scholarly journals Antimicrobial and modulation effects of selected Ghanaian medicinal plants

2017 ◽  
Vol 36 (3) ◽  
pp. 1-7
Author(s):  
E. Ekuadzi ◽  
R. A. Dickson ◽  
T. C. Fleischer ◽  
S. O. Dapaah ◽  
E. O. Reynolds ◽  
...  
Keyword(s):  
Medicinal Plants ◽  
Plant Extracts ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Checkerboard Assay ◽  
Ethanol Extracts ◽  
Antibiotic Discovery

The alarming rise in the incidences of multidrug-resistant microorganisms and the decline innew antibiotic discovery make the search for new antimicrobial agents or efforts at restoring the activity of older antibiotics to which the microbes have developed resistance very necessary. The aim of the present study is to investigate the antimicrobial and modulation effects of the 70% ethanol extracts of Lannea schimperi, Commelina nudiflora and Piliostigma reticulatum against usceptible strains of microorganisms. Using the broth microdilution method, the minimum inhibitory concentrations (MICs) of the extracts were determined. The checkerboard assay was used to determine the modulation effects when sub-inhibitory concentrations of plant extracts were combined with the standard antibiotics. All three plants extracts possessed weak antimicrobial effects. For the modulation experiments, fifteen of the twenty-seven combinatorial casesyielded biologically significant effects. The ethanol extracts of the three plants studied here are good modulators as they reduced the MIC of ciprofloxacin and ketoconazole by factors that are comparable to that of reserpine. However the exact compounds and their exact mechanism of modulation require further investigation.Keywords: Anti-infective, modulation, Lannea schimperi, Commelina nudiflora, Piliostigmareticulatum, ethnomedicine

scholarly journals In VitroAntistaphylococcal Effects ofEmbelia schimperiExtracts and Their Component Embelin with Oxacillin and Tetracycline

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Johana Rondevaldova ◽  
Olga Leuner ◽  
Alemtshay Teka ◽  
Ermias Lulekal ◽  
Jaroslav Havlik ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Medicinal Plants ◽  
Bacterial Infections ◽  
Inhibitory Concentration ◽  
Developed Countries ◽  
Positive Interactions ◽  
Fractional Inhibitory Concentration ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Broth Microdilution Method

Bacterial infections are in less-developed countries traditionally treated by remedies prepared from medicinal plants.Embelia schimperi(Vatke) is a plant used as a taenicide or disinfectant in Ethiopia, very often taken mixed with another plant species. In the present study, we examined two extracts prepared from seeds and twigs with leaves ofE. schimperiand its main present secondary metabolite embelin for their antibacterial combinatory effect with oxacillin and tetracycline against sensitive and resistantStaphylococcus aureusstrains. Minimum inhibitory concentrations were determined through the broth microdilution method, whereas the combinatory effect was evaluated through fractional inhibitory concentration sum (ΣFIC) indices. Results show many positive interactions and synergy occurring in embelin and oxacillin combinations against 4 out of 9 strains (ΣFIC 0.203–0.477) and for embelin and tetracycline combination against 3 out of 9 strains (ΣFIC 0.400–0.496). Moreover, the resistance to oxacillin has been overcome in 2 strains and to tetracycline in 3 strains. According to our knowledge, this is the first study showing antimicrobial combinatory effect ofE. schimperias well as of embelin. These findings can be used for the further research targeted on the development of new antistaphylococcal agents.

Colorimetric broth microdilution method for the antifungal screening of plant extracts against yeasts

Methods ◽  
2007 ◽  
Vol 42 (4) ◽  
pp. 325-329 ◽  
Author(s):  
Manjuan Liu ◽  
Veronique Seidel ◽  
David R. Katerere ◽  
Alexander I. Gray
Keyword(s):  
Plant Extracts ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Broth Microdilution Method

scholarly journals Determination of CEM-101 Activity Tested against Clinical Isolates of Neisseria meningitidis from a Worldwide Collection

2010 ◽  
Vol 54 (9) ◽  
pp. 4009-4011 ◽  
Author(s):  
Douglas J. Biedenbach ◽  
Mariana Castanheira ◽  
Ronald N. Jones
Keyword(s):  
Neisseria Meningitidis ◽  
Meningococcal Disease ◽  
Antimicrobial Agents ◽  
Clinical Isolates ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Broth Microdilution Method

ABSTRACT The activity of CEM-101, a fluoroketolide, was compared to those of 11 other antimicrobial agents using the reference broth microdilution method tested against 103 Neisseria meningitidis strains, including ciprofloxacin-nonsusceptible isolates with confirmed gyr A (T91I) mutations. Among the tested isolates, 79.6% were serogroup B or C and all isolates were susceptible to ceftriaxone, azithromycin, minocycline, and rifampin. However, penicillin-nonsusceptible strains were observed (15.5%) and susceptibility to trimethoprim-sulfamethoxazole was only 50.5%. CEM-101 was the most active macrolide-like compound (MIC90, ≤0.015 μg/ml) compared with MIC90s of telithromycin (MIC90, 0.03 μg/ml), azithromycin and clarithromycin (MIC90, 0.12 μg/ml), and erythromycin (MIC90, 0.25 μg/ml). CEM-101 could provide a potent alternative for the prophylaxis of meningococcal disease.

scholarly journals Comparison of Broth Microdilution Method UsingHaemophilus Test Medium and Agar Dilution Method for Susceptibility Testing of Eikenella corrodens

1998 ◽  
Vol 36 (8) ◽  
pp. 2386-2388 ◽  
Author(s):  
Luis Alcalá ◽  
Fernando García-Garrote ◽  
Emilia Cercenado ◽  
Teresa Peláez ◽  
Gema Ramos ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Broth Microdilution ◽  
Test Medium ◽  
Eikenella Corrodens ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Agar Dilution

Susceptibility testing of Eikenella corrodens is usually performed by a Mueller-Hinton sheep blood agar dilution (AD) method. However, this method is impractical for testing only a few strains. We compared AD with the broth microdilution method usingHaemophilus test medium (HTM) in order to determine the susceptibility of 36 clinical isolates of E. corrodens to eight antimicrobial agents. MICs obtained by the HTM method yielded 95.5 and 84% agreement (within 2 and 1 log2 dilutions, respectively) with those obtained by AD. The HTM method with incubation in CO2 for 48 h was highly reproducible and constitutes an easy alternative for antimicrobial susceptibility testing of E. corrodens.

scholarly journals 656. Sulbactam-Durlobactam MIC Determination: Comparative Evaluation of the New ETEST® SUD to the CLSI 2021 Broth Microdilution Method

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S430-S430
Author(s):  
Veronique Sauvonnet ◽  
Elodie Escoffier ◽  
Christine Franceschi ◽  
Diane Halimi ◽  
Roland Martelin ◽  
...  
Keyword(s):  
Reference Method ◽  
Multidrug Resistant ◽  
Error Rates ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Mueller Hinton ◽  
Broth Microdilution Method ◽  
Lactam Antibiotic ◽  
Visible Growth ◽  
Resistant Strains

Abstract Background Species belonging to the Acinetobacter baumannii-calcoaceticus (ABC) complex, such as A. baumannii, A. pittii and A. nosocomialis, are a major cause of hospital acquired infections and outbreaks with increasing occurrence of multidrug-resistance. Sulbactam-durlobactam (SUD), a combination of one active β-lactam antibiotic (sulbactam) with a new β-lactamase inhibitor (durlobactam), is currently being tested in a phase 3 clinical trial by Entasis Therapeutics for the treatment of serious infections caused by ABC, including multidrug-resistant strains. At the same time, an ETEST® SUD (sulbactam-durlobactam - MIC range 0.004/4-64/4 µg/mL) has been developed and calibrated versus the broth microdilution reference method (BMD) as described by the Clinical and Laboratory Standards Institute (CLSI). This test is intended to determine the MIC of sulbactam-durlobactam for species of the ABC complex. The aim of this study was to perform a first comparative study of ETEST SUD with the CLSI BMD method on a panel of 263 isolates. Methods The panel consisted of 204 A. baumannii, 29 A. pittii, 30 A. nosocomialis, including 24 SUD-resistant strains, and one CLSI QC strain. BMD was performed using the 2021 CLSI guidelines. ETEST SUD was evaluated using the standard ETEST procedure for Acinetobacter spp. (inoculum 0.5 McFarland, Mueller Hinton medium, incubation at 35°C for 20-24h). For each method, the MIC was read at complete inhibition of visible growth. To determine category agreement (CA) and error rates, the sulbactam-durlobactam provisional breakpoint of 4 µg/mL was applied. Results The QC strain MICs were in the expected range with reproducible results. The essential MIC agreement [EA, ±1 dilution] was 97.7% without any tendency to over- or underestimate the MIC when compared to BMD. The CA was 98.5%. Two Very Major Errors, both within the EA, and two Major Errors, one within the EA, were observed. Conclusion In this study, the ETEST SUD was found to be equivalent to the CLSI reference method. MIC end points were easy to read. With a 15-dilution range and simplicity of use, ETEST SUD could represent a valuable tool for MIC determination and could be an alternative to BMD. For Research Use Only. The performance characteristics of this product have not been established yet. Disclosures All Authors: No reported disclosures

scholarly journals Therapeutic Drug Monitoring of Tigecycline in 67 Infected Patients and a Population Pharmacokinetics/Microbiological Evaluation of A. baumannii Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Tianli Yang ◽  
Hekun Mei ◽  
Jin Wang ◽  
Yun Cai
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Population Pharmacokinetics ◽  
Drug Monitoring ◽  
Plasma Concentrations ◽  
Multidrug Resistant ◽  
Diffusion Method ◽  
Therapeutic Drug ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Broth Microdilution Method

BackgroundThe widespread use of antibiotics has led to the emergence of multidrug-resistant (MDR) bacteria such as multidrug-resistant Acinetobacter baumannii (AB). Tigecycline (TGC), as the first glycylcycline antibiotic approved by FDA, is a broad-spectrum antibiotic which remains highly effective to treat AB infections.ObjectiveTo confirm the TGC treatment dosage and effectiveness to treat AB infections in the Chinese population by performing therapeutic drug monitoring (TDM).MethodsThis study was performed from October 2018 through March 2019 at the PLA General Hospital. A high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was validated and employed to determine the plasma concentrations of TGC in patients with infectious diseases. The minimum inhibitory concentration (MIC) of TGC to clinically isolated AB was determined by broth microdilution method, agar dilution method, and disk diffusion method. Moreover, a model of population pharmacokinetics/pharmacodynamics (PPK/PD) was constructed.ResultsA total of 186 plasma samples from 67 patients were detected by the validated HPLC-MS/MS method. The MIC values determined by the broth microdilution method were more sensitive and accurate than the other two methods. The microbial and clinical PK/PD breakpoints were reached when the maintenance dose of TGC was 100 mg.ConclusionOur study established a validated HPLC-MS/MS method to monitor the plasma concentrations of TGC. In view of the MIC range to AB isolates in our hospital and the PPK/PD modeling results, we recommend a relatively high dose of 100 mg q12h regimen to achieve the optimal clinical efficacy and antimicrobial response.

scholarly journals In VitroActivity of Plazomicin against Gram-Negative and Gram-Positive Bacterial Pathogens Isolated from Patients in Canadian Hospitals from 2013 to 2017 as Part of the CANWARD Surveillance Study

2018 ◽  
Vol 63 (1) ◽  
Author(s):  
Andrew Walkty ◽  
James A. Karlowsky ◽  
Melanie R. Baxter ◽  
Heather J. Adam ◽  
George G. Zhanel
Keyword(s):  
Antimicrobial Agents ◽  
Bacterial Pathogens ◽  
Multidrug Resistant ◽  
Surveillance Study ◽  
Gram Positive ◽  
Gram Negative ◽  
Content Type ◽  
Microdilution Method ◽  
Broth Microdilution Method

ABSTRACTThe Clinical and Laboratory Standards Institute (CLSI) broth microdilution method was used to evaluate thein vitroactivities of plazomicin and comparator antimicrobial agents against 7,712 Gram-negative and 4,481 Gram-positive bacterial pathogens obtained from 2013 to 2017 from patients in Canadian hospitals as part of the CANWARD Surveillance Study. Plazomicin demonstrated potentin vitroactivity againstEnterobacteriaceae(MIC90≤ 1 µg/ml for all species tested exceptProteus mirabilisandMorganella morganii), including aminoglycoside-nonsusceptible, extended-spectrum β-lactamase (ESBL)-positive, and multidrug-resistant (MDR) isolates. Plazomicin was equally active against methicillin-susceptible and methicillin-resistant isolates ofStaphylococcus aureus.

scholarly journals Susceptibility of bacteria of the Enterococcus genus isolated on Lithuanian poultry farms

2010 ◽  
Vol 54 (No. 12) ◽  
pp. 583-588 ◽  
Author(s):  
M. Ruzauskas ◽  
R. Siugzdiniene ◽  
V. Spakauskas ◽  
J. Povilonis ◽  
V. Seputiene ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Broth Microdilution ◽  
Diagnostic Systems ◽  
Microtitre Plate ◽  
Predominant Species ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Poultry Farms ◽  
Clinical Breakpoints

The aim of this study was to test and analyse the antimicrobial susceptibility of <I>Enterococcus</I> isolates from Lithuanian poultry farms. Investigations were carried out during the years 2008–2009. The sampling sites, located all over the country, included eight poultry farms of large capacity. All samples were collected from broilers. <I>Enterococcus</I> spp. were isolated from intestines immediately after slaughtering. A total of 160 samples were collected, 20 samples from each farm. The MICs (Minimum Inhibitory Concentrations) of eleven antimicrobial agents were determined for each of the isolates using the broth microdilution method with specific microtitre plate panels (Trek Diagnostic Systems, Inc.). Susceptibility according to clinical breakpoints of chloramphenicol, linezolid, erythromycin, penicillin, quinupristin/dalfopristin, tetracycline, vancomycin, ciprofloxacin and nitrofurantoin was evaluated. One hundred and forty seven samples (92%) from a total of 160 tested samples were positive for <I>Enterococcus</I> spp., however, only 74 strains were selected as non-duplicate isolates. The most predominant species were identified as <I>E. faecium</I> (38%), <I>E. faecalis</I> (17.5%), <I>E. gallinarum</I> (12%) and <I>E. casseliflavus</I> (12%). The most frequent resistance properties were resistances to tetracycline (75.6%), erythromycin (56.8%) and ciprofloxacin (41.9%). No strains resistant to vancomycin and linezolid were found. High percentages of susceptibility to chloramphenicol (82.4%) and penicillin (71.6%) were also observed. A high MIC of tigecycline (≥ 1 mg/l) to 12.2% of enterococci was determined during this study. 44.6% of tested strains had a high MIC (≥ 64 mg/l) to tylosin. There was no significant correlation found between resistances of different species to different antimicrobial agents <I>in vitro</I>.

scholarly journals Antimicrobial Susceptibility of Bacteria Isolated from Orthopedic Implants following Revision Hip Surgery

1998 ◽  
Vol 42 (11) ◽  
pp. 3002-3005 ◽  
Author(s):  
Michael M. Tunney ◽  
Gordon Ramage ◽  
Sheila Patrick ◽  
James R. Nixon ◽  
Philip G. Murphy ◽  
...  
Keyword(s):  
Bone Cement ◽  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Orthopedic Implants ◽  
Hip Surgery ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Revision Hip Surgery

The susceptibilities of 49 isolates recovered from orthopedic implants to seven antimicrobial agents were evaluated by the broth microdilution method. Ciprofloxacin and vancomycin were more active than gentamicin, representing aminoglycosides which are routinely incorporated into bone cement, and also more active than the peroperative antimicrobial agents cefamandole and erythromycin. The use of ciprofloxacin and vancomycin in vivo, therefore, warrants further evaluation.

scholarly journals Antimicrobial Activity of Ceftaroline Tested against Staphylococci with Reduced Susceptibility to Linezolid, Daptomycin, or Vancomycin from U.S. Hospitals, 2008 to 2011

2013 ◽  
Vol 57 (7) ◽  
pp. 3178-3181 ◽  
Author(s):  
Helio S. Sader ◽  
Robert K. Flamm ◽  
Ronald N. Jones
Keyword(s):  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Coagulase Negative Staphylococci ◽  
Methicillin Resistant ◽  
Content Type ◽  
Microdilution Method ◽  
Medical Centers ◽  
Broth Microdilution Method ◽  
Valuable Treatment

ABSTRACTVancomycin, linezolid, and daptomycin are very active against staphylococci, but isolates with decreased susceptibility to these antimicrobial agents are isolated sporadically. A total of 19,350Staphylococcus aureusisolates (51% methicillin resistant [MRSA]) and 3,270 coagulase-negative staphylococci (CoNS) were collected consecutively from 82 U.S. medical centers from January 2008 to December 2011 and tested for susceptibility against ceftaroline and comparator agents by the reference broth microdilution method. AmongS. aureusstrains, 14 isolates (0.07%) exhibited decreased susceptibility to linezolid (MIC, ≥8 μg/ml), 18 (0.09%) to daptomycin (MIC, ≥2 μg/ml), and 369 (1.9%) to vancomycin (MIC, ≥2 μg/ml; 368 isolates at 2 μg/ml and 1 at 4 μg/ml). Fifty-one (1.6%) CoNS were linezolid resistant (MIC, ≥8 μg/ml), and four (0.12%) were daptomycin nonsusceptible (MIC, ≥2 μg/ml). Ceftaroline was very active againstS. aureusoverall (MIC50/90, 0.5/1 μg/ml; 98.5% susceptible), including MRSA (MIC50/90, 0.5/1 μg/ml; 97.2% susceptible). All daptomycin-nonsusceptible and 85.7% of linezolid-resistantS. aureusisolates were susceptible to ceftaroline. AgainstS. aureusisolates with a vancomycin MIC of ≥2 μg/ml, 91.9, 96.2, and 98.9% were susceptible to ceftaroline, daptomycin, and linezolid, respectively. CoNS strains were susceptible to ceftaroline (MIC50/90, 0.25/0.5 μg/ml; 99.1% inhibited at ≤1 μg/ml), including methicillin-resistant (MIC50/90, 0.25/0.5 μg/ml), linezolid-resistant (MIC50/90, 0.5/0.5 μg/ml), and daptomycin-nonsusceptible (4 isolates; MIC range, 0.03 to 0.12 μg/ml) strains. In conclusion, ceftaroline demonstrated potentin vitroactivity against staphylococci with reduced susceptibility to linezolid, daptomycin, or vancomycin, and it may represent a valuable treatment option for infections caused by these multidrug-resistant staphylococci.

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