Antibacterial activity of Thymoquinone, an active principle of Nigella sativa and its potency to prevent bacterial biofilm formation

<p>Abstract</p> <p>Background</p> <p>Thymoquinone is an active principle of <it>Nigella sativa </it>seed known as "Habbah Al-Sauda" in Arabic countries and "Sinouj" in Tunisia. Bacterial biofilms tend to exhibit significant tolerance to antimicrobials drugs during infections.</p> <p>Methods</p> <p>The antibacterial activity of Thymoquinone (TQ) and its biofilm inhibition potencies were investigated on 11 human pathogenic bacteria. The growth and development of the biofilm were assessed using the crystal violet (CV) and the 2, 3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) reduction assay.</p> <p>Results</p> <p>TQ exhibited a significant bactericidal activity against the majority of the tested bacteria (MICs values ranged from 8 to 32 μg/ml) especially Gram positive cocci (<it>Staphylococcus aureus </it>ATCC 25923 and <it>Staphylococcus epidermidis </it>CIP 106510). Crystal violet assay demonstrated that the minimum biofilm inhibition concentration (BIC50) was reached with 22 and 60 μg/ml for <it>Staphylococcus aureus </it>ATCC 25923 and <it>Staphylococcus epidermidis </it>CIP 106510 respectively. In addition our data revealed that cells oxidative activity was influenced by TQ supplementation. In the same way, TQ prevented cell adhesion to glass slides surface.</p> <p>Conclusion</p> <p>The ability of TQ to prevent biofilm formation warrants further investigation to explore its use as bioactive substances with antibiofilm potential.</p

Dormancy of Trichophyton mentagrophytes arthroconidia.

Arthroconidia of Trichophyton mentagrophytes demonstrated an exogenous type of dormancy under environmental conditions unsuitable for germination, provided that these conditions were not lethal. Germination did not occur at 4 degrees C unless arthroconidia were shifted up to 37 degrees C. At 45 degrees C germination was inhibited even when arthroconidia were shifted down to 37 degrees C. Germination was dependent on humidified incubation conditions. The presence of human corneocytes enhanced the germination of arthroconidia in the presence of moisture

DIE EMPFINDLICHKEITSPRUFUNG IN VITRO VON TRICHOPHYTON MENTAGROPHYTES FUR CLOTRIMAZOL UND GRISEOFULVIN IN SUSPENSIONEN MENSCHLICHER KORNEOZYTEN

The use of corneocytes in suspension as a medium for the study of the effect of antifungal drugs on Trichophyton mentagrophytes arthroconidia was investigated. In the presence of clotrimazole or griseofulvin, arthroconidia germination in a suspension of corneocytes and in Sabouraud glucose liquid medium was significantly reduced compared with germination in drug-free media. Where antifungals were added to arthroconidia after an activation period during which germination occurred, any further germination was inhibited. The data showed that the growth of T. mentagrophytes in the presence of corneocytes offered a simple, rapid, inexpensive and relevant model for the assessment of antifungal activity of compounds for the treatment of dermatophytosis