scholarly journals In vitro activities of oxazolidinone compounds U100592 and U100766 against Staphylococcus aureus and Staphylococcus epidermidis.

1996 ◽  
Vol 40 (3) ◽  
pp. 799-801 ◽  
Author(s):  
G W Kaatz ◽  
S M Seo
Keyword(s):  
Staphylococcus Aureus ◽  
Staphylococcus Epidermidis ◽  
Inhibitory Activity ◽  
Antimicrobial Agents ◽  
Methicillin Resistant ◽  
Clinical Strains ◽  
Time Kill

The new oxazolidinone antimicrobial agents U100592 and U100766 demonstrated good in vitro inhibitory activity against clinical strains of Staphylococcus aureus and Staphylococcus epidermidis regardless of methicillin susceptibility. Both agents appeared bacteriostatic by time-kill analysis. Stable resistance to low multiples of the MIC of either drug could be produced only in methicillin-resistant S. aureus.

scholarly journals In vitro activities of two novel oxazolidinones (U100592 and U100766), a new fluoroquinolone (trovafloxacin), and dalfopristin-quinupristin against Staphylococcus aureus and Staphylococcus epidermidis.

1996 ◽  
Vol 40 (10) ◽  
pp. 2428-2430 ◽  
Author(s):  
L Mulazimoglu ◽  
S D Drenning ◽  
V L Yu
Keyword(s):  
Staphylococcus Aureus ◽  
Staphylococcus Epidermidis ◽  
Methicillin Resistant ◽  
Highly Active ◽  
Resistant Strains ◽  
Time Kill

Two oxazolidinones (U100592 and U100766), trovafloxacin, and a streptogramin combination (dalfopristin-quinupristin) were highly active in vitro against Staphylococcus aureus and Staphylococcus epidermidis, including methicillin-resistant strains. Trovafloxacin was more active than ciprofloxacin. Time-kill synergy studies demonstrated indifference for the oxazolidinones combined with vancomycin and rifampin against methicillin-resistant staphylococci. Spontaneous resistance was observed with all agents.

scholarly journals Pharmacodynamic Functions of Synthetic Derivatives for Treatment of Methicillin-Resistant Staphylococcus aureus (MRSA) and Mycobacterium tuberculosis

2020 ◽  
Vol 11 ◽  
Author(s):  
Mojdeh Dinarvand ◽  
Malcolm P. Spain ◽  
Fatemeh Vafaee
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Mycobacterium Tuberculosis ◽  
Antimicrobial Agents ◽  
Resistant Bacteria ◽  
Synthetic Compounds ◽  
Methicillin Resistant ◽  
Chemical Structures ◽  
Time Kill

Drug resistant bacteria have emerged, so robust methods are needed to evaluate combined activities of known antibiotics as well as new synthetic compounds as novel antimicrobial agents to treatment efficacy in severe bacterial infections. Marine natural products (MNPs) have become new strong leads in the drug discovery endeavor and an effective alternative to control infections. Herein, we report the bioassay guided fractionation of marine extracts from the sponges Lendenfeldia, Ircinia, and Dysidea that led us to identify novel compounds with antimicrobial properties. Chemical synthesis of predicted compounds and their analogs has confirmed that the proposed structures may encode novel chemical structures with promising antimicrobial activity against the medically important pathogens. Several of the synthetic analogs exhibited potent and broad spectrum in vitro antibacterial activity, especially against the Methicillin-resistant Staphylococcus aureus (MRSA) (MICs to 12.5 μM), Mycobacterium tuberculosis (MICs to 0.02 μM), uropathogenic Escherichia coli (MIC o 6.2 μM), and Pseudomonas aeruginosa (MIC to 3.1 μM). Checkerboard assay (CA) and time-kill studies (TKS) experiments analyzed with the a pharmacodynamic model, have potentials for in vitro evaluation of new and existing antimicrobials. In this study, CA and TKS were used to identify the potential benefits of an antibiotic combination (i.e., synthetic compounds, vancomycin, and rifampicin) for the treatment of MRSA and M. tuberculosis infections. CA experiments indicated that the association of compounds 1a and 2a with vancomycin and compound 3 with rifampicin combination have a synergistic effect against a MRSA and M. tuberculosis infections, respectively. Furthermore, the analysis of TKS uncovered bactericidal and time-dependent properties of the synthetic compounds that may be due to variations in hydrophobicity and mechanisms of action of the molecules tested. The results of cross-referencing antimicrobial activity, and toxicity, CA, and Time-Kill experiments establish that these synthetic compounds are promising potential leads, with a favorable therapeutic index for antimicrobial drug development.

scholarly journals Antistaphylococcal Activity of Oritavancin and Its Synergistic Effect in Combination with Other Antimicrobial Agents

2014 ◽  
Vol 58 (10) ◽  
pp. 6251-6254 ◽  
Author(s):  
Gengrong Lin ◽  
Glenn Pankuch ◽  
Peter C. Appelbaum ◽  
Klaudia Kosowska-Shick
Keyword(s):  
Staphylococcus Aureus ◽  
Synergistic Effect ◽  
Antimicrobial Agents ◽  
Methicillin Resistant ◽  
Content Type ◽  
Antistaphylococcal Activity ◽  
Vancomycin Resistant ◽  
Time Kill

ABSTRACTOritavancin exhibitedin vitroactivity against 169 strains of vancomycin-susceptible, methicillin-resistantStaphylococcus aureus(MRSA) with MICs ranging from 0.03 to 1 μg/ml and against vancomycin-intermediate MRSA (VISA;n= 29), heterogeneous vancomycin-intermediate MRSA (hVISA;n= 5), and vancomycin-resistant MRSA (n= 5) strains, with MICs ranging from 0.12 to 4 μg/ml. For 10 MRSA isolates comprising 5 VISA and 5 hVISA strains, synergy between oritavancin and gentamicin, linezolid, or rifampin was observed against most of the strains tested using a time-kill method.

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 Novel Antibiotic Combinations of Diverse Subclasses for Effective Suppression of Extensively Drug-Resistant Methicillin-Resistant Staphylococcus aureus (MRSA)

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Shumyila Nasir ◽  
Muhammad Sufyan Vohra ◽  
Danish Gul ◽  
Umm E Swaiba ◽  
Maira Aleem ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Clavulanic Acid ◽  
Antimicrobial Agents ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Multidrug Resistant ◽  
Methicillin Resistant ◽  
Development Of Resistance ◽  
Amoxicillin Clavulanic Acid ◽  
Combination Antibiotics ◽  
Time Kill

The emergence of multidrug-resistant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA), the chief etiological agent for a range of refractory infections, has rendered all β-lactams ineffective against it. The treatment process is further complicated with the development of resistance to glycopeptides, primary antibiotics for treatment of MRSA. Antibiotic combination therapy with existing antimicrobial agents may provide an immediate treatment option. Minimum inhibitory concentrations (MICs) of 18 different commercially available antibiotics were determined along with their 90 possible pairwise combinations and 64 triple combinations to filter out 5 best combinations. Time-Kill kinetics of these combinations were then analyzed to find collateral bactericidal combinations which were then tested on other randomly selected MRSA isolates. Among the top 5 combinations including levofloxacin-ceftazidime; amoxicillin/clavulanic acid-tobramycin; amoxicillin/clavulanic acid-cephradine; amoxicillin/clavulanic acid-ofloxacin; and piperacillin/tazobactam-tobramycin, three combinations were found to be collaterally effective. Levofloxacin-ceftazidime acted synergistically in 80% of the tested clinical MRSA isolates. First-line β-lactams of lower generations can be used effectively against MRSA infection when used in combination. Antibiotics other than glycopeptides may still work in combination.

Increase in the in vitro susceptibility of Staphylococcus aureus to antimicrobial agents in the presence of Candida albicans

1979 ◽  
Vol 25 (4) ◽  
pp. 429-435 ◽  
Author(s):  
J. deRepentigny ◽  
R. Lévesque ◽  
L. G. Mathieu
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Candida Albicans ◽  
Inhibitory Activity ◽  
Antimicrobial Agents ◽  
Mixed Cultures ◽  
Alpha Toxin ◽  
In Vitro Susceptibility ◽  
Pure Cultures

In experiments with mixed cultures of Staphylococcus aureus and Candida albicans both in the absence and in the presence of 5-fluorocytosine (5-FC), we have observed that (1) there is an inhibition of S. aureus growth in mixed cultures with C. albicans in media supplemented with 1 μg/mL of 5-FC and that 5-FC has no effect on staphylococci in pure cultures; (2) this inhibition occurred with clinically isolated and laboratory strains and could be reversed by specific metabolites; (3) Staphylococcus aureus was inhibited by filtrates of C. albicans cultures treated with 5-FC and this seemed to be favored by some C. albicans filterable product which can affect the cell wall and the permeability of the staphylococcal cells since they become sensitive to 5-FC; (4) nine other commonly used antimicrobials showed an increased inhibitory activity against S. aureus in mixed cultures with C. albicans; and (5) there is a decrease in the number of precipitating antigens of S. aureus and of the activity of alpha toxin when this species was grown with both C. albicans and 5-FC. Our results indicate that the susceptibility of some species to antimicrobials could be significantly modified in the presence of other species. One cannot exclude that a similar phenomenon could happen in hosts under treatment with antibiotics against infection.

scholarly journals Ceftobiprole EfficacyIn Vitroagainst Panton-Valentine Leukocidin Production andIn Vivoagainst Community-Associated Methicillin-Resistant Staphylococcus aureus Osteomyelitis in Rabbits

2012 ◽  
Vol 56 (12) ◽  
pp. 6291-6297 ◽  
Author(s):  
Azzam Saleh-Mghir ◽  
Oana Dumitrescu ◽  
Aurélien Dinh ◽  
Yassine Boutrad ◽  
Laurent Massias ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant ◽  
Content Type ◽  
The Mean ◽  
Mrsa Strains ◽  
Time Kill ◽  
Panton Valentine Leukocidin ◽  
Valentine Leukocidin

ABSTRACTCommunity-associated methicillin-resistantStaphylococcus aureus(CA-MRSA) can cause osteomyelitis with severe sepsis and/or local complications in which a Panton-Valentine leukocidin (PVL) role is suspected.In vitrosub-MIC antibiotic effects on growth and PVL production by 11 PVL+MRSA strains, including the major CA-MRSA clones (USA300, including the LAC strain; USA400; and USA1000), and 11 PVL+methicillin-susceptibleS. aureus(MSSA) strains were tested in microplate culture. Time-kill analyses with ceftobiprole at its MIC were also run with LAC. Efficacies of ceftobiprole (40 mg/kg of body weight subcutaneously [s.c.] four times a day [q.i.d.]) or vancomycin (60 mg/kg intramuscularly [i.m.] twice a day [b.i.d.]) alone or combined with rifampin (10 mg/kg b.i.d.) against rabbit CA-MRSA osteomyelitis, induced by tibial injection of 3.4 × 107CFU of LAC, were compared. Treatment, started 14 days postinoculation, lasted 14 days.In vitro, 6/11 strains cultured with sub-MICs of ceftobiprole produced 1.6- to 4.8-fold more PVL than did the controls, with no link to specific clones. Rifampin decreased PVL production by all tested strains. In time-kill analyses at the LAC MIC (0.75 mg/liter), PVL production rose transiently at 6 and 8 h and then declined 2-fold at 16 h, concomitant with a 2-log10-CFU-count decrease.In vivo, the mean log10CFU/g of bone for ceftobiprole (1.44 ± 0.40) was significantly lower than that for vancomycin (2.37 ± 1.22) (P= 0.034), with 7/10 versus 5/11 bones sterilized, respectively. Combination with rifampin enhanced ceftobiprole (1.16 ± 0.04 CFU/g of bone [P= 0.056], 11/11 sterile bones) and vancomycin (1.23 ± 0.06 CFU/g [P= 0.011], 11/11 sterile bones) efficacies. Ceftobiprole bactericidal activity and the rifampin anti-PVL effect could play a role in these findings, which should be of interest for treating CA-MRSA osteomyelitis.

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 VitroActivity of Retapamulin against Staphylococcus aureus Resistant to Various Antimicrobial Agents

2013 ◽  
Vol 57 (9) ◽  
pp. 4547-4550 ◽  
Author(s):  
Louis D. Saravolatz ◽  
Joan Pawlak ◽  
Stephanie N. Saravolatz ◽  
Leonard B. Johnson
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Good Activity ◽  
Methicillin Resistant ◽  
Content Type ◽  
Vancomycin Resistant ◽  
Time Kill

ABSTRACTRetapamulin and six other antimicrobial agents were evaluated against 155 methicillin-resistantStaphylococcus aureus(MRSA) isolates, including strains resistant to vancomycin, linezolid, daptomycin, and mupirocin by microdilution tests. Time-kill assays were performed against representative MRSA, vancomycin-intermediateS. aureus(VISA), and vancomycin-resistantS. aureus(VRSA) isolates. Retapamulin and mupirocin demonstrated MIC90s of 0.12 μg/ml and 8 μg/ml, respectively, with resistance seen in 2.6% and 10% of isolates, respectively. Retapamulin maintained good activity against 94% (15/16) of mupirocin-resistant isolates.

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