• Biomedical Science Letters
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• v.24 no.1
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• pp.30-34
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• 2018

Silver (Ag) has been widely used in commercial products and medical fields since ancient times because of its antibacterial effect. It is harmless and non-toxic to the human body. For this reason, recent research has actively evaluated antimicrobial activity using silver (Ag). In this study, we investigated the inhibitory effect of a silver-based compound, silver phosphate ($Ag_3PO_4$) on the growth of Staphylococcus aureus and the activation of human immunity. First, the inhibitory effect of $Ag_3PO_4$ on the growth of Staphylococcus aureus was confirmed by a growth curve and a colonyounting method. As a result, the growth inhibitory effect increased as the concentration of $Ag_3PO_4$ increased. Specifically, treatment with $5{\mu}g/mL$ of $Ag_3PO_4$ resulted in no bacteria growth, and the colony-counting method showed a remarkable inhibition. In addition, the expression of cytokine IL-8 by $Ag_3PO_4$ was examined to investigate the cellular immune system activation by $Ag_3PO_4$. After pretreatment of Staphylococcus aureus for 1 hour with $50{\mu}g/mL$ $Ag_3PO_4$, an increased IL-8 mRNA expression resulted. In cells treated with $Ag_3PO_4$, we found that the expression of IL-8 was enhanced in a time-dependent fashion compared to non-treated cells. These results indicate that $Ag_3PO_4$ induces antimicrobial activity against Staphylococcus aureus and activates human immunity. These results are expected to contribute to the future study of the mechanism of silver (Ag) and silver-based compounds in relation to antibacterial activity.

• Korean Journal of Veterinary Service
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• v.40 no.3
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• pp.219-225
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• 2017

This study was investigated the synergistic effects from the combination of cefalexin and gentamicin (CCG) against Staphylococcus spp. isolated from bovine milk. Minimum inhibitory concentrations (MICs) and fractional inhibitory concentration (FIC) index were determined for 16 bacteria from 13 bovine farms in Gyeongsangnam province by the National Committee for Clinical Laboratory Standards broth microdilution procedure. Antimicrobial agents tested included cefalexin, gentamicin and CCG. Against Staphylococcus spp. tested, the MIC ranges of cefalexin, gentamicin and CCG were 0.25~1.0, 0.5~0.125 and $0.06{\sim}0.125{\mu}g/mL$, respectively. In addition, the FIC index ranges of CCG against most of the isolates was 0.28~0.43 and the FIC index of CCG against 2 strains of Staphylococcus haemolyticus (S. haemolyticus) was 0.59. In conclusion, CCG has a high antibacterial activity against Staphylococcus isolates, then the combination may be applied for the treatment of bovine mastitis caused by Staphylococcus spp.

• Journal of Life Science
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• v.21 no.11
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• pp.1511-1517
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• 2011

We isolated a potent phenanthrene-degrading bacterium from oil-contaminated soils of Suzhou, China, and assessed the potential use of these bacteria for bioremediation of soils contaminated by polycyclic aromatic hydrocarbons (PAHs) in a microcosm. Based on 16S rDNA sequencing, we identified this bacteria as Sphigobacterium sp. SW-09. By PCR amplification, we also identified catechol 2,3-dioxygenase genes (nahH genes) mediating PAH degradation. Staphylococcus sp. KW-07, which has been identified in our previous study, showed potential for use in bioremediation of oil-contaminated soils. In this experiment, we compared the rate of phenanthrene-degradation between Staphylococcus sp. KW-07 and Sphingobacterium sp. SW-09 in a microcosm condition. Newly isolated Sphingobacterium sp. SW-09 showed a higher phenanthrene-degradation rate than that of Staphylococcus sp. KW-07 in soil microcosms. Together, our results suggest that the Sphingobacterim sp. SW-09 strain isolated from the Suzhou area may also be useful in bioremediation of PAH-contaminated soils.

• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.642-647
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• 2005

Lonicerae Flos was extracted with methanol and successively fractionated with petroleum ether, chloroform, ethyl acetate, and methanol to investigate their antimicrobial effects against food-borne pathogens and food spoilage bacteria using paper disc method. Ethyl acetate extracts of L. Flos showed highest antimicrobial activity against Shigella dysenteriae. Synergistic effect in inhibition was observed when L. Flos extract was mixed with Artemisa capillaris extract as compared to using each extract alone. Growth inhibition curves were determined using ethyl acetate extracts of L. Flos against Staphylococcus epidermidis and S. dysenteriae. Ethyl acetate extract of L. Flos had antimicrobial activity against S. dysenteriae at 3,000 ppm, retarding growth of S. dysenteriae up to 12 hr.

• Journal of Environmental Health Sciences
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• v.31 no.2 s.83
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• pp.115-119
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• 2005

This study was performed to investigate inhibitory effect on growth of Staphylococcus aureus and Bacillus cereus in lactic acid, hydrogen peroxide and combination of lactic acid and hydrogen peroxide. The minimun inhibitory concentration (MIC) of lactic acid in Staphylococcus aureus were 2500 ppm at pH 7.0, 1250 ppm at pH 5.5, 6.0 and 6.5, while in Bacillus cereus 625 ppm at pH 5.5 and 6.0, 1250 ppm at pH 6.5 and 7.0, respectively. MICs of hydrogen peroxide in Staphylococcus aureus were 50 ppm at pH 6.0, 75 ppm at pH 6.5 and 7.0, while in Bacillus cereus was 75 ppm at pH 5.0, 5.5 and 6.0, respectively. MICs of combined treatment of lactic acid and hydrogen peroxide in Staphylococcus aureus were 1250 ppm of lactic acid with 25 ppm of hydrogen peroxide and 625 ppm of lactic acid with 50 ppm of hydrogen peroxide. When Bacillus cereus were with 1250 ppm of lactic acid with 50 ppm of hydrogen per-oxide and 625 ppm of lactic acid with 75 ppm of hydrogen peroxide at 6.5. The correlations between MICs of lactic acid and hydrogen peroxide in S. aureus and B. cereus obtained through the coefficient of determination ($R^2$). $R^2$ value were 0.9934 and 0.9986, respectively. The inhibitory effect of lactic acid and hydrogen peroxide in S. aureus and B. cereus could be confirmed from the result of this experiment.

• Korean Journal of Microbiology
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• v.47 no.4
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• pp.381-385
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• 2011

Methicillin-resistant Staphylococcus aureus (MRSA) is one of major pathogen causing hospital infection and several diseases such as purulent infection, bacteremia. The isolation ratio of MRSA is gradually increased up to 80% in the hospital, which makes a limitation for treatment of antibiotics because the isolated MRSA show resistance to methicillin as well as other antibiotics. This study proposes that mecA detecting methods which are not commonly used because of cost in the hospital is a more accurate method than Susceptibility Testing to detect a MRSA. We compared Staphylococcus aureus ATCC 29213 as a negative control and 20 MRSA strains isolated from patients by these two methods. We amplified mecA gene by polymerase chain reaction (PCR) and confirmed the PCR products by sequencing. All of the MRSA showed oxacillin and cefoxitin resistance whereas 85% (16/19) of the strains had mecA wildtype. These results suggest that some of the MRSA are mecA mutants therefore mecA genotyping reinforces the MRSA detection by antibiotic susceptibility test.

• Journal of Veterinary Science
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• v.25 no.1
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• pp.12.1-12.10
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• 2024

Background: Staphylococcus aureus and S. pseudintermedius are the major etiological agents of staphylococcal infections in humans, livestock, and companion animals. The misuse of antimicrobial drugs has led to the emergence of antimicrobial-resistant Staphylococcus spp., including methicillin-resistant S. aureus (MRSA) and methicillin-resistant S. pseudintermedius (MRSP). One novel therapeutic approach against MRSA and MRSP is a peptide nucleic acid (PNA) that can bind to the target nucleotide strands and block expression. Previously, two PNAs conjugated with cell-penetrating peptides (P-PNAs), antisense PNA (ASP)-cmk and ASP-deoD, targeting two essential genes in S. aureus, were constructed, and their antibacterial activities were analyzed. Objectives: This study analyzed the combined antibacterial effects of P-PNAs on S. aureus and S. pseudintermedius clinical isolates. Methods: S. aureus ATCC 29740 cells were treated simultaneously with serially diluted ASP-cmk and ASP-deoD, and the minimal inhibitory concentrations (MICs) were measured. The combined P-PNA mixture was then treated with S. aureus and S. pseudintermedius veterinary isolates at the determined MIC, and the antibacterial effect was examined. Results: The combined treatment of two P-PNAs showed higher antibacterial activity than the individual treatments. The MICs of two individual P-PNAs were 20 and 25 µM, whereas that of the combined treatment was 10 µM. The application of a combined treatment to clinical Staphylococcus spp. revealed S. aureus isolates to be resistant to P-PNAs and S. pseudintermedius isolates to be susceptible. Conclusions: These observations highlight the complexity of designing ASPs with high efficacy for potential applications in treating staphylococcal infections in humans and animals.

• The Journal of Korean Obstetrics and Gynecology
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• v.26 no.1
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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.

• Korean Journal of Microbiology
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• v.47 no.3
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• pp.255-262
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• 2011

Six protein-degrading bacteria were isolated from digestive organ of Harmonia axyridis. These isolates were categorized as Staphylococcus sciuri subsp. sciuri (3 strains), Bacillus subtilis (1 strain), and Bacillus thuringiensis (2 strains) by 16S rRNA gene sequence analysis. The Staphylococcus sp. CB2-3 was selected as a protease-producing bacterium which showed the highest protease activity of 58.5 U/ml at the pH 5.0 medium. The optimal pH and temperature of protease activity were pH 5.0 and $40^{\circ}C$, respectively. This acid protease had a relatively high stability of 80% between $30-50^{\circ}C$ at broad temperature range. The opimal medium compositions of carbon, nitrogen and mineral source for cell growth and protease activity were investigated. When sorbitol (0.5%) was used as carbon source, enzyme activity was increased about 2 times than that of the basal medium. When skim milk (0.5%) was used as nitrogen source, activity was increased about 2.5 times than that of the control. Cell growth and enzyme activity were increased by mineral source such as KCl, $K_2HPO_4$, $FeSO_4$, but was completely inhibited by divalent ions such as $Co^{2+}$, $Zn^{2+}$, $Mn^{2+}$, $Cu^{2+}$.

• Journal of fish pathology
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• v.7 no.1
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• pp.23-36
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• 1994

A total of 8 strains of Staphylococcus epidermidis isolated in land-marine tank system of Kyongnam and Kyongbuk. Prefecture were tested for the biological and biochemical characteristics. These strains were isolated from pathologic specimens of cultured flounder. Paralichthys olivaceus. Growth of the isolates was good on BHIA, HIA. Staphylococcus No. 110 and ETGP. Growth was good at NaCl concentration between 2.0 and 3.0%, about $30^{\circ}C$ and at pH values about 7.0. DNase and coagulase production were negative, and all isolates except FSJ-2 strain were positive in hemolysis. Urease was positive reaction, and novobiocin resistance was negative. Acid was produced anaerobically from glucose and maltose. All isolates except FSJ-19 strain produced weakly were negative in anaerobic acid production from mannitol. Acid was produced aerobically from glucose, fructose, galactose, sucrose, maltose and dextrine. But all isolates were not gas production. In characterization of clinically isolates, four different biotype codes were obtained when the all isolated were tested simultaneously. Four different antibiotic susceptibility patterns were obtained. On the basis of these characteristics, the isolates were identified as Staphylococcus epidermidis.