Molecular typing of enteroviruses: comparing 5'UTR, VP1 and whole genome sequencing methods

Enteroviruses (EV) commonly cause hand, foot and mouth disease (HFMD), and can also cause potentially fatal neurological and systemic complications. In our laboratory, sequencing 5' untranslated region (UTR) of the viral genome has been the routine method of genotyping EVs. During a recent localised outbreak of aseptic meningitis, sequencing the 5'UTR identified the causative virus as EV-A71, which did not fit with the clinical syndrome or illness severity. When genotyped using a different target gene, VP1, the result was different. This led us to evaluate the accuracy of the two different target genome regions and compare them against whole genome sequencing (WGS). We aimed to optimise the algorithm for detection and characterisation of EVs in the diagnostic laboratory. We hypothesised that VP1 and WGS genotyping would provide different results than 5'UTR in a subset of samples. Clinical samples from around New South Wales which were positive for EV by commercial polymerase chain reaction (PCR) assays were genotyped by targeting three different viral genome regions: the 5'UTR, VP1 and WGS. Sequencing was performed by Sanger and next generation sequencing. The subtyping results were compared. Of the 74/118 (63%) samples that were successfully typed using both the 5'UTR and the VP1 method, the EV typing result was identical for 46/74 (62%) samples compared to WGS as the gold standard. The same EV group but different EV types were found in 22/74 (30%) samples, and 6/74 (8%) samples belonged to different EV groups depending on typing method used. Genotyping with WGS and VP1 is more accurate than 5'UTR. Genotyping by the 5'UTR method is very sensitive, but less specific.

Interfering with Autophagy: The Opposing Strategies Deployed by Legionella pneumophila and Coxiella burnetii Effector Proteins

Autophagy is a fundamental and highly conserved eukaryotic process, responsible for maintaining cellular homeostasis and releasing nutrients during times of starvation. An increasingly important function of autophagy is its role in the cell autonomous immune response; a process known as xenophagy. Intracellular pathogens are engulfed by autophagosomes and targeted to lysosomes to eliminate the threat to the host cell. To counteract this, many intracellular bacterial pathogens have developed unique approaches to overcome, evade, or co-opt host autophagy to facilitate a successful infection. The intracellular bacteria Legionella pneumophila and Coxiella burnetii are able to avoid destruction by the cell, causing Legionnaires' disease and Q fever, respectively. Despite being related and employing homologous Dot/Icm type 4 secretion systems (T4SS) to translocate effector proteins into the host cell, these pathogens have developed their own unique intracellular niches. L. pneumophila evades the host endocytic pathway and instead forms an ER-derived vacuole, while C. burnetii requires delivery to mature, acidified endosomes which it remodels into a large, replicative vacuole. Throughout infection, L. pneumophila effectors act at multiple points to inhibit recognition by xenophagy receptors and disrupt host autophagy, ensuring it avoids fusion with destructive lysosomes. In contrast, C. burnetii employs its effector cohort to control autophagy, hypothesized to facilitate the delivery of nutrients and membrane to support the growing vacuole and replicating bacteria. In this review we explore the effector proteins that these two organisms utilize to modulate the host autophagy pathway in order to survive and replicate. By better understanding how these pathogens manipulate this highly conserved pathway, we can not only develop better treatments for these important human diseases, but also better understand and control autophagy in the context of human health and disease.

EirA Is a Novel Protein Essential for Intracellular Replication of Coxiella burnetii

The zoonotic bacterial pathogen Coxiella burnetii is the causative agent of Q fever, a febrile illness which can cause a serious chronic infection. C. burnetii is a unique intracellular bacterium which replicates within host lysosome-derived vacuoles. The ability of C. burnetii to replicate within this normally hostile compartment is dependent on the activity of the Dot/Icm type 4B secretion system. In a previous study, a transposon mutagenesis screen suggested that the disruption of the gene encoding the novel protein CBU2072 rendered C. burnetii incapable of intracellular replication. This protein, subsequently named EirA (essential for intracellular replication A), is indispensable for intracellular replication and virulence, as demonstrated by infection of human cell lines and in vivo infection of Galleria mellonella The putative N-terminal signal peptide is essential for protein function but is not required for localization of EirA to the bacterial inner membrane compartment and axenic culture supernatant. In the absence of EirA, C. burnetii remains viable but nonreplicative within the host phagolysosome, as coinfection with C. burnetii expressing native EirA rescues the replicative defect in the mutant strain. In addition, while the bacterial ultrastructure appears to be intact, there is an altered metabolic profile shift in the absence of EirA, suggesting that EirA may impact overall metabolism. Most strikingly, in the absence of EirA, Dot/Icm effector translocation was inhibited even when EirA-deficient C. burnetii replicated in the wild type (WT)-supported Coxiella containing vacuoles. EirA may therefore have a novel role in the control of Dot/Icm activity and represent an important new therapeutic target.

Factors influencing uptake of measles, mumps and rubella (MMR) immunization in site-dwelling Gypsy, Roma and Traveller (G&T) communities: a qualitative study of G&T parents' beliefs and experiences

BACKGROUND

Increasing immunization in the Gypsy, Roma and Traveller (G&T) community is a key priority for improving health outcomes in this community. This study aimed to explore G&T parents: (1) beliefs about childhood immunization; (2) beliefs about the risks of immunization and non-immunization; (3) perceived obstacles to, and facilitators of, immunization and (4) views on increasing immunization levels.

METHOD

A cross-sectional, qualitative study was conducted comprising of five focus groups with 16 site-dwelling G&T women with pre-school aged children. Data were transcribed verbatim and analysed thematically.

RESULTS

Five main themes were identified: Lay understandings of causation and risk; Timing of immunization; Children being perceived as vulnerable; The fit between lifestyle and healthcare provision; The impact of living with a high burden of disease.

CONCLUSION

Understanding of the risks and benefits of measles, mumps and rubella immunization did not differ significantly from the wider population or those promoted by the health service. The majority of barriers stemmed from living with the effects of long-standing health inequalities, which posed further barriers to accessing immunization, and shaped beliefs about immunization. Factors facilitating uptake occurred where access to immunization services was made flexible, e.g. immunization on traveller sites.

Testing headings for communicating the personal health record: comparison from the recipients’ perspective

In the spring of 1998, 16 general practitioners and 16 community psychiatric nurses participated in a study to test a draft set of headings for communicating clinical summaries. Eight anonymized psychiatric discharge summaries were used to assess the impact of the presentational format on the time taken by professionals to read the summaries and to answer a series of standard questions about each of them. Respondents also completed a questionnaire on their opinions of the headings. There was considerable variation between individuals in the times taken to read the summaries and answer the questions, but no evidence that any of the formats was associated with decreased reading time or with improvement in retrieving information. Most respondents preferred information structured using the headings rather than the original semi-structured discharge summaries, and information on paper rather than on computer screen.

Respondents were guardedly supportive of the particular draft headings presented. A weak preference was expressed for locally defined headings, with some recognition of advantages in widely agreed headings. There was a view that there were too many headings, and there was overlap between specific heading pairs (for example, ‘aim’ and ‘goal’). Concerns were expressed about specific headings, particularly the ‘softer’ headings, such as ‘informing’ and ‘communicating’.

Applying Fluorescence Resonance Energy Transfer (FRET) to Examine Effector Translocation Efficiency by Coxiella burnetii during siRNA Silencing

Coxiella burnetii, the causative agent of Q fever, is an intracellular pathogen that relies on a Type IV Dot/Icm Secretion System to establish a replicative niche. A cohort of effectors are translocated through this system into the host cell to manipulate host processes and allow the establishment of a unique lysosome-derived vacuole for replication. The method presented here involves the combination of two well-established techniques: specific gene silencing using siRNA and measurement of effector translocation using a FRET-based substrate that relies on β-lactamase activity. Applying these two approaches, we can begin to understand the role of host factors in bacterial secretion system function and effector translocation. In this study we examined the role of Rab5A and Rab7A, both important regulators of the endocytic trafficking pathway. We demonstrate that silencing the expression of either protein results in a decrease in effector translocation efficiency. These methods can be easily modified to examine other intracellular and extracellular pathogens that also utilize secretion systems. In this way, a global picture of host factors involved in bacterial effector translocation may be revealed.

Coxiella burnetii: turning hostility into a home

Coxiella burnetii, the causative agent of the human disease Q fever, is a unique intracellular bacterial pathogen. Coxiella replicates to high numbers within a pathogen-derived lysosome-like vacuole, thriving within a low pH, highly proteolytic and oxidative environment. In 2009, researchers developed means to axenically culture Coxiella paving the way for the development of tools to genetically manipulate the organism. These advances have revolutionized our capacity to examine the pathogenesis of Coxiella. In recent years, targeted and random mutant strains have been used to demonstrate that the Dot/Icm type IV secretion system is essential for intracellular replication of Coxiella. Current research is focused towards understanding the unique cohort of over 130 effector proteins that are translocated into the host cell. Mutagenesis screens have been employed to identify effectors that play important roles for the biogenesis of the Coxiella-containing vacuole and intracellular replication of Coxiella. A surprisingly high number of effector mutants demonstrate significant intracellular growth defects, and future studies on the molecular function of these effectors will provide great insight into the pathogenesis of Coxiella. Already, this expanse of new data implicates many eukaryotic processes that are targeted by the arsenal of Coxiella effectors including autophagy, apoptosis and vesicular trafficking.

Soluble NSF attachment protein receptor molecular mimicry by a Legionella pneumophila Dot/Icm effector

Upon infection, Legionella pneumophila uses the Dot/Icm type IV secretion system to translocate effector proteins from the Legionella-containing vacuole (LCV) into the host cell cytoplasm. The effectors target a wide array of host cellular processes that aid LCV biogenesis, including the manipulation of membrane trafficking. In this study, we used a hidden Markov model screen to identify two novel, non-eukaryotic soluble NSF attachment protein receptor (SNARE) homologs: the bacterial Legionella SNARE effector A (LseA) and viral SNARE homolog A proteins. We characterized LseA as a Dot/Icm effector of L. pneumophila, which has close homology to the Qc-SNARE subfamily. The lseA gene was present in multiple sequenced L. pneumophila strains including Corby and was well distributed among L. pneumophila clinical and environmental isolates. Employing a variety of biochemical, cell biological and microbiological techniques, we found that farnesylated LseA localized to membranes associated with the Golgi complex in mammalian cells and LseA interacted with a subset of Qa-, Qb- and R-SNAREs in host cells. Our results suggested that LseA acts as a SNARE protein and has the potential to regulate or mediate membrane fusion events in Golgi-associated pathways.

Barriers and opportunities of empowerment as applied in diabetes settings: a focus on health care professionals' experiences

This exploratory study examines the opportunities and barriers health care professionals (HCPs) working with diabetes patients face when they try to implement the rhetoric of patient empowerment in practice. A small sample of diabetes HCPs (N=13), from National Health Service (NHS) hospital, walk-in and general practitioner (GP) clinics in South-East England, was interviewed through in-depth semi-structured interviews. Interviews were recorded, transcribed verbatim and analysed thematically. The analysis showed that empowerment was seen as beneficial for patients and HCPs. Time and resources could be moved from successfully empowered patients and focussed on more complex patients, this was termed 'selective empowerment'. The main barriers to empowerment were identified as a lack of resources, time and HCPs trained in empowerment techniques. Empowerment is a popular concept in theory, and presents HCPs with several opportunities but also important barriers in its practical, clinical implementation day-to-day.