Search

Yersinia enterocolitica ( Y. enterocolitica ) is the most frequent etiological agent of yersiniosis and has been responsible for several national outbreaks in Norway and elsewhere. A standardized high-resolution method, such as core genome Multilocus Sequence Typing (cgMLST), is needed for pathogen traceability at the national and international levels. In this study, we developed and implemented a cgMLST scheme for Y. enterocolitica . We designed a cgMLST scheme in SeqSphere + using high-quality genomes from different Y. enterocolitica biotype sublineages. The scheme was validated if more than 95% of targets were found across all tested Y. enterocolitica : 563 Norwegian genomes collected between 2012 and 2022 and 327 genomes from public data sets. We applied the scheme to known outbreaks to establish a threshold for identifying major complex types (CTs) based on the number of allelic differences. The final cgMLST scheme included 2,582 genes with a median of 97.9% (interquartile range 97.6%-98.8%) targets found across all tested genomes. Analysis of outbreaks identified all outbreak strains using single linkage clustering at four allelic differences. This threshold identified 311 unique CTs in Norway, of which CT18, CT12, and CT5 were identified as the most frequently associated with outbreaks. The cgMLST scheme showed a very good performance in typing Y. enterocolitica using diverse data sources and was able to identify outbreak clusters. We recommend the implementation of this scheme nationally and internationally to facilitate Y. enterocolitica surveillance and improve outbreak response in national and cross-border outbreaks., Competing Interests: The authors declare no conflict of interest.

We investigated if diarrhoea-causing bacteria, including Yersinia species, could mimic the symptoms of appendicitis and lead to surgery. This prospective observational cohort study (NCT03349814) included adult patients undergoing surgery for suspected appendicitis. Rectal swabs were analysed with polymerase chain reaction (PCR) for Yersinia, Campylobacter, Salmonella, Shigella and Aeromonas spp. Blood samples were analysed routinely and with an in-house ELISA serological test for Yersinia enterocolitica antibodies. We compared patients without appendicitis and patients with appendicitis confirmed by histopathology. The outcomes included PCR-confirmed infection with Yersinia spp., serologic-confirmed infection with Y. enterocolitica, PCR-confirmed infection with other diarrhoea-causing bacteria and Enterobius vermicularis confirmed by histopathology. A total of 224 patients were included, 51 without and 173 with appendicitis, and followed for 10 days. PCR-confirmed infection with Yersinia spp. was found in one patient (2%) without appendicitis and no patients (0%) with appendicitis (p = 0.23). Serology was positive for Y. enterocolitica for the same patient without appendicitis and two patients with appendicitis (p = 0.54). Campylobacter spp. were detected in 4% vs 1% (p = 0.13) of patients without and with appendicitis, respectively. Infection with Yersinia spp. and other diarrhoea-causing microorganisms in adult patients undergoing surgery for suspected appendicitis was rare., (© 2023 Scandinavian Societies for Pathology, Medical Microbiology and Immunology.)

We herein report a rare case of Yersinia enterocolitica enteritis with a fever and abdominal pain followed by erythema nodosum (EN) a few days later. The diagnosis was confirmed based on characteristic colonoscopy and computed tomography findings, pathology, and mucosal culture. Yersinia enteritis is a curable disease provided a proper diagnosis and treatment are performed. Although EN is a rare clinical course, it should still be considered as a differential diagnosis.

BackgroundYersiniosis is one of the most common food-borne zoonoses in Europe, but there are large variations in the reported incidence between different countries.AimWe aimed to describe the trends and epidemiology of laboratory-confirmed Yersinia infections in England and estimate the average annual number of undiagnosed Yersinia enterocolitica cases, accounting for under-ascertainment.MethodsWe analysed national surveillance data on Yersinia cases reported by laboratories in England between 1975 and 2020 and enhanced surveillance questionnaires from patients diagnosed in a laboratory that has implemented routine Yersinia testing of diarrhoeic samples since 2016.ResultsThe highest incidence of Yersinia infections in England (1.4 cases per 100,000 population) was recorded in 1988 and 1989, with Y. enterocolitica being the predominant species. The reported incidence of Yersinia infections declined during the 1990s and remained low until 2016. Following introduction of commercial PCR at a single laboratory in the South East, the annual incidence increased markedly (13.6 cases per 100,000 population in the catchment area between 2017 and 2020). There were notable changes in age and seasonal distribution of cases over time. The majority of infections were not linked to foreign travel and one in five patients was admitted to hospital. We estimate that around 7,500 Y. enterocolitica infections may be undiagnosed in England annually.ConclusionsFindings suggest a considerable number of undiagnosed yersiniosis cases in England, with possibly important changes in the epidemiology. The apparently low incidence of yersiniosis in England is probably due to limited laboratory testing.

Increasing attention is being paid to the unique roles gut microbes play in both physiological and pathological processes. Crohn's disease (CD) is a chronic, relapsing, inflammatory disease of the gastrointestinal tract with unknown etiology. Currently, gastrointestinal infection has been proposed as one initiating factor of CD. Yersinia enterocolitica , a zoonotic pathogen that exists widely in nature, is one of the most common bacteria causing acute infectious gastroenteritis, which displays clinical manifestations similar to CD. However, the specific role of Y. enterocolitica in CD is controversial. In this Review, we discuss the current knowledge on how Y. enterocolitica and derived microbial compounds may link to the pathogenesis of CD. We highlight examples of Y. enterocolitica -targeted interventions in the diagnosis and treatment of CD, and provide perspectives for future basic and translational investigations on this topic., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Fang, Kang, Qiu, Li and Bai.)

Background: Yersinia infection affects terminal ileum and lymph nodes and could therefore mimic the symptoms of appendicitis. We aimed to systematically characterise the suspected or confirmed abdominal diseases and/or surgeries associated with Yersinia infection., Materials and Methods: This systematic review and meta-analysis was reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A protocol (CRD42016053252) was uploaded to PROSPERO. The searches were conducted in PubMed and EMBASE on October 2, 2020. Original reports on patients with abdominal surgical diseases were included. The primary outcome was to characterise suspected or confirmed abdominal surgical diseases and/or surgeries associated with Yersinia infection, while the secondary outcomes were the positive rate of Yersinia species for each disease and surgery, and to investigate the rate of Yersinia spp. in different geographic regions. We calculated the weighted mean prevalence of positive tests for Yersinia spp. for the different diseases and surgeries according to the detection method and for subgroups based on geographic region., Results: From the search, 33 studies were included in the systematic review and 18 in the meta-analysis. Across geographic regions, the weighted mean prevalence for Yersinia spp. was 51% (95% CI 34%-69%) in mesenteric lymphadenitis, 65% (95% CI 45%-85%) in terminal ileitis, and 8% (95% CI 2%-15%) in normal appendices., Conclusions: Around half of the patients with mesenteric lymphadenitis and terminal ileitis were serologically positive for infections with Yersinia spp. Yersinia infection may cause unnecessary surgery for suspected appendicitis due to symptoms from mesenteric lymphadenitis or terminal ileitis., (Copyright © 2021. Published by Elsevier Inc.)

A multiplex PCR method for rapid and sensitive diagnosis, differentiating three pathogenic Yersinia groups such as the highly pathogenic Y. enterocolitica, including serotype O8, low pathogenic Y. enterocolitica, and Y. pseudotuberculosis, was developed. Four primer pairs were chosen to detect the genes fyuA, ail, inv, and virF, responsible for the virulence in pathogenic Yersinia species. Under the multiplex PCR conditions, the unique band patterns for the highly pathogenic Y. enterocolitica, low pathogenic Y. enterocolitica, and Y. pseudotuberculosis were generated from Yersinia strains. The detection limit of this method was 10 1 -10 3 CFU per reaction tube. This multiplex PCR method could detect highly pathogenic Y. enterocolitica O8 from the wild rodent fecal samples that were culture-positive. Therefore, the new multiplex PCR method developed in this study is a useful tool for rapid and sensitive diagnosis, distinguishing three pathogenic Yersinia groups.

Effective monitoring for subclinical infections is a cornerstone of proactive disease management in aquaculture. Salmonid fish that survive enteric redmouth disease (ERM) can carry Yersinia ruckeri as a latent infection for several months, potentially facilitating cryptic spread between facilities that exchange fish. In this study, fingerling rainbow trout (Oncorhynchus mykiss) were infected by immersion and sampled for up to 14 weeks post-infection. Yersinia ruckeri was cultured from the posterior kidney of more than 89% of fish up to 4 weeks post-infection, but from 2% or fewer of fish sampled at later time points. In contrast, qPCR-based detection of the Y. ruckeri 16s rRNA gene in intestine and spleen extracts revealed a much higher rate of infection: at 14 weeks post-infection Y. ruckeri was detected in nearly 50% of spleens and 15% of intestines. The difference between spleen and intestine is likely due at least in part to technical limitations of qPCR on intestinal DNA extracts; accordingly, we propose that qPCR of spleen DNA ought to be considered the preferred standard for detection of carriers of Y. ruckeri., (© 2021 John Wiley & Sons Ltd.)

Yersinia enterocolitica is a Gram-negative bacterium that causes foodborne illnesses, typically characterised by acute febrile gastroenteritis and is associated with a variety of manifestations. Isolated febrile illness without gastrointestinal symptoms is rare. We report a case of Y.   enterocolitica infection with severe anicteric hepatitis. A 33-year-old Chinese man with no significant medical history presented on multiple occasions to the emergency department with recurrent high-grade fever and chills, but without gastrointestinal symptoms. Hepatic panel showed rising transaminases that peaked at Aspartate Aminotransferase (AST) of 991 U/L and Alanine Aminotransferase (ALT) of 1664 U/L. CT of the abdomen revealed terminal ileitis and mesenteric adenitis. As part of workup, we found positive serology for Y. enterocolitica Ultimately, he improved with supportive care. This case highlights the importance of thorough workup of terminal ileitis and 'Crohn's mimics' which ultimately revealed a unifying diagnosis; and an important addition to the workup for undifferentiated severe isolated hepatocellular liver injury., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

The use of oral fluid (OF) to detect zoonotic pathogens in pigs has been only scarcely assessed. We evaluated OF as a potential specimen for detection by culture of methicillin-resistant Staphylococcus aureus (MRSA) and Yersinia enterocolitica , and the detection of antibodies against Salmonella spp. and hepatitis E virus (HEV) using commercial ELISAs. Samples from 33 pig farms were collected at the beginning and end of the fattening period. Results of the OF samples were compared with the results of serum samples and nasal swabs from individual pigs and pen floor fecal samples, using the Cohen kappa (κ) and the McNemar test. For Salmonella spp. antibodies, OF samples were negative, although the corresponding serum samples were positive. The detection of HEV antibodies in sera and OF had agreement at the first sampling, and poor and significant agreement at the second sampling (κ = 0.185, McNemar p  = 0.238; κ = 0.088, McNemar p  < 0.001). At both sampling times, the detection of MRSA in nasal swabs and OF showed agreement (κ = 0.466, McNemar p  = 0.077; κ = 0.603, McNemar p  = 1); agreement was seen for the detection of Y. enterocolitica in fecal and OF samples (κ = 0.012, McNemar p  = 0.868; κ = 0.082, McNemar p  = 0.061, respectively). According to the McNemar test, the use of pen-based OFs is more feasible for the detection of MRSA and Y. enterocolitica by culture than is detection of antibodies by commercial ELISA.

Background: We report an unusual case of infective colitis by Yersinia enterocolitica complicated by microliver abscesses mimicking multiple liver metastases in a 79 yr old female without any risk factors for bacteriaemia by this pathogen., Case Presentation: The patient was admitted to the Internal Medicine with Stroke Care ward of University Policlinico "P. Giaccone" in Palermo because of the appearance of diarrhoea. After the antimicrobial treatment for infective colitis, the clinicians observed a persistently increased white blood cells (WBC) count and multiple hepatic lesions; after having excluded any neoplastic disease and inflammatory bowel disease (IBD), blood cultures positive for Y. enterocolitica allowed to establish the final diagnosis was infective micro liver abscesses consequent to infective colitis due to Y. enterocolitica, which were successfully treated with cefixime and doxycycline., Conclusions: This case report should make clinicians reflect on how complex the differential diagnosis between microliver abscesses and metastasis could be and the possibility of bacteriaemia by Y. enterocolitica even without iron overload conditions.

The extraintestinal infections caused by Yersinia enterocolitica are very rare, especially in the form of spontaneous bloodstream infection at people without history of blood transfusion. Their clinical symptoms and treatments are still not very clear for now. Here, we report a case of spontaneous bloodstream infection caused by Y. enterocolitica in a 56-year-old Chinese male. The patient presented to outpatient with fever for 1 week, he was diagnosed ankylosing spondylitis for 10 years, and suffered from the pain in his neck, lumbosacral region and limbs constantly. After 4 days of outpatient treatment, there was no sign of improvement so he admitted to inpatient department. Ceftriaxone and metronidazole were initiated in the previous 3 days, the temperature did not drop (highest temperature is 38.3 °C) and the limb joint pain was aggravated. On day 4, antibiotic therapy was changed to moxifloxacin as the growth of Y. enterocolitica showed in blood culture, then changed to amikacin and piperacillin/tazobactam according to culture susceptibility. The patient received a total of 24 days antibacterial treatment before discharge, his body temperature returned to normal, but he remains continuous pain in lumbosacral region and limbs after negative blood culture, which was considered to be caused by AS. Gastrointestinal symptoms such as vomiting, diarrhea and abdominal pain were not reported during the hospitalization, which usually appears in patients with Yersinia enterocolitica infection. We reviewed 12 septicemia cases without the history of blood transfusion from the literature. Not all hosts were under a low immunity or have a clear history of exposure. Clinical symptoms and antibiotic agents were also different from case to case. Physicians should consider the rare diagnosis of Y. enterocolitica infection in patients without clear history of exposure and typical symptoms. And distinguish between pain caused by AS and aseptic arthritis caused by Y. enterocolitica.

Introduction: Yersinia enterocolitica infection is reportedly associated with the development of autoimmune thyroid diseases (AITD). However, evidence that such infection can lead to AITD is controversial. Thus, this study was aimed to investigate the associations of Y. enterocolitica infection with AITD., Methods: A meta-analysis was performed using PubMed, Web of Science, Embase and Cochrane library to identify relevant studies. The odds ratios (OR) and associated 95% confidence intervals [CI] were obtained. Data were analyzed by STATA 13.0 (Stata Corporation, College Station, TX, USA)., Results: Of 215 articles identified, 8 studies with a total of 1490 participants met the criteria and were included in the meta-analysis. There was a significant association between Y. enterocolitica positivity and AITD (OR: 4.31 [CI 95%: 1.81-10.07], P-value: 0.00). According to the subgroup analysis, Y. enterocolitica infection statistically increased the risk of Graves' disease (GD) (OR: 6.12, [CI 95%: 3.71-10.10], P-value: 0.00). Likewise, the pooled OR of association between Y. enterocolitica positivity and hashimoto's thyroiditis (HT) was 2.84 (CI 95%: 0.71-11.25, P-value: 0.1)., Conclusion: The current studies suggest that Y. enterocolitica may be associated with the development of AITD. Further study is needed to explore the underlying mechanisms., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Food-associated outbreaks linked to enteropathogenic Yersinia enterocolitica are of concern to public health. Pigs and their meat are recognized risk factors for transmission of Y. enterocolitica . This study aimed to describe the comparative genomics of Y. enterocolitica along with a number of misclassified Yersinia isolates, now constituting the recently described Yersinia hibernica . The latter was originally cultured from an environmental sample taken at a pig slaughterhouse. Unique features were identified in the genome of Y. hibernica, including a novel integrative conjugative element (ICE), denoted as ICE Yh-1 contained within a 255 kbp region of plasticity. In addition, a zebrafish embryo infection model was adapted and applied to assess the virulence potential among Yersinia isolates including Y. hibernica .

Yersinia enterocolitica is a gram-negative rod causing intestinal infection in humans. It shows different clinical pictures with many different etiologies to be ruled-out, which sometimes makes it difficult to reach a timely and correct diagnosis. We report the case of an adolescent boy presenting with right lower quadrant pain from terminal ileitis with endoscopic findings akin to Crohn´s disease finally diagnosed as Yersinia enterocolitica, highlighting the usefulness of the different ancillary methods employed., Competing Interests: The authors report no conflicts of interest in this work., (Sociedad Argentina de Pediatría.)

This study aims to validate the current diagnostic method for the clinical detection of gastroenteritis. We analyzed 400 stool samples to detect three of the most common enteropathogens: Salmonella spp., Campylobacter spp., and Yersinia enterocolitica. All specimens were tested with a routine clinical diagnosis algorithm and with five real-time PCR assays. A total of 98 specimens (24.5%) were positive for enteropathogens. We found 24 samples positive for Salmonella enterica, 71 positive for Campylobacter spp., and 4 positive for Yersinia enterocolitica. All evaluated methods exhibited a good performance in identifying Salmonella and Yersinia enterocolitica, being the highest positive percent agreement (PPA) value of 95.8% and 100%, respectively. The clinical algorithm showed the highest PPA value identifying Salmonella, due to the enrichment in selenite broth. However, the evaluated methods showed notable differences in the identification of Campylobacter species, obtaining a wide range of PPA values: 59.2%-100%. The clinical algorithm showed the lowest PPA value since it was only able to detect Campylobacter jejuni and Campylobacter coli species. This study revealed the importance of implementing the real-time PCR technique in a clinical algorithm: it improved the accuracy of the diagnosis and provided results in a shorter time compared to routine clinical methods.

Yersiniosis is a zoonotic foodborne infection of public health significance. The aim of this study was to design and validate a simple, accurate and cost-effective polymerase chain reaction (PCR) to detect pathogenic Yersinia spp. in faecal samples. An intercalating dye (EvaGreen)-based real-time multiplex PCR assay was designed to detect yadA, ystB and inv by melt curve analysis, allowing undifferentiated detection of all Yersinia enterocolitica biotypes, including biotype 1A, and Yersinia pseudotuberculosis. The assay was validated using cultured bacteria and clinical samples. A total of 107 positive and 51 negative samples were tested. The sensitivity and specificity was 98% and 100%. The limit of detection was 10 4 -10 5 CFU/g faeces. A total of 605 samples (9 positive) were tested in the clinical verification with an accuracy and negative predictive value of 99% [95% confidence interval (CI) 97.9-99.6%] and 99.8% (95% CI 97.9-99.6%), respectively. This is an accurate, simple and cost-effective assay for the detection of pathogenic Yersinia spp., (Copyright © 2019 Royal College of Pathologists of Australasia. Published by Elsevier B.V. All rights reserved.)

Yersiniosis is one of the "other infectious diarrhea" of the notifiable infectious diseases and also an important food-borne disease. However, it lacked the basis or standard for diagnosis. The Chinese Preventive Medicine Association coordinated experienced researchers from National Institute for Communicable Disease Control and Prevention, China CDC and other institutes to produce the group standard entitled "Diagnosis of Yersiniosis" (T/CPMA 005-2019). Based on the principle of "legality, scientificity, advancement, and feasibility" , the standard gives a clear definition for Yerisiniosis, stipulates diagnosis basis, principles and main differential diagnosis and provides two informative appendixes for epidemiological and clinical characteristics and a normative appendix for laboratory detection. The standard provides accurate basis and methods of Yersiniosis diagnosis for hospitals and CDCs at all levels in China. It will solve the problems that Yersiniosis cannot be clearly diagnosed for clinical cases and in the outbreaks.

Two guereza colobus monkeys (Colobus guereza) reared in a zoological garden in Japan suddenly died of multifocal fibrinonecrotic gastroenteritis and septicemia associated with infection by Yersinia spp. It was necessary to microbiologically differentiate Yersinia frederiksenii and Y. enterocolitica. We described the pathological findings and discuss the causal agent to emphasize the need to revert to using a combination of multiple examinations for diagnosis.

A novel microcantilever sensor was batch fabricated for Yersinia detection. The microcantilever surface modification method was optimized by introducing a secondary antibody to increase the number of binding sites. A novel microfluidic platform was designed and fabricated successfully. A 30 μL solution could fully react with the microcantilever surface. Those routines enhanced the binding efficiency between the target and receptor on the microcantilever. With this novel designed microfluidic platform, the specific adsorption of 10 7 Yersinia on the beam surface with modified F1 antibody was significantly enhanced.

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.

In April 2019, a cross-border outbreak of Yersinia entercolitica O3 was identified in Sweden and Denmark and confirmed using whole genome sequencing. Close cross-border collaboration with representatives from human and food authorities helped direct resources and investigations. Combined epidemiological and trace-back investigations pointed to imported fresh spinach as the outbreak vehicle and highlight that other vehicles of Y. enterocolitica outbreaks than pork should be considered.

Multiplex oligonucleotide ligation-PCR (MOL-PCR) is a rapid method for simultaneous detection of multiple molecular markers within a single reaction. MOL-PCR is increasingly employed in microbial detection assays, where its ability to facilitate identification and further characterization via simple analysis is of great benefit and significantly simplifies routine diagnostics. When adapted to microsphere suspension arrays on a MAGPIX reader, MOL-PCR has the potential to outperform standard nucleic acid-based diagnostic assays. This study represents the guideline towards in-house MOL-PCR assay optimization using the example of foodborne pathogens (bacteria and parasites) with an emphasis on the appropriate choice of crucial parameters. The optimized protocol focused on specific sequence detection utilizes the fluorescent reporter BODIPY-TMRX and self-coupled magnetic microspheres and allows for a smooth and brisk workflow which should serve as a guide for the development of MOL-PCR assays intended for pathogen detection.

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 < 0.001) during the fattening period (from 8.1% to 17.2% and from 30.3% to 72.3%, respectively), while the seroprevalence of T. gondii remained low (<1%). The within-farm seroprevalences of Salmonella spp. and Yersinia spp. differed significantly between the farms and this farm-level serological data could be used as FCI for risk-based decisions to improve food safety. Such potentially feasible decisions could include additional carcass testing, carcass decontamination, carcass processing, slaughtering arrangements and improved biosecurity measures at the farm. However, risk mitigation targets and procedures must be carefully adjusted for each pathogen regarding also economic aspects. Tail biting observed on farm was associated with partial carcass condemnations and arthritis at slaughter. This information could be included in the FCI and used when making decisions regarding meat inspection procedure: visual-only or additional inspections., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Yersiniosis is a foodborne infection caused by Yersinia enterocolitica or Yersinia pseudotuberculosis. Although yersiniosis is most often self-limiting, some patients develop chronic infections, such as reactive arthritis, glomerulonephritis, or myocarditis, which require an antibiotic treatment. Whereas early infections can be diagnosed by direct detection of bacteria, chronic infections can only be identified by serological tests. At this point, a serological method for differentiation between infections with the two Yersinia species is important since antibiotic susceptibility of these bacteria is different. Traditional immunoassays do not distinguish between infections with Y. enterocolitica and Y. pseudotuberculosis. The only test that allows for this differentiation is Mikrogen's strip test where discrimination between the two types of infection is based on two recombinant bacterial proteins, MyfA and PsaA (specific for Y. enterocolitica and Y. pseudotuberculosis, respectively). Here, we show that Y. enterocolitica and Y. pseudotuberculosis, cultured under the conditions that mimic the natural rout of infection, express surface antigens different from MyfA and PsaA that can also be used in a discrimination test. Further, we describe a new ELISA that is based on the whole bacteria and recombinant MyfA and PsaA as antigens, and that allows the differentiation between infections with Y. enterocolitica and Y. pseudotuberculosis and simultaneous detection of yersiniosis.

Purpose: In May 2017 we were notified of a cluster of Yersinia enterocolitica-positive isolates from Liverpool. The purpose of this work was to investigate this cluster of cases and find a possible common source. We combined epidemiological information with whole-genome sequencing (WGS) results, which indicated that these cases were unlikely to be from the same source. This investigation provides evidence that WGS could be used to investigate future clusters of Y. enterocolitica cases., Methods: A case was defined as a person with a laboratory-confirmed isolate of Y. enterocolitica, sampled in 2017, who is a resident in Liverpool local authority at the time of sampling. Faecal samples were cultured at the local laboratory and presumptive isolates of Yersinia sp. were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Positive isolates were whole-genome sequenced by the reference laboratory., Results: Nine cases were identified, which was significantly greater (P<0.0001) than the average number of cases in this area from the last 10 years. Six cases were female (66.67 %) and the ages of the patients ranged from 20 to 81 (median 54). The sample dates ranged from 29 April to 1 August 2017. The WGS results showed that Y. enterocolitica isolates belonged to different sequence types., Conclusion: This was the first time that WGS was used to investigate a cluster of Y. enterocolitica cases; the cases were clustered in time, person and place, but the WGS results indicate that these cases were not from the same source. This result informed the Outbreak Control Team's decision-making and resulted in the investigation being closed.

Yersinia enterocolitica, a member of the Enterobacteriaceae family, is a zoonotic agent that causes gastrointestinal diseases and some extraintestinal disorders in humans. Y. enterocolitica ssp. palearctica bioserotype 4/O:3 is the primary pathogenic bioserotype in Europe, where it has a high public health relevance. The isolation and identification of Y. enterocolitica from various sources on selective media have been seldom successful due to several reasons. In an attempt to overcome the problems associated with traditional culture-based methods, we developed a single duplex PCR assay for the detection of Y. enterocolitica ssp. palearctica bioserotype 4/O:3 using DNA extracted from a source. We combined the primer for tufA (elongation factor Tu) with the primer for rfbC (the biosynthesis of the O side chain) in one single reaction, which showed good results when we analyzed 88 Yersinia strains and when it was tested in the DNA from stool samples of two groups of pregnant women, one comprising HIV-positive women and the other comprising of HIV-negative women. Furthermore, the duplex PCR assay was found to be 16 times better in detecting Yersinia spp. in stool samples than the culture-based method. In addition, it was found to be a rapid screening method for the detection of Y. enterocolitica serotype O:3, and it could still detect other Y. enterocolitica serotypes and Yersinia species as well. We anticipate that the duplex PCR assay could be a useful tool for hospital and veterinary surveillance studies on Yersinia worldwide., (Copyright © 2018 Elsevier B.V. All rights reserved.)

We present the case of a fit and well 12-year-old boy who presented with signs and symptoms suggestive of appendicitis. On laparoscopy, he was found to have a sinister-looking right iliac fossa mass with associated mesenteric lymphadenopathy. He proceeded to have an oncological right hemicolectomy, while the subsequent histology returned an unexpected result. The aim of this report is to highlight an unusual and complex clinical presentation in a young patient presenting with right iliac fossa pain., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2018. No commercial re-use. See rights and permissions. Published by BMJ.)

Finfish with asymptomatic Yersinia ruckeri infections pose a major risk as they can transmit the pathogen and cause clinical outbreaks in stock populations. Current tools have insufficient quantitative ability for accurately detecting the trace levels of Y. ruckeri typically associated with asymptomatic infection, necessitate invasive or lethal sampling, or require long processing times. This study presents a highly sensitive qPCR-based method, targeting part of the Y. ruckeri 16S rRNA sequence, that is capable of detecting extremely low levels of Y. ruckeri in noninvasively collected faecal samples. Quantitative precision and accuracy of faecal sample analysis was consistent, despite the complexity of the faecal matrix. The assay demonstrated linearity over a six log-wide dynamic range. Its limit of detection (LOD) and limit of quantification (LOQ) were 4 and 10 copies of the target sequence, respectively. Sensitivity of the assay was comparable to other qPCR-based methods without requiring invasive or lethal sampling. Applicability as a screening strategy was tested using passively collected faecal samples. Asymptomatic Y. ruckeri infection was detected in all samples, although none of the fish exhibited overt infection. This method will be beneficial for finfish disease management if developed further as a noninvasive, screening tool against asymptomatic Y. ruckeri infection., (© 2018 John Wiley & Sons Ltd.)

Salmonellosis and yersiniosis are notifiable human diseases that are commonly associated with contaminated food. Domestic pigs as well as wild boars and other wild-life have been identified as reservoirs of these bacteria. Methods for cultivation and molecular epidemiological investigations of Salmonella spp. are well established, however, cultivation of enteropathogenic Yersinia spp. is time- consuming and the commonly used method for molecular epidemiological investigations, pulsed-field gel electrophoresis, lack in discriminatory power. The aim of this study was to develop and evaluate a screening protocol well suited for wildlife samples and other highly contaminated samples. The method is based on PCR-screening followed by Multiple Loci Variant number tandem repeat Analysis (MLVA) on enrichment broth to obtain molecular epidemiological data for enteropathogenic Yersinia spp. without the need for pure isolates. The performance of the protocol was evaluated using wild boar samples (n=354) including tonsils, faeces and lymph nodes from 90 Swedish wild boars. The new protocol performed as well as or better than the established ISO-standards for detection and cultivation of Y. enterocolitica and Salmonella spp., however for cultivation of Y. pseudotuberculosis, further development is needed. The selection for motility seems beneficial for the enrichment of Salmonella spp. and Y. enterocolitica. Further, the selective enrichment prior to PCR-analysis eliminates inhibitory factors present in the original sample. In total, ten isolates of Y. enterocolitica of various bio-serotypes were obtained, and the MLVA-profile of these isolates were consistent with the profiles from the corresponding enrichment broth. Further, 22 isolates of Salmonella spp. comprising six different serovars were obtained with S. Fulica, S. Hadar and a monophasic S. Typhimurium being the most common. In conclusion, the presented screening protocol offers a rapid and efficient way to obtain prevalence data from a large sample set as well as MLVA-data within a short time frame. These results can hence improve the knowledge on the epidemiology and distribution of these pathogens and their importance to public health., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The application of DNA-based methods enables to identify Yersinia enterocolitica carrying the ail-gene with a greater sensitivity compared to culture methods and biochemical tests used for detection of pathogenic Y. enterocolitica in animal and food samples. In this study, 100 samples of pig tonsils were examined, among which 17 were positive for the ail gene. Additionally, biochemical tests and RT-PCR showed that nine Y. enterocolitica isolates carried the ail-gene. Two Y. enterocolitica isolates of 1A biotype had the ail gene. The results demonstrated the usefulness of RT-PCR method applied for detection of potentially pathogenic, possessing the ail gene Y. enterocolitica in the material examined.

Yersiniosis is zoonotic disease caused by infection with Yersinia enterocolictica. The variety of clinical signs and the similarity to other diseases causes major diagnostics and therapeutics difficulties. The authors present a case of Yersinia enterocolitica infection in a 38-year-old patient, mimicking Leśniowski Crohn's disease.

Changes in diagnostic laboratory testing procedures can impact on the number of cases notified and the public health surveillance of enteric pathogens. Culture independent diagnostic testing using a multiplex polymerase chain reaction (PCR) test was introduced for the rapid detection of bacterial enteric pathogens in pathology laboratories in Queensland, Australia, from late 2013 onwards. We conducted a retrospective descriptive study using laboratory data to assess the impact of the introduction of PCR testing on four common enteric pathogens, Salmonella, Campylobacter, Shigella and Yersinia, in Queensland between 2010 and 2014. The number of stool specimens tested and the proportion positive for each of the four pathogens increased in 2014 after the introduction of culture independent diagnostic testing. Among the specimens tested by both PCR and culture, 12% of Salmonella positive stools, 36% of Campylobacter positive stools, 74% of Shigella / enteroinvasive Escherichia coli positive stools and 65% of Yersinia positive stools were PCR positive only. Including those where culture was not performed, 19% of Salmonella positive stools, 44% of Campylobacter positive stools, 83% of Shigella positive stools and 79% of Yersinia positive stools had no cultured isolate available for further characterisation. The detection and tracking of foodborne and non-foodborne gastrointestinal outbreaks will become more difficult as culture independent diagnostic testing becomes more widespread. Until new techniques for characterisation of pathogens directly from clinical specimens have been developed, we recommend laboratories continue to culture specimens concurrently or reflexively with culture independent diagnostic tests., (This work is copyright. You may download, display, print and reproduce the whole or part of this work in unaltered form for your own personal use or, if you are part of an organisation, for internal use within your organisation, but only if you or your organisation do not use the reproduction for any commercial purpose and retain this copyright notice and all disclaimer notices as part of that reproduction. Apart from rights to use as permitted by the Copyright Act 1968 or allowed by this copyright notice, all other rights are reserved and you are not allowed to reproduce the whole or any part of this work in any way (electronic or otherwise) without first being given the specific written permission from the Commonwealth to do so. Requests and inquiries concerning reproduction and rights are to be sent to the Online, Services and External Relations Branch, Department of Health, GPO Box 9848, Canberra ACT 2601, or by email to copyright@health.gov.au.)

Objective: To apply a multiplex real-time polymerase chain reaction (PCR) technique to detect Salmonella spp., Listeria monocytogenes, and Yersinia enterocolitica as a diagnostic support tool for the surveillance of foodborne disease outbreaks., Materials and Methods: Molecular methodology was applied on clinical samples taken from individuals who were associated with foodborne disease outbreaks in two departments of Colombia. The results were compared with the data obtained by conventional culture methodology. In addition, the clonal relation of the isolations was evaluated using the Pulsed Field Gel Electrophoresis (PFGE) technique., Results: 123 cases of foodborne disease were determined, of which 45 biological samples were confirmed by laboratory and 88 by epidemiological link. The molecular methodology detected 35/45 positive samples versus 17/45 positive samples detected by conventional methodology. PFGE demonstrated a clonal relation during each outbreak., Conclusion: The results of the study demonstrate the applicability of the molecular technique as a useful diagnostic support tool to characterize foodborne disease outbreaks, allowing a timely and reliable response.

Yersinia enterocolitica is thought to not significantly contribute to diarrheal disease in China, but evidence substantiating this claim is limited. We determined the prevalence of Y. enterocolitica infection and strain types present among children <5 years of age with diarrhea in China. The overall prevalence of pathogenic isolates was 0.59%. Prevalence of pathogenic bioserotype 3/O:3 varied geographically. In this population, the presence of fecal leukocytes was a characteristic of Y. enterocolitica infection and should be used as an indication for microbiological diagnostic testing, rather than for the diagnosis of bacillary dysentery. In contrast with Y. enterocolitica isolates from adults, which were primarily biotype 1A, isolates from children were primarily bioserotype 3/O:3. Most pathogenic isolates from children shared pulsed-field gel electrophoresis patterns with isolates from pigs and dogs, suggesting a possible link between isolates from animals and infections in children. Our findings underscore the need for improved diagnostics for this underestimated pathogen.

Background: Yersiniosis is believed to be the third most common intestinal zoonosis in the European Union, after campylobacteriosis and salmonellosis. Yersinia enterocolitica is the most common species responsible for human infections. Pigs are regarded as the biggest reservoir of pathogenic Y. enterocolitica strains, which are mainly isolated from pig tonsils. The aim of this paper is to examine the prevalence of inv-positive and ail-positive Y. enterocolitica in pigs which were slaughtered in a Polish abattoir., Methods: Real-time PCR and culture methods were used to assess the prevalence of patho- genic Y. enterocolitica strains in pig tonsils. Real-time PCR was applied to detect inv-positive and ail-positive Y. enterocolitica. Y. enterocolitica was also isolated by applying direct plating, unselective (tryptic soy broth) and selective (irgasan-ticarcillin-potassium chlorate bouillon) enrichment., Results: A total of 180 pigs were studied, of which 85% and 32% respectively were found to be infected with inv-positive and ail-positive Y. enterocolitica. The 92 inv-positive and ail-positive isolates, from 57 culture- positive tonsils, underwent bio- and serotyping. The most common was bioserotype 4/O:3, which was found in 53 (93%) out of 57 culture-positive tonsils. Strains of bioserotypes 2/O:5, 2/O:9 and 2/O:5.27 occurred in significantly lower numbers., Conclusions: The prevalence of inv-positive and ail-positive Y. enterocolitica was found to be high in the ton- sils of slaughtered pigs, using real-time PCR. The real-time PCR method for the detection and identification of pathogenic Y. enterocolitica is sensitive and specific, which has been verified by specificity and sensitivity tests using the pure cultures. Serotypes were distinguished from each other using PCR serotyping. The PCR method was essential in forming our conclusions.

Background: The bacterium Yersinia enterocolitica causes gastroenteritis in humans. The study aimed to develop a diagnostic enzyme-linked immunosorbent assay (ELISA) for detection of Yersinia enterocolitica O:3 LPS antibodies in sera from Danish patients with suspected Yersinia enterocolitica O:3 gastrointestinal infection. As a part of this, antibody decay profiles after culture confirmed Yersinia enteritis were studied., Results: An ELISA using Yersinia enterocolitica O:3 LPS as the coating antigen was developed for measuring IgA, IgG and IgM specific antibodies. A longitudinal collection of 220 sera drawn between 20 and 1053 days after onset of symptoms from 85 adult Danish patients with verified Yersinia enteritis were examined. A control group of 100 sera from healthy Danish blood-donors were analysed in order to determine the cut-off for interpretation of results. Serum samples from 62 out of 81 patients who delivered either the first or the second sample were found positive for specific antibodies against Yersinia enterocolitica O:3 LPS (77%). For samples collected within 60 days after onset of symptoms (n = 48) sensitivities of 58%, 42% and 79% for IgA, IgG and IgM antibodies were found. A sensitivity of 81% was found for these samples when using the definition of a positive result in either IgA, IgG or IgM as a combined positive. All samples received up to 36 days after onset of symptoms (n = 10) were found to be positive using this definition. For the period 61 to 90 days after onset of symptoms (n = 32), a combined sensitivity of 63% was found. The antibody levels as well as decay profiles for the three different immunoglobulin classes for the individual patients exhibited a large degree of variation., Conclusions: Using a definition of positive as a positive result for either IgA, IgG or IgM antibodies, a diagnostic sensitivity of 81% was achieved for samples received within 60 days after onset of symptoms. In particular, the levels of specific IgM antibodies were elevated. In comparison, the standard tube-agglutination assay achieved a sensitivity of 60% on the same samples. The sensitivity of the ELISA decreased the longer the duration of time since onset of symptoms. The ELISA was highly specific for Yersinia when testing sera from individuals with confirmed gastrointestinal infections by other bacteria. Moreover, the knowledge gained from this longitudinal study of antibody decay profiles can be used in future epidemiological studies of seroprevalence.

In the spring of 2015, we experienced a cluster of 4 sporadic cases of yersiniosis in children in Nagano prefecture, a rural area of Japan. Two patients developed appendicitis-like episodes; one had acute gastroenteritis, and the other had bacteremia associated with liver abscess. The causative agent of these infections was Yersinia enterocolitica serogroup O:8. None of the patients had an underlying illness, and all have recovered completely. The patients were neither socially nor geographically related to each other. These 4 consecutive cases suggest that Y. enterocolitica O:8 has spread substantially in the middle part of Japan, and that this virulent strain might be more common than previously reported in our country.

Current issue deals with an interesting clinical case of a rare infectious disease in a Caucasian young male patient, caused by Yersinia enterocоlitica. Infection proceeded in the development of secondary focal form, which was accompanied by prolonged polyarthritis. We described a clinical case of secondary focal form with prolonged polyarthritis caused by Y. enterocolitica O:3 serogroup in young patient with the purpose of focusing on the early clinical and laboratory diagnosistics of Yersiniosis that would minimize the role of medical errors in diagnostics made by general practitioners. This case deserves the attention of internal medicine specialists, physicians of the specialty ≪general practitioners≫, rheumatologists, infectious disease specialists taking into consideration the clinics and immunopathogenesis, as well as a high evidence of a prolonged clinical course and chronicity of this disease. It has accented on the feasibility of early serological diagnostics and etiotropic antibiotic therapy of the disease.

In May 2014, a cluster of Yersinia enterocolitica (YE) O9 infections was reported from a military base in northern Norway. Concurrently, an increase in YE infections in civilians was observed in the Norwegian Surveillance System for Communicable Diseases. We investigated to ascertain the extent of the outbreak and identify the source in order to implement control measures. A case was defined as a person with laboratory-confirmed YE O9 infection with the outbreak multilocus variable-number tandem repeat analysis (MLVA)-profile (5-6-9-8-9-9). We conducted a case-control study in the military setting and calculated odds ratios (OR) using logistic regression. Traceback investigations were conducted to identify common suppliers and products in commercial kitchens frequented by cases. By 28 May, we identified 133 cases, of which 117 were linked to four military bases and 16 were civilians from geographically dispersed counties. Among foods consumed by cases, multivariable analysis pointed to mixed salad as a potential source of illness (OR 10.26; 95% confidence interval (CI): 0.85-123.57). The four military bases and cafeterias visited by 14/16 civilian cases received iceberg lettuce or radicchio rosso from the same supplier. Secondary transmission cannot be eliminated as a source of infection in the military camps. The most likely source of the outbreak was salad mix containing imported radicchio rosso, due to its long shelf life. This outbreak is a reminder that fresh produce should not be discounted as a vehicle in prolonged outbreaks and that improvements are still required in the production and processing of fresh salad products., Competing Interests: Conflicts of Interest: None declared., (This article is copyright of The Authors, 2016.)

Diarrhoea is one of the most commonly occurring diseases. This article presents a review of the current state of the treatment of acute infectious diarrhoea, as well as of the most important pathogens. The general principles of the therapy of diarrhoea are exemplified, followed by a description of the targeted antimicrobial therapy of the most important bacterial gastrointestinal infections, including salmonellosis, shigellosis and Campylobacter infections, as well as infections with pathogenic Escherichia coli strains, yersiniosis and cholera. Diarrhoea caused by toxigenic Clostridium difficile strains has increased in incidence and in severity. These infections will therefore be described in detail, including important new aspects of treatment. Symptomatic therapy is still the most important component of the treatment of infectious diarrhoea. However, empirical antibiotic therapy should be considered for severely ill patients with a high frequency of stools, fever, bloody diarrhoea, underlying immune deficiency, advanced age or significant comorbidities. Increasing resistance, in particular against fluoroquinolones, must be taken into consideration. Therapy with motility inhibitors is not recommended for Shiga toxin-producing Escherichia coli (STEC) infections, Clostridium difficile infections (CDI), and severe colitis. The macrocyclic antibiotic fidaxomicin can reduce the rate of recurrent disease in CDI. Furthermore, evidence for the benefits of faecal microbiota transplantation as a treatment option for multiple recurrences of CDI is increasing. In conclusion, the treatment of acute diarrhoea is still primarily supportive. General empirical antibiotic therapy for acute diarrhoea is not evidence-based.

Introduction: Proper analysis of the human immune response is crucial in the laboratory diagnosis of many bacterial infections-The current serological diagnosis of yersiniosis often is carried out using ELISA with native antigens. However, recombinant proteins increase the specificity of the serological assays, particularly in patients with chronic, non- specific infections. The aim of the present study was to evaluate the usefulness of in-house obtained recombinant proteins Yop of Yersinia enterocolitica as highly specific antigens in ELISA and recom-dot performed in the serodiagnosis of yersiniosis., Materials and Methods: Recombinant YopD, YopB, YopE and V-Ag proteins of Y enterocolitica were expressing in E. coli BL21 (DE3) using the pET-30 Ek/LIC expression vector (Novagen). Purification was accomplished by immobilized metal (Ni2) affinity column chromatography (His-trap). The proteins were used as antigens in standard ELISA and recom-dot assay, which was performed on nitrocellulose strips. The study population, used for characterization of the humoral immune response to the recombinant proteins, consisted of 74 patients suspected for Y enterocolitica infection and 41 clinically healthy blood donors. Some of the results obtained by ELISA and recom-dot were compared with results obtained by commercial western-blot Yersinia (Virotech)., Results: In the group of patients suspected for yersiniosis in clinical investigation the most positive results were obtained in ELISA with the recombinant protein YopD (IgA respectively 25 (42.4%), IgG 41 (69.5%), IgM 24 (40.7%). The percentage ofpositive results in the group of blood donors did not exceed 10.0% in IgG and 5.0% in IgA/IgM classes of immunoglobulin. The results obtained in the recom-dot assay showed that among 74 tested serum samples obtained from individuals suspected of yersiniosis the most common IgA, IgG and IgM antibodies were found for recombinant protein YopD (respectively IgG in 60.8%, IgA in 37.8% and IgM in 33.8% of serum samples). IgG antibodies to the protein V-Ag were observed in 32.4%, protein YopB in 27.0% and for the protein YopE in 18.9% serum samples. Immunoglobulin A, and M for the recombinant proteins were found much less frequently than IgG antibodies (respectively 12.2% and 10.8% for V protein-Ag in 10.8% and 14.9% protein and&#95;YopB 2,7% and 10.8% for the protein YopE). Further studies showed that results obtained in recom-dot assay with recombinant protein YopD were comparable with the results of commercial western-blot Yersinia., Conclusions: The study showed that in-house obtained recombinant proteins can be used as highly specific antigens in ELISA and recom-dot performed in the serodiagnosis of yersiniosis. The most useful was the protein YopD.

Although the number of outbreaks caused by Yersinia enterocolitica has been very small in Japan, 4 outbreaks were occurred during the 2 years between 2012 and 2013. We describe herein 2 outbreaks which were examined in Tokyo in the present study. Outbreak 1: A total of 39 people (37 high school students and 2 staff) stayed at a hotel in mountain area in Japan had experienced abdominal pain, diarrhea and fever in August, 2012. The Y. enterocolitica serogroup O:8 was isolated from 18 (64.3%) out of 28 fecal specimens of 28 patients. The infection roots could not be revealed because Y. enterocolitica was not detected from any meals at the hotel or its environment. Outbreak 2: A total of 52 students at a dormitory had diarrhea and fever in April, 2013. The results of the bacteriological and virological examinations of fecal specimens of patients showed that the Y. enterocolitica serogroup O:8 was isolated from 24 fecal specimens of 21 patients and 3 kitchen staff. We performed bacteriological and virological examination of the stored and preserved foods at the kitchen of the dormitory to reveal the suspect food. For the detection of Y. enterocolitica, food samples. together with phosphate buffered saline (PBS) were incubated at 4 degrees C for 21 days. Then, a screening test for Y. enterocolitica using realtime-PCR targeting the ail gene was performed against the PBS culture. One sample (fresh vegetable salad) tested was positive on realtime-PCR. No Y. enterocolitica was isolated on CIN agar from the PBS culture because many bacteria colonies other than Y. enterocolitica appeared on the CIN agar. After the alkaline-treatments of the culture broth or the immunomagnetic beads concentration method using anti-Y. enterocolitica O:8 antibodies, Y. enterocolitica O:8 which was the same serogroup as the patients' isolates was successfully isolated from the PBS culture. The fresh vegetable salad was confirmed as the incrimination food of this outbreak.

In 2010, when I was 17, I presented to hospital with progressive discomfort and pain in the right iliac fossa when eating and moving, associated with mild fever and diarrhoea. Appendicitis was suspected but immediate surgery was deferred, as the inflammatory markers did not adequately support the clinical diagnosis of appendicitis. Further tests, including MRI, were then undertaken. The MRI showed evidence of terminal ileitis and a normal appendix. Crohn's disease was considered as part of the differential diagnosis. However, a Yersinia enterocolitica infection was subsequently confirmed. The episode highlighted several learning points including preventing unnecessary surgery and the advantages of using a multidisciplinary approach involving imaging the abdomen and microbiological input., (2015 BMJ Publishing Group Ltd.)