scholarly journals Bacteriostatic Antimicrobial Combination: Antagonistic Interaction between Epsilon-Viniferin and Vancomycin against Methicillin-ResistantStaphylococcus aureus

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Dayang Fredalina Basri ◽  
Lee Wee Xian ◽  
Nur Indah Abdul Shukor ◽  
Jalifah Latip
Keyword(s):  
Inhibitory Concentration ◽  
Bacterial Killing ◽  
Antagonistic Interaction ◽  
Close Proximity ◽  
Mrsa Infection ◽  
The Individual ◽  
Time Kill ◽  
Microbroth Dilution ◽  
Similar Site ◽  
Mic Value

Stilbenoids have been considered as an alternative phytotherapeutic treatment against methicillin-resistantStaphylococcus aureus(MRSA) infection. The combined effect ofε-viniferin and johorenol A with the standard antibiotics, vancomycin and linezolid, was assessed against MRSA ATCC 33591 and HUKM clinical isolate. The minimum inhibitory concentration (MIC) value of the individual tested compounds and the fractional inhibitory concentration index (FICI) value of the combined agents were, respectively, determined using microbroth dilution test and microdilution checkerboard (MDC) method. Only synergistic outcome from checkerboard test will be substantiated for its rate of bacterial killing using time-kill assay. The MIC value ofε-viniferin against ATCC 33591 and johorenol A against both strains was 0.05 mg/mL whereas HUKM strain was susceptible to 0.1 mg/mL ofε-viniferin. MDC study showed that only combination betweenε-viniferin and vancomycin was synergistic against ATCC 33591 (FICI 0.25) and HUKM (FICI 0.19). All the other combinations (ε-viniferin-linezolid, johorenol A-vancomycin, and johorenol A-linezolid) were either indifferent or additive against both strains. However, despite the FICI value showing synergistic effect forε-viniferin-vancomycin, TKA analysis displayed antagonistic interaction with bacteriostatic action against both strains. As conclusion,ε-viniferin can be considered as a bacteriostatic stilbenoid as it antagonized the bactericidal activity of vancomycin. These findings therefore disputed previous report thatε-viniferin acted in synergism with vancomycin but revealed that it targets similar site in close proximity to vancomycin’s action, possibly at the bacterial membrane protein. Hence, this combination has a huge potential to be further studied and developed as an alternative treatment in combating MRSA in future.

scholarly journals Is In Vitro Antibiotic Combination More Effective than Single-Drug Therapy against Anthrax?

2005 ◽  
Vol 49 (4) ◽  
pp. 1323-1325 ◽  
Author(s):  
Abed Athamna ◽  
Muhammad Athamna ◽  
Aburashed Nura ◽  
Eli Shlyakov ◽  
Darrin J. Bast ◽  
...  
Keyword(s):  
Inhibitory Concentration ◽  
Antibacterial Efficacy ◽  
Bacterial Killing ◽  
Single Drug ◽  
Development Of Resistance ◽  
Single Drug Therapy ◽  
Time Kill ◽  
Synergistic Combinations ◽  
Over Time

ABSTRACT Antibiotic combinations are used to enhance antibacterial efficacy and to prevent the development of resistance. We have tested a possible synergistic effect of several antibacterial combinations on Bacillus anthracis. The in vitro activities of antibiotic combinations against two strains of B. anthracis, strain Sterne and the Russian anthrax vaccine strain STi, were tested by the fractional inhibitory concentration (FIC) method, derived from the MICs of the agents in combination, and by measuring the rate of bacterial killing over time by several antibiotic combinations. The FIC results showed that synergism against both B. anthracis strains was observed only with the combination of rifampin and clindamycin. The telithromycin-amoxicillin combination showed synergism against strain Sterne only. All other combinations were either indifferent or antagonistic. The results of the bacterial time-kill study demonstrated indifferent effects for all combinations. These in vitro results demonstrate the difficulties in obtaining synergistic combinations of antibiotics against B. anthracis.

scholarly journals In VitroPharmacodynamics of Simulated Pulmonary Exposures of Tigecycline Alone and in Combination againstKlebsiella pneumoniaeIsolates Producing a KPC Carbapenemase

2011 ◽  
Vol 55 (4) ◽  
pp. 1420-1427 ◽  
Author(s):  
Dora E. Wiskirchen ◽  
Pornpan Koomanachai ◽  
Anthony M. Nicasio ◽  
David P. Nicolau ◽  
Joseph L. Kuti
Keyword(s):  
Multidrug Resistant ◽  
Pharmacodynamic Model ◽  
High Dose ◽  
Prolonged Infusion ◽  
Bacterial Killing ◽  
Epithelial Lining Fluid ◽  
Multidrug Resistant Organisms ◽  
Time Kill ◽  
Additional Reduction

ABSTRACTMultidrug-resistantKlebsiella pneumoniaestrains that produce a serine carbapenemase (KPC) are emerging worldwide, with few therapeutic options that retain consistent susceptibility. The objective of this study was to determine the effect of combination therapy with tigecycline versus tigecycline alone against KPC-producing isolates (KPC isolates). Anin vitropharmacodynamic model was used to simulate adult steady-state epithelial lining fluid concentrations of tigecycline (50 mg every 12 h) given alone and in combination with either meropenem (2 g by 3-hour infusion every 8 h) or rifampin (600 mg every 12 h). Five KPC isolates with various phenotypic profiles were exposed over 48 h. Time-kill curves were constructed, and the areas under the bacterial killing and regrowth curves (AUBCs) were calculated. No regimens tested were able to maintain bactericidal reductions in CFU over 48 h. The AUBCs for tigecycline and meropenem monotherapies at 48 h ranged from 375.37 to 388.11 and from 348.62 to 383.83 (CFU-h/ml), respectively. The combination of tigecycline plus meropenem significantly reduced the AUBCs at 24 and 48 h for isolates with tigecycline MICs of ≤2 μg/ml and meropenem MICs of ≤16 μg/ml (P< 0.001) but added no additional activity when the meropenem MIC was 64 μg/ml (P= 0.5). Rifampin provided no additional reduction in CFU or AUBC over tigecycline alone (P= 0.837). The combination of tigecycline with high-dose, prolonged-infusion meropenem warrants further study as a potential treatment option for these multidrug-resistant organisms.

scholarly journals Synergistic Interaction of Methanol Extract fromCanarium odontophyllumMiq. Leaf in Combination with Oxacillin against Methicillin-ResistantStaphylococcus aureus(MRSA) ATCC 33591

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Dayang Fredalina Basri ◽  
Vimashiinee Sandra
Keyword(s):  
Inhibitory Concentration ◽  
Methanol Extract ◽  
Bactericidal Effect ◽  
Acetone Extract ◽  
Pharmacodynamic Interaction ◽  
Antistaphylococcal Activity ◽  
Preliminary Study ◽  
Canarium Odontophyllum ◽  
Time Kill ◽  
Acetone Extracts

Canarium odontophyllum(CO) Miq. has been considered as one of the most sought-after plant species in Sarawak, Malaysia, due to its nutritional and pharmacological benefits. This study aimed to evaluate the pharmacodynamic interaction of crude methanol and acetone extracts from CO leaves in combination with oxacillin, vancomycin, and linezolid, respectively, against MRSA ATCC 33591 as preliminary study has reported its potential antistaphylococcal activity. The broth microdilution assay revealed that both methanol and acetone extracts were bactericidal with Minimum Inhibitory Concentration (MIC) of 312.5 μg/mL and 156.25 μg/mL and Minimum Bactericidal Concentration (MBC) of 625 μg/mL and 312.5 μg/mL, respectively. Fractional Inhibitory Concentration (FIC) indices were obtained via the chequerboard dilution assay where methanol extract-oxacillin, acetone extract-oxacillin, methanol extract-linezolid, and acetone extract-linezolid combinations exhibited synergism (FIC index ≤ 0.5). The synergistic action of the methanol extract-oxacillin combination was verified by time-kill analysis where bactericidal effect was observed at concentration of 1/8 × MIC of both compounds at 9.6 h compared to oxacillin alone. As such, these findings postulated that both extracts exert their anti-MRSA mechanism of action similar to that of vancomycin and provide evidence that the leaves ofC. odontophyllumhave the potential to be developed into antistaphylococcal agents.

MEMBRANE-ACTIVE METHANOLIC CRUDE EXTRACT OF THERMOTOLERANT, Aspergillus fumigatus SSH01 AND ITS MODE OF ACTION AGAINST GRAM-POSITIVE PATHOGENS

2017 ◽  
Vol 80 (1) ◽  
Author(s):  
Mohamad Khairil Radzali ◽  
Akmal Hayat Abdul Karim ◽  
Syahida Ahmad ◽  
Wan Zuhainis Saad
Keyword(s):  
Aspergillus Fumigatus ◽  
Crude Extract ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Antibacterial Properties ◽  
Bacterial Membrane ◽  
Antibacterial Effects ◽  
Gram Positive ◽  
Bacillus Subtilis Atcc ◽  
Time Kill

This study was undertaken to investigate the antibacterial properties and the mode of actions of crude extract of Aspergillus fumigatus SSH01. Antibacterial properties was observed against Gram-positive pathogens and showed inhibition against Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 6538, methicillin-resistant S. aureus S547 (MRSA) and Listeria monocytogenes L10 with minimum inhibitory concentration (MIC, 0.097- 12.5 mg/ml) and minimum bactericidal concentration (MBC, 0.195 – 25 mg/ml). No surviving cells were detected after 15 h of treatment with the 2MIC of extracts for time-kill assay. Leakage of cellular contents of the treated test pathogens were identified and increased as the concentrations of the extracts increased. The study of morphological surface has shown the bacterial membrane was disrupted and caused loss of viability. This implies the antibacterial effects of A. fumigatus SSH01 extract may serve as the potential antibiotic. 

scholarly journals Enhanced Antibacterial Activity of Meropenem against Extensively Drug-Resistant Acinetobacter baumannii by Myrtaceae Plant Extracts

2020 ◽  
Vol 17 (11) ◽  
pp. 1168-1176
Author(s):  
Dennapa SAELOH ◽  
Monton VISUTTHI ◽  
Marisa LEEHA ◽  
Surasak LIMSUWAN ◽  
Supayang Piyawan VORAVUTHIKUNCHAI
Keyword(s):  
Acinetobacter Baumannii ◽  
Bacterial Infections ◽  
Inhibitory Concentration ◽  
Inhibitory Effect ◽  
Drug Resistant ◽  
Microdilution Method ◽  
Extensively Drug Resistant ◽  
Resistant Phenotype ◽  
Bacterial Growth Inhibition ◽  
Mic Value

Acinetobacter baumannii (A. baumannii) has been known as a major cause of nosocomial bacterial infections worldwide. The bacteria are increasingly associated with a broad spectrum of antibiotic resistance, and this has become a widespread concern in a variety of hospitals.Antibiotic development and alternative treatment have become priorities for the treatment of bacterial infections.This study investigated the efficacy of meropenem in combination with five ethanolic extracts of plants in Myrtaceae against extensively drug-resistant (XDR) A. baumannii. The resistant phenotype was previously determined by microdilution method. XDR-A. baumannii strains showed resistance to meropenem with the minimum inhibitory concentration (MIC) in a range of 16 - 128 µg/mL, whereas the MIC value of all extracts, including Calistemon lancealatus, Eucalyptus citridora, Rhodomytus tomentasa, Syzygium cumini, and Xanthortemon chrysanthus, was over 1,000 µg/mL. Interestingly, all extracts potentiated the activity of the antibiotic by reducing the MIC values of the antibiotic. Xanthortemon chrysanthus extract displayed excellent synergism against the bacteria by decreasing the MIC value of the drug greater than 8-fold. In addition, the extract, at concentrations of 31.25, 62.5, 125, 250, 500, and 1,000 µg/mL, obviously increased the inhibitory effect of meropenem (1/4´MIC) against A. baumannii. The percentage of bacterial growth inhibition by combination was 87.9, 88.8, 91.8, 93.6, 99.9, and 100, respectively. The results supported that the extract could improve the activity of ineffective antibiotics against drug-resistant pathogens.Therefore, the findings may serve as therapeutic options for XDR-A. baumannii infections in the future.

scholarly journals In vitro synergy of 5-nitrofurans, vancomycin and sodium deoxycholate against Gram-negative pathogens

2021 ◽  
Author(s):  
Catrina Olivera ◽  
Vuong Van Hung Le ◽  
Catherine Davenport ◽  
Jasna Rakonjac
Keyword(s):  
Growth Inhibition ◽  
Type Species ◽  
Sodium Deoxycholate ◽  
Gram Positive ◽  
Bacterial Killing ◽  
Gram Negative ◽  
Content Type ◽  
Link Type ◽  
Time Kill

Introduction. There is an urgent need for effective therapies against bacterial infections, especially those caused by antibiotic-resistant Gram-negative pathogens. Hypothesis. Synergistic combinations of existing antimicrobials show promise due to their enhanced efficacies and reduced dosages which can mitigate adverse effects, and therefore can be used as potential antibacterial therapy. Aim. In this study, we sought to characterize the in vitro interaction of 5-nitrofurans, vancomycin and sodium deoxycholate (NVD) against pathogenic bacteria. Methodology. The synergy of the NVD combination was investigated in terms of growth inhibition and bacterial killing using checkerboard and time-kill assays, respectively. Results. Using a three-dimensional checkerboard assay, we showed that 5-nitrofurans, sodium deoxycholate and vancomycin interact synergistically in the growth inhibition of 15 out of 20 Gram-negative strains tested, including clinically significant pathogens such as carbapenemase-producing Escherichia coli , Klebsiella pneumoniae and Acinetobacter baumannii , and interact indifferently against the Gram-positive strains tested. The time-kill assay further confirmed that the triple combination was bactericidal in a synergistic manner. Conclusion. This study demonstrates the synergistic effect of 5-nitrofurans, sodium deoxycholate and vancomycin against Gram-negative pathogens and highlights the potential of the combination as a treatment for Gram-negative and Gram-positive infections.

scholarly journals Physicochemical Properties and Antimicrobial Activity of Evaporated Extract of Cow Dung Against Some Pathogens

2012 ◽  
Vol 5 (1) ◽  
pp. 135-141
Author(s):  
M. Waziri ◽  
J. S. Suleiman
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Inhibitory Concentration ◽  
Analytical Techniques ◽  
Food Additive ◽  
Cow Dung ◽  
Northern Nigeria ◽  
Elemental Contents ◽  
Mic Value

The evaporated extract of cow dung is traditionally used in Northern Nigeria and Cameroun as food additive and in treatment of infectious diseases. In this study, the cow dung ash extract was prepared and tested for some elemental contents as well as the antimicrobial activity against Cyanobacteria (C.bacteria), Staphylococcus aureus (S.aureus), Bacillus subtilis (B.subtilis) and Escherichia coli (E.coli) using different analytical techniques. The extract was highly basic with pH of 11.7 and the elements vary in the following decreasing order of concentration; K>Na>Mg>Ca>Fe>Al>Zn.  S. aureus was the most sensitive bacteria with minimum inhibitory concentration (MIC) value of 0.082 mg/mL while B. subtilis was the least sensitive with MIC value of 4.3 mg/mL. The result of this study indicate that the extract can supplement the dietary Na and K requirements for the users and supports the folkloric use of the extract in treatment of infections.© 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v5i1.11962        J. Sci. Res. 5 (1), 135-141 (2013)

scholarly journals In VitroandIn VivoActivities of the Novel Ketolide RBx 14255 against Clostridium difficile

2012 ◽  
Vol 56 (11) ◽  
pp. 5986-5989 ◽  
Author(s):  
Manoj Kumar ◽  
Tarun Mathur ◽  
Tarani K. Barman ◽  
G. Ramkumar ◽  
Ashish Bhati ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Time Dependent ◽  
Kinetics Study ◽  
The Novel ◽  
Promising Candidate ◽  
Hamster Model ◽  
Bacterial Killing ◽  
Content Type ◽  
Time Kill

ABSTRACTThe MIC90of RBx 14255, a novel ketolide, againstClostridium difficilewas 4 μg/ml (MIC range, 0.125 to 8 μg/ml), and this drug was found to be more potent than comparator drugs. Anin vitrotime-kill kinetics study of RBx 14255 showed time-dependent bacterial killing forC. difficile. Furthermore, in the hamster model ofC. difficileinfection, RBx 14255 demonstrated greater efficacy than metronidazole and vancomycin, making it a promising candidate forC. difficiletreatment.

scholarly journals Activities of Three Quinolones, Alone and in Combination with Extended-Spectrum Cephalosporins or Gentamicin, against Stenotrophomonas maltophilia

1998 ◽  
Vol 42 (8) ◽  
pp. 2002-2005 ◽  
Author(s):  
Melissa A. Visalli ◽  
Michael R. Jacobs ◽  
Peter C. Appelbaum
Keyword(s):  
Active Compound ◽  
Stenotrophomonas Maltophilia ◽  
Inhibitory Concentration ◽  
Fractional Inhibitory Concentration ◽  
Determination Method ◽  
Extended Spectrum ◽  
Time Kill ◽  
Synergy Testing ◽  
Checkerboard Titration ◽  
Concentration Indices

The present study examined the activities of trovafloxacin, levofloxacin, and ciprofloxacin, alone and in combination with cefoperazone, ceftazidime, cefpirome, and gentamicin, against 100 strains of Stenotrophomonas maltophilia by the MIC determination method and by synergy testing of the combinations by the time-kill and checkerboard titration methods for 20 strains. The respective MICs at which 50% and 90% of isolates were inhibited for the drugs used alone were as follows: trovafloxacin, 0.5 and 2.0 μg/ml; levofloxacin, 2.0 and 4.0 μg/ml; ciprofloxacin, 4.0 and 16.0 μg/ml; cefoperazone, >128.0 and >128.0 μg/ml; ceftazidime, 32.0 and >128.0 μg/ml; cefpirome, >128.0 and >128.0 μg/ml; and gentamicin, 128.0 and >128.0 μg/ml. Synergistic fractional inhibitory concentration indices (≤0.5) were found for ≥50% of strains for trovafloxacin-cefoperazone, trovafloxacin-ceftazidime, levofloxacin-cefoperazone, levofloxacin-ceftazidime, ciprofloxacin-cefoperazone, and ciprofloxacin-ceftazidime, with other combinations affecting fewer strains. For 20 strains tested by the checkerboard titration and time-kill methods, synergy (≥100-fold drop in count compared to the count achieved with the more active compound) was more pronounced after 12 h due to regrowth after 24 h. At 12 h, trovafloxacin at 0.004 to 0.5 μg/ml showed synergy with cefoperazone for 90% of strains, with ceftazidime for 95% of strains with cefpirome for 95% of strains, and with gentamicin for 65% of strains. Levofloxacin at 0.03 to 0.5 μg/ml and ciprofloxacin at 0.5 to 2.0 μg/ml showed synergy with cefoperazone for 80% of strains, with ceftazidime for 90 and 85% of strains, respectively, with cefpirome for 85 and 75% of strains, respectively, and with gentamicin for 65 and 75% of strains, respectively. Time-kill assays were more discriminatory than checkerboard titration assays in demonstrating synergy for all combinations.

scholarly journals Antipneumococcal activities of cefpirome and cefotaxime, alone and in combination with vancomycin and teicoplanin, determined by checkerboard and time-kill methods.

1996 ◽  
Vol 40 (9) ◽  
pp. 1973-1976 ◽  
Author(s):  
S Bajaksouzian ◽  
M A Visalli ◽  
M R Jacobs ◽  
P C Appelbaum
Keyword(s):  
Inhibitory Concentration ◽  
Fractional Inhibitory Concentration ◽  
Beta Lactams ◽  
Pneumococcal Infections ◽  
Titration Method ◽  
Resistant Strains ◽  
Time Kill ◽  
Checkerboard Titration

The checkerboard titration method was used to test the synergy of cefpirome and cefotaxime with teicoplanin or vancomycin against 35 penicillin-susceptible, 34 penicillin-intermediate, and 31 penicillin-resistant pneumococci. The MICs at which 50 and 90% of isolates are inhibited (MIC50s and MIC90s, respectively) of both cefpirome and cefotaxime were 0.016 and 0.06 microgram/ml, respectively, for penicillin-susceptible strains and 0.125 and 0.5 microgram/ml, respectively, for penicillin-intermediate strains. The MIC50s and MIC90s of cefotaxime for penicillin-resistant strains were 1.0 and 2.0 micrograms/ml, respectively, and those of cefpirome were 0.5 and 1.0 microgram/ml, respectively. All pneumococci were inhibited by cefpirome at MICs of < or = 1.0 microgram/ml. The MIC50s and MIC90s of vancomycin and teicoplanin (0.25 and 0.25 microgram/ml and 0.03 and 0.03 microgram/ml, respectively) did not differ for the three groups. Checkerboard synergy studies showed that cefpirome and vancomycin showed synergy for 31 strains (fractional inhibitory concentration [FIC] indices, < or = 0.5) cefpirome and teicoplanin showed synergy for 18 strains, cefotaxime and vancomycin showed synergy for 51 strains, and cefotaxime and teicoplanin showed synergy for 27 strains. Cefpirome and vancomycin had FIC indices indicating indifference (2.0) for two strains, and cefotaxime and vancomycin had FIC indices indicating indifference for one strain. All other FIC indices indicating indifference or additivity were > 0.5 to 1.0. No FIC indices indicating antagonism (> 4.0) were found. Synergy between beta-lactams and glycopeptides for three susceptible, three intermediate, and three resistant strains were tested by the time-kill assay, and all combinations were synergistic by this method. Synergy between cephalosporins and glycopeptides can be demonstrated and may be useful for the treatment of pneumococcal infections, especially meningitis.

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