Antimicrobial Activity of Galangin and Its Effects on Murein Hydrolases of Vancomycin-Intermediate Staphylococcus aureus (VISA) Strain Mu50

Chemotherapy ◽  
2017 ◽  
Vol 63 (1) ◽  
pp. 20-28 ◽  
Author(s):  
Jing Ouyang ◽  
Fengjun Sun ◽  
Wei Feng ◽  
Yonghong Xie ◽  
Lijuan Ren ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Cell Wall ◽  
Morphological Changes ◽  
Control Group ◽  
Cellular Division ◽  
Murein Hydrolase ◽  
Triton X ◽  
Cell Wall Hydrolysis ◽  
Induced Autolysis

Backgroud: Antibiotic treatment for infections caused by vancomycin-intermediate Staphylococcus aureus (VISA) strains is challenging, and only a few effective and curative methods have been developed to combat these strains. This study aimed to investigate the antimicrobial activity of galangin against S. aureus and its effects on the murein hydrolases of VISA strain Mu50. This is the first report on these effects of galangin, and it may help to improve the treatment for VISA infections by demonstrating the effective use of galangin. Methods: Firstly, the minimum inhibitory concentration (MIC) and growth curve were used to investigate the antimicrobial activity of galangin against S. aureus. Secondly, transmission electron microscopy (TEM) was used to observe morphological changes of VISA strain Mu50. Thirdly, Triton X-100-induced autolysis and cell wall hydrolysis assays were performed to determine the activities of the murein hydrolases of Mu50. Finally, fluorescence real-time quantitative PCR was used to investigate the expression of the murein hydrolase-related Mu50 genes. Results: The results indicated that the MIC of galangin was 32 μg/mL against ATCC25293, N315, and Mu50, and galangin could significantly suppress the bacterial growth (p < 0.05) with concentrations of 4, 8 and 16 μg/mL, compared with control group (0 μg/mL). To explore the possible reasons of bacteriostatic effects of galangin, we observed morphological changes using TEM which showed that the division of Mu50 daughter cells treated with galangin was obviously inhibited. Considering the vital role of murein hydrolases in cellular division, assays were performed, and galangin markedly decreased Triton X-100-induced autolysis and cell wall hydrolysis. Galangin also significantly inhibited the expression of the murein hydrolase genes (atl, lytM, and lytN) and their regulatory genes (cidR, cidA, and cidB). Conclusions: Our findings indicated that galangin can effectively inhibit murein hydrolase activity as well as the growth of VISA strain Mu50.

scholarly journals The bacteriostatic effect and mechanism of berberine on Methicillin resistant Staphylococcus aureus in vitro

2020 ◽  
Author(s):  
Lei Wang ◽  
Fangfang Zhou ◽  
Minyi Xu ◽  
Pei Lu ◽  
Ming Lin ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Rna Sequencing ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Differentially Expressed ◽  
Control Group ◽  
High Concentration ◽  
Bacteriostatic Effect ◽  
Low Concentration ◽  
Cell Wall Hydrolysis

Abstract Background: To observe the bacteriostatic effect of berberine (BBR) and BBR combined with gentamicin (GEN), levofloxacin (LEV) and amikacin (AMI) on Methicillin resistant Staphylococcus aureus (MRSA), while also exploring the bacteriostatic mechanism of BBR on MRSA. Results: The MICs range of BBR on 26 strains of MRSA was 32-256 µg/mL. BBR combined with GEN, LEV and AMI had obvious bacteriostatic effect on MRSA. After co-culturing MRSA with BBR at 512 µg/mL, 64 µg/mL and 8 µg/mL, respectively, the electrical conductivity increased, compared with the control group, by 8.14%, 13.08% and 12.01%, respectively. Using transmission electron microscopy, we found that low concentration of BBR (8 µg/mL; 1/8 MIC) caused no significant damage to MRSA, and the bacterial structure of MRSA remained intact, while high concentration of BBR (512 µg/mL; 8 MIC) induced the destruction and dissolution of MRSA cell wall structure and the leakage of bacterial contents, leading to bacterial lysis. RNA-sequencing results showed that there were 754 differentially expressed genes in the high concentration group compared with the normal control group. Compared with the low concentration group, there were 590 differentially expressed genes in the high concentration group. Compared with the control group, only 19 genes were differentially expressed in the low concentration group. The up-regulated genes are mainly related to the cell wall hydrolysis regulatory genes, while the down-regulated genes are mainly related to the serine protease family. Conclusions: BBR displayed an excellent bacteriostatic effect on MRSA. BBR combined with GEN and AMI significantly enhanced the bacteriostatic effect on MRSA, while BBR combined with LEV showed no significant change in the bacteriostatic effect on MRSA. BBR inhibited bacteria by destroying and dissolving the structure of MRSA cell wall. RNA-sequencing results further demonstrated that the expression of cell wall hydrolysis genes ssaA, lytM and virulence factor serine protease genes were significantly differentially expressed when high concentration BBR treated on MRSA.

scholarly journals Opposing Roles of the Staphylococcus aureus Virulence Regulators, Agr and Sar, in Triton X-100- and Penicillin-Induced Autolysis

1998 ◽  
Vol 180 (14) ◽  
pp. 3724-3726 ◽  
Author(s):  
David F. Fujimoto ◽  
Kenneth W. Bayles
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factor ◽  
Regulatory Genes ◽  
Critical Aspect ◽  
Mutant Strains ◽  
Murein Hydrolase ◽  
Triton X ◽  
Induced Autolysis

ABSTRACT The regulation of murein hydrolases is a critical aspect of peptidoglycan growth and metabolism. In the present study, we demonstrate that mutations within the Staphylococcus aureusvirulence factor regulatory genes, agr and sar, affect autolysis, resulting in decreased and increased autolysis rates, respectively. Zymographic analyses of these mutant strains suggest thatagr and sar exert their effects on autolysis, in part, by modulating murein hydrolase expression and/or activity.

Antimicrobial activity of Bulbothrix setschwanensis (Zahlbr.) Hale lichen by cell wall disruption of Staphylococcus aureus and Cryptococcus neoformans

2018 ◽  
Vol 115 ◽  
pp. 12-18 ◽  
Author(s):  
Indresh K. Maurya ◽  
Samer Singh ◽  
Rupinder Tewari ◽  
Manish Tripathi ◽  
Shashi Upadhyay ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Cell Wall ◽  
Cryptococcus Neoformans ◽  
Cell Wall Disruption

scholarly journals Resistance to Autolysis in Vancomycin-Selected Staphylococcus aureus Isolates Precedes Vancomycin-Intermediate Resistance

2003 ◽  
Vol 47 (6) ◽  
pp. 2036-2039 ◽  
Author(s):  
Susan Boyle-Vavra ◽  
Mamatha Challapalli ◽  
Robert S. Daum
Keyword(s):  
Staphylococcus Aureus ◽  
Clinical Isolate ◽  
Resistance Phenotype ◽  
Low Level ◽  
Single Passage ◽  
Intermediate Resistance ◽  
Triton X ◽  
Induced Autolysis

ABSTRACT Four clinical U.S. glycopeptide intermediate resistant Staphylococcus aureus (GISA) isolates were resistant to Triton X-100-induced autolysis. Similar resistance was demonstrated in an isolate obtained after a single passage of a susceptible clinical isolate in low-level vancomycin. Strains with the vancomycin-induced Triton X-100 resistance phenotype produced active murein hydrolases but were resistant to lysis by murein hydrolases.

scholarly journals Metal-Carbon Interactions on Reduced Graphene Oxide under Facile Thermal Treatment: Microbiological and Cell Assay

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
N. L. V. Carreño ◽  
A. M. Barbosa ◽  
V. C. Duarte ◽  
C. F. Correa ◽  
C. Ferrúa ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Graphene Oxide ◽  
Cell Viability ◽  
Reduced Graphene Oxide ◽  
Nanocomposite Films ◽  
Control Group ◽  
Cell Viability Assay ◽  
Viability Assay ◽  
Reduced Graphene

Silver-functionalized reduced graphene oxide (Ag-rGO) nanosheets were prepared by single chemical and thermal processes, with very low concentration of silver. The resulting carbon framework consists of reduced graphene oxide (rGO) sheets or 3D networks, decorated with anchored silver nanoparticles. The Ag-rGO nanosheets were dispersed into a polymer matrix and the composites evaluated for use as biological scaffolds. The rGO material in poly(dimethylsiloxane) (PDMS) has been tested for antimicrobial activity against Gram-positiveStaphylococcus aureus(S. Aureus) bacteria, after exposure times of 24 and 120 hours, as well as in the determination of cell viability on cultures of fibroblast cells (NIH/3T3). Using 1 mL of Ag-rGO in PDMS the antibacterial effectiveness againstStaphylococcus aureuswas limited, showing an increased amount of Colony Forming Units (CFU), after 24 hours of contact. In the cell viability assay, after 48 hours of contact, the group of 1 mL of Ag-rGO with PDMS was the only group that increased cell viability when compared to the control group. In this context, it is believed these behaviors are due to the increase in cell adhesion capacity promoted by the rGO. Thus, the Ag-rGO/PDMS hybrid nanocomposite films can be used as scaffolds for tissue engineering, as they limit antimicrobial activity.

scholarly journals Effect of a Silver Nanoparticles Solution onStaphylococcus aureusandCandidaspp.

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Amanda Fucci Wady ◽  
Ana Lucia Machado ◽  
Camila Cristina Foggi ◽  
Camila Andrade Zamperini ◽  
Valtencir Zucolotto ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Candida Glabrata ◽  
Morphological Changes ◽  
Chemical Reduction ◽  
Total Biomass ◽  
Systemic Diseases ◽  
Planktonic Cells ◽  
Sem Images ◽  
Scanning Electron

An AgNPs solution was synthesized by chemical reduction, characterized, and tested againstCandida glabrata,Candida tropicalis,Staphylococcus aureus, and methicillin-resistantStaphylococcus aureus(MRSA). Minimum inhibitory (MICs) and minimum fungicidal/bactericidal concentrations (MFC/MBC) were determined on planktonic cells. Also, total biofilm mass was determined by crystal violet (CV) staining and morphological changes by scanning electron microscope (SEM). MICs forC. glabrata,C. tropicalis,S. aureus, and MRSA were 15.63, 3.91, 1.95, and 1.95 µg/mL, respectively. MFC forC. glabratawas 62.5 µg/mL and forC. tropicalis15.63 µg/mL The same MBC (3.91 µg/mL) was observed forS. aureusand MRSA. CV assay showed that the AgNPs (1000 μg/mL) promoted reductions in biofilm mass of ~60% forC. glabrataand ~35% forC. tropicalis. A reduction of ~20% inC. tropicalisbiomass was also observed at the concentration of 3.91 µg/mL. No significant effect on total biomass was found forS. aureusand MRSA. SEM images revealed thatC. glabrataandC. tropicalisbiofilm cells, exposed to the AgNPs (1000 μg/mL), had an irregular and shriveled appearance. AgNPs solution exhibited considerable antimicrobial activity against important fungal and bacterial pathogens, associated with several oral and systemic diseases, and has potential as an antimicrobial agent.

scholarly journals Cell Wall Thickening Is Not a Universal Accompaniment of the Daptomycin Nonsusceptibility Phenotype in Staphylococcus aureus: Evidence for Multiple Resistance Mechanisms

2010 ◽  
Vol 54 (8) ◽  
pp. 3079-3085 ◽  
Author(s):  
Soo-Jin Yang ◽  
Cynthia C. Nast ◽  
Nagendra N. Mishra ◽  
Michael R. Yeaman ◽  
Paul D. Fey ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Parental Strain ◽  
Cell Walls ◽  
Treated Patient ◽  
Resistance Mechanisms ◽  
Wall Thickening ◽  
Surface Binding ◽  
Transmission Electron ◽  
Triton X ◽  
Induced Autolysis

ABSTRACT The mechanism(s) of daptomycin (DAP) resistance (DAPr) is incompletely defined. Thickened cell walls (CWs) acting as either a mechanical barrier or an affinity trap for DAP have been purported to be a major contributor to the DAPr phenotype. To this end, we studied an isogenic set of methicillin-resistant Staphylococcus aureus (MRSA) isolates (pulsotype USA 300) from the bloodstream of a DAP-treated patient with endocarditis in which serial strains exhibited increasing DAPr. Of interest, the DAPr isolate differed from its parental strain in several parameters, including acquisition of a point mutation within the putative synthase domain of the mprF gene in association with enhanced mprF expression, increased synthesis of lysyl-phosphotidylglycerol, an enhanced positive envelope charge, and reduced DAP surface binding. Transmission electron microscopy (TEM) revealed no significant increases in CW thickness in the two DAPr isolates (MRSA 11/21 and REF2145) compared with that in the DAP-susceptible (DAPs) parental strain, MRSA 11/11. The rates of Triton X-100-induced autolysis were also identical for the strain set. Furthermore, among six additional clinically isolated DAPs/DAPr S. aureus strain pairs, only three DAPr isolates exhibited CWs significantly thicker than those of the respective DAPs parent. These data confirm that CW thickening is neither universal to DAPr S. aureus nor sufficient to yield the DAPr phenotype among S. aureus strains.

scholarly journals Antimicrobial Activity of the Quinoline Derivative HT61 against Staphylococcus aureus Biofilms

2020 ◽  
Vol 64 (5) ◽  
Author(s):  
C. J. Frapwell ◽  
P. J. Skipp ◽  
R. P. Howlin ◽  
E. M. Angus ◽  
Y. Hu ◽  
...  
Keyword(s):  
Health Care ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Cell Wall ◽  
Wall Stress ◽  
Quinoline Derivative ◽  
Significant Problem ◽  
Content Type ◽  
Health Care Settings ◽  
Cell Wall Stress

ABSTRACT Staphylococcus aureus biofilms are a significant problem in health care settings, partly due to the presence of a nondividing, antibiotic-tolerant subpopulation. Here we evaluated treatment of S. aureus UAMS-1 biofilms with HT61, a quinoline derivative shown to be effective against nondividing Staphylococcus spp. HT61 was effective at reducing biofilm viability and was associated with increased expression of cell wall stress and division proteins, confirming its potential as a treatment for S. aureus biofilm infections.

scholarly journals β-Lactam Resistance in Staphylococcus aureus Cells That Do Not Require a Cell Wall for Integrity

2005 ◽  
Vol 49 (12) ◽  
pp. 5075-5080 ◽  
Author(s):  
Elizabeth Fuller ◽  
Catherine Elmer ◽  
Fiona Nattress ◽  
Richard Ellis ◽  
Glenda Horne ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Methicillin Resistance ◽  
Intact Cell ◽  
Penicillin G ◽  
Coding Regions ◽  
Osmotic Stability ◽  
A Cell ◽  
Triton X ◽  
Resistant Cells

ABSTRACT Staphylococcus aureus ATCC 9144 cells with defective cell walls were generated on a medium with elevated osmolality in the presence of sublethal levels of penicillin G. On removal of antibiotic pressure, the cells exhibited stable penicillin and methicillin resistance. The resistance was homogeneous and its acquisition was enhanced following transient cell wall-defective growth. The resistant cells were mecA negative, β-lactamase negative and did not contain any mutations in the coding regions of pbp genes. When penicillin was added back to resistant cells, they continued to grow and produced a diffuse cell wall that was resistant to the action by lysostaphin but was very sensitive to lysis with Triton X-100. These data indicate that the resistant cells are not dependent upon an intact cell wall for osmotic stability and they are able to switch readily to this mode of growth in the presence of penicillin G.

scholarly journals The bacteriostatic effect and mechanism of berberine on Methicillin resistant Staphylococcus aureus in vitro

2020 ◽  
Author(s):  
Lei Wang ◽  
Fangfang Zhou ◽  
Minyi Xu ◽  
Pei Lu ◽  
Ming Lin ◽  
...  
Keyword(s):  
Cell Wall ◽  
Rna Sequencing ◽  
Differentially Expressed Genes ◽  
Differentially Expressed ◽  
Control Group ◽  
High Concentration ◽  
Bacteriostatic Effect ◽  
Low Concentration ◽  
Transmission Electron ◽  
Cell Wall Hydrolysis

Abstract Background: To observe the bacteriostatic effect of berberine (BBR) and BBR combined with gentamicin (GEN), levofloxacin (LEV) and amikacin (AMI) on Methicillin resistant Staphylococcus aureus (MRSA), while also exploring the bacteriostatic mechanism of BBR on MRSA. Methods: The minimal inhibitory concentration (MIC) of BBR, GEN, LEV and AMI on 26 clinical MRSA strains was determined by broth microdilution, while the MICs of BBR combined with GEN, LEV and AMI against MRSA were determined using a microdilution checkerboard. Time-killing curves were used to determine the kinetics of BBR combined with antibiotics for MRSA. We used conductivity tests to assess the changes in membrane permeability in response to BBR on MRSA, while also investigating the changes in MRSA morphology by transmission electron microscopy. RNA-sequencing was used to analyze the expression of differentially expressed genes in reference strain USA300 after its treatment with BBR at different concentrations.Results: The MICs range of BBR on 26 strains of MRSA was 32-256 µg/mL. BBR combined with GEN, LEV and AMI had obvious bacteriostatic effect on MASA. After co-culturing MRSA with BBR at 512 ug/mL, 64 ug/mL and 8 ug/mL, respectively, the electrical conductivity increased, compared with the control group, by 8.14%, 13.08% and 12.01%, respectively. Using transmission electron microscopy, we found that low concentration of BBR (8 ug/mL) had no significant effect on MRSA structure (keeping intact), medium concentration of BBR (64 ug/mL) thinned the cell wall of MRSA, while high concentration of BBR (512 ug/mL) induced the destruction and dissolution of MRSA cell wall structure and the leakage of bacterial contents, leading to bacterial lysis. RNA-sequencing results showed that there were 754 differentially expressed genes in the high concentration group compared with the normal control group. Compared with the low concentration group, there were 590 differentially expressed genes in the high concentration group. Compared with the control group, only 19 genes were differentially expressed in the low concentration group. The up-regulated genes are mainly related to the cell wall hydrolysis regulatory genes, while the down-regulated genes are mainly related to the serine protease family.Conclusions: BBR displayed an excellent bacteriostatic effect on MRSA. BBR combined with GEN and AMI significantly enhanced the bacteriostatic effect on MRSA, while BBR combined with LEV showed no significant change in the bacteriostatic effect on MRSA. BBR inhibited bacteria by destroying and dissolving the structure of MRSA cell wall. RNA-sequencing results further demonstrated that the expression of cell wall hydrolysis genes ssaA, lytM and virulence factor serine protease genes were significantly differentially expressed when high concentration BBR treated on MRSA.

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