In Vitro and In Vivo Control of Secondary Bacterial Infection Caused by Leishmania major

Leishmania and its relationships with bacteria

Leishmaniasis is a zoonotic and neglected disease, which represents an important public health problem worldwide. Different species of Leishmania are associated with different manifestations, and a practical problem that can worsen the condition of hosts infected with Leishmania is the secondary infection caused by bacteria. This review aims to examine the importance and prevalence of bacteria co-infection during leishmaniasis and the nature of this ecological relationship. In the cases discussed in this review, the facilitation phenomenon, defined as any interaction where the action of one organism has a beneficial effect on an organism of another species, was considered in the Leishmania-bacteria interaction, as well as the effects on one another and their consequences for the host.

The co-infection of Buruli ulcer and cutaneous leishmaniasis in Sudanese patient: An association by choice or by chance?

Buruli ulcer and cutaneous leishmaniasis both have the similar cutaneous clinical presentation. Therefore, relying on clinical diagnosis can be challenging. We present a case of 45 years old woman diagnosed with cutaneous leishmaniasis, confirmed by skin biopsy. She received different modalities of anti-leishmanial treatment (fluconazole 450mg daily for 4 weeks, sodium stibogluconate (SSG) followed by thermal therapy, SSG/IV 20mg/kg for 30 days combined with paromomycin 15mg/kg IM for 17 days). These treatments were associated with partial improvement of the ulcer and failure of healing. A second biopsy demonstrated the presence of Mycobacterium ulcerans and hence the diagnosis of Buruli ulcer as a cause of the delayed healing of the ulcer. M. ulcerans releases a toxin known as mycolactone, which decreases immune system function and results in tissue death. M. ulcerans, is regarded as the third most prevalent Mycobacterium after M. tuberculosis and M. leprae. Treatment with streptomycin intramuscular injections 1g daily and rifampicin 600mg daily for 8 weeks was associated with complete healing of the ulcer. To our knowledge, this is the first report that describes the co-infection of Buruli ulcer and cutaneous leishmaniasis in Sudan.

S-ethyl ethanethiosulfinate, a derivative of allicin, induces metacaspase-dependent apoptosis through ROS generation in Penicillium chrysogenum

Allicin can be used as fumigant to protect food and cultural relics from fungal contamination because of its strong antifungal activity and the characteristics of high volatility and no residues. However, the obvious disadvantages such as high minimal inhibitory concentration and instability prevent it from wide application. In this study, a stable derivative of allicin, S-ethyl ethanethiosulfinate (ALE), was synthesized. We further explored its antifungal activity and apoptosis-inducing effect, as well as the underlying mechanism. ALE had an excellent capability of inhibiting spore germination and mycelial growth of Penicillium chrysogenum observed by inverted microscope and scanning electron microscopy. XTT colorimetric assay indicated ALE could reduce the cell viability obviously and IC₅₀ was 0.92 μg/ml, only 1/42 of allicin (38.68 μg/ml). DHR 123 ROS Assay Kit, flow cytometry assay and confocal immunofluorescence revealed intercellular ROS generation and metacaspase-dependent apoptosis triggered by ALE, while antioxidant tocopherol could reverse ALE-induced cytotoxicity effect and metacaspase activation. These results indicate that ALE induces metacaspase-dependent apoptosis through ROS generation, thus possesses an effective antifungal activity. This new derivative of allicin might be developed as a high efficient alternative to the conventional fungicides for food storage and cultural relic protection.