Wavelength and Bacterial Density Influence the Bactericidal Effect of Blue Light on Methicillin-Resistant Staphylococcus aureus (MRSA)

2013 ◽  
Vol 31 (11) ◽  
pp. 547-553 ◽  
Author(s):  
Violet V. Bumah ◽  
Daniela S. Masson-Meyers ◽  
Susan E. Cashin ◽  
Chukuka S. Enwemeka
Keyword(s):  
Staphylococcus Aureus ◽  
Blue Light ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Bactericidal Effect ◽  
Bacterial Density ◽  
Methicillin Resistant

Silver Nanoparticles Toxicity and Bactericidal Effect Against Methicillin-Resistant Staphylococcus aureus: Nanoscale Does Matter

2009 ◽  
Vol 5 (1-4) ◽  
pp. 2-9 ◽  
Author(s):  
Nilda Vanesa Ayala-Núñez ◽  
Humberto H. Lara Villegas ◽  
Liliana del Carmen Ixtepan Turrent ◽  
Cristina Rodríguez Padilla
Keyword(s):  
Staphylococcus Aureus ◽  
Silver Nanoparticles ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Bactericidal Effect ◽  
Methicillin Resistant ◽  
Nanoparticles Toxicity

scholarly journals ComparativeIn VivoEfficacies of Epithelial Lining Fluid Exposures of Tedizolid, Linezolid, and Vancomycin for Methicillin-Resistant Staphylococcus aureus in a Mouse Pneumonia Model

2012 ◽  
Vol 56 (5) ◽  
pp. 2342-2346 ◽  
Author(s):  
Pamela R. Tessier ◽  
Rebecca A. Keel ◽  
Mao Hagihara ◽  
Jared L. Crandon ◽  
David P. Nicolau
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Bacterial Density ◽  
Epithelial Lining ◽  
Control Groups ◽  
Epithelial Lining Fluid ◽  
Methicillin Resistant ◽  
Content Type ◽  
Treatment Groups

ABSTRACTThe antibacterial efficacies of tedizolid phosphate (TZD), linezolid, and vancomycin regimens simulating human exposures at the infection site against methicillin-resistantStaphylococcus aureus(MRSA) were compared in anin vivomouse pneumonia model. Immunocompetent BALB/c mice were orally inoculated with one of three strains of MRSA and subsequently administered 20 mg/kg TZD every 24 hours (q24h), 120 mg/kg linezolid q12h, or 25 mg/kg vancomycin q12h over 24 h. These regimens produced epithelial lining fluid exposures comparable to human exposures observed following intravenous regimens of 200 mg TZD q24h, 600 mg linezolid q12h, and 1 g vancomycin q12h. The differences in CFU after 24 h of treatment were compared between control and treatment groups. Vehicle-dosed control groups increased in bacterial density an average of 1.1 logs. All treatments reduced the bacterial density at 24 h with an average of 1.2, 1.6, and 0.1 logs for TZD, linezolid, and vancomycin, respectively. The efficacy of TZD versus linezolid regimens against the three MRSA isolates was not statistically different (P> 0.05), although both treatments were significantly different from controls. In contrast, the vancomycin regimen was significantly different from TZD against one MRSA isolate and from linezolid against all isolates. The vancomycin regimen was less protective than either the TZD or linezolid regimens, with overall survival of 61.1% versus 94.7% or 89.5%, respectively. At human simulated exposures to epithelial lining fluid, vancomycin resulted in minimal reductions in bacterial counts and higher mortality compared to those of either TZD or linezolid. TZD and linezolid showed similar efficacies in this MRSA pneumonia model.

scholarly journals Bactericidal effect of photodynamic therapy against methicillin-resistant Staphylococcus aureus strain with the use of various porphyrin photosensitizers.

2007 ◽  
Vol 54 (3) ◽  
pp. 665-670 ◽  
Author(s):  
Mariusz Grinholc ◽  
Bozena Szramka ◽  
Katarzyna Olender ◽  
Alfreda Graczyk
Keyword(s):  
Staphylococcus Aureus ◽  
Photodynamic Therapy ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Bactericidal Effect ◽  
Aureus Strain ◽  
Methicillin Resistant ◽  
Essential Change ◽  
Log10 Unit ◽  
Porphyrin Photosensitizers ◽  
Unit Reduction

Photodynamic therapy (PDT) is based on photosensitizers activated by light of appropriate wavelength. Their activation leads to generation of singlet oxygen and free radicals responsible for the cytotoxic effect. The aim of this project was to compare the bactericidal effect of PDT using different porphyrin photosensitizers against a methicillin-resistant Staphylococcus aureus strain. Exogenous sensitizers (protoporphyrin IX and newly synthesized derivative, protoporphyrin diarginate) induced a 3 log10-unit reduction in bacterial viable counts. With the use of endogenous, ALA-induced porphyrins, a 1.6 log10-unit reduction was obtained. The sensitizers tested executed their antibacterial activity with no essential change in the antibiotic resistance pattern of the studied strain.

scholarly journals Correlation between the Bacteriostatic and Bactericide Effect with Antibiofilm and Anticolony Spreading from Javanese Citronella Oil on Methicillin-Resistant Staphylococcus aureus (MRSA)

2019 ◽  
Vol 55 (1) ◽  
pp. 1
Author(s):  
Amaliyah Nurul Hidayah ◽  
Eddy Bagus Wasito ◽  
Kartuti Debora ◽  
Achmad Basori ◽  
Isnaeni Isnaeni ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Pearson Correlation ◽  
Statistical Significance ◽  
Bactericidal Effect ◽  
Methicillin Resistant ◽  
Citronella Oil ◽  
Bactericidal Effects ◽  
Effect Test

Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogenic bacterium that has been resistant to various types of antibiotics, so it is not easy to be treated with antibiotics and needs other solutions. Javanese citronella oil distilled from the Cymbopogon nardus plant is proven to function as an antibacterial agent (bacteriostatic and bactericidal), fungicide and repellent. This study aimed to prove that there is a positive correlation between bacteriostatic and bactericidal effects with antibiofilm and anticolony spreading from Javanese citronella oil on MRSA. The intended antibiofilm is a barrier to biofilm formation and eradication. Bacteriostatic and antibiofilm effects were tested using microtiter plates assay, bactericidal effect test with subculture into the media and anticolony spreading effect test with spot inoculation in Tryptic Soy Broth media supplemented with 0.24% agar. The bacteriostatic effect test data were analyzed using paired t-test, bactericidal effect using the Friedman test, antibiofilm effect test using Kruskall-Wallis and the results of all the tests correlated using Pearson and Spearman correlation. The statistical significance used was p<0.05. The results showed that Javanese citronella oil had a bacteriostatic concentration of 0.02% (v/v) and bactericidal concentration of 0.78% (v/v). The Pearson correlation test showed that there was a negative correlation between bacteriostatic and bactericidal effects on biofilm formation with r=-0.956 (p=0.000), but the correlation was positive for biofilm eradication with r=0.918 (p=0.000) and anticolony spreading with r=1.000 (p=0.000).

Antibacterial and synergic effects of gallic acid-grafted-chitosan with β-lactams against methicillin-resistant Staphylococcus aureus (MRSA)

2014 ◽  
Vol 60 (10) ◽  
pp. 629-638 ◽  
Author(s):  
Dae-Sung Lee ◽  
Sung-Hwan Eom ◽  
Young-Mog Kim ◽  
Hye Seon Kim ◽  
Mi-Jin Yim ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Gallic Acid ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Synergistic Effects ◽  
Cell Envelope ◽  
Bactericidal Effect ◽  
Clinical Isolates ◽  
Methicillin Resistant ◽  
New Antibiotics ◽  
Time Kill

Methicillin-resistant Staphylococcus aureus (MRSA) is spreading worldwide, emphasizing the need to search for new antibiotics. The anti-MRSA activities of gallic acid-grafted-chitosans (GA-g-chitosans) were investigated against 2 MRSA standards and 10 MRSA clinical isolates by determining the minimum inhibitory concentrations (MICs). GA-g-chitosan (I), which has the highest gallic acid content, exhibited the strongest anti-MRSA activities, with MICs of 32–64 μg/mL. A time-kill investigation revealed that GA-g-chitosan (I) exhibited a bactericidal effect at twice the MIC, also demonstrating good thermal and pH stability. Investigation of cell envelope integrity showed the release of intracellular components with an increasing absorbance value at 260 nm, indicating cell envelope damage caused by the GA-g-chitosan (I), which was further confirmed by transmission electron microscopy. When GA-g-chitosans were combined with β-lactams, including ampicillin and penicillin, synergistic effects were observed on the 2 standard MRSA strains and on the 10 clinical isolates, with fractional inhibitory indices ranging from 0.125 to 0.625. In the time-kill dynamic confirmation test, synergistic bactericidal effects were observed for the combinations of GA-g-chitosans with β-lactams, and over 4.0 log CFU/mL reductions were observed after 24 h when combination treatment was used. These results may prove GA-g-chitosans to be a potent agent when combined with ampicillin and penicillin for the elimination of MRSA.

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