Although there have been great advances in our understanding of the bacterial cytoskeleton, major gaps remain in our knowledge of its importance to virulence. In this study we have explored the contribution of the bacterial cytoskeleton to the ability of Salmonella to express and assemble virulence factors and cause disease. The bacterial actin-like protein MreB polymerises into helical filaments and interacts with other cytoskeletal elements including MreC to control cell-shape. As mreB appears to be an essential gene, we have constructed a viable ΔmreC depletion mutant in Salmonella. Using a broad range of independent biochemical, fluorescence and phenotypic screens we provide evidence that the Salmonella pathogenicity island-1 type three secretion system (SPI1-T3SS) and flagella systems are down-regulated in the absence of MreC. In contrast the SPI-2 T3SS appears to remain functional. The phenotypes have been further validated using a chemical genetic approach to disrupt the functionality of MreB. Although the fitness of ΔmreC is reduced in vivo, we observed that this defect does not completely abrogate the ability of Salmonella to cause disease systemically. By forcing on expression of flagella and SPI-1 T3SS in trans with the master regulators FlhDC and HilA, it is clear that the cytoskeleton is dispensable for the assembly of these structures but essential for their expression. As two-component systems are involved in sensing and adapting to environmental and cell surface signals, we have constructed and screened a panel of such mutants and identified the sensor kinase RcsC as a key phenotypic regulator in ΔmreC. Further genetic analysis revealed the importance of the Rcs two-component system in modulating the expression of these virulence factors. Collectively, these results suggest that expression of virulence genes might be directly coordinated with cytoskeletal integrity, and this regulation is mediated by the two-component system sensor kinase RcsC.

An-Najah National University.

No abstract

Background Infection control had many developments in the COVID 19 (Coronavirus Disease 2019) pandemic, despite this, there were many complications in different health care facilities as well as dentists’ clinics due to the lack of infection control knowledge and compliance failure. This study aimed to assess the level of knowledge and compliance with the infection control measures in the dental clinics in the Nablus and Tulkarm districts. Results The results showed that the total positive response regard all infection control domains were (70.0 %). Whereas the participants gave the highest positive response for personnel protective equipment i.e. gloving was (96.10 %). They gave the instruments related to controls the lowest responses, i.e. instruments sterilization was (59.40 %). The analyzed data showed significant statistical differences in the compliance with infection control measures between Nablus and Tulkarm districts “p < 0.05” in the interest of dentists from Tulkarm. Conclusions In conclusion, the findings of this study showed that there is moderate compliance to infection control protocol in Nablus and Tulkarm dental clinics. Thus, there is a need to strengthen adherence to infection control measures. Method A universal sampling was used to assess the infection control program at the dental clinics in Nablus and Tulkarm Districts. The study sample involved 265 dentists. Data was collected using a questionnaire which has been sent via email between July and August 2020. Descriptive statistics, Chi-square test, One-way ANOVA and Post-Hock tests have been used. Statistical significance was set at ″P <0.05″. Cronbach’s alpha has been conducted to ensure the reliability and validity of the questionnaire.

Background: Infection control had many developments in the COVID 19 pandemic, despite this, there were many complications in different health care facilities as well as dentists’ clinics due to the lack of infection control knowledge and compliance failure.Aim: To assess the level of knowledge and compliance with the infection control measures in the dental clinics in Nablus and Tulkarm districts.Method: A universal Sampling was used to assess the infection control program at the dental clinics in Nablus and Tulkarm District. The study sample involved 265 dentists. Data was collected using a questionnaire which has been sent via email between July and August 2020. Descriptive statistics, Chi-square test, One-way ANOVA and Post-Hock tests have been used. Statistical significance was set at ″P <0.05″. Cronbach's alpha has been conducted to ensure the reliability and validity of the questionnaire.Findings: The results showed that the total positive response regard all infection control domains were (70.0%). Whereas the participants gave the highest positive response for personnel protective equipment i.e gloving (96.10%), they gave the instruments related controls the lowest responses i.e instruments sterilization were (59.40%). The analyzed data showed significant statistical differences in the compliance with infection control measures between Nablus and Tulkarm districts “p < 0.05” in the interest of dentists from Tulkarm.Conclusion: The findings of this study showed that there is a moderate compliance to infection control protocol in Nablus and Tulkarm dental clinics. Thus, there is a need to strengthen the adherence to infection control measures.