scholarly journals Efficacies of BMS 284756 against Penicillin-Sensitive, Penicillin-Resistant, and Quinolone-Resistant Pneumococci in Experimental Meningitis

2002 ◽  
Vol 46 (1) ◽  
pp. 184-187 ◽  
Author(s):  
Philippe Cottagnoud ◽  
Fernando Acosta ◽  
Marianne Cottagnoud ◽  
Marc Pfister ◽  
Martin G. Täuber
Keyword(s):  
Antibacterial Activity ◽  
Bactericidal Activity ◽  
Resistant Strain ◽  
Sensitive Strain ◽  
Standard Regimen

ABSTRACT BMS 284756 penetrated well into inflamed meninges (44% ± 11%) and produced good bactericidal activity (−0.82 ± 0.22 Δlog10 CFU/ml · h) in the treatment of experimental meningitis in rabbits due to a penicillin-sensitive strain. BMS 284756 monotherapy had a greater potency than the standard regimen of ceftriaxone and vancomycin (−0.49 ± 0.08 Δlog10 CFU/ml · h) against a penicillin-resistant strain (MIC, 4 mg/liter). Even against a penicillin- and quinolone-resistant strain, BMS 284756 showed good bactericidal activity (−0.52 ± 0.12 Δlog10 CFU/ml · h). The antibacterial activity of BMS 284756 was confirmed by time-killing assays over 8 h in vitro.

scholarly journals Gemifloxacin Is Efficacious against Penicillin-Resistant and Quinolone-Resistant Pneumococci in Experimental Meningitis

2002 ◽  
Vol 46 (5) ◽  
pp. 1607-1609 ◽  
Author(s):  
Philippe Cottagnoud ◽  
Fernando Acosta ◽  
Marianne Cottagnoud ◽  
Martin G. Täuber
Keyword(s):  
Antibacterial Activity ◽  
Standard Deviation ◽  
Bactericidal Activity ◽  
Resistant Strain ◽  
Activity Change ◽  
Standard Regimen ◽  
Pneumococcal Strain ◽  
Time Kill

ABSTRACT In experimental rabbit meningitis, gemifloxacin penetrated inflamed meninges well (22 to 33%) and produced excellent bactericidal activity (change in log10 [Δlog10] CFU/ml/h, −0.68 ± 0.30 [mean and standard deviation]), even superior to that of the standard regimen of ceftriaxone plus vancomycin (−0.49 ± 0.09 Δlog10 CFU/ml/h), in the treatment of meningitis due to a penicillin-resistant pneumococcal strain (MIC, 4 mg/liter). Even against a penicillin- and quinolone-resistant strain, gemifloxacin showed good bactericidal activity (−0.48 ± 0.16 Δlog10 CFU/ml/h). The excellent antibacterial activity of gemifloxacin was also confirmed by time-kill assays over 8 h in vitro.

scholarly journals Activities of Ertapenem, a New Long-Acting Carbapenem, against Penicillin-Sensitive or -Resistant Pneumococci in Experimental Meningitis

2003 ◽  
Vol 47 (6) ◽  
pp. 1943-1947 ◽  
Author(s):  
P. Cottagnoud ◽  
M. Pfister ◽  
M. Cottagnoud ◽  
F. Acosta ◽  
M. G. Täuber
Keyword(s):  
Cerebrospinal Fluid ◽  
Antibacterial Activity ◽  
Bactericidal Activity ◽  
Resistant Strain ◽  
Half Life ◽  
Resistant Mutant ◽  
Viable Cell ◽  
Cell Counts ◽  
Long Acting

ABSTRACT The penetration of ertapenem, a new carbapenem with a long half-life, reached 7.1 and 2.4% into inflamed and noninflamed meninges, respectively. Ertapenem had excellent antibacterial activity in the treatment of experimental meningitis due to penicillin-sensitive and -resistant pneumococci, leading to a decrease of 0.69 ± 0.17 and 0.59 ± 0.22 log10 CFU/ml · h, respectively, in the viable cell counts in the cerebrospinal fluid. The efficacy of ertapenem was comparable to that of standard regimens (ceftriaxone monotherapy against the penicillin-sensitive strain and ceftriaxone combined with vancomycin against the penicillin-resistant strain). In vitro, ertapenem in concentrations above the MIC was highly bactericidal against both strains. Even against a penicillin- and quinolone-resistant mutant, ertapenem had similar bactericidal activity in vitro.

scholarly journals Daptomycin Is Highly Efficacious against Penicillin-Resistant and Penicillin- and Quinolone-Resistant Pneumococci in Experimental Meningitis

2004 ◽  
Vol 48 (10) ◽  
pp. 3928-3933 ◽  
Author(s):  
Philippe Cottagnoud ◽  
Marc Pfister ◽  
Fernando Acosta ◽  
Marianne Cottagnoud ◽  
Lukas Flatz ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Streptococcus Pneumoniae ◽  
Bactericidal Activity ◽  
Resistant Strain ◽  
Pneumococcal Meningitis ◽  
Standard Regimen ◽  
Bacterial Titer ◽  
Lipopeptide Antibiotic ◽  
Experimental Pneumococcal Meningitis

ABSTRACT The penetration of daptomycin, a new lipopeptide antibiotic, into inflamed meninges ranged between 4.37 and 7.53% (mean, 5.97%). Daptomycin was very efficacious in the treatment of experimental pneumococcal meningitis, producing a decrease of −1.20 ± 0.32 Δlog10 CFU/ml · h in the bacterial titer of Streptococcus pneumoniae against a penicillin-resistant strain and of −0.97 ± 0.32 Δlog10 CFU/ml · h against a penicillin- and quinolone-resistant strain found in cerebrospinal fluid (CSF). For both strains, daptomycin was significantly superior to the standard regimen of a combination of ceftriaxone with vancomycin, sterilizing 9 of 10 CSF samples after 4 h. In vitro, daptomycin produced highly bactericidal activity in concentrations above the MIC.

scholarly journals In vitro anti-mycobacterial activity of (E)-N´-(monosubstituted-benzylidene) isonicotinohydrazide derivatives against isoniazid-resistant strains

2012 ◽  
Vol 4 (1) ◽  
pp. 13 ◽  
Author(s):  
Tatiane S. Coelho ◽  
Jessica B. Cantos ◽  
Marcelle L.F. Bispo ◽  
Raoni S.B. Gonçalves ◽  
Camilo H.S. Lima ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Resistant Strain ◽  
Mechanisms Of Action ◽  
Susceptible Strain ◽  
Clinical Isolates ◽  
Coding Region ◽  
Resistant Strains

A series of twenty-three <em>N-acylhydrazones</em> derived from isoniazid (INH 1-23) have been evaluated for their <em>in vitro</em> antibacterial activity against INH- susceptible strain of <em>M. tuberculosis</em> (RG500) and three INH-resistant clinical isolates (RG102, RG103 and RG113). In general, derivatives 4, 14, 15 and 16 (MIC=1.92, 1.96, 1.96 and 1.86 mM, respectively) showed relevant activities against RG500 strain, while the derivative 13 (MIC=0.98 mM) was more active than INH (MIC=1.14 mM). However, these derivatives were inactive against RGH102, which displays a mutation in the coding region of <em>inhA</em>. These results suggest that the activities of these compounds depend on the inhibition of this enzyme. However, the possibility of other mechanisms of action cannot be excluded, since compounds 2, 4, 6, 7, 12-17, 19, 21 and 23 showed good activities against <em>katG</em>-resistant strain RGH103, being more than 10-fold more active than INH.

Nemonoxacin enhances antibacterial activity and anti-resistant mutation ability of vancomycin against methicillin-resistant Staphylococcus aureus in an in vitro dynamic pharmacokinetic/pharmacodynamic model

2021 ◽  
Author(s):  
Junchen Huang ◽  
Siwei Guo ◽  
Xin Li ◽  
Fang Yuan ◽  
You Li ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Bactericidal Activity ◽  
Pharmacodynamic Model ◽  
Methicillin Resistant ◽  
Mutant Prevention Concentration ◽  
Mrsa Infection ◽  
Independent Risk Factors ◽  
Resistant Mutation

Reduced susceptibility and emergence of resistance to vancomycin in methicillin-resistant Staphylococcus aureus (MRSA) have led to the development of various vancomycin based combinations. Nemonoxacin is a novel nonfluorinated quinolone with antibacterial activity against MRSA. The present study aimed to investigate the effects of nemonoxacin on antibacterial activity and the anti-resistant mutation ability of vancomycin for MRSA and explore whether quinolone resistance genes are associated with a reduction in the vancomycin minimal inhibitory concentration (MIC) and mutant prevention concentration (MPC) when combined with nemonoxacin. Four isolates, all with a vancomycin MIC of 2 μg/mL, were used in a modified in vitro dynamic pharmacokinetic/pharmacodynamic model to investigate the effects of nemonoxacin on antibacterial activity (M04, M23 and M24) and anti-resistant mutation ability (M04, M23 and M25, all with MPC ≥19.2 μg/mL) of vancomycin. The mutation sites of gyrA , gyrB , parC , and parE of 55 clinical MRSA isolates were sequenced. We observed that in M04 and M23, the combination of vancomycin (1g q12h) and nemonoxacin (0.5g qd) showed a synergistic bactericidal activity and resistance enrichment suppression. All clinical isolates resistant to nemonoxacin harbored gyrA (S84→L) mutation; gyrA (S84→L) and parC (E84→K) mutations were the two independent risk factors for the unchanged vancomycin MPC in combination. Nemonoxacin enhances the bactericidal activity and suppresses resistance enrichment ability of vancomycin against MRSA with a MIC of 2 μg/mL. Our in vitro data support the combination of nemonoxacin and vancomycin for the treatment of MRSA infection with a high MIC.

scholarly journals In vitro antibacterial activity of omeprazole and its selectivity for Helicobacter spp. are dependent on incubation conditions.

1996 ◽  
Vol 40 (3) ◽  
pp. 621-626 ◽  
Author(s):  
J E Sjöström ◽  
J Fryklund ◽  
T Kühler ◽  
H Larsson
Keyword(s):  
Antibacterial Activity ◽  
Proton Pump Inhibitors ◽  
Proton Pump ◽  
Bactericidal Activity ◽  
Fetal Calf Serum ◽  
Calf Serum ◽  
Antibacterial Activities ◽  
In Vitro Antibacterial Activity ◽  
H Pylori

Factors affecting the in vitro antibacterial activity of omeprazole were studied. Our data show that 3H-labeled omeprazole covalently bound to Helicobacter pylori and to other gram-negative and gram-positive bacteria. The compound was found to bind to a broad range of proteins in H. pylori, and at pH 5, binding was enhanced 15-fold compared with binding at pH 7. The bactericidal activity correlated to the degree of binding, and at pH 5, a pH at which omeprazole readily converts to the active sulfenamide form, beta-mercaptoethanol, a known scavenger of sulfenamide, and fetal calf serum, to which noncovalent protein binding of omeprazole is known to occur, reduced the level of binding and almost entirely abolished the bactericidal activity. At pH 7 the killing activities of omeprazole and structural analogs (e.g., proton pump inhibitors) were dependent on the time-dependent conversion (half-life) to the corresponding sulfenamide. The bactericidal activity exerted by the sulfenamide form at pH 5 was not specific for the genus Helicobacter. However, in brucella broth at pH 7 with 10% fetal calf serum, only Helicobacter spp. were susceptible to omeprazole, with MBCs in the range of 32 to 64 micrograms/ml, and MBCs for more stable proton pump inhibitors were higher. Wild-type H. pylori and its isogenic urease-deficient mutant were equally susceptible to omeprazole. Thus, the urease is not a lethal target for omeprazole action in H. pylori. In conclusion, the antibacterial activities of omeprazole and analogs are dependent on pH and the composition of the medium used. Thus, at a low pH in buffer, these compounds have a nonselective action, whereas in broth at neutral pH, the mechanism of action is selective for Helicobacter spp.

scholarly journals In Vitro Activity of a Novel Antimicrobial Agent, TG44, for Treatment of Helicobacter pylori Infection

2006 ◽  
Vol 50 (9) ◽  
pp. 3062-3069 ◽  
Author(s):  
Osamu Kamoda ◽  
Kinsei Anzai ◽  
Jun-ichi Mizoguchi ◽  
Masatoshi Shiojiri ◽  
Toshiharu Yanagi ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Antibacterial Activity ◽  
Bactericidal Activity ◽  
Structural Formula ◽  
Therapeutic Modalities ◽  
Resistant Strains ◽  
H Pylori ◽  
Ph Range ◽  
Drug Resistant Strains

ABSTRACT Due to concerns about the current therapeutic modalities for Helicobacter pylori infection, e.g., the increased emergence of drug-resistant strains and the adverse reactions of drugs currently administered, there is a need to develop an anti-H. pylori agent with higher efficacy and less toxicity. The antibacterial activity of TG44, an anti-H. pylori agent with a novel structural formula, against 54 clinical isolates of H. pylori was examined and compared with those of amoxicillin (AMX), clarithromycin (CLR), and metronidazole (MNZ). Consequently, TG44 inhibited the growth of H. pylori in an MIC range of 0.0625 to 1 μg/ml. The MIC ranges of AMX, CLR, and MNZ were 0.0078 to 8 μg/ml, 0.0156 to 64 μg/ml, and 2 to 128 μg/ml, respectively. The antibacterial activity of TG44 against AMX-, CLR-, and MNZ-resistant strains was nearly comparable to that against drug-susceptible ones. In a pH range of 3 to 7, TG44 at 3.13 to 12.5 μg/ml exhibited potent bactericidal activity against H. pylori in the stationary phase of growth as early as 1 h after treatment began, in contrast to AMX, which showed no bactericidal activity at concentrations of up to 50 μg/ml at the same time point of treatment. TG44 at 25 μg/ml exhibited no antibacterial activity against 13 strains of aerobic bacteria, suggesting that its antibacterial activity against H. pylori is potent and highly specific. The present study indicated that TG44 possesses antibacterial activity which manifests quickly and is potentially useful for eradicating not only the antibiotic-susceptible but also the antibiotic-resistant strains of H. pylori by monotherapy.

Synthesis, antitrypanosomal and antimycobacterial activities of coumarinic N-acylhydrazonic derivatives

2020 ◽  
Vol 16 ◽  
Author(s):  
Camila Capelini ◽  
Vitória R. F. Câmara ◽  
José D. Figueroa Villar ◽  
Juliana M. C. Barbosa ◽  
Kelly Salomão ◽  
...  
Keyword(s):  
Resistant Strain ◽  
Sensitive Strain ◽  
Moderate Activity ◽  
Active Compounds ◽  
Meaningful Activity ◽  
The World ◽  
Resistant Strains ◽  
Vitro Effect ◽  
Tuberculosis Activity

Background: Near to 5-7 million people are infected with T. cruzi in the world, and about 10,000 people per year die of problems associated to this disease. Method: We reported herein the synthesis, antitrypanosomal and antimycobacterial activities of seventeen coumarinic N-acylhydrazonic derivatives. Results: These compounds were synthesized using methodology with reactions global yields ranging from 46%-70%. T. cruzi in vitro effect were evaluated against trypomastigote and amastigote forms and M. tuberculosis activity were towards H37Rv sensitive strain and resistant strains. Discussion: Against T. cruzi, the more active compounds revealed only moderate activity IC50/96h~20 µM for both trypomastigotes and amastigotes intracellular forms. (E)-2-oxo-N'-(3,4,5-trimethoxybenzylidene)-2H-chromene-3-carbohydrazide showed meaningful activity in INH resistant/RIP resistant strain. Conclusion: These compound acting as multitarget could be good leads for the development of new trypanocidal and bactericidal agents.

In Vitro Activities of StrychnosAlkaloids and Extracts against Plasmodium falciparum

1999 ◽  
Vol 43 (9) ◽  
pp. 2328-2331 ◽  
Author(s):  
Michel Frederich ◽  
Marie-Pierre Hayette ◽  
Monique Tits ◽  
Patrick De Mol ◽  
Luc Angenot
Keyword(s):  
Plasmodium Falciparum ◽  
Resistant Strain ◽  
Inhibitory Concentration ◽  
Sensitive Strain ◽  
Resistant Strains

ABSTRACT The in vitro antimalarial activities of 46 alkaloids and extracts from Strychnos species were evaluated. Two types of quasidimeric alkaloids exhibit high and selective activities againstPlasmodium. Strychnopentamine and isostrychnopentamine were active against chloroquine-sensitive and -resistant strains (50% inhibitory concentration [IC50] ≈ 0.15 μM), while dihydrousambarensine exhibited a 30-fold higher activity against the chloroquine-resistant strain (IC50 = 0.03 μM) than it did against the chloroquine-sensitive strain.

scholarly journals Antibacterial activity of human natural killer cells.

1989 ◽  
Vol 169 (1) ◽  
pp. 99-113 ◽  
Author(s):  
P Garcia-Peñarrubia ◽  
F T Koster ◽  
R O Kelley ◽  
T D McDowell ◽  
A D Bankhurst
Keyword(s):  
Antibacterial Activity ◽  
Nk Cells ◽  
Bactericidal Activity ◽  
Nk Cell ◽  
Close Contact ◽  
Effector Cells ◽  
Ultrastructural Studies ◽  
Human Natural Killer Cells ◽  
In Vitro Effects

The in vitro effects of human NK cells on viability of Gram-negative and Gram-positive bacteria was investigated. PBLs depleted of glass-adherent cells showed a significant antibacterial activity that was increased as the concentration of NK cells became higher. Leu-11-enriched cells exhibited the most efficient bactericidal activity. Stimulation of NK cells with staphylococcal enterotoxin B for 16 h produced a significant increase in the antibacterial activity of all NK cells tested. The antibacterial activity of monocyte-depleted cells and Leu-11-enriched cells was also enhanced after culturing in vitro for 16-24 h without exogenous cytokines. Dependence of the antibacterial activity on the presence of serum in the culture medium was not found. Ultrastructural studies revealed close contact between NK cell membranes and bacteria, no evidence of phagocytosis, and extracellular bacterial ghosts, after incubation at 37 degrees C. Supernatants from purified NK cells exhibited potent bactericidal activity with kinetics and target specificity similar to that of effector cells. These results document the potent antibacterial activity of purified NK cells and suggest an extracellular mechanism of killing.

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