In vitro antifungal combination of terbinafine with itraconazole against isolates of Trichophyton spp.

Terbinafine is used as first-line therapy for dermatophytosis, but the incidence of terbinafine-resistance is increasing. Combination of terbinafine with itraconazole was tested by checkerboard based on the EUCAST methodology for antifungal susceptibility testing against 9 terbinafine-susceptible and 7 terbinafine-resistant clinical isolates of Trichophyton spp. from India. Synergistic interactions were observed for 4/9 of the susceptible isolates with fractional inhibitory concentration index (FICI) values of 0.3125 to 0.5 and for 4/7 of the resistant isolates with FICI values of 0.032 to 0.3125.

Synergistic activity of diclofenac sodium with oxacillin against planktonic cells and biofilm of methicillin-resistant Staphylococcus aureus strains

Aim: To evaluate the activity of diclofenac sodium and synergism with oxacillin against clinical strains of SARM in plactonic cells, antibiofilm and biofilm. Materials & methods: Synergism activity was assessed using the fractional inhibitory concentration index and its possible mechanism of action by flow cytometry. Results: The synergistic activity of diclofenac sodium with oxacillin was observed against plactonic cells, antibiofilm and in biofilm formed from clinical methicillin-resistant Staphylococcus aureusstrains. Conclusion: This combination caused damage to the integrity of the membrane and ruptures in the DNA of the cells, leading to apoptosis.

FICI Value Determination of Combination of Aquilaria microcarpa Baill. Ethanolic Extract with Amoxicillin against Salmonella typhi

<p>Karas (<em>Aquilaria microcarpa</em> Baill.) adalah tanaman yang memiliki aktivitas antibakteri terhadap beberapa bakteri patogen. Tujuan dari penelitian ini untuk mengetahui nilai FICI dari kombinasi ekstrak etanol daun karas (<em>Aquilaria microcarpa</em> Baill.) dengan amoksisilin terhadap bakteri <em>Salmonella typhi</em>. Metode yang digunakan adalah metode difusi cakram Kirby-Bauer. Analisis data dilakukan secara deskriptif untuk mengetahui karakteristik kombinasi. Hasil penelitian menunjukkan bahwa nilai FICI kombinasi ekstrak etanol daun karas (<em>Aquilaria microcarpa</em> Baill.) dengan amoksisilin terhadap <em>Salmonella typhi</em> adalah 4. Sehingga dapat disimpulkan bahwa karakteristik kombinasi terhadap bakteri <em>Salmonella typhi</em> bersifat <em>indifferent</em> atau tak berbeda.</p><p><strong>Kata kunci :</strong> <em>Aquilaria microcarpa </em>Baill.<em>, </em>ekstrak etanol, amoksisilin, <em>Salmonella typhi</em> , <em>Fractional Inhibitory Concentration Index</em> (FICI)</p>

In vitro synergy of isavuconazole in combination with colistin against Candida auris

The in vitro interactions of isavuconazole with colistin were evaluated against 15 clinical Candida auris isolates by a microdilution checkerboard technique based on the EUCAST reference method for antifungal susceptibility testing and by agar diffusion using isavuconazole gradient concentration strips with or without colistin incorporated RPMI agar. Interpretation of the checkerboard results was done by the fractional inhibitory concentration index and by response surface analysis based on the Bliss model. By checkerboard, combination was synergistic for 93% of the isolates when interpretation of the data was done by fractional inhibitory concentration index, and for 80% of the isolates by response surface analysis interpretation. By agar diffusion test, although all MICs in combination decreased compared to isavuconazole alone, only 13% of the isolates met the definition of synergy. Essential agreement of EUCAST and gradient concentration strip MICs at +/− 2 log2 dilutions was 93.3%. Antagonistic interactions were never observed for any technique or interpretation model used.

Investigation of Copaifera genus as a new source of antimycobaterial agents

Aim: This paper reports on the antimycobacterial activity of the oleoresins and extracts obtained from Copaifera spp. Materials & methods: The minimum inhibitory concentration (MIC) and fractional inhibitory concentration index techniques helped to evaluate the effect of these oleoresins and extracts against six strains of mycobacteria that cause tuberculosis. Results & conclusion: Among the assayed oleoresins and plant extracts, the Copaifera langsdorffii, Copaifera duckei, Copaifera reticulata and Copaifera trapezifolia oleoresins provided the lowest MIC values against some of the tested strains. The combination of Copaifera spp. samples with isoniazid did not evidence any synergistic action. Some Copaifera spp. oleoresins may represent a future source for the discovery of new antimycobacterial drugs due to their low MIC values.

Synergistic effects of ketamine and azole derivatives on Candida spp. resistance to fluconazole

The emergence of Candida spp. with resistance to antifungal molecules, mainly the azole class, is an increasing complication in hospitals around the globe. Aim: In the present research, we evaluated the synergistic effects of ketamine with two azole derivatives, itraconazole and fluconazole, on strains of Candida spp. to fluconazole. Materials & methods: The drug synergy was evaluated by quantifying the fractional inhibitory concentration index and by fluorescence microscopy and flow cytometry techniques. Results: Our achievements showed a synergistic effect between ketamine in addition to the two antifungal agents (fluconazole and itraconazole) against planktonic cells and biofilms of Candida spp. Conclusion: This combination promoted alteration of membrane integrity, generation of reactive oxygen species, damage to and DNA and externalization of phosphatidylserine.

Prevention of Pseudomonas aeruginosa Biofilm Formation on Soft Contact Lenses by Allium sativum Fermented Extract (BGE) and Cannabinol Oil Extract (CBD)

Two natural mixtures, Allium sativum fermented extract (BGE) and cannabinol oil extract (CBD), were assessed for their ability to inhibit and remove Pseudomonas aeruginosa biofilms on soft contact lenses in comparison to a multipurpose Soft Contact Lens-care solution present on the Italian market. Pseudomonas aeruginosa (ATCC 9027 strain) and Pseudomonas aeruginosa clinical strains isolated from ocular swabs were tested. Quantification of the biofilm was done using the microtiter plate assay and the fractional inhibitory concentration index was calculated. Both forms of Pseudomonas aeruginosa generated biofilms. BGE at minimal inhibitory concentration (MIC) showed inhibition percentages higher than 55% for both strains, and CBD inhibited biofilm formation by about 70%. The care solution at MIC inhibited biofilm formation by about 50% for both strains tested. The effect of BGE on the eradication of the microbial biofilm on soft contact lenses at MIC was 45% eradication for P. aeruginosa ATCC 9027 and 36% for P. aeruginosa clinical strain. For CBD, we observed 24% biofilm eradication for both strains. For the care solution, the eradication MICs were 43% eradication for P. aeruginosa ATCC 9027 and 41% for P. aeruginosa clinical strain. It was observed that both the test soft contact lenses solution/BGE (fractional inhibitory concentration index: 0.450) and the test soft contact lenses solution/CBD (fractional inhibitory concentration index: 0.153) combinations exhibited synergistic antibiofilm activity against most of the studied bacteria. The study showed that BGE and CBD have good effect on inhibition of biofilm formation and removal of preformed biofilms, which makes them promising agents that could be exploited to develop more effective care solutions.

Exebacase Demonstrates In Vitro Synergy with a Broad Range of Antibiotics against both Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus

ABSTRACT In vitro synergy between an antimicrobial protein lysin (cell wall hydrolase) called exebacase and each of 12 different antibiotics was examined against Staphylococcus aureus isolates using a nonstandard medium approved for exebacase susceptibility testing by the Clinical and Laboratory Standards Institute. In the checkerboard assay format, fractional inhibitory concentration index values of ≤0.5, consistent with synergy, were observed for the majority of interactions tested. Synergy was further confirmed in time-kill assays.

ANTIMICROBIAL ACTIVITY OF THUJA ORIENTALIS IN COMBINATION WITH CIPROFLOXACIN AGAINST PSEUDOMONAS AERUGINOSA

OBJECTIVES: To compare the combined antimicrobial effect of Thuja orientalis and Ciprofloxacin against Pseudomonas aeruginosa in vitro samples. METHODS: In-vitro antibacterial activity of plant-extracts was evaluated alone and in combination with ciprofloxacin against Pseudomonas aeruginosa using disc-diffusion susceptibility assay (Kirby Bauer method) and minimum inhibitory concentration (96 well broth microdilution method) following CLSI guidelines. Pseudomonas aeruginosa clinical strains were collected from Rehman Medical Institute (RMI) and Northwest General Hospital Peshawar, Pakistan and ATCC strains (no.9721) of this bacterium were collected from Agriculture University Peshawar. The organism was tested six times with crude extract and fractionation with different solvents such as n-hexane, chloroform, ethyl acetate and butanol at concentrations of 1, 4, 8, 12, 16, 20, 24, 30 and 36 mg/ml. The mean MIC and FICI (fractional inhibitory concentration index) was obtained to report the synergism. The data were analysed using SPSS version-21. RESULTS: In combination, methanolic crude extract, chloroform and butanol fraction showed synergistic effect at all tested concentrations against Pseudomonas aeruginosa (ATCC 9721 and clinical) except with 1, 4, 16 mg/ml concentrations. Ethyl acetate and aqueous fractions shows indifference and synergistic effect against Pseudomonas aeruginosa (ATCC 9721 and clinical) at different concentrations. The fractional inhibitory concentration index (FICI) ranged from 1.24 to 3.24 against Pseudomonas aeruginosa alone and in combination with ciprofloxacin. CONCLUSION: By disc diffusion method, this study shows synergistic effect against Pseudomonas aeruginosa in combination with ciprofloxacin. However, through minimum inhibitory concentration method, it shows antagonism and indifference but no synergistic effect against different fractions of plant.