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David Crich - One of the best experts on this subject based on the ideXlab platform.

  • Synthesis, ribosomal selectivity, and antibacterial activity of Netilmicin 4′-derivatives
    MedChemComm, 2019
    Co-Authors: Amr Sonousi, Dimitri Shcherbakov, Andrea Vasella, Erik C. Böttger, David Crich
    Abstract:

    Halogenation of a suitably protected Netilmicin derivative enables preparation of 4'-chloro-, bromo-, and iodo derivatives of Netilmicin after deprotection. Suzuki coupling of a protected 4'-bromo derivative with phenylboronic acid or butyltrifluoroborate affords the corresponding 4'-phenyl and 4'-butyl derivatives of Netilmicin. Sulfenylation of suitably protected Netilmicin derivative with ethanesulfenyl chloride followed by deprotection affords 4'-ethylsulfanylNetilmicin. All Netilmicin 4'-derivatives displayed reduced levels of inhibition for prokaryotic ribosomes and reduced antibacterial activity against typical Gram-positive and Gram-negative strains. None of the derivatives displayed enhanced target selectivity.

  • synthesis ribosomal selectivity and antibacterial activity of Netilmicin 4 derivatives
    MedChemComm, 2019
    Co-Authors: Amr Sonousi, Dimitri Shcherbakov, Andrea Vasella, Erik C. Böttger, David Crich
    Abstract:

    Halogenation of a suitably protected Netilmicin derivative enables preparation of 4'-chloro-, bromo-, and iodo derivatives of Netilmicin after deprotection. Suzuki coupling of a protected 4'-bromo derivative with phenylboronic acid or butyltrifluoroborate affords the corresponding 4'-phenyl and 4'-butyl derivatives of Netilmicin. Sulfenylation of suitably protected Netilmicin derivative with ethanesulfenyl chloride followed by deprotection affords 4'-ethylsulfanylNetilmicin. All Netilmicin 4'-derivatives displayed reduced levels of inhibition for prokaryotic ribosomes and reduced antibacterial activity against typical Gram-positive and Gram-negative strains. None of the derivatives displayed enhanced target selectivity.

F Caron - One of the best experts on this subject based on the ideXlab platform.

  • in vitro synergistic effects of double and triple combinations of beta lactams vancomycin and Netilmicin against methicillin resistant staphylococcus aureus strains
    Antimicrobial Agents and Chemotherapy, 2000
    Co-Authors: Stephanie Rochonedouard, Martine Pestelcaron, Jeanfrancois Lemeland, F Caron
    Abstract:

    Several studies have previously reported synergistic effects between vancomycin and a given beta-lactam or a given aminoglycoside against methicillin-resistant Staphylococcus aureus (MRSA) strains. The aim of our study was to exhaustively compare the effects of different combinations of a beta-lactam, vancomycin, and/or an aminoglycoside against 32 clinical MRSA strains with different aminoglycoside susceptibility patterns. The effects of 26 different beta-lactam-vancomycin and 8 different aminoglycoside-vancomycin combinations were first studied using a disk diffusion screening method. The best interactions with vancomycin were observed with either imipenem, cefazolin, or Netilmicin. By checkerboard studies, imipenem-vancomycin and cefazolin-vancomycin each provided a synergistic bacteriostatic effect against 22 strains; the mean fractional inhibitory concentration (FIC) indexes were 0.35 and 0.46 for imipenem-vancomycin and cefazolin-vancomycin, respectively. The vancomycin-Netilmicin combination provided an indifferent effect against all of the 32 strains tested; the mean of FIC index was 1. 096. The mean concentrations of imipenem, cefazolin, Netilmicin, and vancomycin at which FIC indexes were calculated were clinically achievable. Killing experiments were then performed using imipenem, cefazolin, Netilmicin, and vancomycin at one-half of the MIC, alone and in different combinations, against 10 strains. The vancomycin-Netilmicin regimen was rarely bactericidal, even against strains susceptible to Netilmicin. The imipenem-vancomycin and cefazolin-vancomycin combinations were strongly bactericidal against six and five strains, respectively. The addition of Netilmicin markedly enhanced the killing activity of the combination of cefazolin or imipenem plus vancomycin, but only for the MRSA strains against which the beta-lactam-vancomycin combinations had no bactericidal effect. It is noteworthy that the latter strains were both susceptible to Netilmicin and heterogeneously resistant to methicillin.

Paul M Tulkens - One of the best experts on this subject based on the ideXlab platform.

  • pharmacokinetic and toxicological evaluation of a once daily regimen versus conventional schedules of Netilmicin and amikacin
    Journal of Antimicrobial Chemotherapy, 1991
    Co-Authors: Paul M Tulkens
    Abstract:

    The safety and pharmacokinetics of Netilmicin (6.6 mg/kg) and amikacin (14.5 mg/kg) once daily (od) have been compared to their corresponding conventional schedules thrice daily (tid), and twice daily (bd), in patients (20 per group) suffering from pelvic inflammatory disease. Sensitive criteria of early renal and auditory alterations, namely urinary excretion of phospholipids and audiometry over a wide frequency range (0.25-18 kHz), respectively, were used. The first criterion (phospholipiduria) was validated by an animal study which demonstrated that rats receiving poly-L-aspartic acid, which protects against gentamicin-induced nephrotoxicity, are also protected against renal phospholipidosis and phospholipiduria caused by this antibiotic. On that basis, Netilmicin od was better tolerated than Netilmicin tid. Amikacin caused less phospholipiduria than Netilmicin, and, given od, resulted in little increase over baseline (95% CI, 95-147% increase). Reduction in threshold by greater than or equal to 15 dB for frequencies between 10-18 kHz occurred in nine of 19 patients receiving Netilmicin tid compared with three or four of 19 or 20 patients treated with Netilmicin od or amikacin (od or bd). However, changes at lower frequencies (0.25-8 kHz) were infrequent with all regimens (from 0/19 to 2/20). In conclusion, these very sensitive tests of nephro- and oto-toxicity suggest that od dosing of amikacin or Netilmicin is, if anything, safer than bd or tid dosing.

Masaru Nasu - One of the best experts on this subject based on the ideXlab platform.

  • improved efficacy with nonsimultaneous administration of Netilmicin and minocycline against methicillin resistant staphylococcus aureus in in vitro and in vivo models
    International Journal of Antimicrobial Agents, 1999
    Co-Authors: Yoichiro Goto, Kazufumi Hiramatsu, Masaru Nasu
    Abstract:

    The effect of combined administration of Netilmicin and minocycline against methicillin-resistant Staphylococcus aureus (MRSA) was investigated by using in vitro and in vivo models. Thirty one isolates of MRSA were tested for sensitivity to Netilmicin, minocycline, and combination of both by the chequer board method. We used then a dynamic in vitro system, which simulates in vivo serum kinetics, to assess the effect of various combination regimens of these antibiotics against an MRSA isolate with a fractional inhibitory concentration index of 0.25. The following dose regimens were compared: Netilmicin given alone; minocycline given alone; both antibiotics given simultaneously; Netilmicin followed by minocycline at 2 h; or minocycline followed by Netilmicin at 2 h. Netilmicin showed a stronger activity than minocycline. On the other hand, their combination was synergistic against 19% of isolates and additive against 77% of isolates. Against one isolate only, it was indifferent, and no antagonism was observed. In the auto-simulation system, the combination of antibiotics was generally more effective than single drugs, with the regimen Netilmicin followed by minocycline at 2 h showing the highest antibacterial effect. In the mouse model of pulmonary infection, the bacterial counts and histopathological findings of the lungs improved by treatment with this regimen. This regimen led also to a significantly high survival rate of mice with systemic infection compared to the other treatment regimens. Therefore, it was concluded that administration of Netilmicin followed by minocycline at 2 h may be an effective combination against MRSA infection.

Giovanni Bonfiglio - One of the best experts on this subject based on the ideXlab platform.

  • Effects on adhesiveness and hydrophobicity of sub-inhibitory concentrations of Netilmicin
    International journal of antimicrobial agents, 2003
    Co-Authors: Pio Maria Furneri, Anna Claudia Scuderi, Adriana Garozzo, Maria Pia Musumarra, Andrea Russo, Giovanni Bonfiglio
    Abstract:

    The effect of sub-inhibitory concentrations (SICs) of Netilmicin on bacterial hydrophobicity and adhesiveness to conjunctival cells was investigated. One strain each of Pseudomonas aeruginosa, Pseudomonas spp., Staphylococcus aureus and S. epidermidis was investigated for its susceptibility to Netilmicin, its adherence to conjunctival cells and to the effect of hydrocarbon hexadecane before and after treatment with SIC of Netilmicin. All of the bacteria tested were susceptible to Netilmicin except for Pseudomonas spp. which showed intermediate resistance. Netilmicin-treated Pseudomonas strains exhibited a lower level of hydrophobicity towards n-hexadecane compared with non-treated strains, while Netilmicin-treated S. epidermidis and S. aureus showed a slight increase of hydrophobicity. Adherence of the two Pseudomonas strains to conjunctival cells was significantly reduced after growth in the presence of Netilmicin, while the adherence of the two staphylococci was only slightly reduced.

  • Netilmicin in vitro activity time kill evaluation and postantibiotic effect on microorganisms isolated from ocular infections
    Chemotherapy, 2001
    Co-Authors: Giovanni Bonfiglio, Anna Claudia Scuderi, Giovanni Russo
    Abstract:

    The in vitro activity of Netilmicin and other antibiotics against ocular gram-positive and gram-negative microorganisms was evaluated. Netilmicin showed excellent activity against all the tested microorganisms, with more than 90% susceptibility. Many gentamicin- and tobramycin-resistant strains were still susceptible to Netilmicin, although the minimum inhibitory concentration values of Netilmicin were higher than those for the fully susceptible strains. In time-kill studies, Netilmicin showed bactericidal activity within 1 h against Pseudomonas aeruginosa and Staphylococcus aureus. Moreover, Netilmicin showed a postantibiotic effect of 2.4 h against P. aeruginosa and 1.5 h against S. aureus. These values were longer than those showed by ofloxacin, i.e. 2.1 and 1.4 h, respectively.

  • Netilmicin in vitro activity time kill evaluation and postantibiotic effect on microorganisms isolated from ocular infections
    Chemotherapy, 2001
    Co-Authors: Giovanni Bonfiglio, Anna Claudia Scuderi, Giovanni Russo
    Abstract:

    The in vitro activity of Netilmicin and other antibiotics against ocular gram-positive and gram-negative microorganisms was evaluated. Netilmicin showed excellent activity against all the tested micro