Potentiating activity of luteolin on membrane permeabilizing agent and ATPase inhibitor against methicillin-resistant Staphylococcus aureus

OBJECTIVE@#To investigate the mechanism of antibacterial activity of luteolin (LUT) against methicillin-resistant Staphylococcus aureus (MRSA).@*METHODS@#The mechanism of anti-MRSA activity of LUT was analyzed by the viability assay in membrane permeabilizing agent, ATPase inhibitors, and peptidoglycan (PGN) derived from Staphylococcus aureus (S. aureus). Also, transmission electron microscopy was used to monitor survival characteristics and changes in S. aureus morphology.@*RESULTS@#Compared to the LUT alone, the optical density of suspensions treated with the combination of 125 μg/mL Tris and 250 μg/mL N,N'-dicyclohexylcarbodiimide were reduced to 60% and 46% of the control, respectively. PGN (15.6 μg/mL) gradually impeded the activity of LUT, and PGN (62.5 μg/mL) completely blocked the activity of LUT on S. aureus.@*CONCLUSIONS@#Increased susceptibility to LUT with the Tris-dicyclohexylcarbodiimide combinations is evident in all tested MRSA isolates. The results indicate LUT synergy in increasing cytoplasmic membrane permeability and inhibiting ATPase. S. aureus PGN directly blocks the antibacterial activity of LUT, suggesting the direct binding of LUT with PGN. These findings may be validated for the development of antibacterial agent for low MRSA resistance.

The inhibition effect of Chlorpromazine against the β-lactam resistance of MRSA

OBJECTIVE@#To investigate the gene related to β-lactam resistance and to confirm the mechanism about a synergy effect between CPZ and β-lactam antibiotics.@*METHODS@#To measure antibacterial activity, we performed a minimum inhibitory concentration (MIC) and synergy test. Transmission electron microscopy (TEM) was used in morphological analysis. To analyze gene expression, we conducted reverse transcriptase polymerase chain reaction (PCR).@*RESULTS@#We confirmed a synergy effect between CPZ and β-lactam antibiotics. Furthermore, we observed that CPZ affect the cell envelope of MRSA by using TEM. At the gene level, CPZ reduced the expression of resistance genes.@*CONCLUSIONS@#Through this result, we hypothesize that a decrease of resistance factor expressions was caused by CPZ because it disrupts the activity of a sensor protein located in the cell membrane.

Potentiating activity of luteolin on membrane permeabilizing agent and ATPase inhibitor against methicillin-resistant Staphylococcus aureus

Objective: To investigate the mechanism of antibacterial activity of luteolin (LUT) against methicillin-resistant Staphylococcus aureus (MRSA). Methods: The mechanism of anti-MRSA activity of LUT was analyzed by the viability assay in membrane permeabilizing agent, ATPase inhibitors, and peptidoglycan (PGN) derived from Staphylococcus aureus (S. aureus). Also, transmission electron microscopy was used to monitor survival characteristics and changes in S. aureus morphology. Results: Compared to the LUT alone, the optical density of suspensions treated with the combination of 125 μg/mL Tris and 250 μg/mL N,N'-dicyclohexylcarbodiimide were reduced to 60% and 46% of the control, respectively. PGN (15.6 μg/mL) gradually impeded the activity of LUT, and PGN (62.5 μg/mL) completely blocked the activity of LUT on S. aureus. Conclusions: Increased susceptibility to LUT with the Tris-dicyclohexylcarbodiimide combinations is evident in all tested MRSA isolates. The results indicate LUT synergy in increasing cytoplasmic membrane permeability and inhibiting ATPase. S. aureus PGN directly blocks the antibacterial activity of LUT, suggesting the direct binding of LUT with PGN. These findings may be validated for the development of antibacterial agent for low MRSA resistance.

The inhibition effect of Chlorpromazine against the β-lactam resistance of MRSA

Objective To investigate the gene related to β-lactam resistance and to confirm the mechanism about a synergy effect between CPZ and β-lactam antibiotics. Methods To measure antibacterial activity, we performed a minimum inhibitory concentration (MIC) and synergy test. Transmission electron microscopy (TEM) was used in morphological analysis. To analyze gene expression, we conducted reverse transcriptase polymerase chain reaction (PCR). Results We confirmed a synergy effect between CPZ and β-lactam antibiotics. Furthermore, we observed that CPZ affect the cell envelope of MRSA by using TEM. At the gene level, CPZ reduced the expression of resistance genes. Conclusions Through this result, we hypothesize that a decrease of resistance factor expressions was caused by CPZ because it disrupts the activity of a sensor protein located in the cell membrane.

Antimicrobial activity and synergism of Sami-Hyanglyun-Hwan with ciprofloxacin against methicillin-resistant Staphylococcus aureus

OBJECTIVE@#To investigate the antibacterial activity of SHH extracted with either water or ethanol against methicillin-resistant Staphylococcus aureus (MRSA) and combinatory antimicrobial effect with ciprofloxacin (CIP) by time kill assay and checkerboard dilution test.@*METHODS@#The antibacterial activity determined by broth dilution method indicated that the antibacterial activity of Sami-Hyanglyun-Hwan (SHH) water extract (SHHW) and SHH ethanol extract (SHHE) ranged from 250 to 2000 μg/mL and 125 to 1000 μg/mL against MRSA, respectively.@*RESULTS@#In the checkerboard method, the combinations of SHHE with CIP had a partial synergistic or synergistic effect against MRSA. The time-kill curves showed that a combined SHHE and CIP treatment reduced the bacterial counts dramatically after 24 h.@*CONCLUSIONS@#The present study demonstrates the therapeutic ability of SHHE against MRSA infections.

Antimicrobial activity and synergism of Sami-Hyanglyun-Hwan with ciprofloxacin against methicillin-resistant Staphylococcus aureus

Objective: To investigate the antibacterial activity of SHH extracted with either water or ethanol against methicillin-resistant Staphylococcus aureus (MRSA) and combinatory antimicrobial effect with ciprofloxacin (CIP) by time kill assay and checkerboard dilution test. Methods: The antibacterial activity determined by broth dilution method indicated that the antibacterial activity of Sami-Hyanglyun-Hwan (SHH) water extract (SHHW) and SHH ethanol extract (SHHE) ranged from 250 to 2. 000 μg/mL and 125 to 1. 000 μg/mL against MRSA, respectively. Results: In the checkerboard method, the combinations of SHHE with CIP had a partial synergistic or synergistic effect against MRSA. The time-kill curves showed that a combined SHHE and CIP treatment reduced the bacterial counts dramatically after 24 h. Conclusions: The present study demonstrates the therapeutic ability of SHHE against MRSA infections.

The anti-inflammatory effect of Cheongseoikki-tang ethanol extract on allergic reactions mediated by bone marrow-derived mast cells / 中国结合医学杂志

<p><b>OBJECTIVE</b>Cheongseoikki-tang (CIT, Korean), also called Qingshu Yiqi decoction () and Seisho-ekki-to (Japanese), is well known as an effective traditional combination of herbs for treating cardiovascular diseases. This study was to research its effects on bone marrow-derived mast cell (BMMC)-mediated allergy and inflammation mechanisms.</p><p><b>METHODS</b>In this study, the biological effect of Cheongseoikki-tang ethanol extract (CITE) was evaluated, focusing on its effects on the production of allergic mediators by phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore A23187 (A23187)-stimulated BMMCs. These allergic mediators included interleukin-6 (IL-6), prostaglandin D2 (PGD2), leukotriene C4 (LTC4), and β-hexosaminidase (β-hex).</p><p><b>RESULTS</b>Our data revealed that CITE inhibited the production of IL-6, PGD2, LTC4, and β-hex induced by PMA plus A23187 (P<0.05).</p><p><b>CONCLUSION</b>These findings indicate that CITE has the potential for use in the treatment of allergy.</p>

Genotype, Coagulase Type and Antimicrobial Susceptibility of Methicillin-Resistant Staphylococcus aureus Isolated from Dermatology Patients and Healthy Individuals in Korea

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most prevalent dermatology pathogens in hospitals and increasingly recognized in communities. We determined PFGE pattern of SmaI-restricted genomic DNA, coagulase type, and antimicrobial susceptibility of MRSA isolated in 2008 from dermatology inpatients and healthy hospital employees in A Hospital and from primary school children in Iksan city, Korea. Overall, the isolation rate of MRSA was 3.8% from the 788 normal persons: 4.9% from hospital employees and 1.1% from primary school children. MRSA was isolated in six of 13 (46.2%) family members of four school children with MRSA. The most prevalent coagulase serotype was II from patients and V from healthy individuals. Ten of twenty and six of twenty MRSA isolates from patients and from healthy personnel, respectively, had identical PFGE patterns, suggesting that these are originated from identical clones. Against MRSA from patients, only vancomycin was the most active (MIC range or =90% to amikacin, clindamycin, ciprofloxacin, erythromycin, fusidic acid, gentamicin and tetracycline. In conclusion, the MRSA carriage rates of healthy hospital workers were relatively high, 2.3~7.7%, depending on groups. Family members of a few primary school children with MRSA showed a high carriage rate, suggesting that intrafamily transmission occurred. MRSAs isolated from dermatology inpatients were relatively more resistant to various antimicrobial agents, including mupirocin, but all isolates were susceptibility to vancomycin.