Biology subjects

Siddig, E. E.

Publications and source records attributed to Siddig, E. E..

4 recordsLinked to original sources

bioRxiv2020

The development of a novel diagnostic PCR for Madurella mycetomatis using a comparative genome approach

Eumycetoma is a neglected tropical disease characterized by large tumorous lesions. It is most commonly caused by the fungus Madurella mycetomatis which accounts for more than 70% of cases in central Africa. Currently, identification of the causative agent can only be reliably performed by a species-specific PCR. However, we recently demonstrated that our M. mycetomatis specific PCR can cross-react with Madurella pseudomycetomatis. We therefore used a comparative genome approach to develop a new M. mycetomatis specific PCR for species identification. For this we compared the published M. mycetomatis genome to genomes of other organisms in BLASTCLUST to identify unique M. mycetomatis predicted protein coding sequences. Based on 16 of these unique sequences, PCR primers were developed. The specificity of these primers was further evaluated in other eumycetoma causing agents including the Madurella sibling species. Out of the 16 tested sequences, only one was unique for M. mycetomatis and this should be used as a novel diagnostic marker for M. mycetomatis.

microbiology↗

bioRxiv2019

Prevalence and risk factors profile of seropositive Toxoplasmosis gondii infection among apparently immunocompetent Sudanese women

ObjectivesToxoplasma gondii is an opportunistic parasite that cause a clinical manifestation known as toxoplasmosis. We investigated the prevalence and potential risk factors of T. gondii infection among women in Khartoum, Sudan. A sero-parasitological cross-sectional study included 100 women aging between 15-50 years old was conducted in Khartoum, Sudan between January - November 2018. Serum samples were collected and investigated for presence of anti-T. gondii immunoglobulins.\n\nResultsMean age of the women population included was 26.75{+/-}8.25 with a range between 15 and 50 years. Sero-prevalence of T. gondii antibodies was 27% (27/100) with a 95% confidence interval (CI) of 18.6 - 36.8%. Among seropositive population 81% (22/27), 15% (4/27) and 4% (1/27) were seropositive for IgG antibodies, IgM antibodies and both antibodies respectively. Age group 21-30 years old had the highest frequency of detected IgG (10/45) and IgM (3/45). Married women had the highest frequency of detected IgG or IgM, 18/79 and 3/79, respectively. Risk factors analysis showed a total of 37/100 participants were having direct contact with cats and 66/100 have a frequent raw meat consumption, neither direct cats contact nor raw meat consumption had statistically significant association with seropositivity to T. gondii (P. value =0.052 and 0.565, respectively).

microbiology↗

bioRxiv2018

The Role of Interleukin-1 cytokine family (IL-1β, IL-37) and interleukin-12 cytokine family (IL-12, IL-35) in eumycetoma infection pathogenesis

Mycetoma is a neglected tropical disease, endemic in many tropical and subtropical regions, characterised by massive deformity and disability and can be fatal if untreated early and appropriately. Interleukins (IL)-35 and IL-37 are newly discovered cytokines that play an important role in suppressing the immune system. However, the expression of these interleukins in patients with Madurella mycetomatis (M. mycetomatis) induced eumycetoma has not yet been explored. This study aims to determine the levels of the IL-1 family (IL-1{beta}, IL-37) and IL-12 family (IL-12, IL-35) in a group of these patients and the association between these cytokines levels and the patients demographic characteristics. The present, a case-control study was conducted at the Mycetoma Research Centre, Soba University Hospital, University of Khartoum, Sudan and it included 140 individuals. They were divided into two groups; group I: healthy controls [n = 70; median age 25 years (range 12 to 70 years)]. Group II: mycetoma patients [n = 70 patients; median age 25 (range 13 to 70 years)]. Cytokines levels were measured in sera using enzyme-linked immunosorbent assay (ELISA).\n\nThere was no significant correlation between the IL-1{beta} and IL-12 levels and the lesions size and disease duration, whereas levels of IL-37 and IL-35 were significantly correlated with that. The analysis of the risk factors of higher circulatory levels of IL-37 in patients of mycetoma showed a significant negative association with IL-1{beta} cytokine, where a unit increment in IL-1{beta} will decrease the levels of IL-37 by 35.28 pg/ml. The levels of IL-37 among the patients with a duration of mycetoma infection [≤] one year had significantly decreased by an average of 18.45 compared to patients with a mycetoma infections duration of [≥] 5years (reference group). Furthermore, the risk factors of higher levels of IL-35 in mycetoma patients revealed a significant negative association with IL-12, as a unit increment in IL-12 decreases the levels of IL-35by 8.99 pg/ml (p < 0.001). Levels of IL-35 among the patients with duration of mycetoma infection [≤] one year had significantly decreased (p-value = 0.002) on average by 41.82 compared to patients with a duration of mycetoma infection [≥] five years (reference group). In conclusion, this study indicates that both IL-35 and IL-37 are negatively associated with the levels of IL-1{beta} and IL-12 in eumycetoma mycetoma infection; and high levels of IL-37 and IL-35 may have a negative impact on disease progression.\n\nAuthors SummaryMycetoma is a progressive chronic granulomatous fungal or bacterial infection that may result in massive destruction of subcutaneous tissues, muscles and bones. Mycetoma is a neglected disease which is endemic in many tropical and subtropical areas. If the disease is not treated properly, eventually it ends up with amputation and adverse medical, health and socioeconomic effects on patients and the community.\n\nPrevious data suggested a crucial role of adaptive immunity in host resistance to causative agents and the disease progression. The recently identified IL-35 and IL-37 cytokines revealed an important role in immune suppression. Nevertheless, the expression of these interleukins in patients with mycetoma has not yet been investigated. Therefore, the present case-control study aimed to determine the levels of IL-1 family (IL-1{beta}, IL-37) and IL-12 family (IL-12, IL-35) in these patients and the association between these cytokines levels and the patients demographic characteristics.\n\nThe results of this study showed that the levels of IL-37 and IL-35 were consistently positively correlated with different diameters of mycetoma lesions as well as its duration. However, the levels of IL-1{beta} and IL-12 were consistently negatively correlated with different diameters of lesions and the duration of mycetoma infection. The analysis of the risk factors of higher circulatory levels of IL-37 in patients of mycetoma showed a significant negative association with IL-1{beta} cytokine. Furthermore, the risk factors of higher levels of IL-35 in patients of mycetoma revealed a significant negative association with IL-12. These findings uncover a possible the role of IL-35 and IL-37 in the pathogenesis of mycetoma and may declare their potential value in the treatment of mycetoma.

immunology↗

bioRxiv2018

The Accuracy of Histopathological and Cytopathological Techniques in the Identification of the Mycetoma Causative Agents

Mycetoma is a devastating neglected tropical disease, caused by various fungal and bacterial pathogens. Correct diagnosis to the species level is mandatory for proper treatment. In endemic areas, various diagnostic tests and techniques are in use to achieve that, and that includes grain culture, surgical biopsy histopathological examination, fine needle aspiration cytological (FNAC) examination and in certain centres molecular diagnosis such as PCR.\n\nIn this retrospective study, the sensitivity, specificity and diagnostic accuracy of grain culture, surgical biopsy histopathological examination and FNAC to identify the mycetoma causative organisms were determined. The histopathological examination appeared to have better sensitivity and specificity.\n\nThe histological examination results were correct in 714 (97.5%) out of 750 patients infected with Madurella mycetomatis, in 133 (93.6%) out of 142 patients infected with Streptomyces somaliensis, in 53 (74.6%) out of 71 patients infected with Actinomadura madurae and in 12 (75%) out of 16 patients infected with Actinomadura pelletierii.\n\nFNAC results were correct in 604 (80.5%) out of 750 patients with Madurella mycetomatis eumycetoma, in 50 (37.5%) out of 133 Streptomyces somaliensis patients, 43 (60.5%) out of 71 Actinomadura madurae patients and 11 (68.7%) out of 16 Actinomadura pelletierii. The mean time required to obtain the FNAC result was one day, and for the histopathological examinations results it was 3.5 days, and for grain, it was a mean of 16 days.\n\nIn conclusion, histopathological examination and FNAC are more practical techniques for rapid species identification than grain culture in many endemic regions.\n\nAuthor summaryIn mycetoma endemic regions, the medical and health settings are commonly suboptimal, and only a few diagnostic tests and techniques are available. That had badly affected the patients proper diagnosis and management and thus the late presentation of patients with advanced disease. In this retrospective study, the experience of the MRC on the common in use diagnostic tests in the period between 1991 and 2018 is presented.\n\nIn this study, the sensitivity, specificity rates and diagnostic accuracy of grain culture, surgical biopsy histopathological examination and FNAC to identify the mycetoma causative organisms were determined. The histopathological examination appeared to have better sensitivity and specificity. Furthermore, the grain culture identification needs high experience, it is the tedious procedure, and cross-contamination is common hence misdiagnosis is frequent. It can be concluded that histopathological examination and FNAC are more practical techniques for rapid species identification than grain culture in many endemic regions with poor diagnostic setting.

microbiology↗