Clinical significance of serum cytokine profiles for differentiating between Kawasaki disease and its mimickers.

OBJECTIVES: To investigate the clinical significance of serum cytokine profiles for differentiating between Kawasaki disease (KD) and its mimickers. METHODS: Patients with KD, including complete KD, KD shock syndrome (KDSS), and KD with macrophage activation syndrome (KD-MAS), and its mimickers, including multisystem inflammatory syndrome in children, toxic shock syndrome, and Yersinia pseudotuberculosis infection, were enrolled. Serum levels of interleukin (IL)-6, soluble tumor necrosis factor receptor type II (sTNF-RII), IL-10, IL-18, and chemokine (C-X-C motif) ligand 9 (CXCL9) were measured using enzyme-linked immunosorbent assay and compared them with clinical manifestations. RESULTS: Serum IL-6, sTNF-RII, and IL-10 levels were significantly elevated in patients with KDSS. Serum IL-18 levels were substantially elevated in patients with KD-MAS. Patients with KD-MAS and KD mimickers had significantly elevated serum CXCL9 levels compared with those with complete KD. Area under the receiver operating characteristic curve analysis showed that serum IL-6 was the most useful for differentiating KDSS from the others, IL-18 and CXCL9 for KD-MAS from complete KD, and CXCL9 for KD mimickers from complete KD and KD-MAS. CONCLUSION: Serum cytokine profiles may be useful for differentiating between KD and its mimickers.

Spatiotemporal Variations in Growth Rate and Virulence Plasmid Copy Number during Yersinia pseudotuberculosis Infection.

Pathogenic Yersinia spp. depend on the activity of a potent virulence plasmid-encoded ysc/yop type 3 secretion system (T3SS) to colonize hosts and cause disease. It was recently shown that Yersinia pseudotuberculosis upregulates the virulence plasmid copy number (PCN) during infection and that the resulting elevated gene dose of plasmid-encoded T3SS genes is essential for virulence. When and how this novel regulatory mechanism is deployed and regulates the replication of the virulence plasmid during infection is unknown. In the present study, we applied droplet digital PCR (ddPCR) to investigate the dynamics of Y. pseudotuberculosis virulence PCN variations and growth rates in infected mouse organs. We demonstrated that both PCN and growth varied in different tissues and over time throughout the course of infection, indicating that the bacteria adapted to discrete microenvironments during infection. The PCN was highest in Peyer's patches and cecum during the clonal invasive phase of the infection, while the highest growth rates were found in the draining mesenteric lymph nodes. In deeper, systemic organs, the PCN was lower and more modest growth rates were recorded. Our study indicates that increased gene dosage of the plasmid-encoded T3SS genes is most important early in the infection during invasion of the host. The described ddPCR approach will greatly simplify analyses of PCN, growth dynamics, and bacterial loads in infected tissues and will be readily applicable to other infection models.

Septic shock due to Yersinia pseudotuberculosis infection in an adult immunocompetent patient: a case report and literature review.

BACKGROUND: Yersinia pseudotuberculosis infection can occur in an immunocompromised host. Although rare, bacteremia due to Y. pseudotuberculosis may also occur in immunocompetent hosts. The prognosis and therapeutic strategy, especially for immunocompetent patients with Y. pseudotuberculosis bacteremia, however, remains unknown. CASE PRESENTATION: A 38-year-old Japanese man with a mood disorder presented to our hospital with fever and diarrhea. Chest computed tomography revealed consolidation in the right upper lobe with air bronchograms. He was diagnosed with pneumonia, and treatment with intravenous ceftriaxone and azithromycin was initiated. The ceftriaxone was replaced with doripenem and the azithromycin was discontinued following the detection of Gram-negative rod bacteria in 2 sets of blood culture tests. The isolated Gram-negative rod bacteria were confirmed to be Y. pseudotuberculosis. Thereafter, he developed septic shock. Doripenem was switched to cefmetazole, which was continued for 14 days. He recovered without relapse. CONCLUSIONS: We herein report a case of septic shock due to Y. pseudotuberculosis infection in an adult immunocompetent patient. The appropriate microorganism tests and antibiotic therapy are necessary to treat patients with Y. pseudotuberculosis bacteremia.

A horse and a zebra: an atypical clinical picture including Guillain-Barré syndrome, recurrent fever and mesenteric lymphadenopathy caused by two concomitant infections.

BACKGROUND: While Campylobacter jejuni represents the most common cause of bacterial gastroenteritis, Yersinia pseudotuberculosis infections are very rarely diagnosed in adults. CASE: We report on a previously healthy patient who presented several times at our hospital with fever, Guillain-Barré syndrome, recurrent abdominal symptoms and distinct mesenteric lymphadenopathy, respectively. This complicated and diagnostically challenging course of disease was caused by a C. jejuni and Y. pseudotuberculosis coinfection. Antibiotic treatment with doxycycline was effective. CONCLUSION: Broad serology testing was crucial to discover that two concomitant infections were causing the symptoms. This case demonstrates that when a clinical picture is not fully explained by one known infection, another infection with the same underlying risk factor has to be considered, hence "a horse and a zebra".

Unilateral inguinal lymphadenitis caused by Yersinia pseudotuberculosis. A case report.

Acute inguinal lymphadenitis is usually caused by lower extremity infection and sexually transmitted diseases, such as chancroid, lymphogranuloma venereum, genital herpes, or syphilis. Yersinia pseudotuberculosis is a non-spore forming, pleomorphic, non-lactose fermenting Gram negative bacillus and a member of the family Enterobacteriaceae, which is associated with diarrheal diseases. It also causes mesenteric lymphadenitis at the terminal ileum, which can be clinically indistinguishable from acute appendicitis (pseudoappendicitis). However, lymphadenitis in other regions caused by the organism is rarely reported. Herein, we report a case of a man in his 20s, who presented with unilateral inguinal lymphadenitis caused by Y. pseudotuberculosis, with discussion regarding the pathogenesis of this rare occurrence.

YERSINIA PSEUDOTUBERCULOSIS INFECTIONS IN PRIMATES, ARTIODACTYLS, AND BIRDS WITHIN A ZOOLOGICAL FACILITY IN THE UNITED KINGDOM.

Infection with Yersinia pseudotuberculosis can be difficult to diagnose and treat successfully. Twenty-four cases from the Zoological Society of London (ZSL) London Zoo and ZSL Whipsnade Zoo were identified between 2001 and 2019. Husbandry, medical, and postmortem records for six primates, 10 artiodactyls, and eight birds were reviewed to identify common clinical signs and gross lesions. Most cases occurred during the winter; however, an outbreak in four primates occurred during the summer following a period of stress associated with increased ambient noise and activity. Common clinical signs included lethargy (6/6 primates, 4/10 artiodactyls, 4/8 birds) or death without premonitory signs (3/10 artiodactyls, 4/8 birds). Once clinical signs were observed, disease progressed quickly. Poor condition was common in mammals (6/6 primates, 9/10 artiodactyls), but often went undetected until postmortem examination. Neurological signs occurred in three of six primates. Diarrhea and anorexia were uncommon in all animals. Hepatitis was observed in all groups (4/6 primates, 2/10 artiodactyls, 4/8 birds), mesenteric lymphadenomegaly was common in mammals (4/6 primates, 8/10 artiodactyls), and gastroenteritis was common in artiodactyls (7/10). Erythematous, punctate rashes, which have only been reported with yersiniosis in humans, were present in three of six primates. Bacterial cultures from the liver in primates and birds or enlarged mesenteric lymph nodes in artiodactyls were often diagnostic. All isolates were susceptible to marbofloxacin, oxytetracycline, streptomycin, ceftazidime, amoxicillin clavulanic acid, trimethoprim sulfamethoxazole, azithromycin, and doxycycline, and resistant to clindamycin. Histopathology and Perl's Prussian blue stains were performed on available liver samples (n = 18). Intracellular hemosiderin was present in 17 of 18 cases. Additional research is needed to determine if there is a relationship between hemosiderosis and yersiniosis.

Novel diagnostic ELISA test for discrimination between infections with Yersinia enterocolitica and Yersinia pseudotuberculosis.

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.

Production of recombinant porin from Y. pseudotuberculosis in a water-soluble form for pseudotuberculosis diagnostics.

OmpF porin from the outer membrane of Yersinia pseudotuberculosis was cloned into pET-40b(+) plasmid. Using E. coli Rosetta (DE3) strain, MX medium, IPTG concentration of 0.2 mm and post-induction cultivation at 14°C overnight allowed us to obtain a water-soluble form of the recombinant protein (rs-OmpF). Rs-OmpF was shown to have the ordered spatial structure at the levels of secondary and tertiary structure. Rs-OmpF was found to be effective as diagnostic antigen in ELISA for pseudotuberculosis diagnostics.

[CONSTRUCTION OF A TEST-SYSTEM WITH NANOPARTICLES OF COLLOID SILVER FOR DETECTION OF PSEUDOTUBERCULOSIS AND INTESTINAL YERSINIOSIS FOR CAUSATIVE AGENTS IN DOT-IMMUNOASSAY].

AIM: Construction of an immunologic test-system for detection of causative agents of enteropathogenic Yersinia (Yersinia pseudotuberculosis and Y. enterocolitica) by dot-immunoassay. MATERIALS AND METHODS: Nenoparticles of colloid silver sized 5-9 nm were used as a marker of specific antibodies. IgG fraction was isolated from commercial antisera to Y. pseudotuberculosis (Ο:1) and Y. enterocolitica (Ο:3 and Ο:9). Testing of the obtained test-system was carried out on 20 strains of Y.pseudotuberculosis and Y. enterocolitica (10 of each species). RESULTS: Dot-analysis had a specific character and detected enteropathogenic Yersinia at a level of 5-105 - 8.106 CFU/ml (100 - 1000 CFU in sample). Wherein cross-reaction with heterologic studied microorganisms - Escherichia coli, Salmonella typhimurium, Shigella flexneri, Yersina pestis EV - as not observed. A possibility of simultaneous detection and serotyping of Y. enterocolitica is shown, that is necessary for confirmation of their epidemic significance. CONCLUSION: The developed test-systems allow to study micro volumes of the samples under study (1 µ1), are express (1.5 - 2h), highly sensitive and specific, technically simple and do not require the use of high-cost equipment, special training of the staff, may be successfully used in practical healthcar in laboratories with varying equiptment levels.

Using surface-enhanced Raman spectroscopy and electrochemically driven melting to discriminate Yersinia pestis from Y. pseudotuberculosis based on single nucleotide polymorphisms within unpurified polymerase chain reaction amplicons.

The development of sensors for the detection of pathogen-specific DNA, including relevant species/strain level discrimination, is critical in molecular diagnostics with major impacts in areas such as bioterrorism and food safety. Herein, we use electrochemically driven denaturation assays monitored by surface-enhanced Raman spectroscopy (SERS) to target single nucleotide polymorphisms (SNPs) that distinguish DNA amplicons generated from Yersinia pestis, the causative agent of plague, from the closely related species Y. pseudotuberculosis. Two assays targeting SNPs within the groEL and metH genes of these two species have been successfully designed. Polymerase chain reaction (PCR) was used to produce Texas Red labeled single-stranded DNA (ssDNA) amplicons of 262 and 251 bases for the groEL and metH targets, respectively. These amplicons were used in an unpurified form to hybridize to immobilized probes then subjected to electrochemically driven melting. In all cases electrochemically driven melting was able to discriminate between fully homologous DNA and that containing SNPs. The metH assay was particularly challenging due to the presence of only a single base mismatch in the middle of the 251 base long PCR amplicon. However, manipulation of assay conditions (conducting the electrochemical experiments at 10 °C) resulted in greater discrimination between the complementary and mismatched DNA. Replicate data were collected and analyzed for each duplex on different days, using different batches of PCR product and different sphere segment void (SSV) substrates. Despite the variability introduced by these differences, the assays are shown to be reliable and robust providing a new platform for strain discrimination using unpurified PCR samples.

Outbreak of Yersinia pseudotuberculosis O:1 infection associated with raw milk consumption, Finland, 2014.

In March 2014, a Yersinia pseudotuberculosis (YP) outbreak was detected by a municipal authority in southern Finland. We conducted epidemiological, microbiological and traceback investigations to identify the source. We defined a case as a person with YP infection notified to the National Infectious Disease Registry between February and April 2014, or their household member, with abdominal pain and fever≥38 °C or erythema nodosum. Healthy household members were used as household-matched controls. We identified 43 cases and 50 controls. The illness was strongly associated with the consumption of raw milk from a single producer. The odds ratio of illness increased with the amount of raw milk consumed. Also previously healthy adults became infected by consuming raw milk. Identical YP strains were identified from cases' stool samples, raw milk sampled from a case's refrigerator and from the milk filter at the producer's farm. The producer fulfilled the legal requirements for raw milk production and voluntarily recalled the raw milk and stopped its production. We advised consumers to heat the raw milk to 72 °C for 15 s. Current legislation for raw milk producers should be reviewed and public awareness of health risks linked to raw milk consumption should be increased.

Immunochromatographic system for diagnostics of pseudotuberculosis.

We developed a model immunochromatographic test-system for serological express-diagnostics of pseudotuberculosis. Nitrocellulose membrane sensitized with species-specific antigen, Yersinia pseudotuberculosis thermostable toxin, was used as the immunosorbent. Detection of antibodies to the pathogen was performed using functionalized carbon nanoparticles. System performance was verified in testing of the reference pseudotuberculosis serum. Tests with salmonella, escherichia, and enteral yersinia diagnostic sera and blood serum from a healthy man demonstrated high specificity of the system.

Difficulties in diagnosing terminal ileitis due to Yersinia pseudotuberculosis.

We report three patients with terminal ileitis and positive fecal cultures with Yersinia pseudotuberculosis. From one patient, a virulence plasmid (pYV)-negative Y. pseudotuberculosis was isolated, which represents the second finding of a pYV-negative isolate associated with human disease. All patients were treated with ciprofloxacin and fully recovered. Since conventional culture methods for yersiniosis are gradually replaced with molecular tests not recognizing Y. pseudotuberculosis, we recommend to include a specific culture medium or to apply a specific polymerase chain reaction (PCR) assay on fecal samples from patients suspected of terminal ileitis.

The first imported human case of Yersinia pseudotuberculosis serotype O1 septicemia presents with acute appendicitis-like syndrome in Taiwan.

Human nonplague yersiniosis occurs more commonly in temperate regions than in tropical or subtropical regions. In Taiwan, which is located in a subtropical region of Southeast Asia, only environmental isolates and human infection of Yersinia enterocolitica were reported, but a human case of Y. pseudotuberculosis infection had not been identified. We report the first person with Y. pseudotuberculosis serotype O1 septicemia who presented with acute appendicitis-like syndrome and who was probably contracted the infection via ingestion of raw foods in a barbecue restaurant in Japan.

[The bacteriophages Yersinia pseudotuberculosis: the detection in strains of different O-serovars and their identification].

The sample included five indicator pseudotuberculosis strains. The application of these strains permitted to isolate out of 161 strains of Y. pseudotuberculosis 9 bacteriophages identical by their morphologic and serologic characteristics but having individual particularities in their lytic activity. The test on sensitivity to bacteriophages can be used in laboratory diagnostic to differentiate the strains of Yersinia pseudotuberculosis.

Study of effectiveness of bioluminescent reporter phage assay on Y. pseudotuberculosis strains.

The method describes the phage-mediated transduction of a bioluminescent phenotype to cultivated Y. pseudotuberculosis cells which are subsequently measured using a microplate luminometer. Reporter phage assay is rapid detection technique and its efficiency is not affected by presence of contaminating bacteria, no sample preparation is needed and it has the ability to test multiple samples simultaneously in a 96-well microtiter plate format. Experiments were performed to develop the rapid detection technique for Y. pseudotuberculosis strains and study the ability of a reporter Yersinia phage to confer a bioluminescent signal to Y. pseudotuberculosis strains under different environmental conditions (media, temperature, bacterial number) for detection. Further, to determine if the Yersinia phage can detect Y. pseudotuberculosis in presence of other bacterial species. The results revealed that the developed reporter phage assay is not effective against wide range of Y. pseudotuberculosis. Y. pseudotuberculosis could be rapidly detected within 30 minutes at 28°C. The reporter phage assay could detect luminescence within 45 minutes when the bacterial cells were at the minimal concentration 105 cells/mL. The optimal detectable concentrations were 106-107 cells/mL at 28 and 37°C. The reporter phage assay could detect Y. pseudotuberculosis within 30 minutes in presence of other enteric bacteria without selective enrichment. It should be noted that the Yersinia reporter phage is specific to Yersinia pestis strains and it can be used to detect Y. pseudotuberculosis when samples exclude the existence of Y. pestis strains. In the presented study this aspect was foreseen.

Determination of Growth Rate and Virulence Plasmid Copy Number During Yersinia pseudotuberculosis Infection Using Droplet Digital PCR.

Pathogenic bacteria have evolved the ability to evade their host defenses and cause diseases. Virulence factors encompass a wide range of adaptations that allow pathogens to survive and proliferate in the hostile host environment during successful infection. In human pathogenic Yersinia species, the potent type III secretion system (T3SS) and other essential virulence factors are encoded on a virulence plasmid. Here, we investigated the bacterial growth rate and plasmid copy number following a Yersinia infection using droplet digital PCR (ddPCR). ddPCR is an exceptionally sensitive, highly precise, and cost-efficient method. It enables precise quantification even from very small amounts of target DNA. This method also enables analysis of complex samples with large amounts of interfering DNA, such as infected tissues or microbiome studies.

Association of Yersinia Infection With Kawasaki Disease: A Prospective Multicenter Cohort Study.

BACKGROUND: Yersinia infection is known to present with Kawasaki disease (KD)-like symptoms although differentiating the 2 has been a challenge. The present study aimed to describe the clinical characteristics and prevalence of Yersinia infection presenting with KD-like symptoms. METHODS: The present, prospective, multicenter study enrolled patients who received a diagnosis of KD between January 2021 and January 2022 at 2 hospitals in Tokyo. Stool samples were collected within 3 days of the start of KD treatment, and cultures were performed for Yersinia . Clinical history and symptoms suggestive of Yersinia infection were also evaluated. RESULTS: During the study period, 141 KD patients were screened and 117 patients with evaluable stool samples were registered. Only 1 patient was positive for Yersinia pseudotuberculosis , which was detected from both stool and blood cultures. The patient was refractory to KD treatment but improved after initiation of appropriate antibiotic therapy. CONCLUSIONS: Routine screening for Yersinia is not appropriate for patients with KD and should be limited to certain patients in high-risk areas and those who are refractory to the standard KD treatment.