Identification and characterisation of enteroaggregative Escherichia coli subtypes associated with human disease

Enteroaggregative E. coli (EAEC) are a major cause of diarrhoea worldwide. Due to their heterogeneity and carriage in healthy individuals, identification of diagnostic virulence markers for pathogenic strains has been difficult. In this study, we have determined phenotypic and genotypic differences between EAEC strains of sequence types (STs) epidemiologically associated with asymptomatic carriage (ST31) and diarrhoeal disease (ST40). ST40 strains demonstrated significantly enhanced intestinal adherence, biofilm formation, and pro-inflammatory interleukin-8 secretion compared with ST31 isolates. This was independent of whether strains were derived from diarrhoea patients or healthy controls. Whole genome sequencing revealed differences in putative virulence genes encoding aggregative adherence fimbriae, E. coli common pilus, flagellin and EAEC heat-stable enterotoxin 1. Our results indicate that ST40 strains have a higher intrinsic potential of human pathogenesis due to a specific combination of virulence-related factors which promote host cell colonization and inflammation. These findings may contribute to the development of genotypic and/or phenotypic markers for EAEC strains of high virulence

Improving health professional\u27s knowledge of hepatitis B using cartoon based learning tools: a retrospective analysis of pre and post tests

Background: Hepatitis B serology is complex and a lack of knowledge in interpretation contributes to the inadequate levels of screening and referral for highly effective hepatitis antiviral treatments. This knowledge gap needs to be addressed so that current and future healthcare professionals are more confident in the detection and assessment of hepatitis B to improve the uptake of treatment and reduce long-term complications from the disease. Cartoons have been used effectively as a teaching tool in other settings and were considered as a potentially useful teaching aid in explaining hepatitis B serology. This study examines the impact of cartoons in improving healthcare professionals’ knowledge. Methods: A cartoon based learning tool designed to simplify the complexities of hepatitis B serology was developed as part of an online learning program for medical practitioners, nurses and students in these professions. A retrospective analysis was carried out of pre and post online test results. Results: An average improvement of 96% of correct answers to case study questions in hepatitis B serology was found across all ten questions following the use of an online cartoon based learning tool. Conclusion: The data indicates a significant improvement of participants’ knowledge of hepatitis B serology from pre-test to post-test immediately following an online cartoon based learning tool. However, further research is required to measure its long term impact

Cartoons for e-health informatics

Not only is Hepatitis B serology often misunderstood because of its complex serological implications, but advances in medical science have revolutionised screening and treatment of hepatitis B. To maximise such evolution however, this new information must be relayed effectively and efficiently to current and future medical professionals. Cartoons have been well regarded as a teaching tool in a variety of different settings as is the use of web based technology. Therefore the delivery of a cartoon based learning tool, accessed via on-line learning modules was considered a novel and potentially effective way of disseminating new knowledge. To increase health professionals’ understanding of hepatitis B serology and skill in interpreting the tests that indicate the appropriate treatment, a cartoon series was developed. The cartoons are located on an online educational website and include characters that represent the different antibodies and antigens associated with hepatitis B. The cartoon characters are involved in a series of adventures that represent the various phases of hepatitis B infection, and the paper describes their development. Subsequent research demonstrated that exposure to the online cartoon based learning tool indicates that they are a fun and useful way to increase knowledge

Evaluation of multiplex tandem PCR (MT-PCR) assays for the detection of bacterial resistance genes among Enterobacteriaceae in clinical urines

Background: Increasing resistance drives empirical use of less potent and previously reserved antibiotics, including for urinary tract infections (UTIs). Molecular profiling, without culture, might better guide early therapy.  Objectives: To explore the potential of AusDiagnostics multiplex tandem (MT) PCR UTI assays.  Methods: Two MT-PCR assays were developed successively, seeking 8 or 16 resistance genes. Amplification was tracked in real time, with melting temperatures used to confirm product identity. Assays were variously performed on: (i) extracted DNA; (ii) cultured bacteria; (iii) urine spiked with reference strains; and (iv) bacteria harvested from clinical urines. Results were compared with those from sequencing, real-time SybrGreen PCR or phenotypic susceptibility.  Results: Performance was similar irrespective of whether DNA, cultures or urines were used, with >90% sensitivity and specificity with respect to common β-lactamases, dfr genes and aminoglycoside resistance determinants except aadA1/A2/A3, for which carriage correlated poorly with streptomycin resistance. Fluoroquinolone-susceptible and -resistant Escherichia coli (but not other species) were distinguished by the melting temperatures of their gyrA PCR products. The time from urine to results was <3 h.  Conclusions: The MT-PCR assays rapidly identified resistance genes from Gram-negative bacteria in urines as well as from cultivated bacteria. Used directly on urines, this assay has the potential to guide early therapy

Active site manipulation in MoS2 cluster electrocatalysts by transition metal doping

The development of non-platinum group metal catalysts for the hydrogen evolution reaction (HER) in water electrolyser devices is essential for their widespread and sustainable deployment. In recent years, molybdenum disulfide (MoS2) catalysts have received significant attention as they not only exhibit good electrocatalytic HER activity but also, crucially, acid-stability. However, further performance enhancement is required for these materials to be competitive with Pt and to that end transition metal doping of MoS2 has been explored as a route to further increasing its catalytic activity. In this work, cluster beam deposition was employed to produce controlled cobalt-doped MoS2 clusters (MoS2–Co). We demonstrate that, in contrast to previous observations of performance enhancement in MoS2 resulting from nickel doping (MoS2–Ni), the introduction of Co has a detrimental effect on HER activity. The contrasting behaviours of Ni and Co doping are rationalized by density functional theory (DFT) calculations, which suggest that HER-active surface vacancies are deactivated by combination with Co dopant atoms, whilst their activity is retained, or even partially enhanced, by combination with Ni dopant atoms. Furthermore, the adatom dopant–vacancy combination kinetics appear to be more than three orders of magnitude faster in MoS2–Co than for MoS2–Ni. These findings highlight a fundamental difference in the influence of transition metal dopants on the HER performance of MoS2 electrocatalysts and stress the importance of considering surface atomic defects when predicting their behaviour

Ceftriaxone resistant Salmonella Typhi carries an IncI1-ST31 plasmid encoding CTXM-15

Purpose: Ceftriaxone is the drug of choice for typhoid fever and the emergence of resistant Salmonella Typhi raises major concerns for treatment. There are an increasing number of sporadic reports of ceftriaxone resistant S. Typhi and limiting the risk of treatment failure in the patient and outbreaks in the community must be prioritised. This study describes the use of whole genome sequencing to guide outbreak identification and case management. Methodology: An isolate of ceftriaxone resistant S. Typhi from the blood of a child taken in 2011 at the Popular Diagnostic Center, Dhaka, Bangladesh was subjected to whole genome sequencing, using an Illumina NextSeq 500 and analysis using Geneious software. Results: Comparison with other ceftriaxone resistant S. Typhi revealed an isolate from the Democratic Republic of the Congo in 2015 as the closest relative but no evidence of an outbreak. A plasmid belonging to incompatibility group I1 (IncI1-ST31) which included blaCTX-M-15 (ceftriaxone resistance) associated with ISEcp-1 was identified. High similarity (90%) was seen with pS115, an IncI1 plasmid from S. Enteritidis, and with pESBL- EA11, an incI1 plasmid from E. coli (99%) showing that S. Typhi has access to ceftriaxone resistance through the acquisition of common plasmids. Conclusions: The transmission of ceftriaxone resistance from E. coli to S. Typhi is of concern because of clinical resistance to ceftriaxone, the main stay of typhoid treatment. Whole genome sequencing, albeit several years after the isolation, demonstrated the success of containment but clinical trials with alternative agents are urgently required

Applying phylogenomics to understand the emergence of Shiga Toxin producing Escherichia coli O157:H7 strains causing severe human disease in the United Kingdom

Shiga Toxin producing Escherichia coli (STEC) O157:H7 is a recently emerged zoonotic pathogen with considerable morbidity. Since the serotype emerged in the 1980s, research has focussed on unravelling the evolutionary events from the E. coli O55:H7 ancestor to the contemporaneous globally dispersed strains. In this study the genomes of over 1000 isolates from human clinical cases and cattle, spanning the history of STEC O157:H7 in the United Kingdom were sequenced. Phylogenetic analysis reveals the ancestry, key acquisition events and global context of the strains. Dated phylogenies estimate the time to the most recent common ancestor of the current circulating global clone to 175 years ago, followed by rapid diversification. We show the acquisition of specific virulence determinates occurred relatively recently and coincides with its recent detection in the human population. Using clinical outcome data from 493 cases of STEC O157:H7 we assess the relative risk of severe disease including HUS from each of the defined clades in the population and show the dramatic effect Shiga toxin complement has on virulence. We describe two strain replacement events that have occurred in the cattle population in the UK over the last 30 years; one resulting in a highly virulent strain that has accounted for the majority of clinical cases in the UK over the last decade. This work highlights the need to understand the selection pressures maintaining Shiga-toxin encoding bacteriophages in the ruminant reservoir and the study affirms the requirement for close surveillance of this pathogen in both ruminant and human populations

Rudimentary meningocele: remnant of a neural tube defect?

Background: Rudimentary meningocele, a malformation in which meningothelial elements are present in the skin and subcutaneous tissue, has been described in the past, under a variety of different terms and has also been referred to as cutaneous meningioma. There has been debate as to whether rudimentary meningocele is an atretic form of meningocele or results from growth of meningeal cells displaced along cutaneous nerve

Identification and characterisation of enteroaggregative Escherichia coli subtypes associated with human disease

Enteroaggregative E. coli (EAEC) are a major cause of diarrhoea worldwide. Due to their heterogeneity and carriage in healthy individuals, identification of diagnostic virulence markers for pathogenic strains has been difficult. In this study, we have determined phenotypic and genotypic differences between EAEC strains of sequence types (STs) epidemiologically associated with asymptomatic carriage (ST31) and diarrhoeal disease (ST40). ST40 strains demonstrated significantly enhanced intestinal adherence, biofilm formation, and pro-inflammatory interleukin-8 secretion compared with ST31 isolates. This was independent of whether strains were derived from diarrhoea patients or healthy controls. Whole genome sequencing revealed differences in putative virulence genes encoding aggregative adherence fimbriae, E. coli common pilus, flagellin and EAEC heat-stable enterotoxin 1. Our results indicate that ST40 strains have a higher intrinsic potential of human pathogenesis due to a specific combination of virulence-related factors which promote host cell colonization and inflammation. These findings may contribute to the development of genotypic and/or phenotypic markers for EAEC strains of high virulence