scholarly journals In vitro activity of Isavuconazole against Candida auris by time-kill and postantifungal-effect assays

2018 ◽  
Author(s):  
E Eraso ◽  
Nerea Jauregizar
Keyword(s):  
Vitro Activity ◽  
In Vitro Activity ◽  
Candida Auris ◽  
Time Kill ◽  
Postantifungal Effect

scholarly journals In Vitro Activity of Micafungin (FK-463) against Candida spp.: Microdilution, Time-Kill, and Postantifungal-Effect Studies

2002 ◽  
Vol 46 (12) ◽  
pp. 3846-3853 ◽  
Author(s):  
Erika J. Ernst ◽  
Ellen E. Roling ◽  
C. Rosemarie Petzold ◽  
Douglas J. Keele ◽  
Michael E. Klepser
Keyword(s):  
Fungicidal Activity ◽  
Candida Krusei ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Candida Spp ◽  
Minimum Fungicidal Concentration ◽  
Inhibition Of Growth ◽  
Time Kill ◽  
Postantifungal Effect

ABSTRACT We evaluated the in vitro activity of the new echinocandin antifungal micafungin against Candida spp. using microdilution and time-kill methods. Additionally, we examined the postantifungal effect (PAFE) of micafungin. Finally, we evaluated the effect of the addition of serum and plasma on the MIC of micafungin. Four Candida albicans isolates and two isolates of each Candida glabrata, Candida krusei, and Candida tropicalis were selected for testing. The MICs of micafungin were determined in RPMI 1640 medium buffered with morpholinepropanesulfonic acid alone and with the addition of 10, 20, and 50% human serum and plasma. MICs were determined by using two endpoints: a prominent reduction in growth (the MIC at which 80% of isolates are inhibited [MIC80]) and complete visual inhibition of growth (MIC100). The minimum fungicidal concentration (MFC) of micafungin for each isolate was also determined. Time-kill curves were determined for each isolate in RPMI 1640 medium with micafungin at concentrations ranging from 0.125 to 16 times the MIC80 to assess the correlation between MIC80 and fungicidal activity. PAFE studies were conducted with each isolate by using concentrations ranging between 0.25 and 4 times the MIC80. The MIC80s for the test isolates ranged from 0.0039 to 0.25 μg/ml. Overall, the addition of serum or plasma increased the MIC 6 to 7 doubling dilutions for C. albicans and 3 to 4 doubling dilutions for C. krusei and C. tropicalis. Micafungin time-kill studies demonstrated fungicidal activity at concentrations ranging from 4 to 16 times the MIC80. Micafungin is very potent agent against a variety of Candida spp., producing fungicidal activity against 7 of 10 isolates tested. A PAFE was observed against all isolates. The PAFE was influenced by the drug concentration, with the highest concentration resulting in the longest observed PAFE in each case. The highest concentration tested, four times the MIC, resulted in a PAFE of more than 9.8 h for 5 of 10 isolates tested (range, 0.9 to ≥20.1 h).

In vitro activity of the novel antibacterial agent ibezapolstat (ACX-362E) against Clostridioides difficile

2020 ◽  
Author(s):  
Beverly Murray ◽  
Cindy Wolfe ◽  
Andrea Marra ◽  
Chris Pillar ◽  
Dean Shinabarger
Keyword(s):  
Therapeutic Potential ◽  
Oral Treatment ◽  
Clinical Development ◽  
Vitro Activity ◽  
The Novel ◽  
In Vitro Activity ◽  
Clostridioides Difficile ◽  
Clostridioides Difficile Infection ◽  
Time Kill

Abstract Background Ibezapolstat (ACX-362E) is the first DNA polymerase IIIC inhibitor undergoing clinical development for the oral treatment of Clostridioides difficile infection (CDI). Methods In this study, the in vitro activity of ibezapolstat was evaluated against a panel of 104 isolates of C. difficile, including those with characterized ribotypes (e.g. 027 and 078) and those producing toxin A or B and was shown to have similar activity to those of comparators against these strains. Results The overall MIC50/90 (mg/L) for ibezapolstat against evaluated C. difficile was 2/4, compared with 0.5/4 for metronidazole, 1/4 for vancomycin and 0.5/2 for fidaxomicin. In addition, the bactericidal activity of ibezapolstat was evaluated against actively growing C. difficile by determining the MBC against three C. difficile isolates. Time–kill kinetic assays were additionally performed against the three C. difficile isolates, with metronidazole and vancomycin as comparators. Conclusions The killing of C. difficile by ibezapolstat was observed to occur at concentrations similar to its MIC, as demonstrated by MBC:MIC ratios and reflected in time–kill kinetic assays. This activity highlights the therapeutic potential of ibezapolstat for the treatment of CDI.

scholarly journals In Vitro Activity of Pentamidine Alone and in Combination with Antibiotics against Multidrug-Resistant Clinical Pseudomonas aeruginosa Strains

Antibiotics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 885
Author(s):  
Soraya Herrera-Espejo ◽  
Tania Cebrero-Cangueiro ◽  
Gema Labrador-Herrera ◽  
Jerónimo Pachón ◽  
María Eugenia Pachón-Ibáñez ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Public Health Problem ◽  
Multidrug Resistant ◽  
Vitro Activity ◽  
Synergistic Activity ◽  
In Vitro Activity ◽  
Hospital Acquired Infections ◽  
Time Kill ◽  
Hospital Acquired

Multidrug-resistant (MDR) Pseudomonas aeruginosa is a public health problem causing both community and hospital-acquired infections, and thus the development of new therapies for these infections is critical. The objective of this study was to analyze in vitro the activity of pentamidine as adjuvant in combinations to antibiotics against seven clinical P. aeruginosa strains. The Minimum Inhibitory Concentration (MIC) was determined following standard protocols, and the results were interpreted according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints; however, the gentamicin activity was interpreted according to the Clinical and Laboratory Standards Institute (CLSI) recommendations. The bactericidal in vitro activity was studied at 1×MIC concentrations by time–kill curves, and also performed in three selected strains at 1/2×MIC of pentamidine. All studies were performed in triplicate. The pentamidine MIC range was 400–1600 μg/mL. Four of the strains were MDR, and the other three were resistant to two antibiotic families. The combinations of pentamidine at 1×MIC showed synergistic activity against all the tested strains, except for pentamidine plus colistin. Pentamidine plus imipenem and meropenem were the combinations that showed synergistic activity against the most strains. At 1/2×MIC, pentamidine plus antibiotics were synergistic with all three analyzed strains. In summary, pentamidine in combination with antibiotics showed in vitro synergy against multidrug-resistant P. aeruginosa clinical strains, which suggests its possible use as adjuvant to antibiotics for the therapy of infections from MDR P. aeruginosa.

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 In vitro activity of rezafungin against common and rare Candida species and Saccharomyces cerevisiae

2019 ◽  
Vol 74 (12) ◽  
pp. 3505-3510 ◽  
Author(s):  
Zoltán Tóth ◽  
Lajos Forgács ◽  
Jeffrey B Locke ◽  
Gábor Kardos ◽  
Fruzsina Nagy ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amphotericin B ◽  
Candida Species ◽  
Sensu Stricto ◽  
Candida Guilliermondii ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Candida Auris ◽  
In Vitro Susceptibility

Abstract Background Rezafungin is a novel echinocandin with excellent activity against common Candida species; however, limited data are available regarding rare Candida species. Methods We determined the in vitro susceptibility of 689 clinical isolates of 5 common and 19 rare Candida species, as well as Saccharomyces cerevisiae. The activity of rezafungin was compared with that of anidulafungin, caspofungin, micafungin, amphotericin B and fluconazole, using CLSI broth microdilution methodology (Fourth Edition: M27). Results Rezafungin MIC90 values were 0.06 mg/L for Candida albicans (n=125), Candida tropicalis (n=51), Candida dubliniensis (n=22), Candida inconspicua (n=41), Candida sojae (n=10), Candida lipolytica (n=10) and Candida pulcherrima (n=10), 0.12 mg/L for Candida glabrata (n=81), Candida krusei (n=53), Candida kefyr (n=52) and Candida fabianii (n=15), 0.25 mg/L for Candida lusitaniae (n=46) and Candida auris (n=19), 0.5 mg/L for Candida metapsilosis (n=15) and S. cerevisiae (n=21), 1 mg/L for Candida orthopsilosis (n=15) and Candida guilliermondii (n=27) and 2 mg/L for Candida parapsilosis sensu stricto (n=59). Caspofungin MIC90 values were 0.25–2 mg/L for all species, while micafungin and anidulafungin MIC90 values were similar to those of rezafungin. Fluconazole resistance was found in C. albicans (5.6%) and C. glabrata (4.9%); rezafungin was effective against these isolates as well. Amphotericin B MIC values did not exceed 2 mg/L. Conclusions Rezafungin showed excellent in vitro activity against both WT and azole-resistant Candida species, as well as against S. cerevisiae. Rezafungin had similar activity to other echinocandins (excluding caspofungin) against common Candida species and, notably, against clinically relevant uncommon Candida species.

In vitro activity of ampicillin/sulbactam against enterococci determined by the time-kill method

1989 ◽  
Vol 12 (1) ◽  
pp. 9-11 ◽  
Author(s):  
Richard F. D'Amato ◽  
Anna Mathew ◽  
Lisa Hochstein ◽  
Dennis J. Cleri ◽  
Janet Johnson
Keyword(s):  
Vitro Activity ◽  
In Vitro Activity ◽  
Time Kill

scholarly journals Antistaphylococcal Activity of DX-619 Alone and in Combination with Vancomycin, Teicoplanin, and Linezolid Assessed by Time-Kill Synergy Testing

2007 ◽  
Vol 51 (4) ◽  
pp. 1508-1511
Author(s):  
Kim Credito ◽  
Genrong Lin ◽  
Peter C. Appelbaum
Keyword(s):  
Staphylococcus Aureus ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Antistaphylococcal Activity ◽  
Time Kill ◽  
Synergy Testing

ABSTRACT Time-kill synergy studies testing in vitro activity of DX-619 alone and with added vancomycin, teicoplanin, or linezolid against 101 Staphylococcus aureus strains showed synergy between DX-619 and teicoplanin at 12 to 24 h in 72 strains and between DX-619 and vancomycin in 28 strains. No synergy was found with linezolid, and no antagonism was observed with any combination.

scholarly journals Time-Kill and Synergism Studies of Ceftobiprole against Enterococcus faecalis, Including β-Lactamase-Producing and Vancomycin-Resistant Isolates

2007 ◽  
Vol 51 (6) ◽  
pp. 2043-2047 ◽  
Author(s):  
Cesar A. Arias ◽  
Kavindra V. Singh ◽  
Diana Panesso ◽  
Barbara E. Murray
Keyword(s):  
Enterococcus Faecalis ◽  
Vitro Activity ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
In Vitro Activity ◽  
Inoculum Concentration ◽  
High Inoculum ◽  
Vancomycin Resistant ◽  
Time Kill

ABSTRACT Ceftobiprole (BAL9141) is an investigational cephalosporin with broad in vitro activity against gram-positive cocci, including enterococci. Ceftobiprole MICs were determined for 93 isolates of Enterococcus faecalis (including 16 β-lactamase [Bla] producers and 17 vancomycin-resistant isolates) by an agar dilution method following the Clinical and Laboratory Standards Institute recommendations. Ceftobiprole MICs were also determined with a high inoculum concentration (107 CFU/ml) for a subset of five Bla producers belonging to different previously characterized clones by a broth dilution method. Time-kill and synergism studies (with either streptomycin or gentamicin) were performed with two β-lactamase-producing isolates (TX0630 and TX5070) and two vancomycin-resistant isolates (TX2484 [VanB] and TX2784 [VanA]). The MICs of ceftobiprole for 50 and 90% of the isolates tested were 0.25 and 1 μg/ml, respectively. All Bla producers and vancomycin-resistant isolates were inhibited by concentrations of ≤1 and ≤4 μg/ml, respectively, at the standard inoculum concentration. Ceftobiprole MICs at a high inoculum concentration for a subset of five Bla+ E. faecalis isolates were ≤1 μg/ml. Bactericidal activity was observed against four isolates tested at concentrations as low as 1 μg/ml regardless of the production of β-lactamase or vancomycin resistance. A combination of ceftobiprole (0.5 μg/ml) and streptomycin (25 μg/ml) was synergistic against Bla+ TX0630 and TX5070. Ceftobiprole (0.5 μg/ml) plus gentamicin (10 μg/ml) was synergistic against VanB isolate TX2484 and showed enhanced killing, but not synergism, against TX2784 (VanA), despite the absence of high-level resistance to gentamicin. In conclusion, ceftobiprole exhibited good in vitro activity against E. faecalis, including Bla+ and vancomycin-resistant strains, and exhibited synergism with aminoglycosides against selected isolates.

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