Although what unifies the carcinogenic microorganisms has not been determined by multiple studies, the role of bacteria in the development of neoplasms has not been properly elucidated. In this review, we discuss links between the bacterial species and cancer, with focus on immune responses for the stimulation of tumor cells such as induction of inflammation. Finally, we will describe the potential therapeutic strategies of bacteria on target tumors to improve treatment while mitigating adverse reactions. Cancer is a series of genetic changes that transform normal cells into tumor cells. These changes come from several reasons, including smoking, drinking alcohol, sunlight, exposure to chemical or physical factors, and finally chronic infection with microorganisms, including bacteria. In fact, bacterial infections are not carcinogenic, but recently it was discovered that the association between bacteria and cancer is through two mechanisms, the first stimulating chronic inflammation and the second producing carcinogenic metabolites. While bacteria are carcinogenic agents also, they have a dual role eliminating and removing tumor cells. However, the traditional cancer treatments that include chemotherapy, radiotherapy, surgery, and immunotherapy increase the chances of survival, and there are many side effects of these therapies, including the high toxicity of tissues and normal cells, could not penetrate the tumor cells, and resistance of these therapies by tumor cells. Therefore, the world has turned to an alternative solution, which is the use of genetically engineered microorganisms; thus, the use of living bacteria targeting cancerous cells is the unique option to overcome these challenges. Bacterial therapies, whether used alone or combination with chemotherapy, give a positive effect to treat multiple conditions of cancer. Also, bacteria can be used as vectors for drug, gene, or therapy, and this is a great step to treat cancer. Thus, we review the mechanisms underlying the interaction of the microbiota residents with cancer. Cancer-associated bacteria differ from those in healthy human and are linked with gene-expression profile. We also discuss how live bacteria interact with tumor microenvironments to induce tumor regression through colonization and spread. Finally, we provide past and ongoing clinical trials that include bacteria targeting tumors.

We have previously reported that the absence of sphingosine kinase 1 (SK1) affects both dengue virus (DENV) infection and innate immune responses in vitro. Here we aimed to define SK1-dependancy of DENV-induced disease and the associated innate responses in vivo. The lack of a reliable mouse model with a fully competent interferon response for DENV infection is a challenge, and here we use an experimental model of DENV infection in the brain of immunocompetent mice. Intracranial injection of DENV-2 into C57BL/6 mice induced body weight loss and neurological symptoms which was associated with a high level of DENV RNA in the brain. Body weight loss and DENV RNA level tended to be greater in SK1-/- compared with wildtype (WT) mice. Brain infection with DENV-2 is associated with the induction of interferon-β (IFN-β) and IFN-stimulated gene (ISG) expression including viperin, Ifi27l2a, IRF7, and CXCL10 without any significant differences between WT and SK1-/- mice. The SK2 and sphingosine-1-phosphate (S1P) levels in the brain were unchanged by DENV infection or the lack of SK1. Histological analysis demonstrated the presence of a cellular infiltrate in DENV-infected brain with a significant increase in mRNA for CD8 but not CD4 suggesting this infiltrate is likely CD8+ but not CD4+ T-lymphocytes. This increase in T-cell infiltration was not affected by the lack of SK1. Overall, DENV-infection in the brain induces IFN and T-cell responses but does not influence the SK/S1P axis. In contrast to our observations in vitro, SK1 has no major influence on these responses following DENV-infection in the mouse brain.

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Various of Streptomyces species have two kinds of plasmids, circular plasmids (8 to 31 kb) and linear plasmids (12 to 1700 kb). Covalently closed circular (CCC) plasmids are profuse in the genus of Streptomyces and involved in production and resistance of antibiotics by genetic controlling. We collected fifty clinical soil samples from different regions in Al-Najaf Al-Ashraf province/Iraq. The samples included five from Al-Ghadeer Quarter, five from Al-Karama Quarter, 10 from Kufa University, five from Al-Ameer Quarter, four from Al-Forat Quarter, 10 from North Quarters and eleven from desert roads in Al-Najaf. Diluted samples were cultured on Yeast extract Malt extract (YEME) agar medium as a selective medium; then the presumptive Streptomyces colonies were subcultured on Tryptone Yeast extract (TYE) agar, then incubation at 37ᵒC for 7 days. Seven biochemical tests for identification of Streptomyces isolates these are: Catalase test, Oxidase test, Urase test, Kligler Iron Agar test (KIA), Simmon᾽s Citrate test, addition to MacConkey agar test and Mannitol Salt agar test. Five antibiotic discs were used for detection of antibiotic sensitivity of the Streptomyces isolates; these are: Tetracycline, Gentamycin, Vancomycin, Ampicillin, Erythromycin. The sensitivity of the antibiotics was observed by recorded the diameter of inhibition zone around the discs. Two test bacteria (Staphylococcus aureus and E. coli) were used for the determination of antibacterial activity. Plasmid isolation was done by the alkaline lysis method. This method is characterized by the rapid isolation of DNA from Streptomyces. Then, detection of Plasmid DNA occurred by using agarose gel electrophoresis.