Observations of a Magellanic Corona.

The Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC) are the closest massive satellite galaxies of the Milky Way. They are probably on their first passage on an infalling orbit towards our Galaxy1 and trace the continuing dynamics of the Local Group2. Recent measurements of a high mass for the LMC (Mhalo ≈ 1011.1-11.4 M⊙)3-6 imply that the LMC should host a Magellanic Corona: a collisionally ionized, warm-hot gaseous halo at the virial temperature (105.3-5.5 K) initially extending out to the virial radius (100-130 kiloparsecs (kpc)). Such a corona would have shaped the formation of the Magellanic Stream7, a tidal gas structure extending over 200° across the sky2,8,9 that is bringing in metal-poor gas to the Milky Way10. Here we show evidence for this Magellanic Corona with a potential direct detection in highly ionized oxygen (O+5) and indirectly by means of triply ionized carbon and silicon, seen in ultraviolet (UV) absorption towards background quasars. We find that the Magellanic Corona is part of a pervasive multiphase Magellanic circumgalactic medium (CGM) seen in many ionization states with a declining projected radial profile out to at least 35 kpc from the LMC and a total ionized CGM mass of log10(MH II,CGM/M⊙) ≈ 9.1 ± 0.2. The evidence for the Magellanic Corona is a crucial step forward in characterizing the Magellanic group and its nested evolution with the Local Group.

Norovirus attribution study: Detection of norovirus from the commercial food preparation environment in outbreak and non-outbreak premises.

AIMS: Norovirus remains the most significant virological risk that is transmitted via food and the environment to cause acute gastroenteritis. This study aimed to investigate the hypothesis that the contamination of the commercial food production environment with norovirus will be higher in premises that have recently reported a foodborne norovirus outbreak than those that have not. METHODS: Sampling of commercial food production environments was carried out across a 16-month period between January 2015 and April 2016 in the South East and the North West of England by local authority environmental health departments as part of routine surveillance visits to premises. A total of 2982 samples, 2038 virological and 944 bacteriological, were collected from 256 premises. Sixteen of these premises, six from South East and ten from North West England, were sampled as part of a public health outbreak investigation. RESULTS & CONCLUSIONS: Overall, 2038 swabs were submitted for norovirus testing, with an average of eight swabs per premises (range 4 to 23) and a median of seven. Of the premises sampled, 11.7% (30/256) yielded at least one norovirus-positive sample (environmental, and/or food handler hand swab), and 2.5% of the swabs were positive for norovirus. A peak in the positivity rate was seen in the South East in April 2016. No associations were found between norovirus positivity and bacteriology indicators, or between bacteriology indicators and hygiene ratings. SIGNIFICANCE AND IMPACT OF STUDY: This study demonstrates that food premises and food handlers remain a potential source of norovirus transmission and outbreaks.

Large metallicity variations in the Galactic interstellar medium.

The interstellar medium (ISM) comprises gases at different temperatures and densities, including ionized, atomic and molecular species, and dust particles1. The neutral ISM is dominated by neutral hydrogen2 and has ionization fractions of up to eight per cent3. The concentration of chemical elements heavier than helium (metallicity) spans orders of magnitudes in Galactic stars4, because they formed at different times. However, the gas in the vicinity of the Sun is assumed to be well mixed and to have a solar metallicity in traditional chemical evolution models5. The ISM chemical abundances can be accurately measured with ultraviolet absorption-line spectroscopy. However, the effects of dust depletion6-9-which removes part of the metals from the observable gaseous phase and incorporates it into solid grains-have prevented, until recently, a deeper investigation of the ISM metallicity. Here we report the dust-corrected metallicity of the neutral ISM measured towards 25 stars in our Galaxy. We find large variations in metallicity over a factor of ten (with an average of 55 ± 7 per cent solar metallicity and a standard deviation of 0.28 dex), including many regions of low metallicity, down to about 17 per cent solar metallicity and possibly below. Pristine gas falling onto the Galactic disk in the form of high-velocity clouds can cause the observed chemical inhomogeneities on scales of tens of parsecs. Our results suggest that this low-metallicity accreting gas does not efficiently mix into the ISM, which may help us understand metallicity deviations in nearby coeval stars.

Diagnosis and management of pyothorax in a domestic ferret (Mustela putorius furo).

OBJECTIVE: To describe the diagnosis, management, and outcome of pyothorax in a domestic ferret (Mustela putorius furo). CASE SUMMARY: A domestic ferret was evaluated for a history of lethargy, anorexia, and pyrexia. Pleural effusion was detected with radiography and ultrasonography, and a diagnosis of pyothorax was made following cytologic evaluation of pleural fluid. Bilateral thoracostomy tubes were placed for thoracic drainage and lavage, and the ferret was treated with intravenous crystalloid fluids, antimicrobials, and analgesics. Bacterial culture of the pleural fluid yielded Fusobacterium spp. and Actinomyces hordeovulneris. This treatment protocol resulted in resolution of pyothorax, and a positive clinical outcome. NEW OR UNIQUE INFORMATION PROVIDED: This is the first reported case of successful management of pyothorax caused by Fusobacterium spp. and A. hordeovulneris in a ferret.

Ameloblastoma in a wild black rat snake (Pantherophis alleghaniensis).

Reports of neoplasia in captive reptiles are becoming more frequent; however, there is still scarce knowledge of the occurrence of neoplasia in wild reptiles. A wild black rat snake (Pantherophis alleghaniensis) was presented to the Zoological Medicine service of the University of Georgia's Veterinary Teaching Hospital with a 3 cm in diameter solid mandibular mass that was partially ulcerated. Radiographically, the mass was radiopaque with small bone spicules and partial osteolysis of the adjacent mandible. Histologic examination of the mass revealed a neoplasm composed of cuboidal to polygonal cells arranged in islands, anastomosing cords, and trabeculae of pseudostratified epithelium with a palisading peripheral layer of densely packed columnar cells with cytoplasmic clearing. The neoplastic tissue was separated from the mesenchyme by a prominent band of fine collagen. Neoplastic cells were positive for cytokeratin and negative for smooth muscle actin. Electron microscopy highlighted the presence of tonofilaments and microvilli. These findings led to the diagnosis of ameloblastoma, an odontogenic epithelial tumor known to occur in humans and most veterinary species.

Implications of differential age distribution of disease-associated meningococcal lineages for vaccine development.

New vaccines targeting meningococci expressing serogroup B polysaccharide have been developed, with some being licensed in Europe. Coverage depends on the distribution of disease-associated genotypes, which may vary by age. It is well established that a small number of hyperinvasive lineages account for most disease, and these lineages are associated with particular antigens, including vaccine candidates. A collection of 4,048 representative meningococcal disease isolates from 18 European countries, collected over a 3-year period, were characterized by multilocus sequence typing (MLST). Age data were available for 3,147 isolates. The proportions of hyperinvasive lineages, identified as particular clonal complexes (ccs) by MLST, differed among age groups. Subjects <1 year of age experienced lower risk of sequence type 11 (ST-11) cc, ST-32 cc, and ST-269 cc disease and higher risk of disease due to unassigned STs, 1- to 4-year-olds experienced lower risk of ST-11 cc and ST-32 cc disease, 5- to 14-year-olds were less likely to experience ST-11 cc and ST-269 cc disease, and ≥25-year-olds were more likely to experience disease due to less common ccs and unassigned STs. Younger and older subjects were vulnerable to a more diverse set of genotypes, indicating the more clonal nature of genotypes affecting adolescents and young adults. Knowledge of temporal and spatial diversity and the dynamics of meningococcal populations is essential for disease control by vaccines, as coverage is lineage specific. The nonrandom age distribution of hyperinvasive lineages has consequences for the design and implementation of vaccines, as different variants, or perhaps targets, may be required for different age groups.

High metabolic potential may contribute to the success of ST131 uropathogenic Escherichia coli.

Uropathogenic Escherichia coli (UPEC) is the predominant cause of urinary tract infection in both hospital and community settings. The recent emergence of multidrug-resistant clones like the O25b:H4-ST131 lineage represents a significant threat to health, and numerous studies have explored the virulence potential of these organisms. Members of the ST131 clone have been described as having variable carriage of key virulence factors, and it has been suggested that additional unidentified factors contribute to virulence. Here we demonstrated that ST131 isolates have high metabolic potential and biochemical profiles that distinguish them from isolates of many other sequence types (STs). A collection of 300 UPEC isolates recovered in 2007 and 2009 in the Northwest region of England were subjected to metabolic profiling using the Vitek2 Advanced Expert System (AES). Of the 47 tests carried out, 30 gave a positive result with at least one of the 300 isolates examined. ST131 isolates demonstrated significant association with eight tests, including those for peptidase, decarboxylase, and alkalinization activity. Metabolic activity also correlated with antibiotic susceptibility profiles, with resistant organisms displaying the highest metabolic potential. This is the first comprehensive study of metabolic potential in the ST131 lineage, and we suggest that high metabolic potential may have contributed to the fitness of members of the ST131 clone, which are able to exploit the available nutrients in both the intestinal and urinary tract environments.

Changes in acid-base balance during electrolytic ablation in an ex vivo perfused liver model.

BACKGROUND: Electrolytic ablation (EA) destroys tissues through extreme pH changes in the local microenvironment. An ex vivo perfused liver model was used to assess the systemic effects of EA on the acid-base balance without the influence of compensatory organs (lungs and kidneys). METHODS: Eleven pigs were perfused extracorporeally at 39°C with autologous blood; 4 also underwent EA after 1 hour of reperfusion. Arterial blood samples were obtained hourly. RESULTS: pH and CO(2) levels did not change throughout the experiments. A significant increase of HCO(3)-, anion gap, base excess, and lactate was present after the third hour. No differences were observed between EA experiments and controls. CONCLUSIONS: EA does not alter the acid-base balance even when the confounding influence of compensatory organs is removed. Such findings should be considered when planning ablations in patients with renal failure or respiratory diseases in which EA could avoid undesirable metabolic changes.

Population structure, virulence potential and antibiotic susceptibility of uropathogenic Escherichia coli from Northwest England.

OBJECTIVES: Multilocus sequence typing (MLST) has been used to characterize diverse pathogens, including uropathogenic Escherichia coli (UPEC). There has been significant interest in the contribution of the O25b:H4-ST131 lineage to UPEC disease, as these isolates are often highly virulent and exhibit multidrug resistance. To reveal the wider impact of sequence type (ST) 131, we have examined its contribution to the overall population structure of UPEC isolates that were not selected on the basis of virulence or antibiotic resistance. METHODS: Three hundred UPEC isolates were recovered from community and hospital urine samples examined by clinical microbiology laboratories in the Northwest region of England in June 2007 and June 2009. They were characterized by susceptibility profiling, MLST and virulence gene PCR. PFGE was used to examine isolates from key clones. RESULTS: The most common lineage was ST73 (16.6%) followed by ST131 (13.3%), ST69 (9%), ST95 (6.3%), ST10 (4.3%) and ST127 (3.6%). ST131 isolates were significantly more likely to exhibit high levels of antibiotic resistance (35% being CTX-M-15 PCR positive) and those of ST127 were the most widely susceptible but carried the highest number of virulence genes. Only when the CTX-M-15-O25b-positive strains were examined was a high level of virulence observed for ST131 isolates. PFGE indicated ongoing local evolution in ST131. CONCLUSIONS: ST131 isolates are well established in the wider UPEC population. This clone is still evolving and we further support suggestions that it represents a real threat to health. We suggest that ST127 is a recently emerged, community-associated, virulent clone that warrants further study.

The single kinin receptor signals to separate and independent physiological pathways in Malpighian tubules of the yellow fever mosquito.

In the past, we have used the kinins of the cockroach Leucophaea (the leucokinins) to evaluate the mechanism of diuretic action of kinin peptides in Malpighian tubules of the yellow fever mosquito Aedes aegypti. Now using the kinins of Aedes (the aedeskinins), we have found that in isolated Aedes Malpighian tubules all three aedeskinins (1 microM) significantly 1) increased the rate of fluid secretion (V(S)), 2) hyperpolarized the basolateral membrane voltage (V(bl)), and 3) decreased the input resistance (R(in)) of principal cells, consistent with the known increase in the Cl(-) conductance of the paracellular pathway in Aedes Malpighian tubules. Aedeskinin-III, studied in further detail, significantly increased V(S) with an EC(50) of 1.5 x 10(-8) M. In parallel, the Na(+) concentration in secreted fluid significantly decreased, and the K(+) concentration significantly increased. The concentration of Cl(-) remained unchanged. While the three aedeskinins triggered effects on V(bl), R(in), and V(S), synthetic kinin analogs, which contain modifications of the COOH-terminal amide pentapeptide core sequence critical for biological activity, displayed variable effects. For example, kinin analog 1578 significantly stimulated V(S) but had no effect on V(bl) and R(in), whereas kinin analog 1708 had no effect on V(S) but significantly affected V(bl) and R(in). These observations suggest separate signaling pathways activated by kinins. One triggers the electrophysiological response, and the other triggers fluid secretion. It remains to be determined whether the two signaling pathways emanate from a single kinin receptor via agonist-directed signaling or from a differentially glycosylated receptor. Occasionally, Malpighian tubules did not exhibit a detectable response to natural and synthetic kinins. Hypothetically, the expression of the kinin receptor may depend on developmental, nutritional, and/or reproductive signals.

Comparison of a semi-automated rep-PCR system and multilocus sequence typing for differentiation of Salmonella enterica isolates.

The accurate sub-typing of Salmonella enterica isolates is essential for epidemiological investigations and surveillance of Salmonella infections. Salmonella isolates are currently identified using the Kauffman-White serotyping scheme. Multilocus sequence typing (MLST) schemes have been developed for the major bacterial pathogens including Salmonella and have assisted in understanding the molecular epidemiology and population biology of these organisms. Recently, the DiversiLab rep-PCR system has been developed using micro-fluidic chips to provide standardized, semi-automated fingerprinting for pathogens including S. enterica. In the current study, 71 isolates of S. enterica, representing 21 serovars, were analyzed using MLST and the DiversiLab rep-PCR system. MLST was able to identify 31 sequence types (STs), while the DiversiLab system revealed 38 DiversiLab types (DTs). The rep-PCR distinguished isolates of different serovars and showed greater discriminatory power (0.95) than MLST typing (0.89). Rep-PCR exhibited 92% concordance with MLST and 90% with serotyping, while the concordance level of MLST typing with serotyping was 96%, representing a strong association. Comparison of rep-PCR profiles with those held in an online library database led to the accurate prediction of serovar in 63% of cases and resulted in inaccurate predictions for 10% of profiles. MLST and the rep-PCR system may provide useful additional informative techniques for the molecular identification of S. enterica. We conclude that the DiversiLab rep-PCR system may provide a rapid (less than 4h) and standardized method for sub-typing isolates of S. enterica.

Development of a multiplex primer extension assay for rapid detection of Salmonella isolates of diverse serotypes.

Food-borne salmonellosis is a major manifestation of gastrointestinal disease in humans across the globe. Accurate and rapid identification methods could positively impact the identification of isolates, enhance outbreak investigation, and aid infection control. The SNaPshot multiplex system is a primer extension-based method that enables multiplexing of single nucleotide polymorphisms (SNPs). Here the method has been developed for the identification of five Salmonella serotypes, commonly detected in the United Kingdom, based on serotype-specific SNPs identified in the multilocus sequence typing (MLST) database of Salmonella enterica. The SNPs, in genes hemD, thrA, purE, and sucA, acted as surrogate markers for S. enterica serovars Typhimurium, Enteritidis, Virchow, Infantis, and Braenderup. The multiplex primer extension assay (MPEA) was conducted in two separate panels and evaluated using 152 Salmonella enterica isolates that were characterized by MLST. The MPEA was shown to be 100% specific and sensitive, within this collection of isolates. The MPEA is a sensitive and specific method for the identification and detection of Salmonella serotypes based upon SNPs seen in MLST data. The method can be applied in less than 6 h and has the potential to improve patient care and source tracing. The utility of the assay for identification of Salmonella serotypes directly from clinical specimens and food samples warrants further investigation.

UK epidemic Escherichia coli strains A-E, with CTX-M-15 beta-lactamase, all belong to the international O25:H4-ST131 clone.

OBJECTIVES: Uropathogenic and invasive Escherichia coli O25:H4-ST131 isolates producing CTX-M-15 extended-spectrum beta-lactamase (ESBL) enzymes have recently been shown to be disseminated across the globe. In the UK, many CTX-M-15 ESBL-producing E. coli strains have been previously defined as belonging to the epidemic strains A-E, as determined by PFGE. The present study was carried out to define the relationship between these two groups of pathogenic E. coli. METHODS: Multilocus sequence typing and PFGE were used for molecular characterization of a collection of 61 ESBL-producing E. coli isolates from across the UK. RESULTS: Strains A to E all belonged to the ST131 clone, further underscoring the epidemiological importance of this lineage. CONCLUSIONS: The future spread of the ST131 clone, and its UK variants, should be monitored closely and the pathogenic mechanisms explaining their success should be investigated.

Molecular epidemiology of Campylobacter jejuni populations in dairy cattle, wildlife, and the environment in a farmland area.

We describe a cross-sectional study of the molecular epidemiology of Campylobacter jejuni in a dairy farmland environment, with the aim of elucidating the dynamics of horizontal transmission of C. jejuni genotypes among sources in the area. A collection of 327 C. jejuni isolates from cattle, wildlife, and environmental sources in a 100-km(2) area of farmland in northwest England was characterized by multilocus sequence typing. A total of 91 sequence types and 18 clonal complexes were identified. Clonal complexes ST-21, ST-45, and ST-61, which have been frequently associated with human disease, were the most commonly recovered genotypes in this study. In addition, widely distributed genotypes as well as potentially host-associated genotypes have been identified, which suggests that both restricted and interconnecting pathways of transmission may be operating in the dairy farmland environment. In particular, the ST-61 complex and the ST-21 complex were significantly associated with cattle. In contrast, complex strains ST-45, ST-952, and ST-677 were isolated predominantly from wild birds, wild rabbits, and environmental water. A considerable number of novel sequence types have also been identified, which were unassigned to existing clonal complexes and were frequently isolated from wildlife and environmental sources. The segregated distribution of genotypes among samples from different sources suggests that their transmission to humans is perhaps via independent routes. Insight into the dynamics and interactions of C. jejuni populations between important animal reservoirs and their surrounding environment would improve the identification of sources of Campylobacter infection and the design of control strategies.

Molecular epidemiology of meningococcal disease in England and Wales 1975-1995, before the introduction of serogroup C conjugate vaccines.

A comprehensive meningococcal vaccine is yet to be developed. In the absence of a vaccine that immunizes against the serogroup B capsular polysaccharide, this can only be achieved by targeting subcapsular antigens, and a number of outer-membrane proteins (OMPs) are under consideration as candidates. A major obstacle to the development of such a vaccine is the antigenic diversity of these OMPs, and obtaining population data that accurately identify and catalogue these variants is an important component of vaccine design. The recently proposed meningococcal molecular strain-typing scheme indexes the diversity of two OMPs, PorA and FetA, that are vaccine candidates, as well as the capsule and multilocus sequence type. This scheme was employed to survey 323 meningococci isolated from invasive disease in England and Wales from 1975 to 1995, before the introduction of meningococcal conjugated serogroup C polysaccharide vaccines in 1999. The eight-locus typing scheme provided high typeability (99.4 %) and discrimination (Simpson's diversity index 0.94-0.99). The data showed cycling of meningococcal genotypes and antigenic types in the absence of planned interventions. Notwithstanding high genetic and antigenic diversity, most of the isolates belonged to one of seven clonal complexes, with 11 predominant strain types. Combinations of PorA and FetA, chosen on the basis of their prevalence over time, generated vaccine recipes that included protein variants found in 80 % or more of the disease isolates for this time period. If adequate immune responses can be generated, these results suggest that control of meningococcal disease with relatively simple protein component vaccines may be possible.

Longitudinal study of the molecular epidemiology of Campylobacter jejuni in cattle on dairy farms.

Multilocus sequence typing (MLST), an accurate and phylogenetically robust characterization method for population studies of Campylobacter, was applied to Campylobacter jejuni isolates (n = 297) from the fecal samples of cattle from five dairy farms in Cheshire, United Kingdom, collected throughout 2003. The population dynamics of the C. jejuni strains, as identified by the occurrence of sequence types and clonal complexes, demonstrated variations within and between cattle populations over time. Three clonal lineages have emerged to predominate among the cattle isolates, namely, the ST-61 complex (24.2%), ST-21 complex (23.6%), and ST-42 complex (20.5%). This provided further evidence that the ST-61 clonal complex may present a cattle-adapted C. jejuni genotype. In addition, the ST-42 clonal complex may also represent an important cattle-associated genotype. Strong geographical associations for these genotypes were also found among the farms. This is the first longitudinal study and the largest study to date for C. jejuni involving cattle populations using MLST for accurate strain characterization. This study shows the important associations between cattle and C. jejuni clonal complexes ST-61, ST-21, and ST-42, and it suggests that cattle and/or dairy products are likely to be a source of the human Campylobacter gastroenteritis caused by such genotypes. The reported findings have significant implications for the design of effective intervention strategies for disease control and prevention.

Major uropathogenic Escherichia coli strain isolated in the northwest of England identified by multilocus sequence typing.

A total of 88 uropathogenic Escherichia coli isolates, including 68 isolates from urine and 20 isolates from blood, were characterized by multilocus sequence typing (MLST). MLST has identified an important genetic lineage of E. coli, designated sequence type 131 (ST-131), represented by 52 of these isolates, 51 of which were resistant to extended-spectrum cephalosporins. ST-131 appears to be a drug-resistant uropathogenic strain of E. coli responsible for causing urinary tract infections and bacteremia and is widely disseminated among both community and hospital patients from different geographical areas in the northwest of England. Application of MLST has helped to define the population biology which may underpin the epidemiology of pathogenic E. coli strains. The portability of MLST allows the accurate monitoring of this antibiotic-resistant uropathogenic strain of E. coli and will enhance surveillance for this important group of organisms.

Standardized nonculture techniques recommended for European reference laboratories.

Culture-confirmed diagnosis of meningococcal invasive infections is often hindered by early antibiotic treatment. Nonculture molecular standardized methods are now essential tools for the immediate management of meningococcal infections. The European Monitoring Group on Meningococci (EMGM) recommends the following measures. (1) The implementation of standardized protocols of extraction methods for DNA isolation from clinical specimens for PCR-based identification and genogrouping of Neisseria meningitidis. (2) The use of molecular approaches (sequencing of target genes) for the determination of meningococcal susceptibility to antibiotics, such as sequencing of penA and rpoB genes for susceptibility to penicillin G and rifampicin, respectively. (3) The use of nonculture strain characterization by multilocus sequence typing (MLST) and sequence typing of porA and fetA. These approaches can be implemented either by individual reference laboratories or through collaboration and referral between centres.