Diagnostics and epidemiology of Yersinia pseudotuberculosis

Yersinia pseudotuberculosis is an animal pathogen widespread in nature. The bacterium has caused infections in humans occasionally. Most of the reported Y. pseudotuberculosis -infections are sporadic, and the sources and vehicles of Y. pseudotuberculosis remain obscure. Y. pseudotuberculosis has emerged as an outbreak -associated pathogen in Finland since 1997. Indirect evidence has indicated that Y. pseudotuberculosis is a potential food borne pathogen, but no specific food has been previously confirmed as a source of the human infections. The aim of this thesis was to determine the prevalence of Y. pseudotuberculosis in different animal species and to evaluate them as a possible source of Y. pseudotuberculosis. Clinically healthy pigs were found to carry Y. pseudotuberculosis. The prevalence of Y. pseudotuberculosis was 4 % and 14 % in fattening pigs at slaughterhouse and at farm level, respectively. All Y. pseudotuberculosis isolates from pigs were pathogenic. Migratory birds representing 57 different bird species were studied for pathogenic Y. pseudotuberculosis during spring and autumn migration. Pathogenic Y. pseudotuberculosis was recovered from two species of birds during spring migration. Y. pseudotuberculosis was first time confirmed to be the cause of a food borne outbreak through domestically produced iceberg lettuce in epidemiological study. Contamination of iceberg lettuce was investigated on farm level in a two-year survey. Several factors predisposing to Y. pseudotuberculosis contamination of lettuce were found on the farms, including a large population of deers and free access of wild animals to unfenced lettuce fields and to irrigation water sources. Pulsed-field gel electrophoresis (PFGE) analysis was optimized for efficient molecular typing method for Y. pseudotuberculosis isolates. PFGE was used to compare Y. pseudotuberculosis isolates from different origin. Y. pseudotuberculosis isolates of different sources showed high genetic diversity, while Y. pseudotuberculosis isolates found in same animal species representing the same serotype showed limited genetic diversity. Identification of environmental Y. pseudotuberculosis isolates was found to be incorrect based solely on biochemical tests. Commercial test kits misidentified some environmental Yersinia spp. isolates as Y. pseudotuberculosis. However, no specific virulence genes of Y. pseudotuberculosis were found in these isolates by polymerase chain reaction (PCR) targeting these gene areas.Yersinia pseudotuberculosis on ympäristössä yleisesti tavattava bakteeri, jota on pidetty lähinnä eläimille tautia aiheuttavana patogeenina. Ihmisillä bakteerin aiheuttamia yksittäisiä infektioita on raportoitu satunnaisesti, mutta tartunnanlähdettä ja välittäjää ei ole tarkemmin pystytty selvittämään. Vuodesta 1997 lähtien Y. pseudotuberculosis on noussut merkittäväksi humaaniepidemioiden aiheuttajaksi Suomessa. Y. pseudotuberculosista on epäilty mahdolliseksi ruokamyrkytysbakteeriksi, mutta mitään tiettyä elintarviketta ei ole aikaisemmin voitu osoittaa tartunnanlähteeksi. Väitöskirjatyössä selvitettiin Y. pseudotuberculosiksen esiintymistä eri eläinlajeilla ja arvioitiin näiden merkitystä Y. pseudotuberculosiksen lähteinä. Kliinisesti terveiden sikojen todettiin olevan Y. pseudotuberculosiksen kantajia. Teurastamoilla 4 % ja tiloilla jopa 14 % tutkituista lihasioista oli Y. pseudotuberculosis -positiivisia Kaikki sioista eristetyt Y. pseudotuberculosis -kannat olivat patogeenisia, tautia aiheuttavia. Tutkittaessa Y. pseudotuberculosiksen yleisyyttä muuttolinnuissa kevät- ja syysmuuton aikana, voitiin 57 tutkitusta lintulajista todeta patogeenista Y. pseudotuberculosista kahdesta eri lintulajista kevätmuuton yhteydessä. Tutkimuksessa voitiin myös ensimmäistä kertaa varmistaa Y. pseudotuberculosis -epidemian aiheuttajaksi elintarvikelähde. Kotimainen jäävuorisalaatti osoitettiin tartunnan aiheuttajaksi epidemiologisen tutkimuksen avulla. Jäävuorisalaatin saastumista kasvatustilalla kartoitettiin kaksivuotisella tutkimuksella. Tiloilla havaittiin useita mahdollisia kontaminaatiolähteitä, joista tärkeimpänä pidettiin alueen suurta peurapopulaatiota ja luonnoneläinten vapaata pääsyä suoraan aitaamattomille pelloille sekä kasteluveden ottoon tarkoitetuille vesilähteille. Tutkimuksessa eristettyjen Y. pseudotuberculosis -kantojen tyypittämiseen kehitettiin soveltuvaa molekyylibiologista tyypitysmenetelmää, pulssikenttäelektroforeesia (PFGE). Eri lähteistä eristettyjä Y. pseudotuberculosis -kantoja verrattiin PFGE-menetelmällä. Samasta eläinlajista eristetyt ja samaa serotyyppiä edustavat Y. pseudotuberculosis kannat olivat perimältään hyvin yhdenmukaisia. Tutkimuksessa ympäristönäytteistä eristettyjen Y. pseudotuberculosis -kantojen biokemiallisiin testeihin perustuva tunnistaminen osoittautui riittämättömäksi. Kaupalliset testisarjat tunnistivat osan ympäristönäytteistä eristetyistä Yersinia-suvun bakteereista tutkimuksessa virheellisesti Y. pseudotuberculosikseksi. Y. pseudotuberculosiksen virulenssigeenien osoittamiseen perustuvassa PCR-tutkimuksessa kannoilla ei kuitenkaan voitu todeta Y. pseudotuberculosikselle ominaisia geenialueita

Pathogenicity of sucrose-negative Yersinia strains found in pig tonsils

The aim of this work was to study the pathogenicity of sucrose-negative Yersinia strains isolated from pig tonsils with phenotypic and genotypic methods. All Yersinia pseudotuberculosis and 5 out of 8 of the sucrose-negative Y. enterocolitica strains were pathogenic. Three sucrose-negative Yersinia enterocolitica strains carried the ail gene and were pyrazinamidase negative showing that they were potentially pathogenic and may have lost the virulence plasmid during isolation and storage. Pyrazinamidase test was not reliable to predict the pathogenicity of Y. pseudotuberculosis strains. Using the PCR assays targeting the inv, ail and yadA genes sucrose-negative Yersinia strains could be differentiated from each other

Low prevalence of Yersinia enterocolitica 4:03 in sow tonsils

Yersinia enterocolitica 4:03 is the most common bioserotype causing disease in humans in Finland. Prevalence of Yersinia enterocolitica 4:03 in tonsils of fattening pigs has shown to be high in Finland in earlier studies. However, the prevalence in sow tonsils has not been studied. The aim of this study was to compare the prevalence of Y. enterocolitica 4:03 between tonsils of fattening pig and sows

Anvisning om åtgärder vid botulism

Anvisningen innehåller en beskrivning av epidemiologiska åtgärder med vilka man snabbt kan identifiera personer som insjuknat i botulism och förebygga en eventuell epidemi. Syftet är att förenhetliga hälso- och sjukvårdens rutiner för hantering av misstänkta fall av botulism. Anvisningen riktar sig till bl.a. läkare och sjukskötare som ansvarar för smittskyddsfrågor vid hälsovårdscentralerna, enheter med ansvar för den regionala smittskyddsverksamheten och livsmedelstillsynen samt laboratorier för klinisk mikrobiologi

Salivary and serum levels of neutrophil proteases in periodontitis and rheumatoid arthritis

Objective: The aim was to profile serum and salivary levels of active-matrix metalloproteinase (aMMP)-8, tissue inhibitor MMP (TIMP)-1, aMMP-8/TIMP-1 ratio, total MMP (tMMP)-9, tMMP-9/TIMP-1 ratio, myeloperoxidase (MPO), and human neutrophil elastase (HNE) in periodontitis and rheumatoid arthritis (RA).Materials and Methods: Rheumatoid arthritis patients with periodontitis (RA + P, n = 26), periodontally healthy RA patients (RA, n = 23), systemically healthy periodontitis patients (P, n = 24), and controls (C, n = 24) were included. aMMP-8 levels were determined by a time-resolved immunofluorescence assay (IFMA), TIMP-1, tMMP-9, MPO, and HNE levels were measured by enzyme-linked immunosorbent (ELISA) assays.Results: Higher salivary aMMP-8 (p < 0.001), aMMP-8/TIMP-1 ratio (p = 0.043), tMMP-9 (p = 0.011), tMMP-9/TIMP-1 ratio (p = 0.022), MPO (p = 0.026) and HNE (p < 0.001) levels were detected in P relative to the controls. Salivary TIMP-1 was increased in RA patients regardless of periodontal status (RA + P vs. P: p = 0.038; RA vs. C: p = 0.020). Serum neutrophil proteases were increased in RA groups (RA + P, RA) compared to systemically healthy groups (P, C) (p < 0.05).Conclusions: Serum levels of neutrophil proteases were increased in RA study groups; however rheumatologic status seemingly does not affect salivary levels of these proteins

Toimenpideohje botulismitapausten varalta

Tämä ohje antaa tietoa epidemiologisista toimenpiteistä, joilla voidaan todeta nopeasti botulismiin sairastuneet henkilöt ja ehkäistä mahdollisen epidemian leviäminen. Tavoitteena on yhdenmukaistaa terveydenhuollon toimenpidekäytäntöjä botulismiepäilytapausten yhteydessä. Ohje on tarkoitettu mm. terveyskeskusten tartuntataudeista vastaavien lääkärien ja hoitajien ja alueellisesta tartuntatautien torjunnasta ja elintarvikevalvonnasta vastaavien yksiköiden ja kliinisten mikrobiologian laboratorioiden käyttöön

Salmonella control in poultry flocks and its public health impact

An increase in confirmed human salmonellosis cases in the EU after 2014 triggered investigation of contributory factors and control options in poultry production. Reconsideration of the five current target serovars for breeding hens showed that there is justification for retaining Salmonella Enteritidis, Salmonella Typhimurium (including monophasic variants) and Salmonella Infantis, while Salmonella Virchow and Salmonella Hadar could be replaced by Salmonella Kentucky and either Salmonella Heidelberg, Salmonella Thompson or a variable serovar in national prevalence targets. However, a target that incorporates all serovars is expected to be more effective as the most relevant serovars in breeding flocks vary between Member State (MS) and over time. Achievement of a 1% target for the current target serovars in laying hen flocks is estimated to be reduced by 254,400 CrI95[98,540; 602,700] compared to the situation in 2016. This translates to a reduction of 53.4% CrI95[39.1; 65.7] considering the layer-associated human salmonellosis true cases and 6.2% considering the overall human salmonellosis true cases in the 23 MSs included in attribution modelling. A review of risk factors for Salmonella in laying hens revealed that overall evidence points to a lower occurrence in non-cage compared to cage systems. A conclusion on the effect of outdoor access or impact of the shift from conventional to enriched cages could not be reached. A similar review for broiler chickens concluded that the evidence that outdoor access affects the occurrence of Salmonella is inconclusive. There is conclusive evidence that an increased stocking density, larger farms and stress result in increased occurrence, persistence and spread of Salmonella in laying hen flocks. Based on scientific evidence, an impact of Salmonella control programmes, apart from general hygiene procedures, on the prevalence of Campylobacter in broiler flocks at the holding and on broiler meat at the end of the slaughter process is not expected

Pathogenicity assessment of Shiga toxin‐producing Escherichia coli (STEC) and the public health risk posed by contamination of food with STEC

The provisional molecular approach, proposed by EFSA in 2013, for the pathogenicity assessment of Shiga toxin‐producing Escherichia coli (STEC) has been reviewed. Analysis of the confirmed reported human STEC infections in the EU/EEA (2012–2017) demonstrated that isolates positive for any of the reported Shiga toxin (Stx) subtypes (and encoding stx gene subtypes) may be associated with severe illness (defined as bloody diarrhoea (BD), haemolytic uraemic syndrome (HUS) and/or hospitalisation). Although strains positive for stx2a gene showed the highest rates, strains with all other stx subtypes, or combinations thereof, were also associated with at least one human case with a severe clinical outcome. Serogroup cannot be used as a predictor of clinical outcome and the presence of the intimin gene (eae) is not essential for severe illness. These findings are supported by the published literature, a review of which suggested there was no single or combination of virulence markers associated exclusively with severe illness. Based on available evidence, it was concluded that all STEC strains are pathogenic in humans, capable of causing at least diarrhoea and that all STEC subtypes may be associated with severe illness. Source attribution analysis, based on ‘strong evidence’ outbreak data in the EU/EEA (2012–2017), suggests that ‘bovine meat and products thereof’, ‘milk and dairy products’, ‘tap water including well water’ and ‘vegetables, fruit and products thereof’ are the main sources of STEC infections in the EU/EEA, but a ranking between these categories cannot be made as the data are insufficient. Other food commodities are also potentially associated with STEC infections but rank lower. Data gaps are identified, and are primarily caused by the lack of harmonisation in sampling strategies, sampling methods, detection and characterisation methods, data collation and reporting within the EU.info:eu-repo/semantics/publishedVersio

Salmonella control in poultry flocks and its public health impact

An increase in confirmed human salmonellosis cases in the EU after 2014 triggered investigation of contributory factors and control options in poultry production. Reconsideration of the five current target serovars for breeding hens showed that there is justification for retaining Salmonella Enteritidis, Salmonella Typhimurium (including monophasic variants) and Salmonella Infantis, while Salmonella Virchow and Salmonella Hadar could be replaced by Salmonella Kentucky and either Salmonella Heidelberg, Salmonella Thompson or a variable serovar in national prevalence targets. However, a target that incorporates all serovars is expected to be more effective as the most relevant serovars in breeding flocks vary between Member State (MS) and over time. Achievement of a 1% target for the current target serovars in laying hen flocks is estimated to be reduced by 254,400 CrI95[98,540; 602,700] compared to the situation in 2016. This translates to a reduction of 53.4% CrI95[39.1; 65.7] considering the layer‐associated human salmonellosis true cases and 6.2% considering the overall human salmonellosis true cases in the 23 MSs included in attribution modelling. A review of risk factors for Salmonella in laying hens revealed that overall evidence points to a lower occurrence in non‐cage compared to cage systems. A conclusion on the effect of outdoor access or impact of the shift from conventional to enriched cages could not be reached. A similar review for broiler chickens concluded that the evidence that outdoor access affects the occurrence of Salmonella is inconclusive. There is conclusive evidence that an increased stocking density, larger farms and stress result in increased occurrence, persistence and spread of Salmonella in laying hen flocks. Based on scientific evidence, an impact of Salmonella control programmes, apart from general hygiene procedures, on the prevalence of Campylobacter in broiler flocks at the holding and on broiler meat at the end of the slaughter process is not expected.info:eu-repo/semantics/publishedVersio

Effect of remdesivir post hospitalization for COVID-19 infection from the randomized SOLIDARITY Finland trial

We report the first long-term follow-up of a randomized trial (NCT04978259) addressing the effects of remdesivir on recovery (primary outcome) and other patient-important outcomes one year after hospitalization resulting from COVID-19. Of the 208 patients recruited from 11 Finnish hospitals, 198 survived, of whom 181 (92%) completed follow-up. At one year, self-reported recovery occurred in 85% in remdesivir and 86% in standard of care (SoC) (RR 0.94, 95% CI 0.47-1.90). We infer no convincing difference between remdesivir and SoC in quality of life or symptom outcomes (p > 0.05). Of the 21 potential long-COVID symptoms, patients reported moderate/major bother from fatigue (26%), joint pain (22%), and problems with memory (19%) and attention/concentration (18%). In conclusion, after a one-year follow-up of hospitalized patients, one in six reported they had not recovered well from COVID-19. Our results provide no convincing evidence of remdesivir benefit, but wide confidence intervals included possible benefit and harm.Peer reviewe