Integrated transcriptomic and proteomic analysis of pathogenic mycobacteria and their esx-1 mutants reveal secretion-dependent regulation of ESX-1 substrates and WhiB6 as a transcriptional regulator.

The mycobacterial type VII secretion system ESX-1 is responsible for the secretion of a number of proteins that play important roles during host infection. The regulation of the expression of secreted proteins is often essential to establish successful infection. Using transcriptome sequencing, we found that the abrogation of ESX-1 function in Mycobacterium marinum leads to a pronounced increase in gene expression levels of the espA operon during the infection of macrophages. In addition, the disruption of ESX-1-mediated protein secretion also leads to a specific down-regulation of the ESX-1 substrates, but not of the structural components of this system, during growth in culture medium. This effect is observed in both M. marinum and M. tuberculosis. We established that down-regulation of ESX-1 substrates is the result of a regulatory process that is influenced by the putative transcriptional regulator whib6, which is located adjacent to the esx-1 locus. In addition, the overexpression of the ESX-1-associated PE35/PPE68 protein pair resulted in a significantly increased secretion of the ESX-1 substrate EsxA, demonstrating a functional link between these proteins. Taken together, these data show that WhiB6 is required for the secretion-dependent regulation of ESX-1 substrates and that ESX-1 substrates are regulated independently from the structural components, both during infection and as a result of active secretion.

Barriers encountered during the implementation of a policy guideline on the vaccination of health care workers during the 2013-2014 measles outbreak in the Netherlands: a qualitative study.

BACKGROUND: In 2013 the Netherlands faced a measles epidemic, during which more than 2600 individuals were infected, including 19 health care workers (HCW). Vaccinating health care workers can lead to benefits on both the individual and public health level, underscoring the need for HCW vaccination. In June of 2013 the Dutch National Institute for Public Health and the Environment (RIVM) developed a measles guideline (MG) that advised Dutch hospitals to strengthen their policies concerning measles vaccination of HCWs. A key problem with guidelines, however, is adherence, which can be due to several barriers. The objective of this research was to identify the barriers that Dutch hospital professionals encountered during the implementation of this policy guideline, in order to improve the implementation of similar policies in the future. METHODS: In-depth interviews (n = 9) were conducted with 12 hospital health care professionals involved with prevention and control of communicable diseases. These participants represented ten different Dutch hospitals located in eight of the twelve different provinces. Participants were asked about their experiences during the 2013-2014 measles epidemic regarding infection prevention measures, including vaccination of HCWs, with a specific focus on barriers to the implementation of the RIVM guideline. RESULTS: The implementation of the MG was impeded by several (types of) barriers. First, barriers were found related to knowledge and attitude, and included lack of agreement, barriers associated with leadership and issues related to evidence-based decision making. Second, barriers related to characteristics of the guideline, mostly related to unclear or missing guideline content. Finally, contextual and social factors such as human and financial resources, belief systems, physical facilities and technical support, and national views on vaccination policies also play an important role in policy implementation. CONCLUSIONS: This study has provided valuable insights into the barriers infection prevention specialists encounter during the implementation of new policies concerning vaccination of HCWs in times of a major outbreak. Moreover, this study exposed the complexity and breadth of barriers that are of importance when implementing vaccination policies in the hospital setting. In order to improve the implementation of similar policies in the future, guideline developers and health care providers and administrators alike should aim to eliminate or minimise these identified barriers by taking into account the suggestions made by the authors.