Visualization of translocons in Yersinia type III protein secretion machines during host cell infection.

Type III secretion systems (T3SSs) are essential virulence factors of numerous bacterial pathogens. Upon host cell contact the T3SS machinery-also named injectisome-assembles a pore complex/translocon within host cell membranes that serves as an entry gate for the bacterial effectors. Whether and how translocons are physically connected to injectisome needles, whether their phenotype is related to the level of effector translocation and which target cell factors trigger their formation have remained unclear. We employed the superresolution fluorescence microscopy techniques Stimulated Emission Depletion (STED) and Structured Illumination Microscopy (SIM) as well as immunogold electron microscopy to visualize Y. enterocolitica translocons during infection of different target cell types. Thereby we were able to resolve translocon and needle complex proteins within the same injectisomes and demonstrate that these fully assembled injectisomes are generated in a prevacuole, a PI(4,5)P2 enriched host cell compartment inaccessible to large extracellular proteins like antibodies. Furthermore, the operable translocons were produced by the yersiniae to a much larger degree in macrophages (up to 25% of bacteria) than in HeLa cells (2% of bacteria). However, when the Rho GTPase Rac1 was activated in the HeLa cells, uptake of the yersiniae into the prevacuole, translocon formation and effector translocation were strongly enhanced reaching the same levels as in macrophages. Our findings indicate that operable T3SS translocons can be visualized as part of fully assembled injectisomes with superresolution fluorescence microscopy techniques. By using this technology, we provide novel information about the spatiotemporal organization of T3SS translocons and their regulation by host cell factors.

CLONAL SPREAD OF YERSINIA ENTEROCOLITICA 1B/O:8 IN MULTIPLE ZOO SPECIES.

Yersinia enterocolitica (YE) bioserotype 1B/O:8 (YE 1B/O:8) was identified in routine culture of a variety of zoo species housed at Omaha's Henry Doorly Zoo and Aquarium (OHDZA) from April to July 2011. Animal cases representing 12 species had YE detected from 34 cases during routine fecal monitoring and/or during postmortem examination: Coquerel's sifakas (Propithecus coquereli, two cases), black & white (BW) ruffed lemurs (Varecia variegata variegata, six cases), red ruffed lemurs (Varecia rubra, seven cases), white handed gibbon (Hylobates lar albimana, one case), black lemurs (Eulemur macaco, three cases), mongoose lemurs (Eulemur mongoz, two cases), African hunting dogs (Lycaon pictus, five cases), agile gibbons (Hylobates agilis, three cases), siamangs (Hylobates syndactylus, two cases), colobus monkey (Colobus angolensis palliates, one case), argus pheasant (Argusianus argus, one case), and orangutan (Pongo pygmaeus, one case). Most species were not symptomatic; however, three symptomatic cases in Coquerel's sifakas (two) and a white handed gibbon (one) showed clinical signs of diarrhea and lethargy that resulted in death for the Coquerel's sifakas. One unexpected death also occurred in a BW ruffed lemur. To the authors' knowledge, this is the first report of YE 1B/O:8 in such a large variety of zoo species. The source of the YE could not be identified, prompting the initiation of a diseases surveillance program to prevent further cases for the species that are sensitive to YE. To date, no additional cases have been identified, thus suggesting a single introduction of the YE 1B/O:8 strain into the zoo environment.

Invasive Yersiniosis in a Pediatric Patient With ß-Thalassemia Major: Acute Decompensation After Rapid Blood Transfusion.

Yersinia enterocolitica infection, or yersiniosis, is a common cause of gastroenteritis in developing nations, but the disease is less common in the developed world. Yersiniosis typically presents as a self-limited gastroenteritis in an immunocompetent patient and rarely progresses to the more fulminant disseminated form. Certain patient populations are at greater risk of disseminated disease, and providers caring for these patients should have heightened suspicion for invasive disease. Patients dependent on serial transfusion therapy, such as those with inherited hemoglobinopathies, often have chronically elevated serum iron levels. These patients are at increased risk of fulminant yersiniosis due to the bacteria's siderophilic nature. Yersinia infection can be devastating in these patients, and early intervention with empiric antibiotics combined with targeted resuscitation can be essential in their care. The following case illustrates the utility for heightened surveillance, early intervention, and guided resuscitation in the management of this at-risk population.

Management practices associated with the carriage of Yersinia enterocolitica in pigs at farm level.

Pigs are the most important reservoir of Yersinia enterocolitica infections in humans. Knowledge of farm management practices that contribute to the transmission of this bacterial species in pigs is essential to understand how to control this foodborne pathogen in food production. The prevalence of Y. enterocolitica, and other results obtained from an age trend analysis were used to estimate the on-farm risk of transmission of specific management practices for this pathogen in 30 pig farms in Finland. Log-linear analysis revealed that rearing pigs in pens without or with sparse amounts of bedding and buying piglets from more than one farm were the variables that contribute most to the occurrence of Y. enterocolitica. The study also found that using an all-in/all-out management system and supplying water of municipal origin were factors that might reduce the prevalence of Y. enterocolitica, and therefore the risk of transmission of Y. enterocolitica in pig farms.

Yersinia enterocolitica of porcine origin: carriage of virulence genes and genotypic diversity.

Yersinia enterocolitica is an important foodborne pathogen, and pigs are recognized as a major reservoir and potential source of pathogenic strains to humans. A total of 172 Y. enterocolitica recovered from conventional and antimicrobial-free pig production systems from different geographic regions (North Carolina, Ohio, Michigan, Wisconsin, and Iowa) were investigated to determine their pathogenic significance to humans. Phenotypic and genotypic diversity of the isolates was assessed using antibiogram, serogrouping, and amplified fragment length polymorphism (AFLP). Carriage of chromosomal and plasmid-borne virulence genes were investigated using polymerase chain reaction. A total of 12 antimicrobial resistance patterns were identified. More than two-thirds (67.4%) of Y. enterocolitica were pan-susceptible, and 27.9% were resistant against ß-lactams. The most predominant serogroup was O:3 (43%), followed by O:5 (25.6%) and O:9 (4.1%). Twenty-two of 172 (12.8%) isolates were found to carry Yersinia adhesion A (yadA), a virulence gene encoded on the Yersinia virulence plasmid. Sixty-nine (40.1%) isolates were found to carry ail gene. The ystA and ystB genes were detected in 77% and 26.2% of the strains, respectively. AFLP genotyping of isolates showed wide genotypic diversity and were grouped into nine clades with an overall genotypic similarity of 66.8-99.3%. AFLP analysis revealed that isolates from the same production system showed clonal relatedness, while more than one genotype of Y. enterocolitica circulates within a farm.

Increased susceptibility to Yersinia enterocolitica Infection of Tff2 deficient mice.

TFF2 is one of the members of the trefoil factor family, known for its role in protection of gastrointestinal epithelia upon injury; however, recent studies suggest that TFF2 could also play an important role in the immune system. In the present study Tff2 deficient and wild type mice were infected by Y. enterocolitica which resulted in a lethal outcome in all Tff2 deficient mice, but not in WT animals. Yersinia invaded Peyer's patches more efficiently as shown by high bacterial titers in the KO mice while wild type mice displayed lower titers and a visible bacterial accumulation in the intestine. Bacterial accumulation in Peyer's patches of Tff2 deficient mice was accompanied by increased recruitment of macrophages. While an increased level of MAC-1 positive cells was observed in the spleens of both Tff2 deficient and WT mice at third day post infection, bacterial dissemination to liver, lung and kidneys was observed only in Tff2 knock-out mice. Analysis of the cellular composition of spleen did not reveal any substantial alteration to WT animals, suggesting possible disregulation of hemopoietic cells involved in immune response to Y. enterocolitica. These new data indicate that Tff2 plays an important role in immune response by protecting the organism from consequences of infection and that Tff2 knock-out mice react adversely to bacterial infections, in this case specifically to Y. enterocolitica.

Transfusion-transmitted Yersinia enterocolitica sepsis.

Bacterial sepsis has become the most frequent infectious complication of transfusion. Although Yersinia enterocolitica is a common enteropathogen usually causing relatively mild disease, it is nevertheless a prominent cause of life-threatening post-transfusion infection. To gain a better understanding of the clinical presentation and prognosis of this rare occurrence, we performed a systematic and detailed review of 55 published cases, which we present here after a description of the mechanisms underlying the contamination of red blood cell preparations by Y. enterocolitica. The symptoms are rapid-onset septic shock sometimes heralded by atypical symptoms, such as explosive diarrhea, with an overall fatality rate of 54.5%. Although the pathophysiology involves transfusion of preformed bacterial endotoxin, timely administration of effective antibiotics seems to improve the prognosis. Increased vigilance of the blood supply could help mitigate this transfusion hazard, although cost-effective strategies are difficult to define for this highly serious but infrequent event.

Yersinia enterocolitica palearctica serobiotype O:3/4--a successful group of emerging zoonotic pathogens.

BACKGROUND: High-pathogenic Y. enterocolitica ssp. enterocolitica caused several human outbreaks in Northern America. In contrast, low pathogenic Y. enterocolitica ssp. palearctica serobiotype O:3/4 is responsible for sporadic cases worldwide with asymptomatic pigs being the main source of infection. Genomes of three Y. enterocolitica ssp. palearctica serobiotype O:3/4 human isolates (including the completely sequenced Y11 German DSMZ type strain) were compared to the high-pathogenic Y. enterocolitica ssp. enterocolitica 8081 O:8/1B to address the peculiarities of the O:3/4 group. RESULTS: Most high-pathogenicity-associated determinants of Y. enterocolitica ssp. enterocolitica (like the High-Pathogenicity Island, yts1 type 2 and ysa type 3 secretion systems) are absent in Y. enterocolitica ssp. palearctica serobiotype O:3/4 genomes. On the other hand they possess alternative putative virulence and fitness factors, such as a different ysp type 3 secretion system, an RtxA-like and insecticidal toxins, and a N-acetyl-galactosamine (GalNAc) PTS system (aga-operon). Horizontal acquisition of two prophages and a tRNA-Asn-associated GIYep-01 genomic island might also influence the Y. enterocolitica ssp. palearctica serobiotype O:3/4 pathoadaptation. We demonstrated recombination activity of the PhiYep-3 prophage and the GIYep-01 island and the ability of the aga-operon to support the growth of the Y. enterocolitica ssp. enterocolitica O:8/1B on GalNAc. CONCLUSIONS: Y. enterocolitica ssp. palearctica serobiotype O:3/4 experienced a shift to an alternative patchwork of virulence and fitness determinants that might play a significant role in its host pathoadaptation and successful worldwide dissemination.

Reactive arthritis in a population exposed to an extensive waterborne gastroenteritis outbreak after sewage contamination in Pirkanmaa, Finland.

OBJECTIVES: To assess the occurrence, clinical picture, and triggering infections of reactive arthritis (ReA) associated with a large waterborne gastroenteritis outbreak. METHODS: After an extensive sewage contamination of the water supply system, an estimated 8453 of the 30 016 inhabitants of the town of Nokia fell ill. General practitioners and occupational physicians were advised to refer any patients with suspicion of new ReA to rheumatological examination including faecal culture, human leucocyte antigen (HLA)-B27 and antibody tests for Campylobacter, Salmonella, and Yersinia. RESULTS: Forty-five patients (33 females, 12 males) aged 16-77 years (median 53) were referred. ReA was diagnosed in 21, postinfectious arthralgia in 13, and other musculoskeletal conditions in 11 patients. HLA-B27 was positive in five out of 44 patients (11%). Of the 21 patients with ReA, possible triggering infections were observed in seven (33%), Campylobacter in four, Yersinia in three, and Salmonella in one, who also had Campylobacter infection. ReA was mild in all but one patient who presented with persistent Salmonella enterica serotype enteritidis infection. CONCLUSIONS: Taking into account the large population contaminated with potentially arthritogenic agents, the occurrence of ReA was rare and mild in character.

Factors related to the prevalence of pathogenic Yersinia enterocolitica on pig farms.

A survey of 788 pigs from 120 farms was conducted to determine the within-farm prevalence of pathogenic Yersinia enterocolitica and a questionnaire of management conditions was mailed to the farms afterwards. A univariate statistical analysis with carriage and shedding as outcomes was conducted with random-effects logistic regression with farm as a clustering factor. Variables with a P value <0·15 were included into the respective multivariate random-effects logistic regression model. The use of municipal water was discovered to be a protective factor against carriage and faecal shedding of the pathogen. Organic production and buying feed from a certain feed manufacturer were also protective against total carriage. Tonsillar carriage, a different feed manufacturer, fasting pigs before transport to the slaughterhouse, higher-level farm health classification, and snout contacts between pigs were risk factors for faecal shedding. We concluded that differences in management can explain different prevalences of Y. enterocolitica between farms.

Pathogenic potential and antibiotic resistance of Yersinia enterocolitica, a foodborne pathogen limited to swine tonsils in a pork production chain from Southern Brazil.

In this study, we aimed to characterize the distribution of Yersinia enterocolitica in a pork production chain in Brazil, as well as the virulence profile and antibiotic resistance of the obtained isolates. Samples from 10 pig lots obtained from finishing farms (water, feed, and barn floors, n = 30), slaughterhouse (lairage floors, carcasses at four processing steps, tonsils, and mesenteric lymph nodes, n = 610), and processing (end cuts, processing environment, n = 160) were obtained in Paraná state, Brazil, and subjected to Y. enterocolitica detection by ISO 10,273. The obtained isolates were identified based on biochemical and molecular features (16 s rRNA, inv, bioserotyping) and subjected to PCR assays to detect virulence (ail, ystA, ystB, virF, myfA, fepA, fepD, fes, tccC, ymoA, hreP, and sat) and multidrug resistance-related genes (emrD, yfhD, and marC). Also, isolates were subjected to disk diffusion test to characterize their resistance against 17 antibiotics from 11 classes and to pulsed field gel electrophoresis (PFGE) after XbaI macro-restriction. Y. enterocolitica was detected in a single sample (tonsil), and the obtained three isolates were characterized as serotype O:3, harboring ail, ystA, virF, myfA, tccC, ymoA, hreP, emrD, yfhD, and marC, and resistant to all tested antibiotics. The three isolates presented identical macro-restriction profiles by PFGE, also identical to isolates obtained from Minas Gerais, other Brazilian state; one selected isolate was identified as biotype 4. Despite the low occurrence of Y. enterocolitica in the studied pork production, the virulence potential and the antibiotic resistance profiles of the isolates demonstrated their pathogenic potential, and the macro-restriction profiles indicate strains descending from a common subtype in the pork production chain of two Brazilian States.

Familial outbreak of Yersinia enterocolitica serotype O9 biotype 2.

In Japan, infection with Yersinia enterocolitica of the pathogenic serobiogroup serotype O9 biotype 2 (O9/2) has rarely occurred, and familial outbreaks of Y. enterocolitica are also infrequently reported. We found a familial outbreak of Y. enterocolitica O9/2. Y. enterocolitica O9/2 was detected from stools collected from three persons in the same family. Two patients (an 11-month-old girl and her 68-year-old grandmother) contemporaneously suffered from enterocolitis, and the third person, a carrier (a 5-year-old girl), manifested no symptoms. This bacteria was not detected from other family members or from their pet hamster. All the bacteria obtained from the three people were genetically identified by pulsed-field gel electrophoresis (PFGE). The infection route was likely to have been via food, because Y. enterocolitica was not found from the pet hamster. This is the first report of a familial outbreak of Y. enterocolitica O9/2 genetically identified by PFGE in Japan.

Pathogenic Yersinia enterocolitica 2/O:9 and Yersinia pseudotuberculosis 1/O:1 strains isolated from human and non-human sources in the Plateau State of Nigeria.

Foodborne yersiniosis, caused by enteropathogenic Yersinia, especially Yersinia enterocolitica, is an important cause of diarrhea in developed countries, especially in temperate zones. Since studies concerning the presence of enteropathogenic Yersinia in humans and foods are rare in developing countries and tropical areas, human and non-human samples were studied in Plateau state of Nigeria to obtain information on the epidemiology of Y. enterocolitica and Yersinia pseudotuberculosis. Surprisingly, ail-positive Y. enterocolitica and inv-positive Y. pseudotuberculosis were isolated in Plateau state of Nigeria from several samples of human and non-human origin. Bioserotype 1/O:1 was the only Y. pseudotuberculosis type found. Y. enterocolitica belonging to bioserotype 2/O:9 was the dominating type found in most samples. Bioserotype 4/O:3 was isolated only from one pig and one sheep. Using PFGE, 5 genotypes were obtained among 45 Y. enterocolitica 2/O:9 strains with NotI, ApaI and XhoI enzymes and 3 among 20 Y. pseudotuberculosis 1/O:1 strains with NotI and SpeI enzymes. All human Y. pseudotuberculosis 1/O:1 strains were indistinguishable from pig, sheep or food strains. The dominating genotype of Y. enterocolitica 2/O:9 strains among humans was also found among strains isolated from pig, fermented cow milk and traditional intestine pepper soap samples.

Clonality and antibiotic susceptibility of Yersinia enterocolitica isolated from U.S. market weight hogs.

Pigs are the only known animal reservoir of Yersinia enterocolitica strains pathogenic to humans. In this study 106 ail-positive pathogenic Y. enterocolitica isolates, previously recovered from 2793 swine fecal samples (3.8%) collected during National Animal Health Monitoring System's Swine 2000 study, were examined. The presence of the previously described virulence plasmid, expression of plasmid-associated virulence determinants, and serotype were correlated with genotype, expression of YopE protein, and antibiotic susceptibility. Pulsed-field gel electrophoresis using the enzyme XbaI showed that O:3 and O:5 isolates were highly clonal within a serotype regardless of geographic origin. Antimicrobial resistance profiles of 106 isolates of serotypes O:3 and O:5 were evaluated by agar disk diffusion methodology to 16 different antibiotics. All isolates were susceptible to 13 of the 16 tested antimicrobials; resistance was noted to ampicillin, cephalothin, and tetracycline. The presence of the ail gene, virulence plasmid, the expression of virulence determinants, and serotypes indicate that these isolates from U.S. swine are potentially capable of causing human foodborne illness.

Tularemia, plague, yersiniosis, and Tyzzer's disease in wild rodents and lagomorphs in Canada: a review.

Information related to infection of wild rodents or lagomorphs in Canada by Francisella tularensis, Yersinia pestis, other Yersinia spp., and Clostridium piliforme was searched for this study. Reports on tularemia in humans linked to these species came from diagnostic databases, literature, wildlife health specialists, and public health agencies. Tularemia has been diagnosed in 8 species of wild rodent and 2 species in the genus Lepus in Canada. Tularemia occurred in wild animals, or in humans associated with these species, in all jurisdictions except the Yukon and Nunavut. Tularemia was diagnosed most frequently in beaver, muskrats, and snowshoe hares, and although tularemia is closely linked to cottontail rabbits in the USA, it has not been reported in cottontails in Canada. Tularemia in humans was associated with muskrats and hares more commonly than with beaver. Plague was diagnosed in bushy-tailed woodrats in British Columbia in 1988. Based on surveys, Y. pestis may occur enzootically in southern Alberta, Saskatchewan, and British Columbia. Infection with Yersinia pseudotuberculosis and Y. enterocolitica has been diagnosed in beaver, muskrats, and snowshoe hares in many provinces. Tyzzer's disease has been diagnosed in muskrats in British Columbia, Saskatchewan, Ontario, and Quebec and in snowshoe hares in Ontario. Infection with these bacteria is likely much more frequent than indicated by diagnostic records.

Prevalence of Yersinia enterocolitica in market weight hogs in the United States.

Pigs are the major animal reservoir for Yersinia enterocolitica strains, which are potentially pathogenic for humans. The goals of this study were (i) to estimate the individual animal and on-farm prevalences of Y. enterocolitica in hogs based on tonsil samples collected during National Animal Health Monitoring System Swine 2002 study and (ii) to use these data with data previously published for fecal samples to determine on-farm risk factors for Y. enterocolitica. Tonsil swabs (1,218) and fecal samples (2,847) were collected on 124 farms located in the top 17 pork-producing states. Ten percent of tonsils (122 of 1,218 samples) were positive in irgasan-tiracillin-chlorate (ITC) enrichment broth by real-time PCR, but only 5.6% of samples (68 of 1,218) were positive after subculture on the more selective cefsulodin-irgasan-novobiocin (CIN) agar. For tonsils, the on-farm prevalence based on real-time PCR detection of the ail gene in ITC enrichment broth cultures was 32% (32 of 100 premises sampled); the prevalence based on subculture in CIN agar was 19.6% (20 of 102 premises). Results of bacteriological isolation and real-time PCR analysis of tonsils and feces were combined to estimate prevalence (individual animal and farm), which was subsequently correlated with 40 farm management practices. Four factors and their accompanying odds ratios (ORs) were identified in the final regression model: location in a central state (OR = 0.3), vaccination for Escherichia coli (OR = 3.0), percentage of deaths due to scours (OR = 3.5), and presence of meat or bone meal in grower-finisher diet (OR = 4.1).

[Prevalence of human pathogenic Yersinia enterocolitica in pigs]. / Prevalentie humaanpathogene Yersinia enterocolitica bij varkens.

Pigs have been identified as the main reservoir of human pathogenic Yersinia enterocolitica. In this prevalence study, pathogenic Y. enterocolitica strains were isolated from 13 (9.3%) of 140 samples of porcine tonsils and from 5 (3.3%) of 150 samples of pig faeces. These prevalence percentages are lower than those reported in an earlier study. Good hygienic slaughter practices are essential to prevent the contamination of pork with pathogenic Y. enterocolitica and consequently to minimize the risk of human yersiniosis.

Campylobacteriosis, Salmonellosis, Yersiniosis, and Listeriosis as Zoonotic Foodborne Diseases: A Review.

Zoonoses are diseases transmitted from animals to humans, posing a great threat to the health and life of people all over the world. According to WHO estimations, 600 million cases of diseases caused by contaminated food were noted in 2010, including almost 350 million caused by pathogenic bacteria. Campylobacter, Salmonella, as well as Yersinia enterocolitica and Listeria monocytogenes may dwell in livestock (poultry, cattle, and swine) but are also found in wild animals, pets, fish, and rodents. Animals, often being asymptomatic carriers of pathogens, excrete them with faeces, thus delivering them to the environment. Therefore, pathogens may invade new individuals, as well as reside on vegetables and fruits. Pathogenic bacteria also penetrate food production areas and may remain there in the form of a biofilm covering the surfaces of machines and equipment. A common occurrence of microbes in food products, as well as their improper or careless processing, leads to common poisonings. Symptoms of foodborne infections may be mild, sometimes flu-like, but they also may be accompanied by severe complications, some even fatal. The aim of the paper is to summarize and provide information on campylobacteriosis, salmonellosis, yersiniosis, and listeriosis and the aetiological factors of those diseases, along with the general characteristics of pathogens, virulence factors, and reservoirs.

The yersiniae--a model genus to study the rapid evolution of bacterial pathogens.

Yersinia pestis, the causative agent of plague, seems to have evolved from a gastrointestinal pathogen, Yersinia pseudotuberculosis, in just 1,500-20,000 years--an 'eye blink' in evolutionary time. The third pathogenic Yersinia, Yersinia enterocolitica, also causes gastroenteritis but is distantly related to Y. pestis and Y. pseudotuberculosis. Why do the two closely related species cause remarkably different diseases, whereas the distantly related enteropathogens cause similar symptoms? The recent availability of whole-genome sequences and information on the biology of the pathogenic yersiniae have shed light on this paradox, and revealed ways in which new, highly virulent pathogens can evolve.