- Inferring infection hazard in wildlife populations by linking data across individual and population scales. [Journal Article]
- ELEcol Lett 2017 Jan 16
- Our ability to infer unobservable disease-dynamic processes such as force of infection (infection hazard for susceptible hosts) has transformed our understanding of disease transmission mechanisms an...
Our ability to infer unobservable disease-dynamic processes such as force of infection (infection hazard for susceptible hosts) has transformed our understanding of disease transmission mechanisms and capacity to predict disease dynamics. Conventional methods for inferring FOI estimate a time-averaged value and are based on population-level processes. Because many pathogens exhibit epidemic cycling and FOI is the result of processes acting across the scales of individuals and populations, a flexible framework that extends to epidemic dynamics and links within-host processes to FOI is needed. Specifically, within-host antibody kinetics in wildlife hosts can be short-lived and produce patterns that are repeatable across individuals, suggesting individual-level antibody concentrations could be used to infer time since infection and hence FOI. Using simulations and case studies (influenza A in lesser snow geese and Yersinia pestis in coyotes), we argue that with careful experimental and surveillance design, the population-level FOI signal can be recovered from individual-level antibody kinetics, despite substantial individual-level variation. In addition to improving inference, the cross-scale quantitative antibody approach we describe can reveal insights into drivers of individual-based variation in disease response, and the role of poorly understood processes such as secondary infections, in population-level dynamics of disease.
- Yersinia enterocolitica, a Neglected Cause of Human Enteric Infections in Côte d'Ivoire. [Journal Article]
- PNPLoS Negl Trop Dis 2017; 11(1):e0005216
- CONCLUSIONS: This study demonstrates that pathogenic Y. enterocolitica circulate in the pig reservoir in Côte d'Ivoire and cause human infections with a prevalence comparable to that of many developed countries. The paucity of reports of yersiniosis in West Africa is most likely attributable to a lack of active detection rather than to an absence of the microorganism. The identification of hypermutator strains in pigs and humans is of concern as these strains can rapidly acquire selective advantages that may increase their fitness, pathogenicity or resistance to commonly used treatments.
- Genomic insights into a sustained national outbreak of Yersinia pseudotuberculosis. [Journal Article]
- GBGenome Biol Evol 2017 Jan 09
- In 2014, a sustained outbreak of yersiniosis due to Yersinia pseudotuberculosis occurred across all major cities in New Zealand (NZ), with a total of 220 laboratory-confirmed cases, representing one ...
In 2014, a sustained outbreak of yersiniosis due to Yersinia pseudotuberculosis occurred across all major cities in New Zealand (NZ), with a total of 220 laboratory-confirmed cases, representing one of the largest ever reported outbreaks of Y. pseudotuberculosis Here, we performed whole genome sequencing of outbreak-associated isolates to produce the largest population analysis to date of Y. pseudotuberculosis, giving us unprecedented capacity to understand the emergence and evolution of the outbreak clone. Multivariate analysis incorporating our genomic and clinical epidemiological data strongly suggested a single point-source contamination of the food chain, with subsequent nationwide distribution of contaminated produce. We additionally uncovered significant diversity in key determinants of virulence, which we speculate may help explain the high morbidity linked to this outbreak.
- [Monitoring and research on pathogen spectrum in patients with acute diarrhea from sentinel hospital of Zhejiang Province during 2009 to 2014]. [Journal Article]
- ZYZhonghua Yu Fang Yi Xue Za Zhi 2016 Dec 06; 50(12):1084-1090
- Objective: To explore pathogen spectrum constitution of acute diarrhea in outpatient and emergency of Zhejiang Province, and provide basis for treatment, prevention and control of the disease. Method...
Objective: To explore pathogen spectrum constitution of acute diarrhea in outpatient and emergency of Zhejiang Province, and provide basis for treatment, prevention and control of the disease. Methods: During January 2009 to December 2014, we selected seven sentinel hospitals in different regions of Zhejiang, monitored and researched on pathogen spectrum in patients with acute diarrhea from outpatient and emergency. We recorded patients' personal basic information, the main symptoms and signs, and collected stool samples (5 g). Eight kinds of bacteria (Vibrio cholerae, Shigella spp., Salmonella spp., Diarrheagenic E. coli, Vibrio parahaemolyticus, Aeromonas hydrophila, Yersinia enterocolitica and Plesiomonas shigelloides) and five kinds of viruses (Rotavirus, Norovirus, Sappovirus, Astrovirus and Adenovirus) were detected. Chi-square test and Fisher's exact probability method were used to compare different characteristics of patients with single bacterial infection, single virus infection and multiple infection (bacteria-bacteria, bacteria-viruses, virus-virus). Results: During 2009 to 2014, 9 364 fecal samples from acute diarrhea patients were collected and tested, among which 3 500 cases were tested positive, with total positive rate of 37.38%. Positive rates of bacteria and viruses were 13.14% (1 230 cases) and 20.75% (1 943 cases), respectively. Mixed infection positive rate of multiple pathogens was 3.49% (327 cases). Positive rate of Vibrio parahaemolyticus (5.96% , 558 cases) was the highest among bacterial pathogens, followed by pathogenic Escherichia coli (3.86%, 361 cases). Viruses were mainly Norovirus (10.73%, 1 005 cases) and rotavirus (8.35%, 782 cases). A big difference existed in diarrheogenic pathogen spectrum between patients less than 15 years old and patients equal or older than 15 years old. Pathogens for patients less than 15 years old were mainly virus, with the positive rate of 32.69% (1 014 cases). However, the positive rate of bacteria was 16.86% (1 056 cases) in patients equal or older than 15 years old. Single bacterial infection was highest in age group of 25-34 years old (18.62%, 302 cases) , single virus infection was highest in age group of 1-4 years old (41.12%, 435 cases) , and mixed infections of multiple pathogens were mainly existed in age group of 1-4 years old (7.37%, 78 cases) . Pathogen positive rate were increasing year by year. Pathogen positive rate of patients with acute diarrhea has obvious seasonality, with single bacterial infection being highest during July to September and single virus infection being highest during December to March. Pathogen spectrum of outpatient and emergency patients with acute diarrhea in Zhejiang Province changed a little from 2009 to 2014, mainly rotavirus (22.34% (782/3 500)), norovirus (28.71% (1 005/3 500)), vibrio parahaemolyticus (15.92% (558/3 500)) and Escherichia coli (10.31% (361/3 500)). However, pathogen spectrums in different years owned different features. Conclusion: Common pathogens in outpatient and emergency patients with acute diarrhea in Zhejiang Province were tested with significant seasonal epidemic law. The composition of pathogenic spectrum was variant in different age group. Constitutes of major pathogen spectrum in different years differed a little.
- Sepsis and siderosis, Yersinia enterocolitica and hereditary haemochromatosis. [Journal Article]
- BCBMJ Case Rep 2017 Jan 04; 2017
- A 60-year-old woman was admitted with sepsis, relative bradycardia, CT evidence of numerous small liver abscesses and 'skin bronzing' consistent with hereditary haemochromatosis (HH). Yersinia entero...
A 60-year-old woman was admitted with sepsis, relative bradycardia, CT evidence of numerous small liver abscesses and 'skin bronzing' consistent with hereditary haemochromatosis (HH). Yersinia enterocolitica O:9 infection was confirmed by serology specimens taken 10 days apart. Iron overload was detected, and homozygous C282Y gene mutation confirmed HH. Liver biopsy revealed grade IV siderosis with micronodular cirrhosis. Haemochromatosis is a common, inherited disorder leading to iron overload that can produce end-organ damage from excess iron deposition. Haemochromatosis diagnosis allowed aggressive medical management with phlebotomy achieving normalisation of iron stores. Screening for complications of cirrhosis was started that included hepatoma surveillance. Iron overload states are known to increase patient susceptibility to infections caused by lower virulence bacteria lacking sophisticated iron metabolism pathways, for example, Yersinia enterocolitica Although these serious disseminated infections are rare, they may serve as markers for occult iron overload and should prompt haemochromatosis screening.
- Mechanisms of Yersinia YopO kinase substrate specificity. [Journal Article]
- SRSci Rep 2017 Jan 04; 7:39998
- Yersinia bacteria cause a range of human diseases, including yersiniosis, Far East scarlet-like fever and the plague. Yersiniae modulate and evade host immune defences through injection of Yersinia o...
Yersinia bacteria cause a range of human diseases, including yersiniosis, Far East scarlet-like fever and the plague. Yersiniae modulate and evade host immune defences through injection of Yersinia outer proteins (Yops) into phagocytic cells. One of the Yops, YopO (also known as YpkA) obstructs phagocytosis through disrupting actin filament regulation processes - inhibiting polymerization-promoting signaling through sequestration of Rac/Rho family GTPases and by using monomeric actin as bait to recruit and phosphorylate host actin-regulating proteins. Here we set out to identify mechanisms of specificity in protein phosphorylation by YopO that would clarify its effects on cytoskeleton disruption. We report the MgADP structure of Yersinia enterocolitica YopO in complex with actin, which reveals its active site architecture. Using a proteome-wide kinase-interacting substrate screening (KISS) method, we identified that YopO phosphorylates a wide range of actin-modulating proteins and located their phosphorylation sites by mass spectrometry. Using artificial substrates we clarified YopO's substrate length requirements and its phosphorylation consensus sequence. These findings provide fresh insight into the mechanism of the YopO kinase and demonstrate that YopO executes a specific strategy targeting actin-modulating proteins, across multiple functionalities, to compete for control of their native phospho-signaling, thus hampering the cytoskeletal processes required for macrophage phagocytosis.
- Characterisation of arginase paralogues in salmonids and their modulation by immune stimulation/ infection. [Journal Article]
- FSFish Shellfish Immunol 2016 Dec 23; 61:138-151
- In this study we show that four arginase isoforms (arg1a, arg1b, arg2a, arg2b) exist in rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar). We have characterised these molecules in...
In this study we show that four arginase isoforms (arg1a, arg1b, arg2a, arg2b) exist in rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar). We have characterised these molecules in terms of a) sequence analysis, b) constitutive expression in different tissues, and modulated expression following c) stimulation of head kidney macrophages in vitro, or d) vaccination/infection with Yersinia ruckeri and e) parasite infection (AGD caused by Paramoeba perurans and PKD caused by Tetracapsuloides bryosalmonae). Synteny analysis suggested that these arginase genes are paralogues likely from the Ss4R duplication event, and amino acid identity/similarity analyses showed that the proteins are relatively well conserved across species. In rainbow trout constitutive expression of one or both paralogues was seen in most tissues but different constitutive expression patterns were observed for the different isoforms. Stimulation of rainbow trout head kidney macrophages with PAMPs and cytokines also revealed isoform specific responses and kinetics, with arg1a being particularly highly modulated by the PAMPs and pro-inflammatory cytokines. In contrast the type II arginase paralogues were induced by rIl-4/13, albeit to a lesser degree. Vaccination and infection with Y. ruckeri also revealed isoform specific responses, with variation in tissue expression level and kinetics. Lastly, the impact of parasite infection was studied, where down regulation of arg1a and arg1b was seen in two different models (AGD in salmon and PKD in trout) and of arg2a in AGD. The differential responses seen are discussed in the context of markers of type II responses in fish and paralogue subfunctionalization.
- Genomic insights and its comparative analysis with Yersinia enterocolitica reveals the potential virulence determinants and further pathogenicity for food-borne outbreaks. [Journal Article]
- JMJ Microbiol Biotechnol 2016 Dec 14
- Yersinia enterocolitica is a well-known food-borne pathogen causing gastrointestinal infections worldwide. The strain Y. enterocolitica FORC_002, isolated from the gill of flatfish (plaice) and its g...
Yersinia enterocolitica is a well-known food-borne pathogen causing gastrointestinal infections worldwide. The strain Y. enterocolitica FORC_002, isolated from the gill of flatfish (plaice) and its genome was sequenced. The genomic DNA consists of 4,837,317 bp with a GC content of 47.1%, and is predicted to contain 4,221 open reading frames (ORFs), 81 tRNA genes, and 26 rRNA genes. Interestingly, genomic analysis revealed pathogenesis and host immune evasion-associated genes encoding guanylate cyclase (Yst), invasin (Ail and Inv), outer membrane protein (Yops), autotransporter adhesin A (YadA), RTX-like toxins, and a type III secretion system (TTSS). In particular, guanylate cyclase is a heat-stable enterotoxin causing Yersinia-associated diarrhea, and RTX-like toxins are responsible for attachment to integrin on the target cell for cytotoxic action. This genome can be used to identify virulence factors that can be applied for the development of novel biomarkers for rapid detection of this pathogen in foods.
- Prevalence, seasonal variation, and antibiotic resistance pattern of enteric bacterial pathogens among hospitalized diarrheic children in suburban regions of central Kenya. [Journal Article]
- TMTrop Med Health 2016; 44:39
- CONCLUSIONS: This study suggests that DEC is the leading diarrhea-causing bacterial pathogen circulating in central Kenya, and seasonality has a significant effect on its transmission. Proper antibiotic prescription and susceptibility testing is important to guide appropriate antimicrobial therapy.
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- Sheep carrying pathogenic Yersinia enterocolitica bioserotypes 2/O:9 and 5/O:3 in the feces at slaughter. [Journal Article]
- VMVet Microbiol 2016 Dec 25; 197:78-82
- Yersinia enterocolitica is a heterogeneous species including non-pathogenic strains belonging to biotype 1A and pathogenic strains belonging to biotypes 1B and 2-5. Pathogenic strains of biotypes 2-4...
Yersinia enterocolitica is a heterogeneous species including non-pathogenic strains belonging to biotype 1A and pathogenic strains belonging to biotypes 1B and 2-5. Pathogenic strains of biotypes 2-4 carrying the ail virulence gene have frequently been isolated from domestic pigs at slaughter. In sheep, mostly non-pathogenic biotype 1A strains have been reported. In our study, the prevalence of ail-positive Y. enterocolitica was studied by PCR and culturing in 406 young sheep (<1year of age) and 139 older sheep at slaughter in Finland. When using PCR, the detection rate was 11% (45/406) in young sheep originating from 11 (18%) farms. Surprisingly, Y. enterocolitica belonging to bioserotypes 2/O:9 and 5/O:3, carrying both chromosomal and plasmid-borne virulence genes, were isolated from the fecal samples of 10 (2%) and 23 (4%) sheep, respectively. All isolates of bioserotypes 2/O:9 (19 isolates) and 5/O:3 (53 isolates) carried the chromosomal virulence genes ail, inv, ystA, and myfA, and almost all isolates (71/72) also carried the virulence genes virF and yadA located on the virulence plasmid. The isolates showed high susceptibility to tested antimicrobials and low genetic diversity by PFGE. Y. enterocolitica bioserotype 5/O:3 is a very rare bioserotype, and has earlier only sporadically been reported in European wildlife and in sheep in Australia and New Zealand. Bioserotype 2/O:9 is a common bioserotype found in humans with yersiniosis, and has sporadically been isolated in wild and domestic animals.