Yersinia Research Articles

172 Multiplex Polymerase Chain Reaction Stool Testing Detects Pathogens Not Frequently Detected on Concurrent Stool Culture With Ova and Parasite Exam

INTRODUCTION: Rapid, highly sensitive and specific multiplex polymerase chain reaction-based stool assays for gastrointestinal pathogens (GI PCR) are increasingly being used alternatively to conventional stool culture. We investigated the concordance between simultaneous GI PCR and stool culture with an ova and parasite (O&P) exam in outpatients presenting with symptoms of infectious gastroenteritis. METHODS: We performed a cross-sectional study of outpatients who received a FilmArray GI PCR test for acute diarrhea at an academic medical center from September 2015 to February 2019 to identify patients who had a concomitant stool culture with an ova and parasite exam (conventional testing) at the same time, on the same stool sample. The primary outcome was detection of an infection on GI PCR or conventional stool testing. Correlation was evaluated using McNemar's test for pathogens detected on both tests. Other categorical variables were compared with Chi-square analysis. RESULTS: We identified 150 outpatients who received GI PCR and stool culture with an ova and parasite exam for an episode of acute gastroenteritis. 106 (71%) patients had a pathogen isolated on GI PCR for 144 total pathogens including 128 (88%) bacteria, 13 (9%) viruses, and 3 (2%) parasites; 21 (14%) patients had a pathogen isolated on conventional testing for 18 total pathogens including 9 (50%) bacteria and 9 (50%) parasites (Table 1). Multiple pathogens were found in 38 (26%) GI PCR tests. PCR testing most commonly identified Enteropathogenic Escherichia coli (EPEC), representing 42 (33%) positive PCR tests. Conventional testing most commonly identified Campylobacter jejuni with 13 (54%) positive tests. Of 28 total C. jejuni infections, 15 (54%) were positive only on PCR, 3 (10%) only on conventional testing, and 10 (36%) on both modalities, showing that conventional testing missed 54% of all infections (P = 0.008). Conventional testing missed 4/6 (67%, P = 0.125) Salmonella infections and 9/14 (64%, P = 0.0215) Yersinia infections, nor did it detect any viral or diarrheagenic E. coli infections. Overall, PCR detected 144 of 191 (75%) of possible pathogens whereas conventional testing detected 47 of 179 possible pathogens (26%). CONCLUSION: GI PCR testing identified multiple pathogens unidentified by conventional testing, such as enteric viruses and pathogenic strains of E. coli. Conventional testing missed 88% of enteric bacteria showing poor concordance between simultaneous GI PCR testing and stool culture with an ova and parasite exam.

Acute kidney injury associated with Yersinia pseudotuberculosis infection: Forgotten but not gone.

BackgroundYersinia pseudotuberculosis is known to cause fever, gastroenteritis, or acute kidney injury (AKI). There have been several Y. pseudotuberculosis infection outbreaks to date associated with ingestion of contaminated food or unsterile water. While this disease was considered to have practically been eradicated with the improvement in public health, we encountered several cases of AKI associated with Yersinia infection.MethodsWe retrospectively collected data from medical records of patients with suspected Y. pseudotuberculosis infection who visited Seoul National University Children’s Hospital in 2017.ResultsThere were nine suspected cases of Yersinia infection (six males and three females; age range 2.99–12.18 years). Among them, five cases occurred in May, and seven patients were residing in the metropolitan Seoul area. Three patients had history of drinking mountain water. Every patient first presented with fever for a median of 13 days, followed by gastrointestinal symptoms and oliguria. Imaging studies revealed mesenteric lymphadenitis, terminal ileum wall thickening, and increased renal parenchymal echogenicity. Creatinine levels increased to 5.72 ± 2.18 mg/dL. Urinalysis revealed sterile pyuria, proteinuria, and glycosuria. Oliguria continued for 4 to 17 days, and two patients required dialysis; however, all of them recovered from AKI. Mucocutaneous manifestations developed later. In the diagnostic work-up, Yersinia was isolated from the stool culture in one patient. Anti-Yersinia immunoglobulin (Ig) A and IgG were positive in 6 patients.ConclusionY. pseudotuberculosis infection is an infrequent cause of interstitial nephritis presenting with AKI. When a patient presents with fever, gastroenteritis, and AKI not resolving despite hydration, the clinician should suspect Y. pseudotuberculosis infection.

Actinomyces in Crohn's-like appendicitis.

Appendicitis with a Crohn's-like histological appearance generally raises concern for Crohn's disease, Yersinia infection, and interval appendectomy. Actinomyces infection is a recognised cause of chronic appendicitis that can histologically mimic Crohn's disease. We report on 20 cases of appendicitis with Crohn's-like histological features that were due to Actinomyces. Most patients presented with acute or chronic abdominal pain. Imaging studies suggested a mass in five cases. Two patients had interval appendectomy. Histological features showed Crohn's-like appendicitis in 16 cases, with moderate to marked fibrosis and granulomas in seven cases. The other four cases had less consistent histological findings. None of the patients developed Crohn's disease during the follow-up interval (median, 37months). Actinomyces can be associated with Crohn's-like appendicitis with marked fibrosis, transmural inflammation, lymphoid hyperplasia, and granulomas.

Biocontrol of anthracnose on yellow passion fruits by antagonic bacteria to plant pathogens

– In this study was evaluated the efficacy of the bacterial strains: BB-4 ( Bacillus cereus GC, subgroup B), BS-2 ( Photorhabdus luminescens ), BB- 1 ( Bacillus alcalophilus ), BS-5 ( B. cereus GC, subgroup B), BB-5 ( Stenotrophomonas maltophilia ), BB-6 ( Yersinia bercovieri ) and BS-6 ( P. luminescens ) on the control of anthracnose in yellow passion fruit, on antagonism tests and fruits tests under laboratory conditions. The plant pathogen was grown in Petri dishes containing BDA medium for 15 days and the bacterial strains were multiplied in AN medium for two days at 28°C. In passion fruits test, a wound was performed at a depth of 2 mm, followed by spraying with a suspension containing a bacterial antagonist strain (10 8 cfu. mL -1 ). On the wound, a BDA disc with 4 mm in diameter completely colonized by the pathogen and maintenance for 7 days (25oC, high RU% and 12 hours of photoperiod) until the evaluation of diameter of lesions. The experimental design adopted was the completely randomized (9 treatments and 4 replications). The data were submitted to variance analysis and Tukey test (5%). In antagonism test, only BS-5 ( B. cereus GC, Subgroup B) and BS-2 ( P. luminescens ) strains did not inhibit the mycelial growth of the pathogen. The other strains were efficient in inhibition, with levels ranging from 35% to 53%, highlighting the strains BB-4 ( B. cereus GC. Sub group B), BS-3 ( P. luminescens ) and BB-4 ( S. maltophilia ), with 52.5%, 52.5% and 53.3% of control, respectively. In the fruit test, BS-2 ( P. luminescens ), BS-5 ( B. cereus GC, Subgroup B), BB-1 ( B. alcalophilus ), BS-3 ( P. luminescens ) and BB-6 ( Y. bercovieri ) inhibited the development of the pathogen, with control levels varying between 23.4% and 43.6%, with emphasis on BB-1 ( B. alcalophilus ) and BS-3 ( P. luminescens ), with 43.6% of control, indicating potential of use on the biocontrol of anthracnose on passion fruits.

Analysis of interferon-gamma producing cells during infections by Yersinia enterocolitica O:9 and Brucella abortus in cattle.

One of the major constraints in the diagnosis of animal brucellosis is the cross-reactivity that occurs between Brucella and Yersinia surface antigens. With the aim to find a method to distinguish Brucella from Yersinia infection, the expansion of interferon gamma producing (IFN-γ+) T cell subsets obtained from peripheral blood mononuclear cells (PBMC) isolated from cattle either infected by Brucella abortus or experimentally immunized with Yersinia enterocolitica O:9 were compared. The lymphocytes were analyzed by flow cytometry after PBMC were in vitro re-exposed to Yersinia or Brucella antigens. The results highlighted a statistically significant difference in the expansion of the CD4+ and CD8+ IFN-γ+ T cells occurring when PBMC of animals immunized with Yersinia are in vitro exposed to Y. enterocolitica O:9 antigen but not to Brucella antigen. This method could thus be suggested in those cases where results obtained by serodiagnosis need to be further clarified.

Non-canonical activation of Caspase 8 mediates pyroptosis

Abstract Cell death and inflammation are intimately linked during homeostasis, host defense, and tumorigenesis. Pathogenic Yersinia inhibits the MAP kinase TGFβ-activated kinase 1 (TAK1) via the effector YopJ, thereby silencing cytokine expression while activating caspase-8–mediated cell death. Here, using Yersinia pseudotuberculosis in corroboration with costimulation of lipopolysaccharide and (5Z)-7-Oxozeaenol, a small-molecule inhibitor of TAK1, we show that caspase-8 activation during TAK1 inhibition results in cleavage of both gasdermin D (GSDMD) and gasdermin E (GSDME) in murine macrophages, resulting in pyroptosis. The ensuing cell death is rapid and morphologically is similar to pyroptosis. Loss of GsdmD delays membrane rupture, reverting the cell-death morphology to apoptosis. The IL1 response arises from asynchrony of macrophage death during bulk infections in which two cellular populations provide signal 1 for transcriptional upregulation and signal 2 for the inflammasome assembly. Furthermore, we found that human macrophages are resistant to YopJ-mediated pyroptosis, with dampened IL-1β production. Our results uncover a form of caspase-8–mediated pyroptosis and suggest a hypothesis for the increased sensitivity of humans to Yersinia infection compared with the rodent reservoir. Altogether, this knowledge will be fundamental for our understanding of the mechanism of regulation of cell death and the discovery of new drug targets that can span areas from infections to tissue injury both in and ex vivo. This work was supported by the NIH grant AI056234 and Russian Science Foundation Grant 15-15-00100 (to A.P.)

Serine 25 phosphorylation inhibits RIPK1 kinase-dependent cell death in models of infection and inflammation

RIPK1 regulates cell death and inflammation through kinase-dependent and -independent mechanisms. As a scaffold, RIPK1 inhibits caspase-8-dependent apoptosis and RIPK3/MLKL-dependent necroptosis. As a kinase, RIPK1 paradoxically induces these cell death modalities. The molecular switch between RIPK1 pro-survival and pro-death functions remains poorly understood. We identify phosphorylation of RIPK1 on Ser25 by IKKs as a key mechanism directly inhibiting RIPK1 kinase activity and preventing TNF-mediated RIPK1-dependent cell death. Mimicking Ser25 phosphorylation (S > D mutation) protects cells and mice from the cytotoxic effect of TNF in conditions of IKK inhibition. In line with their roles in IKK activation, TNF-induced Ser25 phosphorylation of RIPK1 is defective in TAK1- or SHARPIN-deficient cells and restoring phosphorylation protects these cells from TNF-induced death. Importantly, mimicking Ser25 phosphorylation compromises the in vivo cell death-dependent immune control of Yersinia infection, a physiological model of TAK1/IKK inhibition, and rescues the cell death-induced multi-organ inflammatory phenotype of the SHARPIN-deficient mice.

A Combined YopB and LcrV Subunit Vaccine Elicits Protective Immunity against Yersinia Infection in Adult and Infant Mice.

Yersinia enterocolitica causes a severe enteric infection in infants and young children. There is no vaccine approved for use in humans. We investigated the immunogenicity and protective capacity of Yersinia YopB, a conserved type III secretion system protein, alone or combined with LcrV in adult mice immunized intranasally. YopB or LcrV (5 μg) administered with the Escherichia coli double mutant heat-labile toxin (dmLT) adjuvant afforded modest (10-30%) protection against lethal Y. enterocolitica oral infection. The combination of YopB and LcrV (5 μg each) dramatically improved vaccine efficacy (70-80%). Additionally, it afforded complete protection against Y. pestis pulmonary infection. Immunization with YopB/LcrV+dmLT resulted in Ag-specific serum IgG, systemic and mucosal Ab-secreting cells, as well as IFN-γ, TNF-α, IL-2, IL-6, IL-17A, and KC production by spleen cells. Serum Abs elicited by YopB/LcrV+dmLT had enhanced bactericidal and opsonophagocytic killing activity. After Y. enterocolitica challenge, YopB/LcrV+dmLT-vaccinated mice exhibited intact intestinal tissue, active germinal centers in mesenteric lymph nodes, IgG+ and IgA+ plasmablasts in the lamina propria, and Abs in intestinal fluid. On the contrary, complete tissue destruction and abscesses were seen in placebo recipients that succumbed to infection. Mice immunized as infants with YopB+dmLT or LcrV+dmLT achieved 60% protection against lethal Y. enterocolitica infection, and vaccine efficacy increased to 90-100% when they received YopB/LcrV+dmLT. YopB+dmLT also afforded substantial (60%) protection when administered intradermally to infant mice. YopB/LcrV+dmLT is a promising subunit vaccine candidate with the potential to elicit broad protection against Yersinia spp.

The epidemiology of non-viral gastroenteritis in New Zealand children from 1997 to 2015: an observational study

BackgroundAcute gastroenteritis is a substantial cause of hospitalization in children. Shigella, Salmonella, Campylobacter, Yersinia, enterotoxigenic Escherichia coli (ETEC), Giardia and Cryptosporidium are gastrointestinal pathogens that are notifiable in New Zealand (NZ). The impact of these infections in the pediatric population has not yet been analyzed. The aim of this study was to describe the epidemiological trends in disease notifications and hospital admissions due to non-viral gastroenteritis in NZ children.MethodsIn this population-based descriptive study, age-specific and age-standardized notification and hospital admission rates were analyzed from 1997-to-2015 for Shigella, Salmonella, Campylobacter, Yersinia, ETEC, Giardia and Cryptosporidium infections in children < 15 years of age. Variations in disease by gender, age, ethnicity and geography were described.ResultsFrom 1997-to-2015 there were 74,454 notifications (57.6% male) and 3192 hospitalizations (56.4% male) due to non-viral gastroenteritis in NZ children aged < 15 years. There was an overall trend towards a reduction in disease notifications and hospitalizations, however each disease showed a unique pattern of change over time. Campylobacter was the pathogen most frequently notified, accounting for 51.7% of notifications and 43.4% of hospitalizations. The hospitalization-to-notification ratios were, from highest to lowest, Salmonella typhi (1:1.09), Shigella (1:4.0), ETEC (1:7.81), nontyphoidal Salmonella (1:13.1), Campylobacter (1:27.8), Yersinia (1:29.2), Cryptosporidium (1,33.4), and Giardia (1,72.5). Compared to females, male notification rates were approximately 40% higher for Campylobacter, 25% higher for Giardia and Yersinia, and 15% higher for Cryptosporidium and nontyphoidal Salmonella (p < 0.001). Notification rates were highest in children 1–4 years, with the exceptions of nontyphoidal Salmonella, Salmonella typhi and Yersinia. Notification rates for nontyphoidal Salmonella and Yersinia were highest in children < 1 year, and for Salmonella typhi those aged 5–9 years. Children < 1 year were most likely to be hospitalized.ConclusionsThe incidence of non-viral gastroenteritis in NZ children reduced during the 19-year period considered. The burden of disease was highest in the community, with only a small percentage of cases requiring hospitalization. This study provides important insight into the non-viral causes of gastroenteritis in NZ children and how environmental influences and changes in food safety practices may have helped to reduce the burden of these diseases in children.

Kinetics of serum antibodies in response to infection with Yersinia enterocolitica.

Information on the kinetics of the serum antibody response to infection with Yersinia enterocolitica is essential to allow the estimation and comparison of seroconversion rates in a diversity of pools of cross-sectional serum antibody measurements. Data from 94 patients with acute enteritis caused by Yersinia infection were used. The follow-up period for the longitudinal study was 36 months, addressed by questionnaire. An indirect enzyme-linked immunosorbent assay method was adapted to determine the concentration of antibodies against Y. enterocolitica in human sera. A mathematical within-host model was used to describe the interaction between pathogen and immune system and the waning of immunity after clearing of the pathogen. All observed antibodies (IgG, IgM, IgA) reached peak levels shortly after infection and then decayed slowly indicating that the median levels decreased only little during the observation period. Estimated maximum peak antibody levels were highest in IgG. Seroresponse curves of all antibodies showed large individual variation between patients. There was no apparent pattern of variation with age, nor any notable difference between genders. Estimated half-times were very long for all antibodies, and their posterior distributions were highly skewed. IgA appeared to have the most persistent antibody response, compared with IgG and IgM. Median peak levels of all three antibodies were similar. There was no significance found between peak antibody levels and severity of symptoms of gastrointestinal infection and severity of joint pain. Our findings allow the use of cross-sectional serum antibody measurements as biomarkers, to estimate seroconversion rates. Such seroincidence estimates include asymptomatic seroconversions, thereby avoiding under-reporting, and allows the comparison of infection pressures among countries, independent of their healthcare and surveillance systems.

Monitoring gasdermin pore formation in vitro.

The gasdermin (GSDM) family consists of gasdermin A (GSDMA), B (GSDMB), C (GSDMC), D (GSDMD), E or DNFA5 (GSDME), and DFNB59 in human. Expressed in the skin, gastrointestinal tract, and various immune cells, GSDMs mediate homeostasis and inflammation upon activation by caspases and unknown proteases. In particular, GSDMD is activated by inflammasome-activated caspases-1/-4/-5/-11 as well as a caspase-8-mediated pathway during Yersinia infection. These caspases cleave GSDMD to release its functional N-terminal fragment (GSDMD-NT) from its auto-inhibitory C-terminal fragment (GSDMD-CT). GSDMD-NTs bind to acid lipids in mammalian cell membranes and bacterial membranes, oligomerize, and insert into the membranes to form large transmembrane pores. Consequently, cellular contents including inflammatory cytokines are released and cells can undergo pyroptosis, a highly inflammatory form of cell death. In this chapter, we summarize recent research findings and present experimental procedures to obtain pure recombinant GSDMs for biochemical studies. We highlight a liposome-based assay that yields robust fluorescence signals for characterizing GSDM activities in vitro and may be applicable to other pore-forming proteins and ion channels in general.

Analysis of Inflammasome Activation in Response to Yersinia Infection by Fluorescence Microscopy Detection of Active Caspase-1 Puncta.

The type of cell death triggered by a particular environmental stimulus influences the outcome of infection or inflammatory disease processes. The ability to identify the cell death pathway that is activated in response to infection is essential for understanding the pathogenesis and host response to infection. Activation of the cysteine protease caspase-1 in various inflammasome complexes indicates that cells are undergoing pyroptosis, a regulated, proinflammatory cell death. Inflammasome assembly and caspase activation can be measured by various methods ranging from detection of inflammasome-dependent cell death, cytokine secretion, cleavage of caspase-1, or the formation of "puncta" within the cell that contain inflammasome components, such as caspase-1 or the adapter protein ASC. Here we describe a method for detecting caspase-1 activation on a single cell level in the context of infection by the Gram-negative pathogen Yersinia using immunofluorescence microscopy. We previously used this approach to quantify caspase-1 puncta formation in cells containing Yersinia translocon components (Zwack et al., MBio 6:e02095-14, 2015). This is a modification of methods used previously by Broz et al. (Cell Host Microbe 8:471-483, 2010) and Case and Roy (MBio 2:e00117-11, 2011). By taking a microscopy-based approach that allows us to quantify puncta as well as other cell-biological features of infection (i.e., number of bacteria associated with a particular cell; levels of bacterial effector or translocon proteins in caspase-1 puncta-containing cells; or levels or localization of host cellular proteins), we can better quantify the heterogeneity between cells undergoing pyroptosis and cells that are not under the same infection conditions. These approaches have the potential to generate hypotheses that can enable further mechanistic insight into activation of pyroptosis in response to bacterial infection.

Detection of Cells Translocated with Yersinia Yops in Infected Tissues Using β-Lactamase Fusions.

Development of the TEM-CCF2/4-AM FRET-based system has enabled investigators to track translocation of effector proteins into mammalian cells during infection. This allows for separation of translocated and non-translocated cell populations for further study. Yersinia strains expressing translational Yop-TEM fusions, containing the secretion and translocation signals of a Yop with the TEM-1 portion of β-lactamase, are used to infect mice, tissues isolated from mice, or mammalian cells in culture. Infected and harvested mammalian cells are treated with either CCF2-AM or CCF4-AM, and cleavage of this fluorescent compound by TEM is detected by fluorescence-activated cell sorting(FACS) analysis. A shift from green to blue emission spectra of individual cells is indicative of translocation of a given Yop-TEM fusion protein into the host cell during Yersinia infection due to a disruption in FRET between the two fluors of the compound. In Yersinia, this method has been used to understand Type III secretion dynamics and Yop functions in cells translocated by effectors during infection. Here, we describe how to generate Yop-TEM constructs, and how to detect, quantify, isolate, and study Yop-TEM containing cells in murine tissues during infection and in ex vivo tissues by cell sorting and flow cytometry analysis. In addition, we provide guidance for analyzing TEM-positive cells via a plate reader and fluorescent microscopy.

Mouse Models of Yersiniosis.

Yersiniosis is common foodborne gastrointestinal disease caused by the enteric pathogens Yersinia enterocolitica and Yersinia pseudotuberculosis. The mouse model of oral infection serves as a useful tool to study enteropathogenic Yersinia infection in mammals. The following protocol describes two distinct oral infection methods: the commonly used oral gavage method in which the bacterial inoculum is instilled directly into the mouse stomach using a feeding needle, and an alternative method in which mice are fed bread soaked with Yersinia culture.

Yersinia infections and Graves’ disease

Background. The most common thyroid disease, accompanied by thyrotoxicosis syndrome, is Graves&amp;apos; disease (GD). Information about the role of Yersinia in the development of this disease is contradictory.&#x0D; Aims. To study the significance of Yersinia (Y.) enterocolitica and Y. pseudotuberculosis in the development of Graves&amp;apos; disease.&#x0D; Materials and methods. 78 patients with GD. Identification of antibodies to Y. was carried out by the following methods: 1. agglutination test (AT) with suspensions of live virulent cultures Y. pseudotuberculosis, Y. enterocolitica O:3 and O:9; 2. indirect hemagglutination test (IHET) with the use of erythrocyte diagnosticum; 3. determination of IgA and IgG antibodies against pathogenicity factors of Y. enterocolitica strains by immunoblotting (30 patients with GD).&#x0D; Results. Diagnostically significant titers of antibodies to Y. pseudotuberculosis and Y. enterocolitica were obtained in all patients with GD by AT. The greatest total thyroid volume determined by ultrasound investigation (p = 0.010) and the maximum duration of the disease (p = 0.040) were determined in the group of patients with the maximum antibody titer. No significant relation was found between the titer of antibodies to Yersinia and the levels of thyroid hormones stimulating the thyroid antibodies.The test for detection of IgA antibodies by immunoblotting was negative in 30 patients with GD (9 patients with a titer of antibodies by AT 1:800 – 1:1600, 17 – 1:400, 4 – 1:200). In all cases with the maximum antibody titer in AT, the positive IgG antibodies to the antigens YopM (Yop2a), YopH (Yop2b), V-antigen, YopD were found. The GD duration in patients with negative titers of antibodies by the immunoblotting test was less than with the positive one (p = 0.010). The privative clinical and anamnestic data and negative results by IHET confirmed the absence of active and/or transferred Yersinia infections in all the examined patients with GD.&#x0D; Conclusions. The cross-reacting antibodies to the antigens of Y. enterocolitica are determined in the serum of GD patients by AT and immunoblotting. The diagnostic titer of these antibodies is more often detected in patients with greater GD duration and larger volume of the thyroid gland. The absence of a link between the titer of these antibodies and the levels of thyroid hormones, the antibodies to the thyrotropin receptors of pituitary, as well as negative results by IHET with a diagnosticum that does not contain outer membrane proteins of pathogenic Yersinia, deny the trigger role of Yersinia infections as an initiating factor in the development of GD.

Investigating biochemical phenotypes of Yersinia pestis in soil matrices using novel 3D printed culturing apparatus

Investigating biochemical phenotypes of Yersinia pestis in soil matrices using novel 3D printed culturing apparatus

Saúde Animal, Biossegurança e Segurança dos alimentos

Pork meat and processed pork meat products may carry some hazards that threaten the consumer’s health. These hazards are related with animal health or with the way in which the raw materials are manipulated during slaughtering and manufacturing until the consumption. Substances having anabolic effects, the residues of veterinary drugs and chemical contaminants, some of them with origin in animal production but others produced during the transformation processes should be considered among chemical hazards. Concerning biological hazards, we can mention some parasites like Toxoplasma gondii, Trichinella spiralis, Taenia solium and also some bacteria like Salmonella spp., Campylobacter spp., Yersinia enterocolitica and Listeria monocytogenes. The physicochemical characteristics of fresh meat further facilitate the growth of various microorganisms, other than those mentioned above, which turns it into a highly perishable product. Several transformation processes of the raw material, provide different food products to consumers and constitute ways to increase its shelf-life. Drying, fermentation and cure are among these processing methods. In Portugal there is a wide variety of processed meat products, such as Chourico, Paio, Presunto, Salsichao and Catalao many of them manufactured according to traditional techniques of their regions of origin. Some of these products have been studied at the Universidade de Evora. Some results, which show the favourable effect of a range of transformation processes in controlling some of the mentioned biological hazards, will be presented.

Identification and characterization of Yersinia enterocolitica strains isolated from pig tonsils at slaughterhouse in Central Italy.

Yersinia enterocolitica causes foodborne disease in humans and infections are usually acquired from contaminated raw or undercooked pork. Pigs are considered the primary reservoir of human pathogenic bio-serotypes. A total of 376 tonsil tissue samples collected after evisceration and cutting from pig carcasses were tested for Yersinia enterocolitica. Animals came from an abattoir located in the Abruzzo region, Italy. Yersinia enterocolitica was isolated from 35 out of 376 (9.31%) samples. A total of 47 strains were isolated, the prevalent bio-serotype was 4÷O:3 (95.74%), followed by bio-serotype 4÷O:9 (2.13%), and 3÷O:9 (2.13%). When characterized by DNA microarray, all strains clustered into 2 main groups. The bigger group was characterised by the presence of plasmid genes of the secretion apparatus as well as by the genes for the agellum transport machinery, while the smaller group was characterised only by genes for the agellum transport machinery. The high frequency of the pathogenic biotype 4÷O:3 able to infect humans and considered an emerging zoonotic pathogen con rms the role of pigs as natural reservoir. Since there is no official data on Yersinia enterocolitica, it is difficult to assess the implications of this food pathogen for public health. A monitoring program should be implemented for contamination in food in order to assess the risk for the consumer linked to raw or undercooked pork products.

Yersinia enterocolitica Bloodstream Infection

An elderly male presented with abdominal pain and constipation. He was diagnosed with Yersinia enterocolitica bloodstream infection associated with an abdominal aortic aneurysm and synthetic endovascular graft. This demonstrates a rare but known complication of Y. enterocolitica bloodstream infection. J Med Cases. 2017;8(11):359-360 doi: https://doi.org/10.14740/jmc2931w

PSEUDOTUBERCULOSIS: PATHOGENETIC VALUE OF INNATE IMMUNITY CELLS

Novel data on mechanisms of innate immunity during infections with pathogenic Yersiniae are summarized in the review, that was mostly determined by complex developments regarding a unique pair of genetically related causative agents Y. pseudotuberculosis/Y. pestis. Our previous studies have revealed a morphological substrate of relative granulocyte immune deficiency that determines characteristic pathomorphologic features of pseudotuberculosis. To date, evidence has been obtained, that pathogenic for human Yersinia predominately activate protective function of innate immunity cells that is an important strategy to avoid elimination and cause the disease for the bacteria. Neutrophils (PMNs) play a fundamental role in response to infection by pathogenic Yersiniae in primary immune response and limit of primary spread of bacteria that use several mechanisms of eradication ofbacteria, e.g.: phagocytosis, oxidative stress, secretory degranulation, formation of neutrophil extracellular traps, efferocytosis. Infected PMNs can act as an intermediate host for consequent non-inflammatory infection of macrophages. Further elaboration of questions relating to primary anti-infection protection during Yersinia infections gives a key to understanding of immune pathogenesis of epidemic pseudotuberculosis (far Eastern scarlet-like fever) and yersiniosis in general.