bacterial potency with change of volume(100%) was increased in propotion to increase volume on all samples. Anti-bacterial potency with change of volume(10%) was appeared in $50{\mu}l$. Anti-bacterial potency of Coptidis rhizoma extract on S. epidermidis was appeared continuous. Conclusions Anti-bacterial potency of Coptidis rhizoma extract on cultivation of S. aureus & S. epidermidis was showed continuous.

• 한국축산식품학회지
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• 제40권5호
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• pp.758-771
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• 2020

This study was to investigate the prevalence and characteristics of antimicrobial-resistant Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) from 4,264 retail meat samples including beef, pork, and chicken in Korea between 2013 and 2018. A broth microdilution antimicrobial susceptibility testing was performed for S. aureus. Molecular typing by multilocus sequence typing (MLST), spa typing, and pulsed-field gel electrophoresis (PFGE), was performed on mecA-positive S. aureus strain. S. aureus was isolated at a rate of 18.2% (777/4,264), of which MRSA comprised 0.7% (29 strains). MLST analysis showed that 11 out of the 29 MRSA isolates were predominantly sequence type (ST) 398 (37.9%). In addition, ST72, ST692, ST188, ST9, and ST630 were identified in the MRSA isolates. The spa typing results were classified into 11 types and showed a high correlation with MLST. The antimicrobial resistance assays revealed that MRSA showed 100% resistance to cefoxitin and penicillin. In addition, resistance to tetracycline (62.1%), clindamycin (55.2%), and erythromycin (55.2%) was relatively high; 27 of the 29 MRSA isolates exhibited multidrug resistance. PFGE analysis of the 18 strains excluding the 11 ST398 strains exhibited a maximum of 100% homology and a minimum of 64.0% homology. Among these, three pairs of isolates showed 100% homology in PFGE; these results were consistent with the MLST and spa typing results. Identification of MRSA at the final consumption stage has potential risks, suggesting that continuous monitoring of retail meat products is required.

• 대한약침학회지
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• 제10권2호통권23호
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• pp.67-71
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• 2007

Objectives : This experimental study was performed to investigate the continuous anti-bacterial potency of Tangpo-san on cultivation of Staphylococcus species(S. aureus, S. epidermidis)that induce eye disease. Methods : Minimal inhibitory concentration(MIC) was measured by dropping to 50 ${\mu}$l diluted Tangpo-san(100%, 10%, 1%, 0.1%) on S. aureus, S. epidermidis that were cultivated from 2 to 6 days. Anti-bacterial potency was measured by the size of inhibition zone with change of volume(20 ${\mu}$l,30 ${\mu}$l,40 ${\mu}$l,50 ${\mu}$l). Results : 1. Anti-bacterial potency of Tanpo-san on S. aureus was not appeared all samples. Anti-bacterial potency with change of volume was increased in propotion to increase volume, and the Anti-bacterial potency of 2 days was equal to 6 days. Anti-bacterial potency of Tangpo-san on S. aureus was appeared continuous. 2. Anti-bacterial potency of Tangpo-san on S. epidermidis was appeared in 100%, 10% on 2 and 6 days, and the Anti-bacterial potency of 6 days was decreased. In 2 days, Anti-bacterial potency was appeared 40 and 50u1, in 6 days, Anti-bacterial potency was appeared all samples. Anti-bacterial potency with change of volume was increased in propotion to increase volume and increased on 6 days, but bacteria was increased. Anti-bacterial potency of Tangpo-san on S. epidermidis wasn't appeared continuous. Conclusions : Anti-bacterial potency of Tangpo-san on cultivation of S. aureus showed continuous, but on cultivation of S. epidermidis was not showed continuous.

• 대한약침학회지
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• 제10권2호통권23호
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• pp.19-23
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• 2007

Objectives : This experimental study was performed to investigate the continuous anti-bacterial potency of Sean-tang on cultivation of Staphylococcus species(S. aureus, S. epidermidis) that induce eye disease. Methods : Minimal inhibitory concentration(MIC) was measured by dropping to 50${\mu}$l diluted Sean-tang(100%, 10%,1%, 0.1%) on S. aureus, S. epidermidis that were cultivated from 2 to 6 days. 1. Anti-bacterial potency was measured by the size of inhibition zone with change of volume(20${\mu}$l, 30${\mu}$l, 40${\mu}$l, 50${\mu}$l). Results : 1. Anti-bacterial potency of Sean-tang on S. aureus was appeared in 100% and increased on 6 days. Anti-bacterial potency with change of volume was increased in propotion to increase volume. Anti-bacterial potency of Sean-tang on S. aureus was appeared continuous. 2. Anti-bacterial potency of S. epidermidis was appeared in 100%, 10%, 1% on 2 days and in100%, 10% on 6 days. In 100% Sean-tang, Anti-bacterial potency of 6 days was increased, in 10%, 1%, Anti-bacterial potency of 2 days was increased. Anti-bacterial potency with change of volume was increased inpropotion to increase volume and increased on 6 days, but bacteria was increased. Anti-bacterial potency Sean-tang on S. epidermidis wasn't appeared continuous. Conclusions : Anti-bacterial potency of Sean-tang on cultivation of S. aureus was showed continuous, but on cultivation of S. epidermidis was not showed continuous.

• 대한영양사협회학술지
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• 제25권1호
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• pp.30-43
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• 2019

This study compared the predictive models for the growth kinetics of Staphylococcus aureus in ham rice balls. In addition, a semi-quantitative risk assessment of S. aureus on ham rice balls was conducted using FDA-iRISK 4.0. The rice was rounded with chopped ham, which was mixed with mayonnaise (SHM), soy sauce (SHS), or gochujang (SHG), and was contaminated artificially with approximately $2.5{\log}\;CFU{\cdot}g^{-1}$ of S. aureus. The inoculated rice balls were then stored at $7^{\circ}C$, $15^{\circ}C$, and $25^{\circ}C$, and the number of viable S. aureus was counted. The lag phases duration (LPD) and maximum specific growth rate (SGR) were calculated using a Baranyi model as a primary model. The growth parameters were analyzed using the polynomial equation as a function of temperature. The LPD values of S. aureus decreased with increasing temperature in SHS and SHG. On the other hand, those in SHM did not show any trend with increasing temperature. The SGR positively correlated with temperature. Equations for LPD and SGR were developed and validated using $R^2$ values, which ranged from 0.9929 to 0.9999. In addition, the total DALYs (disability adjusted life years) per year in the ham rice balls with soy sauce and gochujang was greater than mayonnaise. These results could be used to calculate the expected number of illnesses, and set the hazard management method taking the DALY value for public health into account.

• 대한한방부인과학회지
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• 제26권1호
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• pp.25-40
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• 2013

Objectives: The object of this study was to observe the in vitro antibacterial effects of five single(Pulsatillae Radix, Patrinae Radix, Sanguisorbae Radix, Sophorae Flos, and Sophorae Radix) aqueous herbal extracts, traditionally used for treating various gynecological diseases including mastitis in Korea, against Staphylococcus aureus. Methods: Antibacterial activities against Staphylococcus aureus of aqueous extracts of Pulsatillae Radix, PatrinaeRadix, Sanguisorbae Radix, Sophorae Flos, and Sophorae Radix were detected using standard agar microdilution methods. In addition, the effects on the bacterial growth curve were also monitored at Minimal Incubation Concentration(MIC) and $MIC{\times}2$ levels. The effects on the intracellular killing and bacterial invasion of individual test materials were also observed using murine macrophage(Raw 264.7) and human mammary gland carcinoma cell(MCF-7). Results: MIC of aqueous extracts of Pulsatillae Radix, Patrinae Radix, Sanguisorbae Radix, Sophorae Flos, and Sophorae Radix against Staphylococcus aureus were detected as $0.215{\pm}0.107$ mg/ml, $0.273{\pm}0.107$ mg/ml, $0.469{\pm}0.297$ mg/ml, $11.850{\pm}8.406$ mg/ml, and $0.664{\pm}0.546$ mg/ml, respectively. MIC of Ciprofloxacin was detected as $0.469{\pm}0.297{\mu}g/ml$ at same conditions. In addition, all five single aqueous herbal extracts were also showed marked dosage-dependent inhibition of bacterial growth. The effects of intracellular killing with Raw 264.7 and inhibition of bacterial invasion with MCF-7 cells were detected, in the order of Sophorae Flos, Pulsatillae Radix, Patrinae Radix, Sanguisorbae Radix and Sophorae Radix aqueous extracts in the present study. Conclusions: The results obtained in this study suggest that all five single aqueous herbal extracts showed antibacterial effects against Staphylococcus aureus and they also showed dosage-dependent inhibitory effects on the bacterial growth. They showed the significant intracellular killing and inhibition of bacterial invasion effects. It means, all five single aqueous herbal extracts may show potent anti-infectious effects against Staphylococcus aureus for mastitis.

• 대한약침학회지
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• 제12권1호
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• pp.21-33
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• 2009

Objective : This experimental study was performed to investigate the safety of Soyeom Pharmacopunture solution manufactured by extraction of alcohol and water. To identify the use of it as eyedrops, the eye irritation test of rabbits and antibacterial test of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Aspergillus niger, Fusarium oxysporum, and Candida albicans was performed. Methods : 1. The eye irritation test of this material was performed according to the Regulation of Korea Food & Drug Administration(2005. 10. 21, KFDA 2005-60). After Soyeom pharmacopuncture solution was administered in the left eye of the rabbits, eye irritation of the cornea, iris and conjunctiva was observed at 1, 2, 3, 4 & 7day. 2. After administering Soyeom Pharmacopuncture solution on bacterial species (Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Aspergillus niger, Fusarium oxysporum, Candida albicans) which cause Keratitis, MIC(Minimum Inhibition Concentration) and the size of inhibition zone were measured. Anti-bacterial potency was also measured using the size of inhibition zone. Results : 1. After Soyeom pharmacopuncture solution was administered in the left eye of the rabbits, it was found that none of nine rabbits have abnormal signs and weight changes. 2. After Soyeom pharmacopuncture solution was medicated in the left eye of the rabbits, no eye irritation of the cornea, iris and conjunctiva was observed at 1, 2, 3, 4 & 7day. 3. There was no response to MIC on bacterial species (Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Aspergillus niger, Fusarium oxysporum, Candida albicans) after Soyeom pharmacopuncture solution was medicated. Conclusions : The present study suggests that Soyeom pharmacopuncture solution is a non-toxic and non-irritant medicine, which does not cause eye irritation in rabbits, but dosen't have anti-bacterial effects on bacterial species which cause Keratitis. These study result recommends that more research on other herbal medicines of eye drop for Keratitis are required.