scholarly journals Activity of OPT-80, a Novel Macrocycle, Compared with Those of Eight Other Agents against Selected Anaerobic Species

2004 ◽  
Vol 48 (11) ◽  
pp. 4430-4434 ◽  
Author(s):  
Kim L. Credito ◽  
Peter C. Appelbaum
Keyword(s):  
Gram Positive ◽  
Amoxicillin Clavulanate ◽  
Agar Dilution

ABSTRACT Agar dilution MIC was used to compare activities of OPT-80, linezolid, vancomycin, teicoplanin, quinupristin/dalfopristin, amoxicillin/clavulanate, imipenem, clindamycin, and metronidazole against 350 gram-positive and -negative anaerobes. OPT-80 was active against gram-positive strains only, especially Clostridium spp. (85 strains tested, including 21 strains of C. difficile), with MICs ranging between ≤0.016 and 0.25 μg/ml.

Antianaerobic activity of the ketolide RU 64004 compared to activities of four macrolides, five beta-lactams, clindamycin, and metronidazole.

1997 ◽  
Vol 41 (5) ◽  
pp. 1037-1041 ◽  
Author(s):  
L M Ednie ◽  
S K Spangler ◽  
M R Jacobs ◽  
P C Appelbaum
Keyword(s):  
Clostridium Difficile ◽  
Bacteroides Fragilis ◽  
The Other ◽  
Beta Lactams ◽  
Gram Positive ◽  
Amoxicillin Clavulanate ◽  
Bacteroides Fragilis Group ◽  
Agar Dilution ◽  
Bacteroides Ovatus ◽  
Fusobacterium Varium

Agar dilution methodology (with added Oxyrase in the case of the macrolide group to allow incubation without added CO2) was used to compare the activity of RU 64004, a new ketolide, with the activities of erythromycin, azithromycin, clarithromycin, roxithromycin, clindamycin, amoxicillin with and without clavulanate, piperacillin with and without tazobactam, metronidazole, and imipenem against 379 anaerobes. Overall, RU 64004 yielded an MIC at which 50% of the isolates are inhibited (MIC50) of 1.0 microg/ml and an MIC90 of 16.0 microg/ml. In comparison, MIC50s and MIC90s of erythromycin, azithromycin, clarithromycin, and roxithromycin were 2.0 to 8.0 and >64.0 microg/ml, respectively. MICs of macrolides, including RU 64004, were higher for Bacteroides ovatus, Fusobacterium varium, Fusobacterium mortiferum, and Clostridium difficile than for the other species. RU 64004 was more active against gram-positive rods and cocci, Prevotella and Porphyromonas spp., and fusobacteria other than F. mortiferum and F. varium than against the Bacteroides fragilis group. Overall MIC50s and MIC90s (in micrograms per milliliter), respectively, of other compounds were as follows: clindamycin, 1.0 and 16.0; amoxicillin, 4.0 and 64.0; amoxicillin-clavulanate, 0.5 and 4.0; piperacillin, 8.0 and >64.0; piperacillin-tazobactam, 1.0 and 16.0; metronidazole, 1.0 and 4.0; and imipenem, 0.25 and 1.0.

scholarly journals Activities of Tizoxanide and Nitazoxanide Compared to Those of Five Other Thiazolides and Three Other Agents against Anaerobic Species

2006 ◽  
Vol 50 (3) ◽  
pp. 1112-1117 ◽  
Author(s):  
Glenn A. Pankuch ◽  
Peter C. Appelbaum
Keyword(s):  
Gram Positive ◽  
Minimum Inhibitory Concentrations ◽  
Amoxicillin Clavulanate ◽  
Agar Dilution

ABSTRACT Agar dilution was used, and MICs of metronidazole, tizoxanide, nitazoxanide, denitrotizoxanide, RM 4803, RM 4807, RM 4809, RM 4819, amoxicillin-clavulanate, and clindamycin were measured against 412 anaerobes. Nitazoxanide, tizoxanide, RM 4807, and RM 4809 were active against all groups, except for gram-positive non-spore-forming rods with 50% minimum inhibitory concentrations (when the latter were excluded) of 1 to 2 μg/ml and 90% minimum inhibitory concentrations of 4 to 8 μg/ml, respectively. Metronidazole MICs were usually lower against all groups except clostridia.

scholarly journals Antifungal and Antibacterial Metabolites from a French Poplar Type Propolis

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Séverine Boisard ◽  
Anne-Marie Le Ray ◽  
Anne Landreau ◽  
Marie Kempf ◽  
Viviane Cassisa ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Antifungal Activity ◽  
Antimicrobial Effect ◽  
Antibacterial Activities ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Gram Positive ◽  
Weak Activity ◽  
Agar Dilution

During this study, thein vitroantifungal and antibacterial activities of different extracts (aqueous and organic) obtained from a French propolis batch were evaluated. Antifungal activity was evaluated by broth microdilution on three pathogenic strains:Candida albicans, C. glabrata, andAspergillus fumigatus. Antibacterial activity was assayed using agar dilution method on 36 Gram-negative and Gram-positive strains includingStaphylococcus aureus. Organic extracts showed a significant antifungal activity againstC. albicansandC. glabrata(MIC80between 16 and 31 µg/mL) but only a weak activity towardsA. fumigatus(MIC80= 250 µg/mL). DCM based extracts exhibited a selective Gram-positive antibacterial activity, especially againstS. aureus(SA) and several of its methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) strains (MIC10030–97 µg/mL). A new and active derivative of catechin was also identified whereas a synergistic antimicrobial effect was noticed during this study.

In Vitro Activity of Gepotidacin Against Gram-negative and Gram-positive Anaerobes

2021 ◽  
Author(s):  
Meredith A. Hackel ◽  
James A. Karlowsky ◽  
Michele A. Canino ◽  
Daniel F. Sahm ◽  
Nicole E. Scangarella-Oman
Keyword(s):  
Clinical Trials ◽  
Vitro Activity ◽  
Phase Iii ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Negative ◽  
Phase Iii Clinical Trials ◽  
Agar Dilution

Gepotidacin (formerly GSK2140944) is a first in class triazaacenaphthylene antibacterial currently in Phase III clinical trials. When tested against Gram-negative ( n =333) and Gram-positive ( n =225) anaerobes by agar dilution, gepotidacin inhibited 90% of isolates (MIC 90 ) at concentrations of 4 and 2 μg/ml, respectively. Given gepotidacin’s in vitro activity against the anaerobic isolates tested, further study is warranted to better understand gepotidacin’s utility in the treatment of infections caused by clinically relevant anaerobic organisms.

scholarly journals MIC and time-kill studies of antipneumococcal activity of GV 118819X (sanfetrinem) compared with those of other agents.

1997 ◽  
Vol 41 (1) ◽  
pp. 148-155 ◽  
Author(s):  
S K Spangler ◽  
M R Jacobs ◽  
P C Appelbaum
Keyword(s):  
United States ◽  
The United States ◽  
Broth Microdilution ◽  
Beta Lactam ◽  
Beta Lactams ◽  
Amoxicillin Clavulanate ◽  
Agar Dilution ◽  
Resistant Strains ◽  
Time Kill

Agar dilution MIC methodology was used to test the activities of GV 118819X (sanfetrinem), ampicillin, amoxicillin, amoxicillin-clavulanate, cefpodoxime, loracarbef, levofloxacin, clarithromycin, ceftriaxone, imipenem, and vancomycin against 53 penicillin-susceptible, 84 penicillin-intermediate and 74 penicillin-resistant pneumococci isolated in the United States. GV 118819X was the most active oral beta-lactam, with MIC at which 50% of the isolates were inhibited (MIC50)/MIC90 values of 0.008/0.03, 0.06/0.5, and 0.5/1.0 micrograms/ml against penicillin-susceptible, -intermediate, and -resistant stains, respectively. Amoxicillin and amoxicillin in the presence of clavulanate (2:1) were the second most-active oral beta-lactams, followed by ampicillin and cefpodoxime; loracarbef was not active against penicillin-intermediate and -resistant strains. Clarithromycin was most active against penicillin-susceptible strains but was less active against intermediate and resistant stains. All pneumococcal stains were inhibited by ceftriaxone and imipenem at MICs of < or = 4.0 and < or = 1.0 micrograms/ml, respectively. The activities of levofloxacin and vancomycin were unaffected by penicillin susceptibility. Time-kill studies of three penicillin-susceptible, three penicillin-intermediate, and three penicillin-resistant pneumococci showed that all compounds, at the broth microdilution MIC, yielded 99.9% killing of all strains after 24 h. Kinetic patterns of all oral beta-lactams, ceftriaxone, and vancomycin were similar relative to the MIC, with 90% killing of all strains first observed after 12 h. However, killing by amoxicillin-clavulanate, imipenem, and levofloxacin was slightly faster and that by clarithromycin was slower than that by the above-described drugs. At 2 x the MIC, more strains were killed earlier than was the case at the MIC, but the pattern seen at the MIC prevailed. When MICs and kill kinetics were combined, sanfetrinem was the most active oral antipneumococcal agent in this study.

scholarly journals In vitro activity of RU 64004, a new ketolide antibiotic, against gram-positive bacteria.

1997 ◽  
Vol 41 (5) ◽  
pp. 1196-1202 ◽  
Author(s):  
T Schülin ◽  
C B Wennersten ◽  
R C Moellering ◽  
G M Eliopoulos
Keyword(s):  
Vitro Activity ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Agar Dilution ◽  
Resistant Strains ◽  
Erythromycin A

The comparative in vitro activity of RU 64004 (also known as HMR 3004), a new ketolide antibiotic, was tested by agar dilution against approximately 500 gram-positive organisms, including multiply resistant enterococci, streptococci, and staphylococci. All streptococci were inhibited by < or = 1 microg of RU 64004 per ml. The ketolide was more potent than other macrolides against erythromycin A-susceptible staphylococci and was generally more potent than clindamycin against erythromycin A-resistant strains susceptible to this agent. Clindamycin-resistant staphylococci (MIC, > 128 microg/ml) proved resistant to the ketolide, but some erythromycin A- and clindamycin-resistant enterococci remained susceptible to RU 64004.

scholarly journals 686. Evaluation of Contezolid Activity to Anaerobic and Gram-positive-cocci Isolates from a Phase 3 Acute Bacterial Skin and Skin Structure Infection Clinical Trial (MRX-I-06)

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S312-S312
Author(s):  
Yang Yang ◽  
Demei Zhu
Keyword(s):  
Dilution Method ◽  
Phase 3 ◽  
Gram Positive ◽  
In Vitro Susceptibility ◽  
Skin Structure ◽  
Prevotella Bivia ◽  
In Vitro Antibacterial Activity ◽  
Agar Dilution ◽  
Leuconostoc Lactis

Abstract Background Contezolid (MRX-I) is an oxazolidinone in development for the treatment of acute bacterial skin and skin structure infections (ABSSSIs). In this study, in vitro susceptibility (S) for Contezolid and comparator agents for Gram-positive (GP) and anaerobic isolates from Phase 3 ABSSSI clinical trials were determined. Methods 313 isolates were collected from 65 participated sites and sent to a central laboratory for MIC testing. Clinical isolates included 34 anaerobes (15 Finegoldia magna, 8 Actinomyces spp., 4 Prevotella spp., 3 Propionibacterium avidum, 2 Peptostreptococcus spp., 1 Veillonella spp. and 1 Bacteroides fragilis), 187 S. aureus (59.7%). 12 S. pyogenes, 5 Enterococcus, and 75 other Gram-positive organisms. Broth micro-dilution method was used to determine the MIC of contezolid, linezolid, and other comparators to facultative isolates. Agar dilution was carried out for the anaerobes. Results For both 33 MRSA and 154 MSSA MIC50/90 values of contezolid and linezolid were 2 mg/L. One E. faecalis showed decreased susceptibility to oxazolidinones (both MIC = 4). 1 mg/L contezolid and linezolid could inhibit 12 S. pyogenes. 2 mg/L contezolid and linezolid could inhibit 15 Finegoldia magna. 0.5 mg/L contezolid and linezolid could inhibit 8 Actinomyces spp. To one Bacteroides fragili, two Prevotella bivia and one Leuconostoc lactis (Intrinsic resistant to vancomycin) the MIC of contezolid were 4 or 8 mg/L. In general, Contezolid had lower or equal MIC50/90 values against both GP and ANA species compared with linezolid for all organisms. Conclusion Contezolid demonstrated potent in vitro antibacterial activity against Gram-positive and anaerobic isolates tested. These data suggest that contezolid might be a beneficial supplement to the arena against MDR Gram-positive infection. Disclosures All authors: No reported disclosures.

scholarly journals In Vitro Activities of Peptide Deformylase Inhibitors against Gram-Positive Pathogens

2002 ◽  
Vol 46 (4) ◽  
pp. 1117-1118 ◽  
Author(s):  
R. Wise ◽  
J. M. Andrews ◽  
J. Ashby
Keyword(s):  
Respiratory Tract ◽  
Respiratory Tract Infections ◽  
Active Agent ◽  
Peptide Deformylase ◽  
Gram Positive ◽  
Similar Activity ◽  
Amoxicillin Clavulanate ◽  
Tract Infections

ABSTRACT The activities of six peptide deformylase (PDF) inhibitors against 107 respiratory tract pathogens were studied and compared to those of ciprofloxacin and amoxicillin-clavulanate. Against Streptococcus pneumoniae, BB-83698 and BB-83815 were the most active PDF inhibitors (MIC at which 90% of the organisms tested were inhibited [MIC90], 0.25 μg/ml). Five of the agents showed similar activity against Moraxella catarrhalis (MIC90, 0.12 μg/ml). All PDF inhibitors were less active against Haemophilus influenzae; BB-3497 was the most active agent (MIC90, 2 μg/ml). Five agents were studied against Chlamydia spp. and showed activity similar to that of ciprofloxacin (MIC, 0.5 to 4 μg/ml). This study demonstrates that PDF inhibitors have the potential to be developed for the treatment of respiratory tract infections.

scholarly journals In Vitro Activities of a New Des-Fluoro(6) Quinolone, Garenoxacin, against Clinical Anaerobic Bacteria

2003 ◽  
Vol 47 (11) ◽  
pp. 3667-3671 ◽  
Author(s):  
A. Liebetrau ◽  
A. C. Rodloff ◽  
J. Behra-Miellet ◽  
L. Dubreuil
Keyword(s):  
Clostridium Difficile ◽  
Anaerobic Bacteria ◽  
Bacteroides Fragilis ◽  
Antimicrobial Activities ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Gram Positive ◽  
Agar Dilution ◽  
Gram Positive Cocci

ABSTRACT The antimicrobial activities of garenoxacin and eight other antibiotics against 641 anaerobic isolates were evaluated with the NCCLS agar dilution method. Overall, the MICs of garenoxacin for 50 and 90% of the strains tested (in micrograms per milliliter) were as follows: Bacteroides fragilis group, 0.5 and 2; Prevotella spp., 0.25 and 2; Fusobacterium spp., 0.25 and 0.5; Porphyromonas spp., 0.125 and 0.25; Bilophila wadsworthia, 0.5 and 1; Veillonella spp., 0.25 and 0.5; Clostridium spp., 0.25 and 1; Clostridium difficile, 2 and >64; Bifidobacterium spp., 1 and 2; Eggerthella lenta, 0.25 and 1; Propionibacterium spp., 0.5 and 0.5; gram-positive cocci, 0.125 and 0.25.

scholarly journals Reconciling the potentially irreconcilable? Genotypic and phenotypic amoxicillin-clavulanate resistance in Escherichia coli

2019 ◽  
Author(s):  
Timothy J. Davies ◽  
Nicole Stoesser ◽  
Anna E Sheppard ◽  
Manal Abuoun ◽  
Philip Fowler ◽  
...  
Keyword(s):  
Fixed Effects ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
E Coli ◽  
Reliable Assessment ◽  
Genetic Features ◽  
Amoxicillin Clavulanate ◽  
Agar Dilution ◽  
Phenotypic Methods ◽  
Promoter Mutations

AbstractResistance to amoxicillin-clavulanate, a widely used beta-lactam/beta-lactamase inhibitor combination antibiotic, is rising globally, yet susceptibility testing remains challenging. To test whether whole-genome sequencing (WGS) could provide a more reliable assessment of susceptibility than traditional methods, we predicted resistance from WGS for 976 E. coli bloodstream infection isolates from Oxfordshire, UK, comparing against phenotypes from the BD Phoenix (calibrated against EUCAST guidelines). 339/976 (35%) isolates were amoxicillin-clavulanate resistant. Predictions based solely on beta-lactamase presence/absence performed poorly (sensitivity 23% (78/339)) but improved when genetic features associated with penicillinase hyper-production (e.g. promoter mutations, copy number estimates) were considered (sensitivity 82% (277/339); p<0.0001). Most discrepancies occurred in isolates with peri-breakpoint MICs. We investigated two potential causes; the phenotypic reference and the binary resistant/susceptible classification. We performed reference standard, replicated phenotyping in a random stratified subsample of 261/976 (27%) isolates using agar dilution, following both EUCAST and CLSI guidelines, which use different clavulanate concentrations. As well as disagreeing with each other, neither agar dilution phenotype aligned perfectly with genetic features. A random-effects model investigating associations between genetic features and MICs showed that some genetic features had small, variable and additive effects, resulting in variable resistance classification. Using model fixed-effects to predict MICs for the non-agar dilution isolates, predicted MICs were in essential agreement (±1 doubling dilution) with observed (BD Phoenix) MICs for 691/715 (97%) isolates. This suggests amoxicillin-clavulanate resistance in E. coli is quantitative, rather than qualitative, explaining the poorly reproducible binary (resistant/susceptible) phenotypes and suboptimal concordance between different phenotypic methods and with WGS-based predictions.

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