Browsing by Subject "Yersinia"

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  • Elina, Felin; Outi, Hälli; Mari, Heinonen; Jukola, Elias; Maria, Fredriksson-Ahomaa (2019)
    Current macroscopic meat inspection cannot detect the most common pork-borne pathogens (Salmonella spp., Yersinia enterocolitica and Toxoplasma gondii). Furthermore, food chain information (FCI) may not provide sufficient data for visual-only inspection, which is supposed to be the common way of inspection of pigs in the European Union. Our observational study aimed to evaluate the serological monitoring and the clinical evaluation of on-farm health status of pigs and assess the feasibility of these data as part of the FCI in meat inspection. We studied the serological status of Salmonella spp., Yersinia spp. and T. gondii in pigs during the fattening period. Additionally, we evaluated the association between on-farm health status and meat inspection findings. On 57 indoor fattening pig farms in Finland, we collected blood samples (mean of 20 pigs/farm) and assessed the on-farm health (coughing, tail biting, lameness) at the end of the fattening period. We visited 34 of these farms also at the beginning of the fattening for sampling and on-farm health evaluation of the same pigs. Meat inspection results were obtained after slaughter for all 57 farms. Salmonella seroprevalence was low at the end of the fattening period: it was 17.6%, 10.6% or 1.9%, with the cut-off values of OD15% (recommended by the test manufacturer), OD20% (used by Danish monitoring programme) and OD40% (used by German monitoring programme), respectively. The overall seroprevalence of Salmonella spp. and Yersinia spp. increased significantly (P 
  • Hammerl, Jens Andre; Barac, Andrea; Bienert, Anja; Demir, Aslihan; Drueke, Niklas; Jaeckel, Claudia; Matthies, Nina; Jun, Jin Woo; Skurnik, Mikael; Ulrich, Juliane; Hertwig, Stefan (2022)
    Yersinia pseudotuberculosis is an important animal pathogen, particularly for birds, rodents, and monkeys, which is also able to infect humans. Indeed, an increasing number of reports have been published on zoo animals that were killed by this species. One option to treat diseased animals is the application of strictly lytic (virulent) phages. However, thus far relatively few phages infecting Y. pseudotuberculosis have been isolated and characterized. To determine the prevalence of Y. pseudotuberculosis phages in zoo animals, fecal samples of birds and some primates, maras, and peccaries kept in the Tierpark Berlin were analyzed. Seventeen out of 74 samples taken in 2013 and 2017 contained virulent phages. The isolated phages were analyzed in detail and could be allocated to three groups. The first group is composed of 10 T4-like phages (PYps2T taxon group: Myoviridae; Tevenvirinae; Tequatrovirus), the second group (PYps23T taxon group: Chaseviridae; Carltongylesvirus; Escherichia virus ST32) consists of five phages encoding a podovirus-like RNA polymerase that is related to an uncommon genus of myoviruses (e.g., Escherichia coli phage phiEcoM-GJ1), while the third group is comprised of two podoviruses (PYps50T taxon group: Autographiviridae; Studiervirinae; Berlinvirus) which are closely related to T7. The host range of the isolated phages differed significantly. Between 5.5 and 86.7% of 128 Y. pseudotuberculosis strains belonging to 20 serotypes were lysed by each phage. All phages were additionally able to lyse Y. enterocolitica B4/O:3 strains, when incubated at 37 degrees C. Some phages also infected Y. pestis strains and even strains belonging to other genera of Enterobacteriaceae. A cocktail containing two of these phages would be able to lyse almost 93% of the tested Y. pseudotuberculosis strains. The study indicates that Y. pseudotuberculosis phages exhibiting a broad-host range can be isolated quite easily from zoo animals, particularly birds.
  • Felin, E.; Jukola, E.; Raulo, S.; Fredriksson-Ahomaa, M. (2015)
    The seroprevalence of Salmonella spp., pathogenic Yersinia spp., Toxoplasma gondii and Trichinella spp. was studied in 1353 finishing pigs from 259 farms that were allocated according to farm types: large fattening farms (1000 pig places), small fattening farms (<1000 pig places) and farrow-to-finish farms. The antibodies were analysed with commercial ELISA kits in meat juice samples that were collected at Finnish slaughterhouses. Salmonella antibodies were rare (3% of pigs, 14% of farms) when the cut-off optical density (OD) value 0.2 was used. Antibodies to pathogenic Yersinia spp. and T.gondii were detected in 57% of pigs and 85% of farms (OD 0.3) and in 3% of pigs and 9% of farms (OD 0.15), respectively. No antibodies to Trichinella spp. were detected (OD 0.3). The European Food Safety Authority (EFSA) considers Salmonella spp., Yersinia enterocolitica, T.gondii and Trichinella spp. as the most relevant biological hazards in the context of meat inspection of pigs. The seroprevalence of these important zoonotic pathogens was low in Finland, except that of Yersinia. The seroprevalence of Toxoplasma was significantly higher in pigs originating from small-scale fattening farms (P<0.05). Strong positive correlation was observed at the animal level between Salmonella and Yersinia seropositivity and between Salmonella and Toxoplasma seropositivity (P<0.05). We suggest that these results reflect the level and importance of biosecurity measures applied on the farms. Meat juice serology at slaughter is a useful tool for targeting measures to control these pathogens. The information obtained from analyses should be used as part of the food chain information (FCI).
  • Woivalin, Emma (Helsingin yliopisto, 2020)
    Työn tavoitteena oli selvittää metsästetyn sorsanlihan elintarvikehygieenistä laatua mikrobien kokonaispesäkeluvun ja Escherichia coli -bakteerimäärän avulla, sekä kartoittaa sorsissa esiintyvien elintarvikevälitteisten patogeenien esiintyvyyttä. Kirjallisuuskatsaus tutustuu sinisorsaan lintulajina sekä sorsan metsästykseen yleisellä tasolla. Kokeellisessa osassa tutkittiin metsästettyjen sorsien pintasivelynäytteitä. Ruhonäytteistä todettiin aerobisten bakteerien kokonaismäärän keskiarvo 3,5 log10 pmy/cm2 ja E. colin 1,2 log10 pmy/cm2. Tutkimuksessa eristettiin Listeria monocytogenes bakteeria 13 %:ssa näytteistä ja Yersinia enterocoliticabakteeria 3 %:ssa näytteistä. Näytteistä 9 % oli PCR:llä Campylobakteeri-positiivisia ja kaikki olivat Salmonella negatiivisia. Sorsanlihan hygieeninen laatu osoittautui hyväksi tai kohtalaiseksi. Näytteiden välillä esiintyi vaihtelua. Tutkimus osoittaa, että sorsanliha voi sisältää myös ruokamyrkytyksiä aiheuttavia bakteereja, mistä syystä ruhon käsittelyn ja lihan valmistuksen hyvät hygieniakäytännöt tulisi muistaa sekä ammatti- että kotikeittiöissä.
  • Seecharran, Tristan; Kalin-Manttari, Laura; Koskela, Katja; Nikkari, Simo; Dickins, Benjamin; Corander, Jukka; Skurnik, Mikael; McNally, Alan (2017)
    Yersinia pseudotuberculosis is a Gram-negative intestinal pathogen of humans and has been responsible for several nationwide gastrointestinal outbreaks. Large-scale population genomic studies have been performed on the other human pathogenic species of the genus Yersinia, Yersinia pestis and Yersinia enterocolitica allowing a high-resolution understanding of the ecology, evolution and dissemination of these pathogens. However, to date no purpose-designed large-scale global population genomic analysis of Y. pseudotuberculosis has been performed. Here we present analyses of the genomes of 134 strains of Y. pseudotuberculosis isolated from around the world, from multiple ecosystems since the 1960s. Our data display a phylogeographic split within the population, with an Asian ancestry and subsequent dispersal of successful clonal lineages into Europe and the rest of the world. These lineages can be differentiated by CRISPR cluster arrays, and we show that the lineages are limited with respect to inter-lineage genetic exchange. This restriction of genetic exchange maintains the discrete lineage structure in the population despite co-existence of lineages for thousands of years in multiple countries. Our data highlights how CRISPR can be informative of the evolutionary trajectory of bacterial lineages, and merits further study across bacteria.
  • Laaksonen, Sauli; Oksanen, Antti; Julmi, Jerome; Zweifel, Claudio; Fredriksson-Ahomaa, Maria; Stephan, Roger (2017)
    Background: Various food-producing animals were recognized in recent years as healthy carriers of bacterial pathogens causing human illness. In northern Fennoscandia, the husbandry of semi-domesticated reindeer (Rangifer tarandus tarandus) is a traditional livelihood and meat is the main product. This study determined the presence of selected foodborne pathogens, methicillin-resistant Staphylococcus aureus (MRSA), and extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in healthy semi-domesticated reindeer at slaughter in northern Finland and Norway. Results: All 470 reindeer fecal samples tested negative for Salmonella spp., whereas L. monocytogenes was detected in 3%, Yersinia spp. in 10%, and Shiga toxins genes (stx1 and/or stx2) in 33% of the samples. Listeria monocytogenes isolates belonged to the serotype 1/2a (14/15) and 4b, Yersinia spp. were identified mainly as Y. kristensenii (30/46) and Y. enterocolitica (8/46), and stx2 predominated among the Shiga toxin genes (stx2 alone or in combination with stx1 was found in 25% of the samples). With regard to the frequency and distribution of stx1/stx2, striking differences were evident among the 10 different areas of origin. Hence, reindeer could constitute a reservoir for Shiga toxin-producing E. coli (STEC), but strain isolation and characterization is required for verification purposes and to assess the potential human pathogenicity of strains. On the other hand, the favorable antibiotic resistance profiles (only 5% of 95 E. coli isolates were resistant to one or more of the tested antibiotics) and the absence of MRSA and ESBL-producing Enterobacteriaceae (when applying selective methods) suggest only a limited risk of transmission to humans. Conclusions: Healthy semi-domesticated reindeer in northern Finland and Norway can be carriers of certain bacterial foodborne pathogens. Strict compliance with good hygiene practices during any step of slaughter (in particular during dehiding and evisceration) is therefore of central importance to avoid carcass contamination and to prevent foodborne pathogens from entering the food chain.
  • Laaksonen, Sauli; Oksanen, Antti; Julmi, Jérôme; Zweifel, Claudio; Fredriksson-Ahomaa, Maria; Stephan, Roger (BioMed Central, 2017)
    Abstract Background Various food-producing animals were recognized in recent years as healthy carriers of bacterial pathogens causing human illness. In northern Fennoscandia, the husbandry of semi-domesticated reindeer (Rangifer tarandus tarandus) is a traditional livelihood and meat is the main product. This study determined the presence of selected foodborne pathogens, methicillin-resistant Staphylococcus aureus (MRSA), and extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae in healthy semi-domesticated reindeer at slaughter in northern Finland and Norway. Results All 470 reindeer fecal samples tested negative for Salmonella spp., whereas L. monocytogenes was detected in 3%, Yersinia spp. in 10%, and Shiga toxins genes (stx1 and/or stx2) in 33% of the samples. Listeria monocytogenes isolates belonged to the serotype 1/2a (14/15) and 4b, Yersinia spp. were identified mainly as Y. kristensenii (30/46) and Y. enterocolitica (8/46), and stx2 predominated among the Shiga toxin genes (stx2 alone or in combination with stx1 was found in 25% of the samples). With regard to the frequency and distribution of stx1/stx2, striking differences were evident among the 10 different areas of origin. Hence, reindeer could constitute a reservoir for Shiga toxin-producing E. coli (STEC), but strain isolation and characterization is required for verification purposes and to assess the potential human pathogenicity of strains. On the other hand, the favorable antibiotic resistance profiles (only 5% of 95 E. coli isolates were resistant to one or more of the tested antibiotics) and the absence of MRSA and ESBL-producing Enterobacteriaceae (when applying selective methods) suggest only a limited risk of transmission to humans. Conclusions Healthy semi-domesticated reindeer in northern Finland and Norway can be carriers of certain bacterial foodborne pathogens. Strict compliance with good hygiene practices during any step of slaughter (in particular during dehiding and evisceration) is therefore of central importance to avoid carcass contamination and to prevent foodborne pathogens from entering the food chain.
  • Heikkilä, Tiina (Helsingin yliopisto, 2019)
    Lisensiaatintutkielmani sisältää kirjallisuuskatsauksen kissojen raakaruokintaan liittyen ja alkuperäistutkimuksen. Tutkimuksessa pyrittiin selvittämään ihmisille tavallisimpien mahasuolitulehduksia aiheuttavien bakteerien esiintyvyyttä kissoille soveltuvassa raakaruoassa. Tämän lisäksi tutkittiin kahden raakaruokaa syövän kissan ulosteita tavoitteena selvittää erittyvätkö mahdollisesti ruoassa esiintyvät tautia aiheuttavat bakteerit kissojen ulosteeseen. Aihe valittiin, koska lemmikkien raakaruokintaa ei ole vielä kovin paljon Suomessa tutkittu, varsinkaan kissojen kohdalla. Lemmikkien raakaruoan mikrobiologista laatua on tutkittu ulkomailla, missä suurin huoli on tavallisesti ollut salmonella. Suomalaisessa raa’assa lihassa salmonellan esiintyminen on kuitenkin erittäin vähäistä. Suomessa tavallisimmat ihmisille tautia aiheuttavat elintarvikevälitteiset bakteerit ovat Campylobacter spp., Yersinia enterocolitica, Y. pseudotuberculosis, shiga-toksiinia tuottava Escherichia coli eli STEC ja salmonella. Hypoteeseja oli kolme erillistä. Ensimmäisen mukaan oletettiin, että lemmikkien raakaruoasta löytyisi jonkin verran tautia aiheuttavia bakteereita. Toisen perusteella odotettiin yleisimpien löytöjen olevan Y. enterocolitica ja kampylobakteerit. Kolmas hypoteesi oli, että sisäkissan ulosteesta ei juuri löytyisi tautia aiheuttavia bakteereita. Tutkimuksen aikana kerättiin vuoden aikana 48 raakaruokanäytettä ja 73 ulostenäytettä. Ulostenäytteitä kerättiin kahdelta eri kissalta, joista toiselta koko tutkimuksen ajan ja toiselta vain viimeisen puolen vuoden ajan. Näytteet sekoitettiin puskuroituun peptoniveteen ja viljeltiin selektiivisille agareille. Peptonivesiseokset inkuboitiin yön ylitse +37 °C:ssa. Inkuboiduista seoksista tehtiin säilytys 20 % glyserolin kanssa -70 °C ja PCR-ajoa varten DNA-eristys ZR Fecal DNA MiniPrepTM -menetelmää (Zymo Research, USA) käyttäen. Peptonivesiseokset säilöttiin tutkimuksen ajan 4 °C:ssa. PCR-positiiviset näytteet viljeltiin uudelleen selektiiviselle maljoille esirikastetuista seoksista. Tutkituista ruokanäytteistä 42 % sisälsi jotain tutkittua tautia aiheuttavaa bakteeria. Ulostenäytteistä 84 % sisälsi jotain tutkittua bakteeria PCR-tulosten perusteella. Ulostenäytteistä yhteensä 74% oli kampylobakteeripositiivisia, vaikka ruokanäytteet eivät olleet. Ruokanäytteistä saadut PCR-positiiviset näytteet eivät kasvaneet agarmaljoilla lainkaan. Ulostenäytteistä kaksi PCRpositiivista Y. enterocolitica löydöstä kasvoi myös agarmaljoilla. Nämä olivat biotyyppiä 4 ja kaupallisella vasta-aineella tehdyllä testillä serotyyppiä O:3. Kummankin kissanulosteesta eristettiin Campylobacter helveticus. Tulosten perusteella voidaan vetää johtopäätös, että raakaruokinnassa on riskejä lemmikkien ja ihmisten terveydelle. Riskit ovat suuret erityisesti ihmisille, joiden immuunijärjestelmän toiminta ei ole normaalia. Hypoteesit olivat osittain oikein, mutta esimerkiksi ulosteessa esiintyvien tautia aiheuttavien kampylobakteerien korkea esiintyvyys oli yllätys. Tutkimuksen toinen tavoite, mikä oli selvittää siirtyvätkö ruoan patogeenit kissojen ulosteeseen, ei välttämättä onnistunut näytteenottosuunnitelman takia. Näytteitä olisi pitänyt ottaa pidemmän aikaa raakaruoan syöttämisen jälkeen ja tutkia kissat etukäteen, etteivät ne eritä mitään bakteeria valmiiksi ulosteeseensa.
  • Joutsen, Suvi; Laukkanen-Ninios, Riikka; Henttonen, Heikki; Niemimaa, Jukka; Voutilainen, Liina; Kallio, Eva R.; Helle, Heikki; Korkeala, Hannu; Fredriksson-Ahomaa, Maria (2017)
    Yersinia enterocolitica and Yersinia pseudotuberculosis are important zoonotic bacteria causing human enteric yersiniosis commonly reported in Europe. All Y. pseudotuberculosis strains are considered pathogenic, while Y. enterocolitica include both pathogenic and nonpathogenic strains which can be divided into six biotypes (1A, 1B, and 2-5) and about 30 serotypes. The most common types causing yersiniosis in Europe are Y. enterocolitica bioserotypes 4/O:3 and 2/O:9. Strains belonging to biotype 1A are considered as nonpathogenic because they are missing important virulence genes like the attachment-invasion-locus (ail) gene in the chromosome and the virulence plasmid. The role of wild small mammals as a reservoir of enteropathogenic Yersinia spp. is still obscure. In this study, the presence of Yersinia spp. was examined from 1840 wild small mammals, including voles, mice, and shrews, trapped in Finland during a 7-year period. We isolated seven Yersinia species. Y. enterocolitica was the most common species, isolated from 8% of the animals; while most of these isolates represented nonpathogenic biotype 1A, human pathogenic bioserotype 2/O:9 was also isolated from a field vole. Y. pseudotuberculosis of bioserotype 1/O:2 was isolated from two shrews. The ail gene, which is typically only found in the isolates of biotypes 1B and 2-5 associated with yersiniosis, was frequently (23%) detected in the nonpathogenic isolates of biotype 1A and sporadically (6%) in Yersinia kristensenii isolates. Our results suggest that wild small mammals, especially voles, may serve as carriers for ail-positive Y. enterocolitica 1A and Y. kristensenii. We also demonstrate that voles and shrews sporadically excrete pYV-positive Y. enterocolitica 2/O:9 and Y. pseudotuberculosis 1/O:2, respectively, in their feces and, thus, can serve as a contamination source for vegetables by contaminating the soil.