In vitro fluconazole susceptibility of 1565 clinical isolates of candida species evaluated by the disk diffusion method performed using NCCLS M44-A guidelines

Immune Defences: A View from the Side of the Essential Oils

The use of essential oils is increasingly being investigated among new therapeutic approaches based on medicinal plants and their extracts. With the wide use of synthetic and semi-synthetic antimicrobial drugs, the spread of drug-resistant clinical isolates has increased, and research is directed towards natural products, such as essential oils, as useful antimicrobial resources. In the context of a prospective infection, we compared the impact of essential oils and common antimicrobial agents on the microbicidal activity of human phagocytes. Here, we present the results of our decades-long investigation into the effectiveness of thyme red oil (26.52% thymol chemotype), tea tree oil (TTO), and Mentha of Pancalieri [(Mentha x piperita (Huds) var. officinalis (Sole), form rubescens (Camus) (Lamiaceae)] essential oils on human polymorphonuclear leukocytes (PMNs) capacity to kill clinical strains of Candida albicans and C. krusei when compared to three antifungal drugs used to treat candidiasis (fluconazole, anidulafungin, and caspofungin) These essential oils demonstrate antifungal drug-like and/or superior efficacy in enhancing intracellular killing by PMNs, even at subinhibitory concentrations. Our results are compared with data in the literature on essential oils and immune system interactions. This comparison would aid in identifying therapeutic solutions to the increasingly prevalent antibiotic resistance as well as filling in any remaining knowledge gaps on the bioactivity of essential oils.

Chemical Profile, in vitro Antibacterial and Antioxidant Activities ofJuniperus phoeniceaL. and Cotula cinerea (Del.) Essential Oils from Southwestern Algeria

This work aims to study the chemical composition, antimicrobial and antioxidant activities ofJuniperus phoeniceaL. andCotula cinerea(Del.) essential oils from southwestern Algeria. The hydrodistilled oils obtained were characterized by gas chromatography–mass spectrometry (GC– MS). A total of 45 and 25 compounds were identified representing 100% ofJuniperus phoeniceaL. andCotula cinerea(Del.) respectively. The dominant component was α-pinene (46.437%) forJuniperus phoeniceaL. and α-thujone (32.35%) forCotula cinerea(Del.). The in vitro antibacterial activity of the essential oils was evaluated against nine foodborne pathogenic bacteria and one yeast, Candida albicans, using the disk diffusion method; the minimum inhibitory concentration (MIC) values were examined (micro dilution). The results suggest that the essential oil ofJuniperus phoeniceahas a significant to moderate antibacterial activity on all strains of bacteria. The most sensitive strains were Bacillus cereus, Bacillus subtilis,Micrococcus luteus,Pseudomonas aeruginosa, andCandida albicanswith (MIC = 0.04 to 0.63 mg/ml).Cotula cinereaoil showed moderate to low sensitivity to the test strains. Its best activity was against Bacillus subtilis (MIC = 0.303 mg/ml). The DPPH test conducted to evaluate the antioxidant activity of both oils showed a good to moderate capacity forJuniperus phoeniceaL. (concentration of an inhibitor when the response is reduced by half, IC50 = 0.76 mg/ml) andCotula cinerea(Del.) [IC50 = 28. mg/ml] oils respectively. The promising bioactivities of these plants suggest that they may be a new source of preservative molecules.

Design, synthesis, and evaluations of antifungal activity of novel phenyl(2H-tetrazol-5-yl)methanamine derivatives

Fungal infections pose a continuous and serious threat to human health and life. The intrinsic resistance has been observed in many genera of fungi. Many fungal infections are caused by opportunistic pathogens that may be endogenous (Candida infections) or acquired from the environment (Cryptococcus and Aspergillus infections). So, new therapeutic strategies are needed to combat various fungal infections. Fluconazole shows good antifungal activity with relatively low toxicity and is preferred as first line antifungal therapy, but it has suffered from severe drug resistance. So, there is a need to design novel analogues by modification of fluconazole-like structure. A novel series of phenyl(2H-tetrazol-5-yl)methanamine derivatives were synthesized by reaction of α-amino nitrile with sodium azide and ZnCl2 in presence of isopropyl alcohol. They were evaluated for antifungal activity against Candida albicans and Aspergillus niger and subjected to docking study against 1EA1.

Comparison of Tablet and Disk Diffusion Methods for Fluconazole and VoriconazoleIn VitroActivity Testing Against Clinical Yeast Isolates

We have compared a commercially available tablet diffusion method for the in vitro antifungal susceptibility testing of fluconazole (FCZ) and voriconazole (VCZ) with the disk diffusion method M44 (CLSI) with 282 clinical yeast isolates. The superior stability of antifungal agents in tablets can explain the differences for each category of susceptibility by both methods.Neo-Sensitabs tablets antifungal susceptibility testing showed an excellent correlation (0.98 for FCZ and 0.98 for VCZ at 24h and 0.96 for FCZ and 0.94 for VCZ at 48 h ), a reduced percentage of disagreements (4.6% and 8.2% for FCZ at 24h and 48 h respectively; 1.1% and 2.1% for VCZ at 24h and 48 h respectively) and the absence of statistically significant difference in comparison with the reference protocol for performing antifungal susceptibility testing with the agar diffusion method.

Antifungal agent susceptibilities and interpretation of Malassezia pachydermatis and Candida parapsilosis isolated from dogs with and without seborrheic dermatitis skin

Malassezia pachydermatis and Candida parapsilosis are recognized as commensal yeasts on the skin of healthy dogs but also causative agents of eborrheic dermatitis, especially in atopic dogs. We determined and compared the susceptibility levels of yeasts isolated from dogs with and without seborrheic dermatitis (SD) using the disk diffusion method (DD) for itraconazole (ITZ), ketoconazole (KTZ), nystatin (NYS), terbinafine (TERB) and 5-fluorocytosine (5-FC) and the broth microdilution method (BMD) for ITZ and KTZ. The reliability between the methods was assessed using an agreement analysis and linear regression. Forty-five M. pachydermatis and 28 C. parapsilosis isolates were identified based on physiological characteristics and an approved molecular analysis. By DD, all tested M. pachydermatis isolates were susceptible to ITZ, KTZ, NYS and TERB but resistant to 5-FC. Only 46 - 60% of the tested C. parapsilosis isolates were susceptible to KTZ, TERB and 5-FC, but ITZ and NYS were effective against all. By BMD, over 95% of M. pachydermatis isolates were susceptible to KTZ and ITZ with an MIC90 < 0.03 and 0.12 μg/ml, respectively. The frequency of KTZ- and ITZ-resistant C. parapsilosis was 29% and 7%, and the MIC90 values were 1 μg/ml and 0.5-1 μg/ml, respectively. Regarding the agreement analysis, 2.2% of minor errors were observed in M. pachydermatis and 0.2-1% of very major errors occurred among C. parapsilosis. There were no significant differences in the yeast resistance rates between dogs with and without SD. KTZ and ITZ were still efficacious for M. pachydermatis but a high rate of KTZ resistant was reported in C. parapsilosis.

In vitro activities of fluconazole and voriconazole against clinical isolates of Candida spp. determined by disk diffusion testing in Turin, Italy

The in vitro activities of fluconazole and voriconazole against 1,024 clinical isolates of Candida spp. were determined by the agar disk diffusion test using the Clinical and Laboratory Standards Institute (CLSI) M44-A guidelines. The results of this investigation demonstrated the broad-spectrum in vitro activity of voriconazole, relative to that of fluconazole, against yeasts tested, in particular fluconazole-resistant isolates, such as Candida krusei that showed high susceptibility to voriconazole. The situation in Turin, Italy, is quite similar to that of the rest of Italy, reflecting the worldwide trend.

Antifungal resistance in Candida spp. isolated in Italy between 2002 and 2005 from children and adults

The activity of amphotericin B, fluconazole, flucytosine, itraconazole and voriconazole was tested in vitro against 618 clinical Candida spp. isolates, using the broth microdilution or the disk diffusion method (voriconazole). Amphotericin B and voriconazole were the most potent antifungal agents assayed (100% of susceptible strains). Resistance to fluconazole and itraconazole was detected in three (0.7%) and 11 (2.7%) isolates of Candida albicans and in four (3.7%) isolates of Candida glabrata. Flucytosine intermediate, resistant strains, or both, were observed in C. albicans (0.3% and 0.7%), C. glabrata (2.8% intermediate) and C. tropicalis (15.2% and 15.2%). C. krusei was the least susceptible species to azoles. No statistically significant differences in the rates of resistant isolates depending on site of infection and age of the patient were observed, with the exception of C. albicans and itraconazole (higher percentage of resistance in children). At present, acquired antifungal resistance represents an uncommon finding in most Candida spp. circulating in Northern Italy.