scholarly journals Pharmacodynamic activity of ertapenem versus penicillin-susceptible and penicillin-non-susceptible Streptococcus pneumoniae using an in vitro model

2006 ◽  
Vol 59 (1) ◽  
pp. 144-147 ◽  
Author(s):  
G. G. Zhanel ◽  
S. Derkatch ◽  
N. Laing ◽  
A. M. Noreddin ◽  
D. J. Hoban
Keyword(s):  
Streptococcus Pneumoniae ◽  
In Vitro Model ◽  
Vitro Model

scholarly journals Comparative Bactericidal Activities of Ciprofloxacin, Clinafloxacin, Grepafloxacin, Levofloxacin, Moxifloxacin, and Trovafloxacin against Streptococcus pneumoniae in a Dynamic In Vitro Model

2001 ◽  
Vol 45 (3) ◽  
pp. 673-678 ◽  
Author(s):  
Michael E. Klepser ◽  
Erika J. Ernst ◽  
C. Rosemarie Petzold ◽  
Paul Rhomberg ◽  
Gary V. Doern
Keyword(s):  
Streptococcus Pneumoniae ◽  
In Vitro Model ◽  
Rank Order ◽  
Active Agent ◽  
Inhibitory Effect ◽  
Pharmacokinetic Data ◽  
Time Curve ◽  
Bactericidal Activities ◽  
Vitro Model

ABSTRACT Several new quinolones that exhibit enhanced in vitro activity against Streptococcus pneumoniae have been developed. Using a dynamic in vitro model, we generated time-kill data for ciprofloxacin, clinafloxacin, grepafloxacin, levofloxacin, moxifloxacin, and trovafloxacin against three isolates of quinolone-susceptible S. pneumoniae. Three pharmacokinetic profiles were simulated for each of the study agents (0.1, 1, and 10 times the area under the concentration-time curve [AUC]). Target 24-h AUCs were based upon human pharmacokinetic data resulting from the maximal daily doses of each agent. Ciprofloxacin was the least active agent against all three isolates. With regimens that simulated the human 24-h AUC, ciprofloxacin resulted in an initial, modest decline in the numbers of CFU per milliliter; however, by 48 h the numbers of CFU per milliliter returned to or exceeded the starting inoculum. At the AUC, levofloxacin resulted in variable bacteriostatic and bactericidal activities against the isolates. The remaining agents yielded bactericidal (99.9% reduction) activity by 48 h with regimens that simulated the AUC. At 0.1 time the AUC ciprofloxacin and levofloxacin produced no inhibitory effect, grepafloxacin exhibited bacteriostatic activity, trovafloxacin had mixed static and cidal activities, and clinafloxacin and moxifloxacin caused significant reductions in the numbers of CFU per milliliter by 48 h. All six agents produced cidal activity at 10 times the AUC. In this dynamic in vitro model of infection, the quinolones demonstrated various degrees of activity against S. pneumoniae. The rank order of activity, with respect to bactericidal effect, was ciprofloxacin (least active) ≪ levofloxacin < grepafloxacin, trovafloxacin < clinafloxacin and moxifloxacin (most active). The rank order of the agents with respect to the selection of resistance was ciprofloxacin (most likely) > grepafloxacin, moxifloxacin, and trovafloxacin > levofloxacin > clinafloxacin.

scholarly journals Pharmacodynamic Comparisons of Levofloxacin, Ciprofloxacin, and Ampicillin against Streptococcus pneumoniae in an In Vitro Model of Infection

1999 ◽  
Vol 43 (3) ◽  
pp. 672-677 ◽  
Author(s):  
Melinda K. Lacy ◽  
Wen Lu ◽  
Xiaowei Xu ◽  
Pamela R. Tessier ◽  
David P. Nicolau ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
In Vitro Model ◽  
Pharmacokinetic Profile ◽  
Time Curve ◽  
Sustained Activity ◽  
Fluoroquinolone Antibiotics ◽  
Treatment Models ◽  
Dosing Regimens ◽  
Vitro Model

ABSTRACT The increasing frequency of penicillin-resistant pneumococcus continues to be of concern throughout the world. Newer fluoroquinolone antibiotics, such as levofloxacin, have shown enhanced in vitro activity against Streptococcus pneumoniae. In this study, the bactericidal characteristics and pharmacodynamic profiles of levofloxacin, ciprofloxacin, and ampicillin against four isolates ofS. pneumoniae were compared by using an in vitro model of infection. Standard antibiotic dosing regimens which simulated the pharmacokinetic profile observed in humans were used. Control and treatment models were sampled for bacterial CFU per milliliter over the duration of each 24- or 48-h experiment. In addition, treatment models were sampled for MIC determinations and drug concentration. Regrowth of all isolates as well as an increase in MICs throughout the study period was observed in the ciprofloxacin experiments. A limited amount of regrowth was noted during levofloxacin therapy for one isolate; however, no change in MIC was detected for any isolate. Ampicillin showed rapid and sustained bactericidal activity against all isolates. In this study, ratios of effective fluoroquinolone area under the concentration-time curve (AUC):MIC values ranged from 30 to 55. Levofloxacin, owing to its larger AUC0–24 values, has excellent and sustained activity against different pneumococcal strains superior to that of ciprofloxacin.

scholarly journals Activities against Streptococcus pneumoniae of amoxicillin and cefotaxime at physiological concentrations: in vitro pharmacodynamic simulation.

1996 ◽  
Vol 40 (12) ◽  
pp. 2904-2906 ◽  
Author(s):  
I P Balcabao ◽  
L Aguilar ◽  
M Martín ◽  
Y García ◽  
R Dal-Ré ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Human Serum ◽  
In Vitro Model ◽  
In Vitro Susceptibility ◽  
Initial Inoculum ◽  
Vitro Model ◽  
Reduction Percentage ◽  
Over Time

An in vitro model simulating amoxicillin and cefotaxime concentrations in human serum (after standard doses) was used to explore the activities of these drugs over time against penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae strains. An initial inoculum reduction percentage of > or = 90% was obtained with amoxicillin and maintained for 2 to 8 h, regardless of the strain tested. In contrast, experiments showed that cefotaxime had significantly (P < 0.001) less capability to reduce initial inocula of the penicillin-resistant pneumococci from 0.5 h on than amoxicillin, despite the same in vitro susceptibility to amoxicillin and cefotaxime in both strains.

An in vitro model for investigation of vitamin A effects on wound healing

2021 ◽  
pp. 1-6
Author(s):  
Hoda Keshmiri Neghab ◽  
Mohammad Hasan Soheilifar ◽  
Gholamreza Esmaeeli Djavid
Keyword(s):  
Wound Healing ◽  
Endothelial Cell ◽  
Vitamin A ◽  
In Vitro Model ◽  
Cellular Proliferation ◽  
Endothelial Cell Migration ◽  
Normal Fibroblast ◽  
Anti Inflammatory ◽  
Vitro Model

Abstract. Wound healing consists of a series of highly orderly overlapping processes characterized by hemostasis, inflammation, proliferation, and remodeling. Prolongation or interruption in each phase can lead to delayed wound healing or a non-healing chronic wound. Vitamin A is a crucial nutrient that is most beneficial for the health of the skin. The present study was undertaken to determine the effect of vitamin A on regeneration, angiogenesis, and inflammation characteristics in an in vitro model system during wound healing. For this purpose, mouse skin normal fibroblast (L929), human umbilical vein endothelial cell (HUVEC), and monocyte/macrophage-like cell line (RAW 264.7) were considered to evaluate proliferation, angiogenesis, and anti-inflammatory responses, respectively. Vitamin A (0.1–5 μM) increased cellular proliferation of L929 and HUVEC (p < 0.05). Similarly, it stimulated angiogenesis by promoting endothelial cell migration up to approximately 4 fold and interestingly tube formation up to 8.5 fold (p < 0.01). Furthermore, vitamin A treatment was shown to decrease the level of nitric oxide production in a dose-dependent effect (p < 0.05), exhibiting the anti-inflammatory property of vitamin A in accelerating wound healing. These results may reveal the therapeutic potential of vitamin A in diabetic wound healing by stimulating regeneration, angiogenesis, and anti-inflammation responses.

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