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Query: UMLS:C0021311 (Infection)
 38,178 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tularemia is a zoonosis caused by Francisella tularensis; it mainly affects wild animals and only occasionally affects human beings. Uncontrolled trade involving "exotic" animals could become a new route of acquisition. We report the case of a 3-year-old boy who contracted the disease through a bite from a prairie dog. Outbreaks of tularemia have recently been described in some of these animals captured in Texas (USA) and subsequently sold to other countries. Infection due to Yersinia pestis has also been described in humans through contact with prairie dogs with the disease. Streptomycin and gentamicin are currently the drugs of choice against tularemia infection.
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PMID:[Francisella tularensis infection transmitted by prairie dog]. 1520 72

Infections transmitted through consumption of contaminated seafood is a significant source of human morbidity. The aim of this study was to compare the detection of Salmonella, Listeria, Vibrio, and Yersinia enterocolitica in frozen seafood with results from enumeration of conventional faecal indicators. A total of 213 crustaceans or molluscs were purchased from local vendors in Italy: 74% were harvested in Italy, 25% from other European countries and 1% from outside Europe. Listeria spp. was isolated from 20% of samples, Vibrio spp. from 11%, Salmonella from 3% and Y. enterocolitica from 1%. Listeria species isolated were L. monocytogenes, L. innocua, L. welshimeri, L. ivanovii and L. seeligeri. Vibrio species isolated were V. alginolyticus and V. fluvialis. The most contaminated shellfish for both faecal indicator microrganism and pathogens were hen clams (6% contained Salmonella, 27% Listeria spp. and 3% Y. enterocolitica), while from 27% of shrimps Vibrio spp. was recovered. Higher levels of faecal indicators were recovered from samples harvested outside Europe, and 66% of samples harvested in Thailand were contaminated from Salmonella. Significant differences were found in the levels of contamination of seafoods depending upon the freezing regime, but there was a limited association between presence of potential pathogens (particularly Vibrio spp.) and conventional faecal indicators. Hence, we suggest reconsideration of current legal parameters to evaluate microbiological quality of seafood.
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PMID:[Detection of Salmonella, Listeria spp., Vibrio spp., and Yersinia enterocolitica in frozen seafood and comparison with enumeration for faecal indicators: implication for public health]. 1536 11

Yersinia enterocolitica evades innate immunity by expression of a variety of pathogenicity factors. Therefore, adaptive immunity including CD4(+) T cells plays an important role in defense against Y. enterocolitica. We investigated whether Y. enterocolitica might target dendritic cells (DC) involved in adaptive T-cell responses. For this purpose, murine DC were infected with Y. enterocolitica wild-type and mutant strains prior to incubation with ovalbumin (OVA) as antigen and 5-(6)-carboxyfluorescein diacetate N-succinimidyl ester-labeled OVA-specific T cells from DO11.10 mice. While T-cell proliferation was partially affected by infection of DC with plasmid-cured and YopP-deficient Yersinia mutant strains, no T-cell proliferation occurred after infection of DC with wild-type Y. enterocolitica. Infection of DC with Y. enterocolitica wild type resulted in decreased up-regulation of major histocompatibility complex class II, CD54 (intercellular adhesion molecule 1), CD 80, and CD86 expression. Experiments with plasmid-cured Y. enterocolitica or a YopP-deficient mutant strain revealed that YopP accounts for inhibition of surface molecule expression. Wild-type Y. enterocolitica suppressed the release of KC, tumor necrosis factor alpha, interleukin-10 (IL-10), and IL-12 by DC, while infection of DC with plasmid-cured Y. enterocolitica or with the YopP-deficient mutant resulted in the production of these cytokines. Moreover, infection with wild-type Y. enterocolitica induced apoptosis in DC mediated by YopP. Apoptosis occurred despite translocation of NF-kappaB to the nucleus, as demonstrated by electromobility shift assays. Together, these data demonstrate that Y. enterocolitica targets functions of murine DC that are required for T-cell activation. This might contribute to evasion of adaptive immune responses by Y. enterocolitica.
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PMID:Yersinia enterocolitica induces apoptosis and inhibits surface molecule expression and cytokine production in murine dendritic cells. 1555 28

Foodborne illnesses are a substantial health burden in the United States. The Foodborne Diseases Active Surveillance Network (FoodNet) of CDC's Emerging Infections Program collects data from 10 U.S. sites on diseases caused by enteric pathogens transmitted commonly through food. FoodNet quantifies and monitors the incidence of these infections by conducting active, population-based surveillance for laboratory-diagnosed illness. This report describes preliminary surveillance data for 2004 and compares them with baseline data from the period 1996-1998. The 2004 data indicate declines in the incidence of infections caused by Campylobacter, Cryptosporidium, Shiga toxin-producing Escherichia coli (STEC) O157, Listeria, Salmonella, and Yersinia. Declines in Campylobacter and Listeria incidence are approaching national health objectives (objectives 10-1a through 1d); for the first time, the incidence of STEC O157 infections in FoodNet is below the 2010 target. However, further efforts are needed to sustain these declines and to improve prevention of foodborne infections; efforts should be enhanced to reduce pathogens in food animal reservoirs and to prevent contamination of produce.
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PMID:Preliminary FoodNet data on the incidence of infection with pathogens transmitted commonly through food--10 sites, United States, 2004. 1582 64

Select Agents are defined by CDC and the USDA Animal and Plant Health Inspection Service (APHIS) as biological agents or toxins deemed a threat to public, animal, or plant health, or to animal or plant products. They are classified on the basis of their ease of dissemination, mortality/morbidity rate, and potential for social disruption. A subset of these agents includes Bacillus anthracis, Yersinia pestis, Francisella tularensis, ricin toxin (RT), and staphylococcal enterotoxin B (SEB). Infection or intoxication with these agents has been shown to elicit an antigen-specific serum IgG response. We describe a fluorescent covalent microsphere immunoassay (FCMIA) for measurement of specific IgG antibodies to seven different antigens from five different select agents; B. anthracis [protective antigen (PA) and lethal factor (LF)], Y. pestis (F1 and V antigens), F. tularensis, RT and SEB simultaneously in human B. anthracis vaccinee sera (containing anti-PA and anti-LF IgG) which had been spiked with animal specific IgG antibodies to the other select agents. Inter-assay and intra-assay coefficients of variation were 6.5 and 13.4%, respectively (N = 4). There were no significant differences (P > 0.70) between assay responses when the assays were performed individually or multiplexed. When the observed versus expected interpolated concentrations were compared, highly linear relationships were observed (r2 values from 0.981 to 0.999, P < 0.001). Minimum detectable concentrations (MDC) ranged from 0.3 ng mL(-1) (Y. pestis F1) to 300 ng mL(-1) (RT). Finally, the curves showed responses were linear for most analytes from their MDC to 125 (SEB) to 1,300 (Y. pestis F1) x their MDC. These data indicate that multiplexed FCMIA is a sensitive and accurate method for simultaneous measurement of specific IgG in serum to CDC select agents and may be of value in screening either decontamination workers or the general population for exposure to/infection with these agents.
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PMID:Simultaneous measurement of specific serum IgG responses to five select agents. 1593 99

Full virulence of Yersinia enterocolitica Biovar 1B requires two distinct and distantly related contact-dependent type III secretion (T3S) systems. The plasmid-encoded Ysc T3S system is essential for systemic stages of infection and the Yop effector proteins it translocates have been extensively studied. The chromosome-encoded Ysa T3S system contributes to gastrointestinal stages of infection, but the suite of Ysp effectors proteins it translocates into host cells remains obscure. Using a proteomics-based approach, the Ysa T3S system was analysed revealing a complex set of 15 secreted Ysp proteins. Seven of these proteins were previously described (YspA, YspB, YspC, YspD, YopE, YopN and YopP). Eight of these Ysps (YspK, YspI, YspE, YspF, YspP, YspY, YspN and YspL) had not previously been characterized. Several of the new Ysps are homologous to other virulence factors, including YspP with similarity to the Yersinia protein tyrosine phosphatase YopH and YspK with similarity to the Shigella serine/threonine kinase OspG. Biochemical analysis of purified hexa-histidine tagged YspK and YspP established that these proteins have kinase and phosphatase activity respectively. Infection of eukaryotic cells with Y. enterocolitica strains expressing a Ysp-CyaA chimeric protein resulted in Ysa T3S system-dependent increases in cytosolic levels of cAMP for six Ysps (YspK, YspI, YspE, YspF, YspP and YspL), but not two others (YspY and YspN). YspN, however, was required for translocation of effector proteins into eukaryotic cells by the Ysa T3S system. Competition assays in BALB/c mice revealed that mutants defective for the production of an individual Ysp are affected for colonization of gastrointestinal tissues. Collectively, the results of this study support the hypothesis that the Ysa T3S system targets a complex suite of effector proteins into host cells to affect the outcome of an infection. Identification of the suite of effectors delivered by the Ysa T3S system reveals that host cell signalling pathways are the probable targets of several Ysp effectors.
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PMID:Proteomic and functional analysis of the suite of Ysp proteins exported by the Ysa type III secretion system of Yersinia enterocolitica Biovar 1B. 1639 Apr 60

Single-strain infections and coinfections are frequently used to assess roles of virulence factors in infected tissues. After oral inoculation of mice, Yersinia pseudotuberculosis yopE and yopH mutants colonize the intestines and Peyer's patches in single-strain infections but fail to persist in competition with wild-type Y. pseudotuberculosis, indicating that these two infection models provide different insights into the roles of Yops. To determine how wild-type Y. pseudotuberculosis hinders yop mutant survival, yop mutant colonization and host responses were investigated in several different infection models that isolated specific features of wild-type Y. pseudotuberculosis infection. Infection with wild-type Y. pseudotuberculosis caused significantly more inflammation than yop mutants. Results from coinfections of gamma interferon (IFN-gamma)-/- mice revealed that IFN-gamma-regulated defenses target these mutants, suggesting that YopE and YopH protect Y. pseudotuberculosis from these defenses in BALB/c mice. We developed an oral-intraperitoneal infection model to evaluate the effects of spleen and liver colonization by Y. pseudotuberculosis on yop mutants in the intestines. Spleen and liver infection increased inflammation and decreased yop mutant survival in the intestines, indicating that infection of these organs has consequences in intestinal tissues. Finally, competition infections with Y. pseudotuberculosis mutants with various abilities to induce inflammation demonstrated that survival of the yopE, but not the yopH, mutant was consistently decreased in inflamed tissues. In summary, infection with Y. pseudotuberculosis in intestinal and systemic sites induces intestinal inflammation, which decreases yop mutant survival. Thus, competition studies with wild-type yersiniae reveal critical roles of Yops in combating host responses to a normal virulent infection.
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PMID:The proinflammatory response induced by wild-type Yersinia pseudotuberculosis infection inhibits survival of yop mutants in the gastrointestinal tract and Peyer's patches. 1649 22

Infections are major complications and constitute the second most common cause of mortality and a main cause of morbidity in patients with thalassaemia, a group of genetic disorders of haemoglobin synthesis characterised by a disturbance of globin chain production. Thalassaemias are among the most common genetic disorders in the world. Predisposing factors for infections in thalassaemic patients include severe anaemia, iron overload, splenectomy, and a range of immune abnormalities. Major causative organisms of bacterial infections in thalassaemic patients are Klebsiella spp in Asia and Yersinia enterocolitica in western countries. Transfusion-associated viral infections (especially hepatitis C) can lead to liver cirrhosis and hepatocellular carcinoma. A unique and challenging infection detected in Asian patients is pythiosis, caused by a fungus-like organism, the mortality rate of which is very high. Because the prognosis for thalassaemia has much improved, with many patients surviving to the fifth decade of life in developed countries, it is mandatory to reduce mortality by recognising and presumptively treating infections in these patients as quickly as possible.
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PMID:Infections and thalassaemia. 1655 47

Foodborne illnesses are a substantial health burden in the United States. The Foodborne Diseases Active Surveillance Network (FoodNet) of CDC's Emerging Infections Program collects data from 10 U.S. states regarding diseases caused by enteric pathogens transmitted commonly through food. FoodNet quantifies and monitors the incidence of these infections by conducting active, population-based surveillance for laboratory-confirmed illness. This report describes preliminary surveillance data for 2005 and compares them with baseline data from the period 1996-1998. Incidence of infections caused by Campylobacter, Listeria, Salmonella, Shiga toxin-producing Escherichia coli O157 (STEC O157), Shigella, and Yersinia has declined, and Campylobacter and Listeria incidence are approaching levels targeted by national health objectives. However, most of those declines occurred before 2005, and Vibrio infections have increased, indicating that further measures are needed to prevent foodborne illness.
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PMID:Preliminary FoodNet data on the incidence of infection with pathogens transmitted commonly through food--10 States, United States, 2005. 1661 86

Pathogenic Yersinia species share a type III secretion system that translocates Yop effector proteins into host cells to counteract signalling responses during infection. Two of these effectors, YopE and YopT, downregulate Rho GTPases by different mechanisms. Here, we investigate whether YopT and YopE are functionally redundant by dissecting the contribution of these two effectors to the pathogenesis of Yersinia pseudotuberculosis in a mouse infection and tissue culture model. Four days after oral infection, a YopE(+) T (-) strain and a YopE(+) T (+) strain colonized spleens of mice at similar levels, suggesting that YopT is not required for virulence. In contrast, spleen colonization by a YopE(-)T(-) strain was significantly reduced. A YopE(-) T (+) strain colonized spleen at levels comparable to those of the YopE(+) T (-) strain, arguing that YopT can promote virulence in the absence of YopE. Infection of HeLa cells with a YopE(-) T(-)H(-)J(-) strain expressing either YopE or YopT showed that YopE had a stronger antiphagocytic activity than YopT. Expression of YopE strongly inhibited activation of JNK, ERK and NFkappaB, and prevented production of IL-8; whereas YopT moderately inhibited these responses. On the other hand, pore formation was inhibited equally by YopE or YopT. In conclusion, YopE is a potent inhibitor of infection-induced signalling cascades, and YopT can only partially compensate for the loss of YopE.
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PMID:Comparison of YopE and YopT activities in counteracting host signalling responses to Yersinia pseudotuberculosis infection. 1692 68


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