A simple multiplex polymerase chain reaction assay for rapid identification of the common pathogenic dermatophytes: Trichophyton interdigitale, Trichophyton rubrum, and Epidermophyton floccosum.

BACKGROUND AND PURPOSE: The most common etiological agents of human dermatophytosis in various parts of the world are Trichophyton rubrum, Trichophyton interdigitale, and Epidermophyton floccosum. The main aim of this study was to design and evaluate a simple and straightforward multiplex polymerase chain reaction (PCR) assay for reliable identification/differentiation of these species in clinical isolates. MATERIALS AND METHODS: The reliable sequences of several molecular targets of dermatophytes species were used to design a multiplex PCR for the identification of common pathogenic dermatophytes. The isolates and clinical specimens examined in this study included seven standard strains of dermatophytes, 101 isolates of dermatophytes and non-dermatophyte molds/yeasts which had already been identified by sequencing or PCR-restriction fragment length polymorphism (RFLP), and 155 clinical samples from patients suspected of cutaneous mycoses. RESULTS: Species-specific primer pairs for T. rubrum and T. interdigitale/T. mentagrophytes were designed based on the sequence data of the translation elongation factor 1-alpha gene, and the primers for E. floccosum targeted the specific sequence of the internal transcribed spacer region (ITS). The multiplex PCR successfully detected T. rubrum, T. interdigitale/T. mentagrophytes, and E. floccosum strains that were identified by sequencing or PCR-RFLP. However, the primer pairs selected for T. interdigitale/T. mentagrophytes cross-reacted with Trichophyton tonsurans. In testing the PCR system directly for clinical samples, the proportion of positive multiplex PCR was higher than positive culture (68.1% vs. 55.4%, respectively). CONCLUSION: The multiplex assay could detect three common agents out of several causal agents of dermatophytosis, namely T. rubrum, T. interdigitale, and E. floccosum. Therefore, by adding pan-dermatophyte primers it can be used as a comprehensive detection/identification test.

Effect of two hydatid cyst antigens on the growth of melanoma cancer in C57/black mice.

Hydatid cyst is the larval stage of Echinococcus granulosus. In previous studies inhibitory effect of this parasite on cancer cell growth in culture medium has been shown. In this study effect of hydatid cyst antigens on tumor growth in experimental animals has been investigated. Two antigens of hydatid cyst including protoscolices excretory secretory antigen and hydatid fluid absorbed on alum as adjuvant were injected to two groups of C57/black mice as case groups. Control groups were injected with only saline and alum. All mice then were injected with melanoma cells. Both antigens reduced the tumor size in mice in case groups. The difference of tumor size in mice in case groups and control group was statistically significant. In conclusion, anti-tumor effect of hydatid cyst antigens may be related to antigenic similarities which exist between hydatid cyst and cancer cells.

Common antigens between hydatid cyst and cancers.

BACKGROUND: Different research groups reported a negative correlation between cancers and parasitical infections. As an example, the prevalence of a hydatid cyst among patients with cancer was significantly lower than its prevalence among normal population. Tn antigens exist both in cancer and hydatid cyst. This common antigen may be involved in the effect of parasite on cancer growth. So in this work, common antigens between hydatid cyst and cancers have been investigated. MATERIALS AND METHODS: Different hydatid cyst antigens including hydatid fluid, laminated and germinal layer antigens, and excretory secretory antigens of protoscolices were run in SDS PAGE and transferred to NCP paper. In western immunoblotting, those antigens were probed with sera of patients with different cancer and also sera of non-cancer patients. Also, cross reaction among excretory secretory products of cancer cells and antisera raised against different hydatid cyst antigen was investigated. RESULTS: In western immunoblotting, antisera raised against laminated and germinal layers of hydatid cyst reacted with excretory secretory products of cancer cells. Also, a reaction was detected between hydatid cyst antigens and sera of patients with some cancers. CONCLUSION: Results of this work emphasize existence of common antigens between hydatid cyst and cancers. More investigation about these common antigens is recommended.

Parasites and chronic renal failure.

Suppression of the human immune system results in an increase in susceptibility to infection by various infectious agents. Conditions such as AIDS, organ transplantation and chronic renal insufficiency (CRI) are the most important cause of insufficient immune response against infections. Long term renal disorders result in uremia, which can suppress human immune system. Parasitic infections are one of the most important factors indicating the public health problems of the societies. These infections can be more hostile and life threatening in susceptible individuals than in the normal people. In these patients some parasitic infections such as blastocystiosis, cryptosporidiosis and toxoplasmosis have been reported to be more prevalent. This review aimed to give an overview about parasitic infections in patients with renal disorders.