22 results on '"Rivas, Marta"'
Search Results
2. [Isolation of enteropathogenic Escherichia coli O157:H16 identified in a diarrhea case in a child and his household contacts in La Pampa Province, Argentina].
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Silveyra IM, Pereyra AM, Alvarez MG, Villagran MD, Baroni AB, Deza N, Carbonari CC, Miliwebsky E, and Rivas M
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- Argentina, Child, Preschool, Family Health, Female, Humans, Male, Diarrhea microbiology, Enteropathogenic Escherichia coli isolation & purification, Escherichia coli O157 isolation & purification
- Abstract
Enteropathogenic Escherichia coli (EPEC) is a major causative agent of acute diarrhea in children in developing countries. This pathotype is divided into typical EPEC (tEPEC) and atypical EPEC (aEPEC), based on the presence of the bfp virulence factor associated with adhesion, encoded in the pEAF plasmid. In the present study, the isolation of aEPEC O157:H16 from a bloody diarrhea case in a child and his household contacts (mother, father and sister) is described. The strain was characterized as E. coli O157:H16 eae-ɛ-positive, sorbitol fermenter with β-glucuronidase activity, susceptible to all antimicrobials tested, and negative for virulence factors stx1, stx2, ehxA and bfp. XbaI-PFGE performed on all isolates showed the AREXHX01.1040 macrorestriction pattern, with 100% similarity. These results highlight the importance of epidemiological surveillance of E. coli O157-associated diarrhea cases identified in children and their family contacts, as well as the incorporation of molecular techniques that allow the detection of the different E. coli pathotypes., (Copyright © 2015 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)
- Published
- 2015
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3. [Isolation and characterization of Escherichia coli O157 in bovine meat products and cattle in the province of Tucuman].
- Author
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Jure MA, Condorí MS, Pérez Terrazzino G, Catalán MG, López Campo A, Zolezzi G, Chinen I, Rivas M, and Castillo M
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- Animals, Argentina, Bacterial Typing Techniques, DNA, Bacterial genetics, Disease Reservoirs, Electrophoresis, Gel, Pulsed-Field, Escherichia coli Infections transmission, Escherichia coli O157 classification, Escherichia coli O157 genetics, Escherichia coli O157 pathogenicity, Genes, Bacterial, Meat Products microbiology, Polymorphism, Restriction Fragment Length, Serotyping, Virulence genetics, Cattle microbiology, Escherichia coli O157 isolation & purification, Food Microbiology, Meat microbiology
- Abstract
Escherichia coli O157 is an emergent pathogen associated with diarrhea, hemorrhagic colitis and hemolytic uremic syndrome. Meat products constitute an important transmission source of this microorganism. The aims of this study were to characterize E. coli O157 isolated from cattle and meat products collected from abattoirs and retail stores, to establish the clonal relatedness among regional isolates and to compare them with those in the national database. Between 2004 and 2013, 169 minced meat, 35 sausage and 216 carcass samples were analyzed. Thirteen E. coli O157 isolates were identified; 6 of which were O157:H7 and characterized as stx2c(vh-a)/eae/ehxA (n = 5) and stx2/eae/ehxA (n = 1). The 7 remaining isolates were non-toxigenic E. coli strains, and serotyped as O157:NT (n = 4), O157:NM (n = 1), O157:ND (n = 1) and O157:H16 (n = 1). The strains yielded different XbaI-PFGE patterns. Compared to the E. coli O157 isolates in the National Database, none of these patterns have been previously detected in strains of different origin in Argentina., (Copyright © 2014 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)
- Published
- 2015
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4. Geographically distinct Escherichia coli O157 isolates differ by lineage, Shiga toxin genotype, and total shiga toxin production.
- Author
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Mellor GE, Fegan N, Gobius KS, Smith HV, Jennison AV, D'Astek BA, Rivas M, Shringi S, Baker KN, and Besser TE
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- Animals, Argentina epidemiology, Australia epidemiology, Cattle, Cattle Diseases epidemiology, Cattle Diseases microbiology, Escherichia coli Infections epidemiology, Escherichia coli Infections veterinary, Escherichia coli O157 genetics, Humans, Molecular Epidemiology, Polymorphism, Single Nucleotide, Shiga Toxin metabolism, United States epidemiology, Escherichia coli Infections microbiology, Escherichia coli O157 classification, Escherichia coli O157 isolation & purification, Genetic Variation, Genotype, Phylogeography, Shiga Toxin genetics
- Abstract
While the differential association of Escherichia coli O157 genotypes with animal and human hosts has recently been well documented, little is known about their distribution between countries and how this might affect regional disease rates. Here, we used a 48-plex single nucleotide polymorphism (SNP) assay to segregate 148 E. coli O157 isolates from Australia, Argentina, and the United States into 11 SNP lineages. We also investigated the relationship between SNP lineages, Shiga toxin (Stx) gene profiles, and total Stx production. E. coli O157 isolates clearly segregated into SNP lineages that were differentially associated with each country. Of the 11 SNP lineages, seven were detected among isolates from a single country, two were detected among isolates from all three countries, and another two were detected only among U.S. and Argentinean isolates. A number of Australian (30%) and Argentinean (14%) isolates were associated with novel, previously undescribed SNP lineages that were unique to each country. Isolates within SNP lineages that were strongly associated with the carriage of stx2a produced comparatively more Stx on average than did those lacking the stx2a subtype. Furthermore, the proportion of isolates in stx2a-associated SNP lineages was significantly higher in Argentina and the United States than Australia (P < 0.05). This study provides evidence for the geographic divergence of E. coli O157 and for a prominent role of stx2a in total Stx production. These results also highlight the need for more comprehensive studies of the global distribution of E. coli O157 lineages and the impacts of regionally predominant E. coli O157 lineages on the prevalence and severity of disease., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)
- Published
- 2015
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5. Prevalence of Escherichia coli O157:H7 in surface water near cattle feedlots.
- Author
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Tanaro JD, Piaggio MC, Galli L, Gasparovic AM, Procura F, Molina DA, Vitón M, Zolezzi G, and Rivas M
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- Animal Husbandry, Animals, Argentina, Cattle, Electrophoresis, Gel, Pulsed-Field, Escherichia coli O157 genetics, Fresh Water microbiology, Polymerase Chain Reaction, Environmental Monitoring, Escherichia coli O157 isolation & purification, Water Microbiology
- Abstract
Between April 2009 and July 2011, 311 surface water samples in 48 cattle feedlots distributed in an area of about 67,000 km(2) were analyzed to examine the environmental dissemination of Escherichia coli O157:H7. Samples were taken inside and outside the pens, exposed and not exposed to runoff from corrals, near the feedlots. Two types of samples were defined: (1) exposed surface waters (ESW; n=251), downstream from cattle pens; and (2) nonexposed surface waters (NESW; n=60), upstream from cattle pens. By multiplex PCR, 177 (70.5%) ESW samples were rfb(O157)-positive, and 62 (24.7%) E. coli O157, and 32 (12.7%) Shiga toxin-producing E. coli (STEC) O157:H7 strains were isolated. In the NESW samples, 36 (60.0%) were rfb(O157)- positive, and 9 (15.0%) E. coli O157, and 6 (10.0%) STEC O157:H7 strains were isolated. These results showed that the environmental surface waters exposed to liquid discharges from intensive livestock operations tended to be contaminated with more STEC O157:H7 than NESW. However, no significant difference was found. This fact emphasizes the relevance of other horizontal routes of transmission, as the persistence of E. coli in the environment resulting from extensive livestock farming. By XbaI-PFGE, some patterns identified are included in the Argentine Database of E. coli O157, corresponding to strains isolated from hemolytic uremic syndrome and diarrhea cases, food, and animals, such as AREXHX01.0022, second prevalent pattern in Argentina, representing 5.5% of the total database. In the study area, characterized by the abundance of waterways, pathogens contained in feedlot runoff could reach recreational waters and also contaminate produce through irrigation, increasing the potential dissemination of STEC O157:H7 and the risk of human infections. The control of runoff systems from intensive livestock is necessary, but other alternatives should be explored to solve the problem of the presence of E. coli O157 in the aquatic rural environment.
- Published
- 2014
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6. Genotypic characterization of Escherichia coli O157:H7 strains that cause diarrhea and hemolytic uremic syndrome in Neuquén, Argentina.
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Pianciola L, Chinen I, Mazzeo M, Miliwebsky E, González G, Müller C, Carbonari C, Navello M, Zitta E, and Rivas M
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- Argentina epidemiology, Cluster Analysis, Diarrhea epidemiology, Escherichia coli Infections epidemiology, Escherichia coli O157 genetics, Escherichia coli O157 isolation & purification, Escherichia coli Proteins genetics, Foodborne Diseases epidemiology, Genotype, Hemolytic-Uremic Syndrome epidemiology, Humans, Molecular Epidemiology, Molecular Typing, Virulence Factors genetics, Diarrhea microbiology, Escherichia coli Infections microbiology, Escherichia coli O157 classification, Foodborne Diseases microbiology, Hemolytic-Uremic Syndrome microbiology
- Abstract
Shiga toxin-producing Escherichia coli (STEC) are important food-borne pathogens associated with cases of diarrhea, hemorrhagic colitis and hemolytic uremic syndrome (HUS). E. coli O157:H7 is the dominant serotype in Argentina and also in Neuquén Province, in which HUS incidence is above the national average, with a maximum of 28.6 cases per 100,000 children less than 5 years old reported in 1998. The aim of this study was to characterize a collection of 70 STEC O157 strains isolated from patients with diarrhea and HUS treated in the province of Neuquén, Argentina, between 1998 and 2011. All strains harbored eae, ehxA, rfbO157, and fliCH7 genes, and stx2a/stx2c (78.7%) was the predominant genotype. A total of 64 (91.4%) STEC O157 strains belonged to the hypervirulent clade 8 tested using both 4 and 32 SNP typing schemes. The strains showed the highest values reported in the literature for 6 of the 7 virulence determinants described in the TW14359 O157 strain associated with the raw spinach outbreak in the U.S. in 2006. Clade 8 strains were strongly associated with two of them: ECSP_3286, factor encoding an outer membrane protein that facilitates the transport of the heme complex (P=0.001), and in particular extracellular factor ECSP_2870/2872, coding proteins related to adaptation to plant hosts (P=0.000004). The q933 allele, which has been related to high toxin production, was present in 97.1% of the strains studied for the anti-terminator Q gene. In summary, this study describes, for the first time in Argentina, the almost exclusive circulation of strains belonging to the hypervirulent clade 8, and also the presence of putative virulence factors in higher frequencies than those reported worldwide. These data may help to understand the causes of the particular epidemiological situation related to HUS in Neuquén Province., (Copyright © 2014 Elsevier GmbH. All rights reserved.)
- Published
- 2014
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7. The long polar fimbriae operon and its flanking regions in bovine Escherichia coli O157:H43 and STEC O136:H12 strains.
- Author
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Sváb D, Galli L, Horváth B, Maróti G, Dobrindt U, Torres AG, Rivas M, and Tóth I
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- Animals, Caco-2 Cells, Cattle, Escherichia coli classification, Escherichia coli genetics, Escherichia coli Infections veterinary, Escherichia coli O157 classification, Genes, Bacterial, Hep G2 Cells, Humans, Escherichia coli Infections microbiology, Escherichia coli O157 genetics, Escherichia coli Proteins genetics, Fimbriae Proteins genetics, Operon
- Abstract
Long polar fimbriae (Lpf) are intestinal adhesins and important virulence factors of pathogenic Escherichia coli strains. We cloned and sequenced the lpf2-1 operon (lpf2ABCD) and its flanking regions of an intimin- and Shiga toxin-negative atypical E. coli O157:H43 strain of bovine origin and also sequenced the lpf2-1 operon of six additional atypical O157 bovine E. coli strains of various serotypes. Nucleotide sequence comparison of these lpf operons showed sequence conservation as they contained only four polymorphic nucleotide positions. Investigation of these O157 strains as well as 13 E. coli Reference Collection (ECOR) strains carrying the lpf2-1 allele revealed high degree of sequence conservation in the lpf2 flanking regions. The lpf2-1 allele is also present in a bovine Shiga toxin-producing E. coli STEC O136:H12 strain, and in vitro adherence assays revealed that the absence of lpf2-1 in this strain did not affect its host cell-binding properties. Our data indicate that lpf2 loci are highly conserved in E. coli isolates; however, its role in adherence might be masked by other uncharacterized adhesins., (© 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.)
- Published
- 2013
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8. Phylogenetically related Argentinean and Australian Escherichia coli O157 isolates are distinguished by virulence clades and alternative Shiga toxin 1 and 2 prophages.
- Author
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Mellor GE, Sim EM, Barlow RS, D'Astek BA, Galli L, Chinen I, Rivas M, and Gobius KS
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- Argentina, Australia, DNA, Bacterial chemistry, DNA, Bacterial genetics, Escherichia coli O157 genetics, Escherichia coli O157 isolation & purification, Molecular Sequence Data, Sequence Analysis, DNA, Virulence, Virulence Factors genetics, Coliphages genetics, Escherichia coli Infections microbiology, Escherichia coli O157 pathogenicity, Escherichia coli O157 virology, Prophages genetics, Shiga Toxin 1 genetics, Shiga Toxin 2 genetics
- Abstract
Shiga toxigenic Escherichia coli O157 is the leading cause of hemolytic uremic syndrome (HUS) worldwide. The frequencies of stx genotypes and the incidences of O157-related illness and HUS vary significantly between Argentina and Australia. Locus-specific polymorphism analysis revealed that lineage I/II (LI/II) E. coli O157 isolates were most prevalent in Argentina (90%) and Australia (88%). Argentinean LI/II isolates were shown to belong to clades 4 (28%) and 8 (72%), while Australian LI/II isolates were identified as clades 6 (15%), 7 (83%), and 8 (2%). Clade 8 was significantly associated with Shiga toxin bacteriophage insertion (SBI) type stx(2) (locus of insertion, argW) in Argentinean isolates (P < 0.0001). In Argentinean LI/II strains, stx(2) is carried by a prophage inserted at argW, whereas in Australian LI/II strains the argW locus is occupied by the novel stx(1) prophage. In both Argentinean and Australian LI/II strains, stx(2c) is almost exclusively carried by a prophage inserted at sbcB. However, alternative q(933)- or q(21)-related alleles were identified in the Australian stx(2c) prophage. Argentinean LI/II isolates were also distinguished from Australian isolates by the presence of the putative virulence determinant ECSP_3286 and the predominance of motile O157:H7 strains. Characteristics common to both Argentinean and Australian LI/II O157 strains included the presence of putative virulence determinants (ECSP_3620, ECSP_0242, ECSP_2687, ECSP_2870, and ECSP_2872) and the predominance of the tir255T allele. These data support further understanding of O157 phylogeny and may foster greater insight into the differential virulence of O157 lineages.
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- 2012
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9. Shiga toxin-producing Escherichia coli O157 : H7 shows an increased pathogenicity in mice after the passage through the gastrointestinal tract of the same host.
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Fernandez-Brando RJ, Miliwebsky E, Mejías MP, Baschkier A, Panek CA, Abrey-Recalde MJ, Cabrera G, Ramos MV, Rivas M, and Palermo MS
- Subjects
- Animals, Feces microbiology, Female, Humans, Male, Mice, Mice, Inbred BALB C, Serial Passage, Survival Analysis, Virulence, Escherichia coli O157 pathogenicity, Gastrointestinal Tract microbiology
- Abstract
Haemolytic uraemic syndrome (HUS) is a rare but life-threatening complication of Shiga toxin (Stx)-producing Escherichia coli (STEC) infections, characterized by acute renal failure, thrombocytopenia and haemolytic anaemia. Although the main infection route is the consumption of contaminated food or water, person-to-person transmission has been suggested in several situations. Moreover, epidemiological data indicate that the horizontal transmission of several pathogens, including STEC, among individuals of the same species requires significantly lower doses than those used in animal models infected with laboratory-cultured bacteria. Thus, the aim of this study was to evaluate whether the passage of a clinically isolated STEC strain through the gastrointestinal tract of mice affects its pathogenicity in mice. To test this, weaned mice were orally inoculated by gavage with either an E. coli O157:H7 isolate from an HUS patient, or the same strain recovered from stools after one or two successive passages through the gastrointestinal tract of the mice. We show that stool-recovered strains are able to induce a more generalized and persistent colonization than the parent strain. Furthermore, a 10(4)-fold-reduced inoculum of the stool-recovered strains still causes gut colonization and mouse mortality, which are not observed with the parent strain. These results indicate an increased pathogenicity in stool-recovered strains that may be associated with an increased ability to colonize the mouse intestine.
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- 2012
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10. Subtyping of Escherichia coli O157:H7 strains isolated from human infections and healthy cattle in Argentina.
- Author
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D'Astek BA, del Castillo LL, Miliwebsky E, Carbonari C, Palladino PM, Deza N, Chinen I, Manfredi E, Leotta GA, Masana MO, and Rivas M
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- Abattoirs, Amplified Fragment Length Polymorphism Analysis, Animals, Argentina epidemiology, Bacteriophage Typing, Carrier State microbiology, Dysentery, Bacillary epidemiology, Dysentery, Bacillary physiopathology, Electrophoresis, Gel, Pulsed-Field, Endemic Diseases, Escherichia coli Infections epidemiology, Escherichia coli Infections physiopathology, Escherichia coli O157 classification, Escherichia coli O157 metabolism, Gastrointestinal Hemorrhage etiology, Genotyping Techniques, Hemolytic-Uremic Syndrome epidemiology, Hemolytic-Uremic Syndrome physiopathology, Humans, Population Surveillance, Severity of Illness Index, Shiga Toxin 2 genetics, Shiga Toxin 2 metabolism, Cattle microbiology, Disease Reservoirs microbiology, Dysentery, Bacillary microbiology, Escherichia coli Infections microbiology, Escherichia coli O157 isolation & purification, Hemolytic-Uremic Syndrome microbiology
- Abstract
Shiga toxin-producing Escherichia coli (STEC) cause nonbloody (NBD) and bloody diarrhea (BD), and hemolytic uremic syndrome (HUS). Cattle have been described as their main reservoir. STEC O157:H7 is recognized as the predominant serotype in clinical infections, but much less is known about the dominant subtypes in humans and animals or their genetic relatedness. The aims of this study were to compare the STEC O157 subtypes found in sporadic human infections with those in the bovine reservoir using stx-genotyping, phage typing, and XbaI-pulsed-field gel electrophoresis (PFGE), and correlate the subtypes with the severity of clinical manifestations. The 280 STEC O157:H7 strains collected included in this study were isolated from HUS (n=122), BD (n=69), and NBD (n=30) cases, and healthy carriers (n=5), and from bovines (n=54) in the abattoirs. The stx-genotyping showed that stx₂/stx(2c(vh-a)) was predominant in human (76.1%) and in bovine strains (55.5%), whereas the second more important genotype was stx₂ (20.8%) in human and stx(2c(vh-a)) (16.7%) in cattle strains. In human strains, PT4 (37.6%), PT49 (24.3%), and PT2 (18.6%) were the most frequent PTs (80.5%). In bovine isolates, PT2 (26%), PT39 (16.7%), and PT4 and PT49 (11.1% each) were predominant. By XbaI-PFGE, all 280 strains yielded 148 patterns with 75% similarity, and 169 strains were grouped in 37 clusters. Identical PT-PFGE-stx profile combinations were detected in strains of both origins: PT4-AREXH01.0011-stx₂/stx(2c(vh-a)) (12 humans and one bovine), PT4-AREXH01.0543-stx₂/stx(2c(vh-a)) (one human and four bovines), PT2-AREXH01.0076-stx₂/stx(2c(vh-a)) (one human and four bovines), PT49-AREXH01.0175-stx₂/stx(2c(vh-a)) (seven humans and one bovine), and PT49-AREXH01.0022-stx₂/stx(2c(vh-a)) (seven humans and one bovine). No correlation was found among the stx-genotypes, the phage type, and the clinical symptoms.
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- 2012
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11. Two cases of urinary tract infection caused by Shiga toxin-producing Escherichia coli O157:H7 strains.
- Author
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Gadea Mdel P, Deza N, Mota MI, Carbonari C, Robatto M, D'Astek B, Balseiro V, Bazet C, Rügnitz E, Livrelli V, Schelotto F, Rivas M, and Varela G
- Subjects
- Adhesins, Bacterial genetics, Aged, Aged, 80 and over, Argentina epidemiology, Bacterial Typing Techniques, Cystitis microbiology, Diarrhea complications, Escherichia coli Infections epidemiology, Escherichia coli O157 drug effects, Escherichia coli O157 genetics, Escherichia coli Proteins genetics, Female, Fimbriae Proteins genetics, Humans, Kidney Failure, Chronic complications, Microbial Sensitivity Tests, Shiga Toxins genetics, Urinary Tract Infections complications, Escherichia coli Infections microbiology, Escherichia coli O157 isolation & purification, Urinary Tract Infections microbiology
- Abstract
STEC strains can infect extra-intestinal sites such as the human urinary tract and sometimes cause severe complications. We report two cases of urinary tract infection caused by STEC in two elderly women with comorbidities. Although both strains belonged to the O157:H7 serotype and carried genes associated with severe illness, none of the patients developed hemolytic uremic syndrome (HUS). These findings provide additional evidence for the presence of these agents in our country and in the region, and highlight the need to maintain an active surveillance system of HUS cases, placing special emphasis on the study of other sites of infection in patients with non-diarrheal HUS.
- Published
- 2012
12. Prevalence, characterization and clonal analysis of Escherichia coli O157: non-H7 serotypes that carry eae alleles.
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Feng PC, Keys C, Lacher D, Monday SR, Shelton D, Rozand C, Rivas M, and Whittam T
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- Animals, Bacterial Typing Techniques, Cluster Analysis, DNA Fingerprinting, DNA, Bacterial genetics, Electrophoresis, Gel, Pulsed-Field, Escherichia coli O157 isolation & purification, Food Microbiology, Genotype, Humans, Prevalence, Sequence Analysis, DNA, Water Microbiology, Adhesins, Bacterial genetics, Escherichia coli Infections microbiology, Escherichia coli Infections veterinary, Escherichia coli O157 classification, Escherichia coli O157 genetics, Escherichia coli Proteins genetics, Virulence Factors genetics
- Abstract
We examined O157:non-H7 strains isolated from various sources and geographical locations and found 15/57 strains to carry eae alleles, including alpha, beta, epsilon and kappa/delta, suggesting that these strains may be prevalent. All strains were serologically and genetically confirmed to be O157, but none were the H7 serotype or carried any trait virulence factors of the Escherichia coli O157:H7 serotype. Genetic H typing of the eae-positive strains showed that the alpha-eae-bearing strain was H45, while the beta- and epsilon-eae strains were H16 and the kappa/delta-eae strains were H39. The beta- and epsilon-eae-bearing O157:H16 strains shared approximately 90% pulsed-field gel electrophoresis (PFGE) similarity and were distinct from the other strains that had other eae alleles. Interestingly, an epsilon-eae O157:H16 strain isolated from meat in France shared PFGE similarity to the O157:H16 strains from water in the United States. Multilocus sequence typing showed that there is clonal diversity within the O157 serogroup, as some O157:non-H7 strains clustered with EPEC clonal groups, while others clustered within the ST-171 group of diverse strains and serotypes that had not previously included any strains from the O157 serogroup. Clonal analysis also showed that none of the eae-positive O157:non-H7 strains we examined were closely related to the pathogenic O157:H7 serotype.
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- 2010
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13. Escherichia coli O157 in bovine feces and surface water streams in a beef cattle farm of Argentina.
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Tanaro JD, Leotta GA, Lound LH, Galli L, Piaggio MC, Carbonari CC, Araujo S, and Rivas M
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- Animal Husbandry methods, Animals, Argentina, Bacterial Proteins genetics, Cattle Diseases epidemiology, Disease Reservoirs microbiology, Disease Reservoirs veterinary, Escherichia coli Infections epidemiology, Escherichia coli Infections veterinary, Escherichia coli O157 classification, Escherichia coli O157 drug effects, Microbial Sensitivity Tests veterinary, Phylogeny, Prevalence, Seasons, Serotyping veterinary, Shiga Toxin 1 genetics, Shiga Toxin 2 genetics, Shiga-Toxigenic Escherichia coli classification, Shiga-Toxigenic Escherichia coli drug effects, Shiga-Toxigenic Escherichia coli genetics, Shiga-Toxigenic Escherichia coli isolation & purification, Cattle microbiology, Escherichia coli O157 genetics, Escherichia coli O157 isolation & purification, Feces microbiology, Genes, Bacterial, Rivers microbiology, Shiga Toxin genetics
- Abstract
Shiga toxin-producing Escherichia coli (STEC) is an important foodborne pathogen, and ruminants are recognized as the main natural reservoir. The purposes of this study were to detect E. coli O157 in bovine feces and surface water in a beef cattle farm of Gualeguaychú, Argentina; to characterize the isolates; and to establish the clonal relatedness by pulsed-field gel electrophoresis. Between September 2005 and November 2006, 288 samples of bovine feces and 79 samples of water troughs were studied. E. coli O157 was detected by immunomagnetic separation and polymerase chain reaction as screening techniques. The rfb(O157) gene was detected in 3.8% of the 288 fecal samples and in 17.7% of the 79 water samples. The stx gene was detected in all rfb(O157)-positive fecal samples and in 5.1% of water samples. Eleven E. coli O157 strains isolated from bovine fecal samples and eight from water samples were characterized. The most frequent stx genotype identified was stx(1) and stx(2c(vh-a)). Twelve (63.2%) strains harbored fliC(H7), eae, and ehxA genes. Using pulsed-field gel electrophoresis with the enzyme XbaI, a total of eight patterns with at least 72.1% similarity were identified among the 19 strains. The patterns of 15 strains were grouped into four clusters: two of them included only bovine strains and the other two only aquatic strains. No genetic correlation was established between the bovine and water STEC strains detected. The prevalence of STEC O157:H7 established in the herd studied was higher than that previously reported for Argentine grazed cattle.
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- 2010
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14. Shiga toxin-producing Escherichia coli O157 in beef and chicken burgers, and chicken carcasses in Buenos Aires, Argentina.
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Chinen I, Epszteyn S, Melamed CL, Aguerre L, Martínez Espinosa E, Motter MM, Baschkier A, Manfredi E, Miliwebsky E, and Rivas M
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- Animals, Argentina, Cattle, Cluster Analysis, Cooking, Electrophoresis, Gel, Pulsed-Field, Escherichia coli O157 classification, Food Handling methods, Genotype, Humans, Phylogeny, Chickens microbiology, Escherichia coli O157 isolation & purification, Food Contamination analysis, Meat Products microbiology, Poultry Products microbiology
- Abstract
We describe the isolation and characterization of Shiga toxin (Stx)-producing Escherichia coli (STEC) O157:H7 from cooked and uncooked beef and chicken burgers and from chicken carcasses collected during sampling procedures in 2001 and 2002 in Buenos Aires City, Argentina. Of the 24 STEC O157:H7 strains isolated, 20 were recovered from 19 (6.8%) out of 279 samples of beef and chicken burgers, and 4 strains from 4 (10.3%) out of 39 chicken carcasses. The samples were analyzed following the USDA/FSIS 2002 method. The prevalent stx genotype was stx(2) and stx(2c) (12 strains, 50%). All strains were characterized as eae and ehxA-positive. By XbaI-PFGE, the strains yielded 10 different patterns. Eighteen out of 24 strains were grouped in four clusters: #1 (4 strains, AREXHX01.0043), #2 (4 strains, AREXHX01.0022), #3 (8 strains, AREXHX01.0139), and #4 (2 strains, AREXHX01.0200). Identical strains by phage typing, stx genotyping and PFGE were detected in uncooked and cooked beef and chicken burgers in different restaurants, which had been collected on the same or different sampling dates. These findings help to underline the importance of STEC O157 detection in meat products, to improve active surveillance, and to define control strategies in order to prevent new cases of STEC infection.
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- 2009
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15. Characterisation of Shiga toxin-producing Escherichia coli O157 strains isolated from humans in Argentina, Australia and New Zealand.
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Leotta GA, Miliwebsky ES, Chinen I, Espinosa EM, Azzopardi K, Tennant SM, Robins-Browne RM, and Rivas M
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- Adhesins, Bacterial genetics, Argentina, Australia, Bacterial Proteins genetics, Bacterial Typing Techniques, Bacteriophage Typing, Cluster Analysis, DNA Fingerprinting, DNA, Bacterial genetics, Electrophoresis, Gel, Pulsed-Field, Escherichia coli O157 classification, Escherichia coli O157 isolation & purification, Escherichia coli Proteins biosynthesis, Escherichia coli Proteins genetics, Genotype, Hemolysin Proteins biosynthesis, Hemolytic-Uremic Syndrome microbiology, Humans, Molecular Epidemiology, New Zealand, Polymorphism, Restriction Fragment Length, Serotyping, Shiga Toxin 1 genetics, Shiga Toxin 2 genetics, Escherichia coli Infections microbiology, Escherichia coli O157 genetics, Escherichia coli O157 metabolism
- Abstract
Background: Shiga toxin-producing Escherichia coli (STEC) is an important cause of bloody diarrhoea (BD), non-bloody diarrhoea (NBD) and the haemolytic uraemic syndrome (HUS). In Argentina and New Zealand, the most prevalent STEC serotype is O157:H7, which is responsible for the majority of HUS cases. In Australia, on the other hand, STEC O157:H7 is associated with a minority of HUS cases. The main aims of this study were to compare the phenotypic and genotypic characteristics of STEC O157 strains isolated between 1993 and 1996 from humans in Argentina, Australia and New Zealand, and to establish their clonal relatedness., Results: Seventy-three O157 STEC strains, isolated from HUS (n = 36), BD (n = 20), NBD (n = 10), or unspecified conditions (n = 7) in Argentina, Australia and New Zealand, were analysed. The strains were confirmed to be E. coli O157 by biochemical tests and serotyping. A multiplex polymerase chain reaction (PCR) was used to amplify the stx1, stx2 and rfbO157 genes and a genotyping method based on PCR-RFLP was used to determine stx1 and stx2 variants. This analysis revealed that the most frequent stx genotypes were stx2/stx2c (vh-a) (91%) in Argentina, stx2 (89%) in New Zealand, and stx1/stx2 (30%) in Australia. No stx1-postive strains were identified in Argentina or New Zealand. All strains harboured the eae gene and 72 strains produced enterohaemolysin (EHEC-Hly). The clonal relatedness of strains was investigated by phage typing and pulsed-field gel electrophoresis (PFGE). The most frequent phage types (PT) identified in Argentinian, Australian, and New Zealand strains were PT49 (n = 12), PT14 (n = 9), and PT2 (n = 15), respectively. Forty-six different patterns were obtained by XbaI-PFGE; 37 strains were grouped in 10 clusters and 36 strains showed unique patterns. Most clusters could be further subdivided by BlnI-PFGE., Conclusion: STEC O157 strains isolated in Argentina, Australia, and New Zealand differed from each other in terms of stx-genotype and phage type. Additionally, no common PFGE patterns were found in strains isolated in the three countries. International collaborative studies of the type reported here are needed to detect and monitor potentially hypervirulent STEC clones.
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- 2008
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16. TccP2 of O157:H7 and non-O157 enterohemorrhagic Escherichia coli (EHEC): challenging the dogma of EHEC-induced actin polymerization.
- Author
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Ogura Y, Ooka T, Whale A, Garmendia J, Beutin L, Tennant S, Krause G, Morabito S, Chinen I, Tobe T, Abe H, Tozzoli R, Caprioli A, Rivas M, Robins-Browne R, Hayashi T, and Frankel G
- Subjects
- Amino Acid Sequence, Base Sequence, Blotting, Western, Carrier Proteins metabolism, DNA, Bacterial chemistry, DNA, Bacterial genetics, Epithelial Cells chemistry, Epithelial Cells microbiology, Escherichia coli metabolism, Escherichia coli O157 metabolism, Escherichia coli Proteins metabolism, Gene Deletion, Genetic Complementation Test, HeLa Cells, Humans, Immunohistochemistry, Microscopy, Fluorescence, Molecular Sequence Data, Phosphorylation, Polymerase Chain Reaction, Receptors, Cell Surface biosynthesis, Receptors, Cell Surface genetics, Receptors, Cell Surface metabolism, Sequence Analysis, DNA, Actins metabolism, Carrier Proteins biosynthesis, Carrier Proteins genetics, Escherichia coli genetics, Escherichia coli O157 genetics, Escherichia coli Proteins biosynthesis, Escherichia coli Proteins genetics, Virulence Factors genetics
- Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 and enteropathogenic E. coli (EPEC) trigger actin polymerization at the site of bacterial adhesion by inducing different signaling pathways. Actin assembly by EPEC requires tyrosine phosphorylation of Tir, which subsequently binds the host adaptor protein Nck. In contrast, Tir(EHEC O157) is not tyrosine phosphorylated and instead of Nck utilizes the bacterially encoded Tir-cytoskeleton coupling protein (TccP)/EspF(U), which mimics the function of Nck. tccP is carried on prophage CP-933U/Sp14 (TccP). Typical isolates of EHEC O157:H7 harbor a pseudo-tccP gene that is carried on prophage CP-933 M/Sp4 (tccP2). Here we report that atypical, beta-glucuronidase-positive and sorbitol-fermenting, strains of EHEC O157 harbor intact tccP and tccP2 genes, both of which are secreted by the LEE-encoded type III secretion system. Non-O157 EHEC strains, including O26, O103, O111, and O145, are typically tccP negative and translocate a Tir protein that encompasses an Nck binding site. Unexpectedly, we found that most clinical non-O157 EHEC isolates carry a functional tccP2 gene that encodes a secreted protein that can complement an EHEC O157:H7 DeltatccP mutant. Using discriminatory, allele-specific PCR, we have demonstrated that over 90% of tccP2-positive non-O157 EHEC strains contain a Tir protein that can be tyrosine phosphorylated. These results suggest that the TccP pathway can be used by both O157 and non-O157 EHEC and that non-O157 EHEC can also trigger actin polymerization via the Nck pathway.
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- 2007
- Full Text
- View/download PDF
17. Isolation and characterization of Shiga toxin-producing Escherichia coli from precooked sausages (morcillas).
- Author
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Oteiza JM, Chinen I, Miliwebsky E, and Rivas M
- Subjects
- Animals, Colony Count, Microbial, Consumer Product Safety, Enterobacteriaceae isolation & purification, Food-Processing Industry methods, Humans, Hygiene, Meat Products standards, Swine, Escherichia coli isolation & purification, Escherichia coli O157 isolation & purification, Food Contamination analysis, Food-Processing Industry standards, Meat Products microbiology, Shiga Toxins biosynthesis
- Abstract
The aim of the study was to establish the microbiological quality of morcillas, typical Argentine sausages, and to investigate the presence of Shiga toxin-producing Escherichia coli (STEC). Between October 2001 and October 2002, a total of 100 morcilla samples were analysed. Several samples showed high levels of total aerobic mesophilic bacteria counts, molds and yeasts. The samples analysed contained Enterobacteriaceae (100%) and fecal coliforms (81%), indicating inadequate application of the thermal treatment and deficient hygiene conditions during the elaboration of the product. STEC strains were isolated from three out of 100 (3%) morcilla samples. Two strains (2%) were characterized as E. coli O157:H7 stx2+stx2vh-a/eae/EHEC-hlyA and one strain (1%), as E. coli O26:H11 stx1/eae/EHEC-hlyA. Considering both the high microbial count in all tested samples and the presence of STEC strains in three of them, morcillas should be considered a food unsafe to consume when inadequately cooked.
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- 2006
- Full Text
- View/download PDF
18. Home-prepared hamburger and sporadic hemolytic uremic syndrome, Argentina.
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Rivas M, Caletti MG, Chinen I, Refi SM, Roldán CD, Chillemi G, Fiorilli G, Bertolotti A, Aguerre L, and Sosa Estani S
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- Animals, Argentina, Cattle, Child, Preschool, Escherichia coli O157 pathogenicity, Female, Hemolytic-Uremic Syndrome diagnosis, Humans, Escherichia coli O157 isolation & purification, Food Microbiology, Hemolytic-Uremic Syndrome microbiology, Meat microbiology
- Published
- 2003
- Full Text
- View/download PDF
19. Serotypes and Shiga toxin genotypes among Escherichia coli isolated from animals and food in Argentina and Brazil.
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Guth BE, Chinen I, Miliwebsky E, Cerqueira AM, Chillemi G, Andrade JR, Baschkier A, and Rivas M
- Subjects
- Adhesins, Bacterial chemistry, Adhesins, Bacterial genetics, Animals, Argentina, Brazil, Carrier Proteins chemistry, Carrier Proteins genetics, Cattle, DNA, Bacterial chemistry, DNA, Bacterial genetics, Electrophoresis, Gel, Pulsed-Field veterinary, Escherichia coli Infections microbiology, Escherichia coli O157 isolation & purification, Escherichia coli O157 metabolism, Escherichia coli O157 pathogenicity, Escherichia coli Proteins chemistry, Escherichia coli Proteins genetics, Female, Hemolysin Proteins chemistry, Hemolysin Proteins genetics, Male, Meat microbiology, Nucleic Acid Hybridization, Phylogeny, Sequence Analysis, DNA, Shiga Toxins chemistry, Escherichia coli Infections veterinary, Escherichia coli O157 genetics, Food Microbiology, Shiga Toxins genetics
- Abstract
Shiga toxin (Stx)-producing Escherichia coli (STEC) strains isolated from animals and food in Argentina (n=44) and Brazil (n=20) were examined and compared in regard to their phenotypic and genotypic characteristics to evaluate their pathogenic potential. The clonal relatedness of STEC O157 isolates (n=22) was established by phage typing (PT) and pulsed-field gel electrophoresis (PFGE). All O157 strains studied carried eae and enterohemorrhagic E. coli (EHEC)-hly sequences. In Argentina, these strains occurred both in cattle and meat, and 50% of them carried stx2/stx2vh-a genes, whereas in Brazil the O157 strains were isolated from animals, and most harbored the stx2vh-a sequence. At least 13 different O:H serotypes were identified among the non-O157 strains studied, with serotype O113:H21 being found in both countries. All but one non-O157 strains did not carry eae gene, but EHEC-hlyA gene was found in 85.7% of them, and the stx2 genotype was also more prevalent in Argentina than in Brazil (P<0.01), where stx1 alone or in association was most common (68.8%). One STEC strain isolated from a calf in Brazil harbored the new variant referred to as stx2-NV206. PFGE analysis showed that STEC O157 strains were grouped in four clusters. One Brazilian strain was considered possibly related (> or =80%) to Argentinean strains of cluster I. Differences in the pathogenic potential, especially in regard to serotypes and stx genotypes, were observed among the STEC strains recovered from animals and food in both countries.
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- 2003
- Full Text
- View/download PDF
20. Genotypic characterization of Escherichia coli O157:H7 strains that cause diarrhea and hemolytic uremic syndrome in Neuquén, Argentina
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Navello Mariano, Chinen Isabel, Miliwebsky Elizabeth, Pianciola Luis, Mazzeo Melina, Zitta Eugenia, González Gladys, Rivas Marta, Müller Constanza, and Carbonari Carolina
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Microbiology (medical) ,Serotype ,Diarrhea ,Genotype ,Virulence Factors ,Argentina ,Virulence ,Biology ,medicine.disease_cause ,Escherichia coli O157 ,Microbiology ,Foodborne Diseases ,STX2 ,medicine ,Cluster Analysis ,Humans ,Typing ,Escherichia coli ,Escherichia coli Infections ,Molecular Epidemiology ,Escherichia coli Proteins ,Outbreak ,General Medicine ,Virology ,Molecular Typing ,Infectious Diseases ,Hemolytic-Uremic Syndrome ,medicine.symptom - Abstract
Shiga toxin-producing Escherichia coli (STEC) are important food-borne pathogens associated with cases of diarrhea, hemorrhagic colitis and hemolytic uremic syndrome (HUS). E. coli O157:H7 is the dominant serotype in Argentina and also in Neuquen Province, in which HUS incidence is above the national average, with a maximum of 28.6 cases per 100,000 children less than 5 years old reported in 1998. The aim of this study was to characterize a collection of 70 STEC O157 strains isolated from patients with diarrhea and HUS treated in the province of Neuquen, Argentina, between 1998 and 2011. All strains harbored eae, ehxA, rfbO157, and fliCH7 genes, and stx2a/stx2c (78.7%) was the predominant genotype. A total of 64 (91.4%) STEC O157 strains belonged to the hypervirulent clade 8 tested using both 4 and 32 SNP typing schemes. The strains showed the highest values reported in the literature for 6 of the 7 virulence determinants described in the TW14359 O157 strain associated with the raw spinach outbreak in the U.S. in 2006. Clade 8 strains were strongly associated with two of them: ECSP_3286, factor encoding an outer membrane protein that facilitates the transport of the heme complex (P = 0.001), and in particular extracellular factor ECSP_2870/2872, coding proteins related to adaptation to plant hosts (P = 0.000004). The q933 allele, which has been related to high toxin production, was present in 97.1% of the strains studied for the anti-terminator Q gene. In summary, this study describes, for the first time in Argentina, the almost exclusive circulation of strains belonging to the hypervirulent clade 8, and also the presence of putative virulence factors in higher frequencies than those reported worldwide. These data may help to understand the causes of the particular epidemiological situation related to HUS in Neuquen Province.
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- 2014
21. The long polar fimbriae (lpf) operon and its flanking regions in atypical bovine Escherichia coli O157:H43 and STEC O136:H12 strains
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Sváb, Domonkos, Galli, Lucía, Horváth, Balázs, Maróti, Gergely, Dobrindt, Ulrich, Torres, Alfredo G., Rivas, Marta, and Tóth, István
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ATYPICAL E. COLI ,Biología ,Ciencias Veterinarias ,H12 [O136] ,Atypical e. coli ,Ppathogenic E. col ,H43 [O157] ,Escherichia coli O157 ,purl.org/becyt/ford/1 [https] ,Ciencias Biológicas ,Biología Celular, Microbiología ,Long polar fimbriae ,ESCHERICHIA COLI ,purl.org/becyt/ford/1.6 [https] ,LPF ,CIENCIAS NATURALES Y EXACTAS - Abstract
Long polar fimbriae (Lpf) are intestinal adhesins and important virulence factors of pathogenic Escherichia coli strains. We cloned and sequenced the lpf2-1 operon (lpf2ABCD) and its flanking regions of an intimin- and Shiga toxin-negative E. coli O157:H43 strain of bovine origin, and also sequenced the lpf2-1 operon of 6 additional atypical O157 bovine Escherichia coli strains of various serotypes. Nucleotide sequence comparison of these lpf operons showed sequence conservation as they contained only four polymorphic nucleotide positions. Investigation of these O157 strains as well as 13 Escherichia coli Reference Collection (ECOR) strains carrying the lpf2-1 allele revealed high degree of sequence conservation in the lpf2 flanking regions. The lpf2-1 allele is also present in a bovine Shiga toxin-producing E. coli STEC O136:H12 strain and in vitro adherence assays revealed that the absence of lpf2-1 in this strain did not affect its host cell-binding properties. Our data indicate that lpf2 loci is highly conserved in E. coli isolates, however, its role in adherence might be masked by other uncharacterized adhesins., Instituto de Genética Veterinaria
- Published
- 2013
22. Primer aislamiento en Uruguay de Escherichia coli productora de toxina Shiga del serotipo O157:H7 en una niña con síndrome urémico hemolítico
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Gadea, María del Pilar, Varela, Gustavo, Bernadá, Mercedes, Sirok, Alfredo, Mota, María Inés, Sabelli, Rosana, Grotiuz, Germán, Schelotto, Felipe, Chinen, Isabel, Chillemi, Germán, and Rivas, Marta
- Subjects
INFECCIONES POR ESCHERICHIA COLI ,TOXINA SHIGA ,ESCHERICHIA COLI O157 ,SÍNDROME HEMOLÍTICO-URÉMICO - Abstract
En mayo de 2002 se aisló por primera vez en Uruguay Escherichia coli O157:H7, productora de toxina Shiga a partir del coprocultivo de una niña de 16 meses procedente de Melo, con diagnóstico de síndrome urémico hemolítico. La cepa, productora de toxinas Shiga tipo 2 y tipo 2 variante humana a, era genéticamente distinta de las cepas circulantes en Argentina. Summary Shiga toxin-producing Escherichia coli OI57:H7 was isolated for the first time in Uruguay in May 2002 from fecal specimens cultures of a 16-month-female child coming from Melo with hemolytic uremic syndrome. The strain, Shiga type 2 and human variant a type 2 toxine-producing, was genetically different from current Argentinian strains. Résumé En mai 2002 on a isolé pour la première fois en Uruguay Escherichia coli O 157:H7, producteur de toxine Shiga à partir de la coproculture d'une fille de 16 mois provenant de Melo, avec un diagnostic de syndrôme urémique hémolytique. La cèpe, productrice de toxines Shiga type 2 et type 2 variante humaine a, était génétiquement différente aux cèpes présentes en Argentine.
- Published
- 2004
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