scholarly journals In vitro activities of ciprofloxacin and rifampin alone and in combination against growing and nongrowing strains of methicillin-susceptible and methicillin-resistant Staphylococcus aureus.

1997 ◽  
Vol 41 (6) ◽  
pp. 1293-1297 ◽  
Author(s):  
D Bahl ◽  
D A Miller ◽  
I Leviton ◽  
P Gialanella ◽  
M J Wolin ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Drug Interaction ◽  
Growth Inhibition ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Bactericidal Effect ◽  
Drug Combinations ◽  
Bactericidal Effects ◽  
Time Kill ◽  
Phosphate Buffered Saline

We characterized the effects of ciprofloxacin and rifampin alone and in combination on Staphylococcus aureus in vitro. The effects of drug combinations (e.g., indifferent, antagonistic, or additive interactions) on growth inhibition were compared by disk approximation studies and by determining the fractional inhibitory concentrations. Bactericidal effects in log-phase bacteria and in nongrowing isolates were characterized by time-kill methods. The effect of drug combinations was dependent upon whether or not cells were growing and whether killing or growth inhibition was the endpoint used to measure drug interaction. Despite bactericidal antagonism in time-kill experiments, our in vitro studies suggest several possible explanations for the observed benefits in patients treated with a combination of ciprofloxacin and rifampin for deep-seated staphylococcal infections. Notably, when growth inhibition rather than killing was used to characterize drug interaction, indifference rather than antagonism was observed. An additive bactericidal effect was observed in nongrowing bacteria suspended in phosphate-buffered saline. While rifampin antagonized the bactericidal effects of ciprofloxacin, ciprofloxacin did not antagonize the bactericidal effects of rifampin. Each antimicrobial prevented the emergence of subpopulations that were resistant to the other.

scholarly journals In Vitro Killing of Community-Associated Methicillin-Resistant Staphylococcus aureus with Drug Combinations

2004 ◽  
Vol 48 (10) ◽  
pp. 4016-4019 ◽  
Author(s):  
Samuel A. Shelburne ◽  
Daniel M. Musher ◽  
Kristina Hulten ◽  
Heather Ceasar ◽  
Michael Y. Lu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Drug Combinations ◽  
Methicillin Resistant ◽  
Common Drug ◽  
Time Kill ◽  
Hospital Acquired

ABSTRACT This study employs time-kill techniques to examine the most common drug combinations used in the therapy of methicillin-resistant Staphylococcus aureus (MRSA) infections, vancomycin plus either gentamicin or rifampin. Community-associated MRSA were more likely to be synergistically inhibited by combinations of vancomycin and gentamicin versus vancomycin alone compared to inhibition associated with hospital-acquired strains.

scholarly journals ComparativeIn VitroActivities of Oritavancin, Dalbavancin, and Vancomycin against Methicillin-Resistant Staphylococcus aureus Isolates in a Nondividing State

2016 ◽  
Vol 60 (7) ◽  
pp. 4342-4345 ◽  
Author(s):  
Adam Belley ◽  
David Lalonde Seguin ◽  
Francis Arhin ◽  
Greg Moeck
Keyword(s):  
Staphylococcus Aureus ◽  
Bactericidal Activity ◽  
Antibacterial Agents ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Methicillin Resistant ◽  
Content Type ◽  
Skin Structure ◽  
Persistent Infections ◽  
Time Kill

ABSTRACTAntibacterial agents that kill nondividing bacteria may be of utility in treating persistent infections. Oritavancin and dalbavancin are bactericidal lipoglycopeptides that are approved for acute bacterial skin and skin structure infections in adults caused by susceptible Gram-positive pathogens. Using time-kill methodology, we demonstrate that oritavancin exerts bactericidal activity against methicillin-resistantStaphylococcus aureus(MRSA) isolates that are maintained in a nondividing statein vitro, whereas dalbavancin and the glycopeptide vancomycin do not.

scholarly journals In Vitro 24-Hour Time-Kill Studies of Vancomycin and Linezolid in Combination versus Methicillin-Resistant Staphylococcus aureus

2009 ◽  
Vol 53 (10) ◽  
pp. 4495-4497 ◽  
Author(s):  
Shveta Rani Singh ◽  
Alfred E. Bacon ◽  
David C. Young ◽  
Kimberly A. Couch
Keyword(s):  
Staphylococcus Aureus ◽  
Conventional Therapy ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Antagonistic Activity ◽  
Vitro Activity ◽  
Synergistic Activity ◽  
In Vitro Activity ◽  
Methicillin Resistant ◽  
Time Kill

ABSTRACT Many clinicians are trying unique strategies, including vancomycin and linezolid in combination, for treatment of patients who do not respond to conventional therapy against methicillin (meticillin)-resistant Staphylococcus aureus. In our study, which illustrated in vitro activity only, no synergistic activity was seen when the two agents were combined. Conversely, antagonistic activity occurred in three of five strains when linezolid was added to vancomycin. Our results indicate that vancomycin and linezolid in combination should be avoided.

scholarly journals Efficacy of Telavancin in a Rabbit Model of Aortic Valve Endocarditis Due to Methicillin-Resistant Staphylococcus aureus or Vancomycin-Intermediate Staphylococcus aureus

2005 ◽  
Vol 49 (8) ◽  
pp. 3163-3165 ◽  
Author(s):  
Andres G. Madrigal ◽  
Li Basuino ◽  
Henry F. Chambers
Keyword(s):  
Staphylococcus Aureus ◽  
Aortic Valve ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
No Reduction ◽  
Rabbit Model ◽  
Daily Regimen ◽  
Methicillin Resistant ◽  
Days Of Therapy ◽  
Time Kill

ABSTRACT The activities of telavancin and vancomycin were compared in vitro and in the rabbit model of aortic valve endocarditis against a methicillin-resistant Staphylococcus aureus strain, COL, and a vancomycin-intermediate S. aureus (VISA) strain, HIP 5836. Telavancin was bactericidal in time-kill studies at a concentration of 5 μg/ml against both COL and HIP5836. Vancomycin was bacteriostatic at 5 μg/ml and bactericidal at 10 μg/ml against COL and was bacteriostatic at 10 μg/ml against VISA strain HIP 5836. Compared to untreated controls, a twice-daily regimen of 30 mg/kg of telavancin reduced mean aortic valve vegetation titers of the COL strain by 4.7 log10 CFU/g after 4 days of therapy and sterilized 6/11 vegetations compared to 3.4 log10 CFU/g with 3/10 vegetations sterilized for a regimen of twice-daily vancomycin, 30 mg/kg; these differences were not statistically significant. Telavancin was significantly more effective than vancomycin in the VISA model, producing a 5.5 log10 CFU/g reduction versus no reduction in CFU with vancomycin. In experiments comparing 2-day regimens of telavancin at 30 mg/kg and 50 mg/kg twice daily, organisms were rapidly eliminated from vegetations, but the effect was not different between the two doses. These results suggest that telavancin may be an effective treatment for endocarditis and other serious staphylococcal infections accompanied by bacteremia, including infections caused by staphylococci not susceptible to vancomycin.

scholarly journals Antibacterial Activity of Silver Nanoparticles (AgNP) Confined to Mesostructured, Silica-Based Calcium Phosphate against Methicillin-Resistant Staphylococcus aureus (MRSA)

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1264
Author(s):  
Jung-Chang Kung ◽  
Wei-Hsun Wang ◽  
Chung-Lin Lee ◽  
Hao-Che Hsieh ◽  
Chi-Jen Shih
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Ceramic Powders ◽  
Methicillin Resistant ◽  
Bioactive Ceramic ◽  
Colony Forming Capacity ◽  
Phosphate Buffered Saline ◽  
Kinetics Of

Staphylococcus aureus, which is commonly found in hospitals, has become a major problem in infection control. In this study, Ag/80S bioactive ceramics used for enhanced antibacterial applications have been developed. An in vitro bioactivity test of the Ag/80S bioactive ceramic powders was performed in a phosphate-buffered saline (PBS). To explore the antibacterial activity of the Ag/80S bioactive ceramic powders, the Kirby-Bauer susceptibility test, the kinetics of microbial growth analysis and the colony-forming capacity assay were used to determine their minimum inhibitory concentration (MIC) against methicillin-resistant Staphylococcus aureus (MRSA). The results confirmed that the Ag/80S bioactive ceramic powders have antibacterial activity against MRSA (ATCC 33592) and MRSA (ATCC 49476).

scholarly journals Addition of Gentamicin or Rifampin Does Not Enhance the Effectiveness of Daptomycin in Treatment of Experimental Endocarditis Due to Methicillin-Resistant Staphylococcus aureus

2009 ◽  
Vol 53 (10) ◽  
pp. 4172-4177 ◽  
Author(s):  
J. M. Miró ◽  
C. García-de-la-Mària ◽  
Y. Armero ◽  
D. Soy ◽  
A. Moreno ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Statistical Difference ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Acquired Resistance ◽  
Rabbit Model ◽  
Human Pharmacokinetics ◽  
Methicillin Resistant ◽  
Time Kill

ABSTRACT This study evaluated the activity of daptomycin combined with either gentamicin or rifampin against three methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates in vitro and one isolate in vivo against a representative strain (MRSA-572). Time-kill experiments showed that daptomycin was bactericidal against these strains at concentrations over the MIC. Daptomycin at sub-MIC concentrations plus gentamicin at 1× and 2× the MIC yielded synergy, while the addition of rifampin at 2 to 4 μg/ml resulted in indifference (two strains) or antagonism (one strain). The in vivo activity of daptomycin (6 mg/kg of body weight once a day) was evaluated ± gentamicin (1 mg/kg intravenously [i.v.] every 8 h [q8h]) or rifampin (300 mg i.v. q8h) in a rabbit model of infective endocarditis by simulating human pharmacokinetics. Daptomycin plus gentamicin (median, 0 [interquartile range, 0 to 2] log10 CFU/g vegetation) was as effective as daptomycin alone (0 [0 to 2] log10 CFU/g vegetation) in reducing the density of bacteria in valve vegetations (P = 0.83), and both were more effective than daptomycin plus rifampin (3 [2 to 3.5] log10 CFU/g vegetation; P < 0.05) for the strain studied. In addition, daptomycin sterilized a ratio of vegetations that was similar to that of daptomycin plus gentamicin (10/15 [67%] versus 9/15 [60%]; P = 0.7), and both regimens did so more than daptomycin plus rifampin (3/15 [20%]; P = 0.01 and P = 0.02, respectively). No statistical difference was noted between daptomycin plus gentamicin and daptomycin alone for MRSA treatment. In the combination arm, all isolates from vegetations remained susceptible to daptomycin, gentamicin, and rifampin. Sixty-one percent of the isolates (8/13) acquired resistance to rifampin during monotherapy. In the daptomycin arm, resistance was detected in only one case, in which the daptomycin MIC rose to 2 μg/ml among the recovered bacteria. In conclusion, the addition of gentamicin or rifampin does not enhance the effectiveness of daptomycin in the treatment of experimental endocarditis due to MRSA.

scholarly journals The Combination of Daptomycin and Fosfomycin Has Synergistic, Potent, and Rapid Bactericidal Activity against Methicillin-ResistantStaphylococcus aureusin a Rabbit Model of Experimental Endocarditis

2018 ◽  
Vol 62 (6) ◽  
Author(s):  
Cristina García-de-la-Mària ◽  
Oriol Gasch ◽  
Javier García-Gonzalez ◽  
Dolors Soy ◽  
Evelyn Shaw ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bactericidal Activity ◽  
Combined Therapy ◽  
Rabbit Model ◽  
Bactericidal Effect ◽  
Methicillin Resistant ◽  
Content Type ◽  
Mrsa Strains ◽  
Time Kill

ABSTRACTWe investigated whether the addition of fosfomycin or cloxacillin to daptomycin provides better outcomes in the treatment of methicillin-resistantStaphylococcus aureus(MRSA) experimental aortic endocarditis in rabbits. Five MRSA strains were used to performin vitrotime-kill studies using standard (106) and high (108) inocula. Combined therapy was compared to daptomycin monotherapy treatment in the MRSA experimental endocarditis model. A human-like pharmacokinetics model was applied, and the equivalents of cloxacillin at 2 g/4 h, fosfomycin at 2 g/6 h, and daptomycin at 6 to 10 mg/kg/day were administered intravenously. A combination of daptomycin and either fosfomycin or cloxacillin was synergistic in the five strains tested at both inocula. A bactericidal effect was detected in four of five strains tested with both combinations. The MRSA-277 strain (vancomycin MIC, 2 μg/ml) was used for the experimental endocarditis model. Daptomycin plus fosfomycin significantly improved the efficacy of daptomycin monotherapy at 6 mg/kg/day in terms of both the proportion of sterile vegetations (100% versus 72%,P= 0.046) and the decrease in the density of bacteria within the vegetations (P= 0.025). Daptomycin plus fosfomycin was as effective as daptomycin monotherapy at 10 mg/kg/day (100% versus 93%,P= 1.00) and had activity similar to that of daptomycin plus cloxacillin when daptomycin was administered at 6 mg/kg/day (100% versus 88%,P= 0.48). Daptomycin nonsusceptibility was not detected in any of the isolates recovered from vegetations. In conclusion, for the treatment of MRSA experimental endocarditis, the combination of daptomycin plus fosfomycin showed synergistic and bactericidal activity.

scholarly journals Bactericidal Effects of Low-Irradiance Low Level Light Therapy on Methicillin-Resistant Staphylococcus Aureus in Vitro

Fine Focus ◽  
2016 ◽  
Vol 2 (2) ◽  
pp. 104-115
Author(s):  
Patrick J. McMullan ◽  
Jakob Krzyston ◽  
Robert Osgood
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Bacterial Load ◽  
Light Therapy ◽  
Methicillin Resistant ◽  
Low Level Light Therapy ◽  
Bactericidal Properties ◽  
Bactericidal Effects ◽  
Total Fluence

Low Level Light Therapy (LLLT) within the visible blue spectrum (400-470 nanometers) is a well-documented therapeutic alternative to combat multidrug resistant organism infections through the generation of reactive oxygen species (ROS). However, one shortcoming of LLLT is that many studies deliver therapy through high powered lasers and lamps. High powered light sources not only require specialized staff to operate, but they also deliver the total light dose (fluence) at an exceptionally high intensity, or irradiance, which could consequently deplete the oxygen supplies required to promote LLLT’s bactericidal properties. To overcome these faults, low-irradiance LLLT, or delivering the same total fluence of LLLT over an extended period of time with decreased irradiance was evaluated in vitro. To further explore this alternative approach, the bactericidal effects of low-irradiance (10.44 mW/cm2) LLLT using wavelengths of 405-nm, 422-nm and 470-nm were studied on methicillin-resistant Staphylococcus aureus (MRSA) cultures. Among these wavelengths, it was determined that 405-nm LLLT provided the most effective reduction of bacterial load at the lowest total fluence (75 J/cm2) (94.50% reduction). The bactericidal effects of 405-nm low-irradiance LLLT were then further studied by treating MRSA cultures to 75 J/cm2 LLLT while using irradiances of 5.22 mW/cm2 and 3.48 mW/cm2. It was concluded that there was a greater reduction of MRSA bacterial load when samples were exposed to irradiances of 5.22 mW/cm2 (95.71% reduction) and 3.48 mW/cm2 (99.63% reduction). This study validates the bactericidal properties of low-irradiance LLLT on MRSA, and subsequent studies should be completed to optimize its full therapeutic potential.

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).

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