RESUMEN
Escherichia coli sfa+ strains isolated from poultry were serotyped and characterized by polymerase chain reaction (PCR) and amplified fragment length polymorphism (AFLP). Isolates collected from 12 Brazilian poultry farms mostly belonged to serogroup O6, followed by serogroups O2, O8, O21, O46, O78, O88, O106, O111, and O143. Virulence genes associated were: iuc 90%, fim 86% neuS 60%, hly 34%, tsh 28%, crl/csg 26%, iss 26%, pap 18%, and 14% cnf. Strains from the same farm presented more than one genotypic pattern belonging to different profiles in AFLP. AFLP showed a clonal relation between Escherichia coli sfa+ serogroup O6. The virulence genes found in these strains reveal some similarity with extraintestinal E. coli (ExPEC), thus alerting for potential zoonotic risk.
Asunto(s)
Proteínas de Escherichia coli/genética , Escherichia coli/patogenicidad , Genes Bacterianos , Aves de Corral/microbiología , Animales , Secuencia de Bases , Brasil , Cartilla de ADN , Escherichia coli/genética , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , VirulenciaRESUMEN
Escherichia coli isolates from 24 sick psittacine birds were serogrouped and investigated for the presence of genes encoding the following virulence factors: attaching and effacing (eae), enteropathogenic E. coli EAF plasmid (EAF), pili associated with pyelonephritis (pap), S fimbriae (sfa), afimbrial adhesin (afa), capsule K1 (neu), curli (crl, csgA), temperature-sensitive hemagglutinin (tsh), enteroaggregative heat-stable enterotoxin-1 (astA), heat-stable enterotoxin -1 heat labile (LT) and heat stable (STa and STb) enterotoxins, Shiga-like toxins (stx1 and stx2), cytotoxic necrotizing factor 1 (cnf1), haemolysin (hly), aerobactin production (iuc) and serum resistance (iss). The results showed that the isolates belonged to 12 serogroups: O7; O15; O21; O23; O54; O64; O76; O84; O88; O128; O152 and O166. The virulence genes found were: crl in all isolates, pap in 10 isolates, iss in seven isolates, csgA in five isolates, iuc and tsh in three isolates and eae in two isolates. The combination of virulence genes revealed 11 different genotypic patterns. All strains were negative for genes encoding for EAF, EAEC, K1, sfa, afa, hly, cnf, LT, STa, STb, stx1 and stx2. Our findings showed that some E. coli isolated from psittacine birds present the same virulence factors as avian pathogenic E. coli (APEC), uropathogenic E. coli (UPEC) and Enteropathogenic E. coli (EPEC) pathotypes.
Amostras de Escherichia coli isoladas de 24 psitacídeos doentes foram sorogrupadas e investigadas para a presença de genes que codificam os seguintes fatores de virulência: attaching e effacing (eae), plasmídeo EAF (EAF), pili associado à pielonefrite (pap), fímbria S (sfa), adesina afimbrial (afa), cápsula K1 (neu), curli (crl, csgA), hemaglutinina termosensível (tsh), enterotoxina termo-estável 1 de E. coli enteroagregativa (astA), toxina termolábil (LT) e toxina termoestável (STa e STb), Shiga-like toxinas (stx1 e stx2), fator citotóxico necrotizante 1 (cnf1), hemolisina (hly), produção de aerobactina (iuc) e resistência sérica (iss). Os resultados mostraram que os isolados pertenciam a 12 sorogrupos: O7; O15; O21; O23; O54; O64; O76; O84; O88; O128; O152 e O166. Os genes de virulência encontrados foram: crl em todos os isolados, pap em 10 isolados, iss em sete isolados, csgA em cinco isolados, iuc e tsh em três isolados e eae em dois isolados. A combinação dos genes de virulência revelou 11 perfis genotípicos distintos. Todas as amostras foram negativas para os genes que codificam EAF, EAEC, K1, sfa, afa, hly, cnf, LT, STa, STb, stx1 e stx2. Estes resultados demonstraram que algumas amostras de E. coli isoladas de psitacídeos apresentam os mesmos fatores de virulência presentes nos patotipos de E. coli patogênicas para aves (APEC), uropatogênicas (UPEC) e E. coli enteropatogênicas (EPEC).
Asunto(s)
Animales , Escherichia coli , Factores de Virulencia/análisis , Loros/virología , Sepsis/diagnósticoRESUMEN
Escherichia coli isolates from 24 sick psittacine birds were serogrouped and investigated for the presence of genes encoding the following virulence factors: attaching and effacing (eae), enteropathogenic E. coli EAF plasmid (EAF), pili associated with pyelonephritis (pap), S fimbriae (sfa), afimbrial adhesin (afa), capsule K1 (neu), curli (crl, csgA), temperature-sensitive hemagglutinin (tsh), enteroaggregative heat-stable enterotoxin-1 (astA), heat-stable enterotoxin -1 heat labile (LT) and heat stable (STa and STb) enterotoxins, Shiga-like toxins (stx1 and stx2), cytotoxic necrotizing factor 1 (cnf1), haemolysin (hly), aerobactin production (iuc) and serum resistance (iss). The results showed that the isolates belonged to 12 serogroups: O7; O15; O21; O23; O54; O64; O76; O84; O88; O128; O152 and O166. The virulence genes found were: crl in all isolates, pap in 10 isolates, iss in seven isolates, csgA in five isolates, iuc and tsh in three isolates and eae in two isolates. The combination of virulence genes revealed 11 different genotypic patterns. All strains were negative for genes encoding for EAF, EAEC, K1, sfa, afa, hly, cnf, LT, STa, STb, stx1 and stx2. Our findings showed that some E. coli isolated from psittacine birds present the same virulence factors as avian pathogenic E. coli (APEC), uropathogenic E. coli (UPEC) and Enteropathogenic E. coli (EPEC) pathotypes.(AU)
Amostras de Escherichia coli isoladas de 24 psitacídeos doentes foram sorogrupadas e investigadas para a presença de genes que codificam os seguintes fatores de virulência: attaching e effacing (eae), plasmídeo EAF (EAF), pili associado à pielonefrite (pap), fímbria S (sfa), adesina afimbrial (afa), cápsula K1 (neu), curli (crl, csgA), hemaglutinina termosensível (tsh), enterotoxina termo-estável 1 de E. coli enteroagregativa (astA), toxina termolábil (LT) e toxina termoestável (STa e STb), Shiga-like toxinas (stx1 e stx2), fator citotóxico necrotizante 1 (cnf1), hemolisina (hly), produção de aerobactina (iuc) e resistência sérica (iss). Os resultados mostraram que os isolados pertenciam a 12 sorogrupos: O7; O15; O21; O23; O54; O64; O76; O84; O88; O128; O152 e O166. Os genes de virulência encontrados foram: crl em todos os isolados, pap em 10 isolados, iss em sete isolados, csgA em cinco isolados, iuc e tsh em três isolados e eae em dois isolados. A combinação dos genes de virulência revelou 11 perfis genotípicos distintos. Todas as amostras foram negativas para os genes que codificam EAF, EAEC, K1, sfa, afa, hly, cnf, LT, STa, STb, stx1 e stx2. Estes resultados demonstraram que algumas amostras de E. coli isoladas de psitacídeos apresentam os mesmos fatores de virulência presentes nos patotipos de E. coli patogênicas para aves (APEC), uropatogênicas (UPEC) e E. coli enteropatogênicas (EPEC).(AU)
Asunto(s)
Animales , Loros/virología , Factores de Virulencia/análisis , Escherichia coli , Sepsis/diagnósticoRESUMEN
Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrhea. Three adhesins (Tia, TibA, EtpA), an iron acquisition system (Irp1, Irp2, and FyuA), a GTPase (LeoA), and an autotransporter (EatA) are ETEC virulence-related proteins that, in contrast to the classical virulence factors (enterotoxins and fimbrial colonization factors) have not heretofore been targets in characterizing isolates from epidemiological studies. Here, we determined the occurrence of these nonclassical virulence genes in 103 ETEC isolates from Chilean children with diarrhea and described their association with O serogroups and classical virulence determinants. Because tia, leoA, irp2, and fyuA are harbored by pathogenicity islands inserted into the selC and asnT tRNA genes (tDNAs), we analyzed the regions flanking these loci. Ten additional tDNAs were also screened to identify hot spots for genetic insertions. Associations between the most frequent serogroups and classical colonization factor (CF)-toxin profiles included O6/LT-STh/CS1-CS3-CS21 (i.e., O6 serogroup, heat-labile [LT] and human heat-stable [STh] enterotoxins, and CFs CS1, -3 and -21), O6/LT-STh/CS2-CS3-CS21, and O104-O127/STh/CFAI-CS21. The eatA and etpA genes were detected in more than 70% of the collection, including diverse serogroups and virulence profiles. Sixteen percent of the ETEC strains were negative for classical and nonclassical adhesins, suggesting the presence of unknown determinants of adhesion. The leuX, thrW, and asnT tDNAs were disrupted in more than 65% of strains, suggesting they are hot spots for the insertion of mobile elements. Sequences similar to integrase genes were identified next to the thrW, asnT, pheV, and selC tDNAs. We propose that the eatA and etpA genes should be included in characterizations of ETEC isolates in future epidemiological studies to determine their prevalence in other geographical regions. Sequencing of tDNA-associated genetic insertions might identify new ETEC virulence determinants.
Asunto(s)
Escherichia coli Enterotoxigénica/genética , Escherichia coli Enterotoxigénica/patogenicidad , Infecciones por Escherichia coli/microbiología , Islas Genómicas , Mutagénesis Insercional , ARN de Transferencia/genética , Factores de Virulencia/genética , Niño , Chile , ADN Bacteriano/química , ADN Bacteriano/genética , Diarrea/microbiología , Escherichia coli Enterotoxigénica/aislamiento & purificación , Proteínas de Escherichia coli/genética , Genética Microbiana/métodos , Humanos , Tamizaje Masivo/métodos , Datos de Secuencia Molecular , Análisis de Secuencia de ADNRESUMEN
BACKGROUND: Enteropathogenic Escherichia coli (EPEC) produce attaching/effacing (A/E) lesions on eukaryotic cells mediated by the outer membrane adhesin intimin. EPEC are sub-grouped into typical (tEPEC) and atypical (aEPEC). We have recently demonstrated that aEPEC strain 1551-2 (serotype O non-typable, non-motile) invades HeLa cells by a process dependent on the expression of intimin sub-type omicron. In this study, we evaluated whether aEPEC strains expressing other intimin sub-types are also invasive using the quantitative gentamicin protection assay. We also evaluated whether aEPEC invade differentiated intestinal T84 cells. RESULTS: Five of six strains invaded HeLa and T84 cells in a range of 13.3%-20.9% and 5.8%-17.8%, respectively, of the total cell-associated bacteria. The strains studied were significantly more invasive than prototype tEPEC strain E2348/69 (1.4% and 0.5% in HeLa and T84 cells, respectively). Invasiveness was confirmed by transmission electron microscopy. We also showed that invasion of HeLa cells by aEPEC 1551-2 depended on actin filaments, but not on microtubules. In addition, disruption of tight junctions enhanced its invasion efficiency in T84 cells, suggesting preferential invasion via a non-differentiated surface. CONCLUSION: Some aEPEC strains may invade intestinal cells in vitro with varying efficiencies and independently of the intimin sub-type.
Asunto(s)
Adhesinas Bacterianas/genética , Escherichia coli Enteropatógena/genética , Proteínas de Escherichia coli/genética , Virulencia/genética , Citoesqueleto de Actina/metabolismo , Escherichia coli Enteropatógena/clasificación , Escherichia coli Enteropatógena/patogenicidad , Genes Bacterianos , Células HeLa , Humanos , Microscopía Electrónica de Transmisión , Serotipificación , Uniones Estrechas/metabolismoRESUMEN
This study characterized 76 atypical enteropathogenic Escherichia coli (aEPEC) strains, previously classified by the eae(+) EAF-negative stx(-) genotype, isolated from children with diarrhea in Brazil. Presence of bfpA and bfpA/perA was detected in 2 and 6 strains, respectively. The expression of bundle-forming pilus (BFP), however, was observed by immunofluorescence in 1 bfpA and 3 bfpA/perA strains, classifying them as typical EPEC (tEPEC). The remaining 72 aEPEC strains were characterized by serotyping, intimin typing, adherence patterns to HEp-2 cells, capacity to induce actin aggregation (fluorescent actin staining test), and antimicrobial resistance. Our results show that aEPEC comprise a very heterogeneous group that does not present any prevalence or association regarding the studied characteristics. It also suggest that tEPEC and aEPEC must not be classified only by the reactivity with the EAF probe, and that the search of other markers present in pEAF, as well as the BFP expression, must be considered for this matter.
Asunto(s)
Adhesinas Bacterianas/genética , Diarrea/microbiología , Escherichia coli Enteropatógena/genética , Escherichia coli Enteropatógena/patogenicidad , Infecciones por Escherichia coli/microbiología , Proteínas de Escherichia coli/genética , Toxina Shiga/genética , Adhesión Bacteriana , Técnicas de Tipificación Bacteriana , Brasil , Línea Celular , Niño , Escherichia coli Enteropatógena/clasificación , Escherichia coli Enteropatógena/aislamiento & purificación , Proteínas Fimbrias/genética , Técnica del Anticuerpo Fluorescente/métodos , Humanos , Reacción en Cadena de la Polimerasa/métodos , Proteínas Represoras/genética , Serotipificación , VirulenciaRESUMEN
A collection of 69 eae-positive strains expressing 29 different intimin types and eight tir alleles was characterizedwith respect to their adherence patterns to HeLa cells, ability to promote actin accumulation in vitro, the presence of bfpA alleles in positive strains, and bundle-forming pilus (BFP) expression. All of the nine typical enteropathogenic Escherichia coli (tEPEC) studied harbored the enteropathogenic E. coli adherence factor (EAF) plasmid, as shown by PCR and/or EAF probe results. In addition, they were positive for bfpA, as shown by PCR, and BFP expression, as confirmed by immunofluorescence(IFL) and/or immunoblotting (IBL) assays. Localized adherence (LA) was exclusively displayed by those ninetEPEC, while localized-adherence-like (LAL) was the most frequent pattern among atypical EPEC (aEPEC) and Shiga-toxinproducing E. coli (STEC). All LA and LAL strains were able to cause attaching and effacing (AE) lesions, as established by means of the FAS test. There was a significant association between the presence of tir allele á1 and bfpA-positive strains, and consequently, with the LA pattern. However, intimin type or bfpA was not associated with the adherence pattern displayed in HeLa cells. Among the eight bfpA alleles detected, a new type (â10; accession number FN391178) was identified in a strain of serotype O157:H45, and a truncated variant (â3.2-t; accession number FN 391181) in four strains belonging to differentpathotypes.
Asunto(s)
Humanos , Escherichia coli , Escherichia coli Enteropatógena , Toxinas Shiga , Células HeLa/citologíaRESUMEN
To analyze whether Escherichia coli strains that cause urinary tract infections (UPEC) share virulence characteristics with the diarrheagenic E. coli (DEC) pathotypes and to recognize their genetic diversity, 225 UPEC strains were examined for the presence of various properties of DEC and UPEC (type of interaction with HeLa cells, serogroups and presence of 30 virulence genes). No correlation between adherence patterns and serogroups was observed. Forty-five serogroups were found, but 64% of the strains belonged to one of the 12 serogroups (O1, O2, O4, O6, O7, O14, O15, O18, O21, O25, O75, and O175) and carried UPEC virulence genes (pap, hly, aer, sfa, cnf). The DEC genes found were: aap, aatA, aggC, agg3C, aggR, astA, eae, ehly, iha, irp2, lpfA(O113), pet, pic, pilS, and shf. Sixteen strains presented aggregative adherence and/or the aatA sequence, which are characteristics of enteroaggregative E. coli (EAEC), one of the DEC pathotypes. In summary, certain UPEC strains may carry DEC virulence properties, mostly associated to the EAEC pathotype. This finding raises the possibility that at least some faecal EAEC strains might represent potential uropathogens. Alternatively, certain UPEC strains may have acquired EAEC properties, becoming a potential cause of diarrhoea.
Asunto(s)
Escherichia coli/clasificación , Escherichia coli/patogenicidad , Infecciones Urinarias/microbiología , Virulencia/genética , Adhesinas de Escherichia coli/metabolismo , Escherichia coli/aislamiento & purificación , Infecciones por Escherichia coli/microbiología , Proteínas de Escherichia coli/inmunología , Proteínas de Escherichia coli/metabolismo , Regulación Bacteriana de la Expresión Génica , Células HeLa , Humanos , Virulencia/fisiologíaRESUMEN
The present study was conducted in Lima Metropolitana to evaluate the prevalence of Shiga toxin-producing Escherichia coli (STEC) O157:H7 in raw beef, raw ground beef, soft cheese and fresh vegetables, sampled at different markets in the city. Between October 2000 and February 2001, 407 food samples were collected from different markets in the 42 districts of Lima Metropolitana. Samples were assayed for E. coli O157 by selective enrichment in modified Tryptic Soy Broth containing novobiocin, followed by immunomagnetic separation (IMS) and plating onto sorbitol MacConkey agar supplemented with cefixime and potassium tellurite. Fifty (12.3%) of 407 food samples resulted positive for E. coli O157 isolation (23 of 102 ground beef; 15 of 102 beef meat; eight of 102 soft cheese and four of 101 fresh vegetables). Thirty-five E. coli O157 isolates were further analysed for the presence of virulence genes. All 35 were positive by PCR for O157 rfbE, fliCh7, eae-gamma1 and ehxA genes. In addition, genes encoding Shiga toxins were detected in 33 of 35 isolates, five isolates (14%) encoded stx(1), stx(2), and 28 (80%) stx2 only. The isolates were of seven different phage types (PT4, PT8, PT14, PT21, PT34, PT54, and PT87) with three phage types accounting for 80% of isolates: PT4 (15 isolates), PT14 (8 isolates), and PT21 (5 isolates). Interestingly, the majority (31 of 35; 89%) of E. coli O157:H7 isolates characterized in this study belonged mainly to the phage types previously found in STEC O157:H7 strains associated with severe human disease in Europe and Canada. Pulsed-field gel electrophoresis (PFGE) of 32 isolates revealed 14 XbaI-PFGE groups (I to XIV) of similarity >85%, with 23 (72%) isolates grouped in five clusters. Some isolates from different districts presented a high clonal relatedness. Thus, PFGE group VIII clustered eleven strains from nine different districts. The broad range of PFGE subtypes found in this study demonstrates the natural occurrence of many genetic variants among STEC O157:H7 spread in Lima.
Asunto(s)
Escherichia coli O157 , Contaminación de Alimentos/análisis , Microbiología de Alimentos , Toxinas Shiga/biosíntesis , Animales , Tipificación de Bacteriófagos , Bovinos , Queso/microbiología , Recuento de Colonia Microbiana , Seguridad de Productos para el Consumidor , Electroforesis en Gel de Campo Pulsado , Escherichia coli O157/genética , Escherichia coli O157/metabolismo , Escherichia coli O157/patogenicidad , Humanos , Separación Inmunomagnética , Carne/microbiología , Productos de la Carne/microbiología , Perú , Toxinas Shiga/análisis , Verduras/microbiología , Virulencia/genéticaRESUMEN
A total of 71 enteropathogenic Escherichia coli (EPEC) strains isolated from children with diarrhoea in Montevideo, Uruguay, were characterized in this study. PCR showed that 57 isolates carried eae and bfp genes (typical EPEC strains), and 14 possessed only the eae gene (atypical EPEC strains). These EPEC strains belonged to 21 O : H serotypes, including eight novel serotypes not previously reported among human EPEC in other studies. However, 72% belonged to only four serotypes: O55:H- (six strains), O111:H2 (13 strains), O111:H- (14 strains) and O119:H6 (18 strains). Nine intimin types, namely, alpha1 (two O142 strains), beta1 (29 strains, including 13 O111:H2 and 14 O111:H-), gamma1 (three O55:H- strains), theta (five strains, including three strains with H40 antigen), kappa (two strains), epsilon1 (one strain), lambda (one strain), muB (six strains of serotypes O55:H51 and O55:H-) and xiR/beta2B (22 strains, including 18 O119:H6) were detected among the 71 EPEC strains. The authors have identified two novel intimin genes (muB and xiR/beta2B) in typical EPEC strains of serotypes O55:H51/H- and O119:H6/H-. The complete nucleotide sequences of the novel muB and xiR/beta2 variant genes were determined. PFGE typing after XbaI DNA digestion was performed on 44 representative EPEC strains. Genomic DNA fingerprinting revealed 44 distinct restriction patterns and the strains were clustered in 12 groups. Only 15 strains clustered in six groups of closely related (similarity>85%) PFGE patterns, suggesting the prevailing clonal diversity among EPEC strains isolated from children with diarrhoea in Montevideo.
Asunto(s)
Adhesinas Bacterianas/clasificación , Adhesinas Bacterianas/genética , Infecciones por Escherichia coli/microbiología , Proteínas de Escherichia coli/clasificación , Proteínas de Escherichia coli/genética , Escherichia coli/clasificación , Escherichia coli/genética , Antígenos Bacterianos/análisis , Niño , Preescolar , Análisis por Conglomerados , Dermatoglifia del ADN , ADN Bacteriano/química , ADN Bacteriano/genética , Desoxirribonucleasas de Localización Especificada Tipo II , Electroforesis en Gel de Campo Pulsado , Escherichia coli/aislamiento & purificación , Genes Bacterianos , Genotipo , Humanos , Datos de Secuencia Molecular , Antígenos O/análisis , Filogenia , Polimorfismo de Longitud del Fragmento de Restricción , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Serotipificación , UruguayRESUMEN
Thirty-six enteropathogenic Escherichia coli strains isolated from Cuban pigs with diarrhea were serotyped and screened by PCR for the presence of virulence genes. The 36 isolates belonged to 11 O serogroups and 14 O:H serotypes, with 53% of the isolates belonging to only two serotypes: O141:H- (13 isolates) and O157:H19 (6 isolates). Genes coding for STb, STa, VT2e, and LT toxins were identified in 69, 61, 53, and 6% of the isolates, respectively. The most prevalent fimbrial adhesin was F18, detected in 22 (61%) isolates. The gene encoding F6 (P987) colonization factor was identified in three (8%) isolates. None of the 36 isolates assayed contained genes encoding F4 (K88), F5 (K99), or F41. The seropathotype O141:H-:STa/STb/VT2e/F18 (13 isolates) was the most frequently detected, followed by O157:H19:VT2e/F18 (5 isolates). A genetic diversity study, carried out by pulsed-field gel electrophoresis (PFGE) of 24 representative isolates, revealed 21 distinct restriction patterns clustered in 18 groups (I-XVIII). Isolates of the same serotype were placed together in a dendrogram, but isolates of serotype O157:H19 showed a high degree of polymorphism. The results of this study demonstrate the presence in Cuba of different clusters among one of the most prevalent serotypes isolated from pigs with diarrhea. Further experiments are needed to determine whether some of these clusters have appeared recently; if so, their evolution, as well as their possible association with pathogenicity in farms should be studied.
Asunto(s)
Diarrea/veterinaria , Escherichia coli/genética , Escherichia coli/patogenicidad , Genes Bacterianos , Enfermedades de los Porcinos/microbiología , Adhesinas Bacterianas/genética , Animales , Cuba , Diarrea/microbiología , Electroforesis en Gel de Campo Pulsado , Enterotoxinas/genética , Escherichia coli/clasificación , Serotipificación , Porcinos , Virulencia/genéticaRESUMEN
The value of E. coli virulence factors in patients with neurogenic bladder has not been established. The aim of this study is to correlate E. coli virulence factors with asymptomatic and symptomatic UTI in children with neurogenic bladder. Fifty E. coli strains, which were collected in sequence, underwent analysis in relation to: the association to pyuria, serotype (O:H), the presence of genes and expression of fimbriae P, type 1, S and hemagglutinin Dr, the presence of the gene and production of hemolysins and cytotoxins (CNF1). We also analyzed the cell adherence capability and pattern and presence of usp (uropathogenic-specific protein). Pyuria was present in most of the positive urine cultures, with 86% AB and 97% UTI. Low rates of uropathogenic strains were observed in the two groups, with 18% AB and 21% UTI. Type 1 fimbria predominated in 44% of the E. coli strains. Of the bacteria studied, 30% (15 strains) exhibited papG genotypes (11 class II and 4 class III). Of these, 12/15 patients presented AB. Production of hemolysins was detected in 38% of the strains (16 AB and 3 UTI) and usp in only 18% of the strains, with 8 AB and 1 UTI. Adherence tests demonstrated the adhesive capacity in all samples analyzed. Neither group (AB or symptomatic UTI) presented a statistically significant difference in relation to the virulence factors studied. E. coli clones that caused symptomatic UTI in children with neurogenic bladder expressed few virulence factors, with no statistically significant difference in comparison to the AB group.
Asunto(s)
Bacteriuria/microbiología , Infecciones por Escherichia coli/microbiología , Escherichia coli/metabolismo , Vejiga Urinaria Neurogénica/microbiología , Infecciones Urinarias/microbiología , Factores de Virulencia/metabolismo , Adhesión Bacteriana , Niño , Citotoxinas/metabolismo , Escherichia coli/clasificación , Escherichia coli/genética , Infecciones por Escherichia coli/complicaciones , Femenino , Fimbrias Bacterianas/genética , Hemaglutininas/metabolismo , Proteínas Hemolisinas/metabolismo , Humanos , Masculino , Vejiga Urinaria Neurogénica/complicaciones , Vejiga Urinaria Neurogénica/orina , Infecciones Urinarias/complicaciones , Infecciones Urinarias/orinaRESUMEN
The culture supernatant of Escherichia coli, isolated from ostriches with diarrhea in Brazil, caused elongation in Vero cell, rounding in Chinese hamster ovary (CHO) cells and a cytoplasmic vacuolation in ostrich embryo fibroblasts (OEF), but it was not cytotoxic for chicken embryo fibroblasts (CEF). These effects were not neutralized by antiserum to cholera toxin. Polymerase chain reaction assays showed that the ostrich E. coli contained the gene encoding (eltII-A), but not those for type 1 heat-labile enterotoxin (eltA), heat-stable enterotoxins (estA, estB), verocytotoxins (stx-I, stx-II), or cytotoxic necrotizing factors (cnf 1, cnf 2). All isolates belonged to serotype O15:H8. The enteropathogenic relevance of LT-II in ostrich diarrhea remains undetermined.
Asunto(s)
Toxinas Bacterianas/biosíntesis , Enfermedades de las Aves/microbiología , Diarrea/veterinaria , Enterotoxinas/biosíntesis , Proteínas de Escherichia coli/biosíntesis , Escherichia coli/aislamiento & purificación , Struthioniformes/microbiología , Animales , Células CHO , Chlorocebus aethiops , Cricetinae , Cricetulus , Diarrea/microbiología , Escherichia coli/genética , Escherichia coli/metabolismo , Heces/microbiología , Genes Bacterianos , Células VeroRESUMEN
Grazing-fed cattle were previously demonstrated to be reservoir of non-O157 Shigatoxigenic Escherichia coli (STEC) serotypes in Argentina. The acid-resistance of some STEC strains makes it reasonable to assume the presence in feedlot of particular STEC serotypes. Fifty-nine animals were sampled every 2 weeks during 6 months by rectal swabs. Twenty-seven of 59 animals (45.8%) were shown to be Stx2(+); 3/59 (5.1%) carried Stx1(+) and 7/59 (11.9%) were Stx1(+) Stx2(+). Among 44 STEC isolates, 31 isolates were associated to 10 O serogroups (O2, O15, O25, O103, O145, O146, O157, O171, O174, O175) and 13 were considered non-typable (NT). Six H antigens (H2, H7, H8, H19, H21, H25) were distributed in 21 isolates whereas 23 were non-mobile (H-). Seventeen of 44 strains (38.6%) were eaeA(+) and 14 (31.8%) harbored the 60MDa plasmid. The megaplasmid (Mp) and eaeA gene were simultaneously found in a limited number of serotypes belonging to the enterohaemorrhagic E. coli (EHEC). E. coli O157:H7 strains, isolated from four (6.8%) animals, corresponded to the Stx2(+), eaeA(+), Mp(+) pattern. Three O157:H7 strains belonged to phage type 4 and the other strain was atypical. Many serotypes isolated from grain-fed cattle (O2:H25, O15:H21, O25:H19, O145:H-, O146:H-, O146:H21, O157:H7, O175:H8) also differed from those isolated by us previously from grazing animals. The serotypes O15:H21, O25:H19 and O175:H8 had not been identified at present as belonging to STEC. This work provides new data for the understanding of the ecology of STEC in grain-fed cattle and confirms that cattle are an important reservoir of STEC.
Asunto(s)
Enfermedades de los Bovinos/microbiología , Infecciones por Escherichia coli/veterinaria , Escherichia coli/clasificación , Toxina Shiga I/genética , Toxina Shiga II/genética , Adhesinas Bacterianas/química , Adhesinas Bacterianas/genética , Pruebas de Aglutinación/veterinaria , Animales , Argentina , Tipificación de Bacteriófagos/veterinaria , Proteínas Portadoras/química , Proteínas Portadoras/genética , Bovinos , ADN Bacteriano/química , ADN Bacteriano/genética , Escherichia coli/genética , Escherichia coli/crecimiento & desarrollo , Escherichia coli/patogenicidad , Infecciones por Escherichia coli/microbiología , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Antígenos O/genética , Reacción en Cadena de la Polimerasa/veterinaria , Serotipificación/veterinaria , Toxina Shiga I/química , Toxina Shiga II/química , VirulenciaRESUMEN
A total of 153 Shiga-toxin-producing Escherichia coli (STEC) isolates from feces of cattle and beef products (hamburgers and ground beef) in Argentina were characterized in this study. PCR showed that 22 (14%) isolates carried stx1 genes, 113 (74%) possessed stx2 genes and 18 (12%) both stx1 and stx2. Intimin (eae), enterohemolysin (ehxA), and STEC autoagglutinating adhesin (saa) virulence genes were detected in 36 (24%), 70 (46%) and in 34 (22%) of the isolates, respectively. None of 34 saa-positive isolates carried the gene eae, and 31 were ehxA-positive. Fourteen (7 of serotype O26:H11 and 4 of serotype O5:H-) isolates had intimin b1, 16 isolates possessed intimin g1 (11 of serotype O145:H- and 5 of serotype O157:H7), 5 isolates had intimin type e1 (4 of serotypes O103:H- and O103:H2), and one isolate O111:H- showed intimin type q/g2. Although the 153 STEC isolates belonged to 63 different seropathotypes, only 12 accounted for 58% of isolates. Seropathotype ONT:H- stx2 (18 isolates) was the most common, followed by O171:H2 stx2 (12 isolates), etc. The majority (84%) of STEC isolates belonged to serotypes previously found in human STEC and 56% to serotypes associated with STEC isolated from patients with hemolytic uremic syndrome (HUS). Thus, this study confirms that cattle are a major reservoir of STEC pathogenic for humans. To our knowledge, this is the first study that described the presence of saa gene in STEC of serotypes O20:H19, O39:H49, O74:H28, O79:H19, O116:H21, O120:H19, O141:H7, O141:H8, O174:H21, and ONT:H21. The serotypes O120:H19 and O185:H7 were not previously reported in bovine STEC.
Asunto(s)
Adhesinas Bacterianas/clasificación , Infecciones por Escherichia coli/veterinaria , Escherichia coli O157/patogenicidad , Proteínas de Escherichia coli/clasificación , Proteínas de Escherichia coli/genética , Toxina Shiga I/metabolismo , Toxina Shiga II/metabolismo , Adhesinas Bacterianas/genética , Adhesinas Bacterianas/metabolismo , Animales , Argentina , Bovinos , Enfermedades de los Bovinos/microbiología , Infecciones por Escherichia coli/microbiología , Escherichia coli O157/clasificación , Escherichia coli O157/genética , Escherichia coli O157/metabolismo , Proteínas de Escherichia coli/metabolismo , Humanos , Productos de la Carne/microbiología , Reacción en Cadena de la Polimerasa/métodos , Serotipificación , Toxina Shiga I/genética , Toxina Shiga II/genética , Virulencia/genéticaRESUMEN
Escherichia coli strains isolated from sporadic cases of acute diarrhea in children and adults and from children without diarrhea were investigated for the presence of the pAA plasmid. Strains harboring the pAA plasmid were isolated at similar frequencies from children with (19.6%) and without (10.8%) diarrhea and from adults with diarrhea (11.8%). The genotypic and phenotypic virulence markers of these strains were further analyzed. Most of the strains were positive for EAST1 (73%), and this toxin was detected significantly more frequently in strains from children with diarrhea than in strains from adults with diarrhea (P < 0.05). Likewise, pic sequences were detected significantly more frequently in strains from children with diarrhea than in strains from adults with diarrhea (P < 0.005) and controls (P < 0.025). Furthermore, the association of pAA positivity (pAA(+)) and pic positivity (pic(+)) was more frequently found for strains from children with diarrhea than for strains from controls, indicating that pAA(+) pic(+) strains may represent a subset of pAA(+) strains associated with disease in children. Most of the strains (82.5%) adhered to cells presenting the typical aggregative pattern. The frequency of occurrence of enteropathogenic E. coli (EPEC) serogroups in the strains from children with diarrhea was very high (56%), while none of the strains from adults with diarrhea belonged to EPEC serogroups. Extraintestinal virulence markers were very commonly found in strains from adults with diarrhea. The frequencies of occurrence of the adhesins AFA and SFA were significantly higher in strains from adults with diarrhea than in strains from children with diarrhea. More than one extraintestinal virulence marker was found in 58% of the strains from adults with diarrhea but in only 7.7% of the strains from children with diarrhea. Our results show that pAA(+) strains isolated from children and adults with diarrhea present very different profiles when enteroaggregative E. coli virulence markers, serotypes, and extraintestinal virulence markers are considered.
Asunto(s)
Diarrea/microbiología , Infecciones por Escherichia coli/microbiología , Escherichia coli/patogenicidad , Adulto , Adhesión Bacteriana/genética , Secuencia de Bases , Brasil , Estudios de Casos y Controles , Preescolar , Cartilla de ADN/genética , ADN Bacteriano/genética , Escherichia coli/clasificación , Escherichia coli/genética , Escherichia coli/aislamiento & purificación , Marcadores Genéticos , Genotipo , Células HeLa , Humanos , Lactante , Recién Nacido , Fenotipo , Plásmidos/genética , Plásmidos/aislamiento & purificación , Reacción en Cadena de la Polimerasa , Serotipificación , Virulencia/genéticaRESUMEN
BACKGROUND: Enterohaemorrhagic Escherichia coli (EHEC) is considered to be common cause of haemorrhagic colitis (HC), thrombotic thrombocytopenic purpura and haemolytic uraemic syndrome (HUS) in humans. In a previous paper, we have demonstrated that EHEC are commonly found in the intestines of livestock. Infections in humans are, in part, a consequence of consumption of undercooked meat or raw milk. Argentina has one of the highest records of HUS (300-400 cases/year; 22/100,000 children under 4 years of age). The aim of this work is to communicate the first isolation of O145:H-from cattle in this country and characterize the virulence cassette, providing useful information to evaluate the risk of foodborne transmission of this emergent non-O157:H7 serotype. RESULTS: EHEC O145:H- was isolated from cattle in an Argentinian feedlot. Pheno- and genotype of nine strains were characterized, corresponding to several virulence cassettes: VT2+eaeA+ Mp+ (n = 5), VT2+eaeA+ (n = 1), VT1+eaeA+ Mp+ (n = 2), and VT1+eaeA+ (n = 1). Strains isolated from the same animal were considered only when they showed a different virulence pattern. The clonal relationship was studied by RAPD. Strains were distributed in two RAPD profiles, which corresponded to the presence of either, VT1+ or VT2+ genotype. No difference was detected by RAPD analysis between Mp+ or Mp- strains. CONCLUSIONS: This was the first isolation of EHEC O145:H- serotype in Argentina enlarging the list of non-O157:H7 serotypes isolated from cattle in this country by us. All O145:H-strains carried several virulence factors which allow us to predict their potential ability to develop haemolytic uraemic syndrome in humans.
Asunto(s)
Alimentación Animal/microbiología , Escherichia coli O157/aislamiento & purificación , Hemorragia/microbiología , Animales , Argentina , Bovinos , Escherichia coli O157/inmunología , Escherichia coli O157/metabolismo , Escherichia coli O157/patogenicidad , Técnica del ADN Polimorfo Amplificado Aleatorio , Serotipificación , Toxinas Shiga/metabolismo , VirulenciaRESUMEN
Durante estudos epidemiológicos de casos de diarréia em crianças de duas regiöes do Brasil, 17 cepas de E.coli foram isoladas cujos sobrenadantes induziram alteraçöes morfológicas em células Vero semelhantes aquelas induzidas pelo fator citotóxico e necrotizante (CNF). Uma vez que tem sido descrito que CNF näo é detectado no sobrenadante de culturas este estudo foi desenvolvido para melhor caracterizar estas cepas. Todas as amostras foram analisadas quanto à presença de CNF nos sobrenadantes e nos extratos sonicados; atividade necrotizante; produçäo de hemolisina; hemaglutinaçäo manose-resistente; hidrofobicidade superficial; e sorogrupo. Os resultados mostraram que todas as cepas säo capazes de causar necrose em pele de coelho e induzir alteraçöes típicas de CNF1, as quais foram observadas tanto nos extratos sonicados quanto nos sobrenadantes das culturas. Produçäo de hemolisina e hidrofobicidade superficial foi encontrada em respectivamente 76 por cento e 54 por cento das cepas analisadas. Os resultados das hemaglutinaçöes com 6 espécies de eritrócitos mostrou que todas as cepas pertenciam aos tipos III ou IVa de MRHA. A análise dos sorogrupos mostrou que a maioria das cepas (14/17) pertenciam ao sorogrupo O6, duas cepas eram O14 e uma pertencia ao sorogrupo O4. Em conclusäo, demostrou-se que cepas de NTEC podem ser isoladas de fezes de crianças com diarréia no Brasil. Estas cepas produzem CNF1 que podem ser detectado tanto nos sobrenadantes como nos extratos celulares e possuem características muito semelhantes às cepas NTEC isoladas na Europa