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A Caprioli

Publications and source records attributed to A Caprioli.

At least 55 records · Page 3Linked to original sources
PubMed1998

Enteroaggregative, Shiga toxin-producing Escherichia coli O111:H2 associated with an outbreak of hemolytic-uremic syndrome.

Shiga toxin-producing Escherichia coli O111:H2 strains from an outbreak of hemolytic-uremic syndrome showed aggregative adhesion to HEp-2 cells and harbored large plasmids which hybridized with the enteroaggregative E. coli probe PCVD432. These strains present a novel combination of virulence factors and might be as pathogenic to humans as the classic enterohemorrhagic E. coli.

Bacterial Adhesion↗
PubMed1997

[Enterohemorrhagic Escherichia coli and hemolytic-uremic syndrome].

Enterohemorrhagic Escherichia coli (EHEC) are increasingly identified as the cause of diarrhea and hemorrhagic colitis in countries with highly developed livestock. In 5-10% of patients, full-blown hemolytic uremic syndrome (HUS) occurs as a postinfectious life-threatening complication. Up to 1996, 5 out of 39 patients (12.8%) with EHEC O157 infections in Austria developed HUS. Acute complications of HUS such as brain edema may also lead to death; one fatal outcome has been observed so far in Austrian patients. Aside from the cytotoxic Shiga toxins, other different pathogenic factors are often found in clinical EHEC isolates. These include a cytolysin termed EHEC-hemolysin and a low molecular heat-stabile enterotoxin. Furthermore, most EHEC strains express an important surface protein, intimin, which is important for adherence to intestinal epithelial cells. EHEC are heterogeneous in their antigenic structure (O-, H-antigens). In Austria O157:H7 and O157:H- are the dominating serogroups; in 1997 the first Austrian case of HUS due to EHEC O26:H11 was documented. Because there are no known reliable phenotypical markers for EHEC, diagnostic strategies should focus on the demonstration of Shiga toxins or Shiga toxin genes. For epidemiological purposes it is also important to attempt to isolate the causative agent. Cows and other ruminants are reservoirs for EHEC. In the Tyrol 3% of unpasteurised milk samples, up to 10% of minced beef samples, and 6% of calves yield EHEC O157. Aside from transmission via contaminated food, direct transmission from person to person also plays a major role in the chain of EHEC infection. In contrast to Italy and Bavaria, Austria has not experienced a major outbreak due to this organism so far. A nationwide surveillance system of HUS has shown an incidence of 0.37 HUS cases per 100,000 residents in the age group 0-14 years for 1995 (Italy: 0.2 cases per 100,000; Bavaria: approx. 1.5 cases per 100,000).

Animals↗
PubMed1997

Atypical strains of verocytotoxin-producing Escherichia coli O157 in beef cattle at slaughter in Veneto region, Italy.

Cattle arriving for slaughter at abattoirs in the Veneto region of N. Italy were examined for intestinal carriage of Escherichia coli O157. Rectal swabs were cultured in modified buffered peptone water and E. coli O157 was concentrated by an immunomagnetic separation technique; the magnetic beads were cultured onto cefixime tellurite sorbitol MacConkey agar. Sorbitol non-fermenting E. coli O157 was isolated from 15 (3.6%) of 419 feedlot cattle but not from 437 veal calves or 65 culled cows. All strains of E. coli O157 hybridized with DNA probes specific for the VT1 or VT2 genes, but two strains did not produce toxin detectable by Vero cell assay. Six different plasmid profiles were observed with all strains harbouring the large 93 kb plasmid characteristic of VTEC. Six strains produced urease but otherwise strains were biochemically typical of E. coli O157. One strain was resistant to streptomycin, tetracycline and sulphonamides but the remainder were sensitive to all antimicrobials tested. This is the first description of the isolation of verocytotoxin-producing E. coli O157 from cattle in Italy. As the contamination of bovine carcasses with E. coli O157 during slaughter and processing has been demonstrated, the risk of transmission of this organism from beef cattle to the human population in the Veneto region, through foods of bovine origin or by other routes, should not be overlooked.

Abattoirs↗
PubMed1996

Detection of a vacuolating cytotoxin in stools from children with diarrhea.

A cytotoxin inducing vacuolation in HEp-2 cells was detected in 19 (3.1%) of 618 stool specimens from children with diarrhea but in none of 135 from control children. Common enteric pathogens were found in only two (10.5%) of the 19 cytotoxin-positive stool specimens. The vacuoles induced by stool filtrates resembled those induced by the vacuolating toxin (VacA) of Helicobacter pylori. The vacuolating toxin was heat-labile and protease-sensitive, and it had an apparent molecular weight of > 100,000 but was not neutralized by an antiserum to H. pylori VacA. Although proper prospective case-control studies are needed to definitely assess the etiologic association between the new vacuolating cytotoxin and diarrhea, the present study suggests that microorganisms of the gastrointestinal tract produce a Helicobacter-like vacuolating toxin and may be responsible for cases of childhood diarrhea whose etiology is currently considered unknown.

Bacterial Proteins↗
PubMed1996

Enteropathogens associated with childhood diarrhea in Italy. The Italian Study Group on Gastrointestinal Infections.

BACKGROUND: Infectious diarrheal diseases remain an important cause of childhood morbidity in industrialized countries. The knowledge of the etiology and epidemiology of childhood diarrhea in a given area is needed to plan any measure designed to prevent or ameliorate diarrheal illness and to develop practice guidelines for the most appropriate stool examination procedures. METHODS: We evaluated 618 children with diarrhea and 135 controls prospectively for viral, bacterial and parasitic enteric pathogens. Diarrheagenic Escherichia coli was identified by gene probes specific to different virulence factors. Stool filtrates were examined for the presence of free bacterial toxins by a cell culture cytotoxicity assay. Clinical and epidemiologic data were recorded and analyzed in relation to microbiologic findings. RESULTS: Enteropathogens were identified in 59% of children with diarrhea and in 10.4% of asymptomatic controls. The agents mainly associated with disease were rotavirus (23.6%), Salmonella (19.2%) and Campylobacter (7.9%). Rotavirus was significantly more frequent among children observed as inpatients whereas Campylobacter was significantly more common in outpatients. Infections with diarrheagenic E. coli, Shigella flexneri, yersinia enterocolitica, Cryptosporidium and Giardia were observed in a limited number of patients. The clinical presentation of children was not sufficiently characteristic to permit presumptive diagnosis of a specific pathogen. conversely the presence of blood and/or leukocytes in stools had a high positive predictive value for Salmonella or Campylobacter infection. CONCLUSION: The results of this study will be useful for planning strategies to prevent and control diarrheal diseases in our country.

Child↗
PubMed1996

Characteristics of Escherichia coli strains belonging to enteropathogenic E. coli serogroups isolated in Italy from children with diarrhea.

Fifty-five Escherichia coli strains belonging to enteropathogenic E. coli (EPEC) serogroups were examined for phenotypic and genetic factors associated with virulence. The strains were isolated in Italy from children with diarrhea and identified as EPEC by clinical laboratories using commercially available antisera. O:H serotyping showed that 35 strains (27 of O26, O111, and O128 serogroups) belonged to 11 serotypes considered to be classical EPEC O:H serotypes. The other 20 isolates were classified as 15 nonclassical EPEC O:H serotypes. All the potential EPEC virulence factors associated with bacterial adhesion (localized adherence, fluorescentactin staining test positivity, presence of the attaching and effacing [eaeA] gene), the production of verotoxin, and the positivity with the enterohemorrhagic E. coli probe were significantly more frequent among isolates belonging to classical than nonclassical serotypes. Strains displaying an aggregative adhesion and hybridizing with the enteroaggregative DNA probe were found in serogroups O86, O111, and O126. Verotoxin-producing isolates belonged to serogroups O26, O111, and O128. Only one of the isolates hybridized with the EPEC adherence factor (EAF) probe, but 33 strains gave positive results with the eae probe, confirming that the former is more suitable in epidemiological studies in European countries. These results indicate that up to 75% of strains identified as EPEC by commercial antisera may possess potential virulence properties and/or belong to classical EPEC O:H serotypes and suggest that O grouping is still a useful diagnostic tool for presumptive identification of diarrheagenic E. coli in clinical laboratories.

Adhesins, Bacterial↗
PubMed1995

Gene clusters encoding the cytotoxic necrotizing factor type 1, Prs-fimbriae and alpha-hemolysin form the pathogenicity island II of the uropathogenic Escherichia coli strain J96.

The uropathogenic Escherichia coli strain J96 (04:K6) is able to produce four adherence factors [P-fimbriae (pap and prs), F1C-fimbriae (foc) and Type 1-fimbriae (fim)], two alpha-hemolysins (hlyI and II) and the cytotoxic necrotizing factor type 1 (cnf1). Using phenotypic test systems and genotypic analysis, it has been shown that the mutant strain J96-M1 has lost the hlyII, prs and cnf1 genes. The three virulence associated determinants are linked on one particular region on the chromosome, which is termed 'pathogenicity island II' (Pai II).

Adhesins, Bacterial↗
PubMed1995

Acetyl-L-Carnitine: chronic treatment improves spatial acquisition in a new environment in aged rats.

Chronic Acetyl-L-Carnitine (ALCAR) treatment prevents some age-related memory impairment. The present experiment examined the effects of aging and ALCAR in Fischer 344 rats on retention of spatial discrimination test in a familiar environment (FE), and on the acquisition of a spatial discrimination in a novel environment (NE). Rats 18 months or 3 months old were trained with a new procedure to assess spatial discrimination in the Morris water maze. Performance during acquisition in FE was used to assign each old rat to one of two classes: Good Performers (GP) and Poor Performers (PP) based on their swim time to reach the platform. The old rats displayed heterogeneous performance and a spatial discrimination deficit. Chronic ALCAR treatment enhanced spatial acquisition in the NE of rats with age-related behavioral impairments and had a slight effect on retention of the spatial discrimination in the FE.

Acetylcarnitine↗
PubMed1995

Role of Clostridium difficile in childhood diarrhea.

To investigate the etiologic role of Clostridium difficile in childhood acute diarrhea, stool specimens from 618 children with diarrhea and 135 controls without enteric symptoms were examined by cell culture assay for the presence of free toxin B. This toxin was found in 4.2% of the fecal specimens examined without finding a significant difference between cases and controls, suggesting no causal relationship between diarrhea and the presence of free C. difficile toxin B. C. difficile strains isolated from toxin B-positive specimens were characterized by cytotoxin and enterotoxin production and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of EDTA-extracted proteins. All but two isolates produced toxin B and toxin A and the remaining were negative for both toxins. Polyacrylamide gel electrophoresis analysis showed eight electrophoretic types, none of them was clearly related with the cases of diarrhea. The majority of isolates from children with diarrhea did not belong to types previously observed in adults with pseudomembranous colitis or antibiotic-associated diarrhea. This study provides additional evidence that C. difficile is not involved in the etiology of childhood diarrhea.

Bacterial Toxins↗
PubMed1995

Genotyping of Shiga-like toxin genes in non-O157 Escherichia coli strains associated with haemolytic uraemic syndrome.

The pheno- and genotypes of Shiga-like toxins (SLTs) in non-O157 Escherichia coli strains from patients with haemolytic uraemic syndrome were determined. The clinical isolates investigated were from Italy and Germany and belonged to serotypes O22:H8, O26:H-, O26:H11, O91:H-, O111:H- and O128:H-; one isolate was non-typable. SLT genotypes were analysed by complete nucleotide sequence analysis of the B-subunit genes. The results showed that 14 strains possessed slt-I alone, two contained slt-II alone and five isolates harboured both slt-I and slt-II genes. In only two strains were slt-II-related genes found, together with either slt-I or slt-II. These findings indicate that variants of SLT-II are rarely found in non-O157 E. coli isolates from patients with haemolytic uraemic syndrome. Polymerase chain reaction (PCR) with Taq cycle sequencing was found to be a suitable method for classification of slt genotypes.

Bacterial Toxins↗
PubMed1995

Pheno-genotyping of verotoxin 2 (VT2)-producing Escherichia coli causing haemorrhagic colitis and haemolytic uraemic syndrome by direct analysis of patients' stools.

The subtype of verotoxin 2 (VT2) found in 22 VT2-positive stool samples from severely diseased Italian and German children with haemorrhagic colitis or haemolytic uraemic syndrome, or both, and that produced by the corresponding VT-producing Escherichia coli (VTEC) strains isolated from the stools were studied by cytotoxicity seroneutralisation assays and by polymerase chain reaction (PCR) amplification of the VT2 B-subunit gene, followed by restriction fragment length polymorphism (RFLP) analysis. The free faecal toxin was serotyped as the classical VT2 in 21 stool samples, and as the VT2 variant VT2c in one. For all but one of the VTEC isolates, the toxin phenotype was consistent with the type of VT produced in vivo and found in the corresponding stool samples. Genotyping was in agreement with phenotyping for those strains harbouring a single type of VT2 gene. Three O157:H7 isolates carrying both VT2 and VT2c genes had the VT2 phenotype, instead of the expected VT2c phenotype. Direct PCR analysis of stools detected VT genes in only 11 of 20 VT-positive stool samples suggesting that the Vero cell cytotoxicity assay is more sensitive in diagnosing VTEC infection. Immunological and genetic subtyping of VT2 performed directly on stool samples from patients with haemolytic uraemic syndrome could be a useful complementary approach to understanding the role of the different types of VT in this syndrome.

Animals↗
PubMed1995

Clonal relatedness of Shiga-like toxin-producing Escherichia coli O101 strains of human and porcine origin.

Shiga-like toxin (SLT)-producing Escherichia coli (SLTEC) O101 has recently been associated with hemorrhagic colitis and hemolytic-uremic syndrome in humans. In this study, SLTEC O101 strains from humans and pigs were characterized for clonal relatedness by nucleotide sequence analysis of their slt genes, DNA finger-printing of genomic DNA, and determination of virulence factors. The slt genes of five E. coli O101 strains were cloned and sequenced. For all strains, the deduced amino acid sequences of the B subunits were identical to those of the SLT-IIe present in the classical SLTEC O139 strains that cause edema disease in pigs. The A subunit revealed more than 99% homology to that of SLT-IIe. DNA fingerprinting revealed a high degree of genetic relatedness between the human and porcine O101 isolates. None of the O101 strains investigated had virulence factors frequently found in porcine (F107 fimbriae or heat-stable or heat-labile enterotoxins) or human SLTEC strains (eaeA or enterohemorrhagic E. coli hemolysin). The absence of virulence factors typical of SLT-I- and SLT-II-producing E. Coli together with the presence of SLT-IIe, a toxin previously seen only in porcine E. coli, suggests a new pathogenic mechanism for E. coli O101 infection of humans. For diagnostic purposes, we recommend the use of PCR primers and DNA probes complementary to slt-IIe to correctly identify such strains and to further evaluate their role in human diseases.

Amino Acid Sequence↗
PubMed1995

Ulcerative colitis precipitated by a verocytotoxin-producing Escherichia coli infection.

The aetiology of ulcerative colitis remains unknown, despite extensive research into likely causes, such as infections, diet, environmental factors, immunological or genetic defects, psychomotor disorders, and abnormalities of mucin. We report here a case of ulcerative colitis in which the first episode of the disease was associated with serologic evidence of infection by verocytotoxin (VT)-producing O157 Escherichia coli (VTEC), possibly the trigger factor of a previously silent ulcerative colitis. Although histological reports of ulcerative colitis associated with VTEC infection are sporadically reported, the trigger role of VTEC in precipitating, aggravating or prolonging this pathology should be more fully elucidated.

Adult↗
PubMed1994

Highly conserved B-subunit genes of Shiga-like toxin II variants found in Escherichia coli O157 strains.

To determine the degree of heterogeneity among Shiga-like toxin-II (SLT-II)-related toxins present in enterohemorrhagic Escherichia coli O157 strains, slt-IIB-related genes of 15 strains were amplified and sequenced. Of these 15 isolates, six contained only the slt-II-related genes, seven strains harbored slt-II-related genes together with slt-II, and two strains had slt-II-related genes plus slt-I. In strains carrying slt-II-related genes alone or in combination with slt-I, the PCR fragments were directly subjected to Taq cycle sequence analysis. Direct sequencing was not possible with the seven strains possessing both slt-II and slt-II-related genes, since the PCR products contained both genes. In order to allow sequence analysis of these slt-II-related genes, the PCR products were first subjected to restriction enzyme digestion with FokI, which selectively digested slt-IIB. This resulted in an undigested 270-bp fragment consisting of pure slt-II-related genes. Interestingly, comparison of the nucleotide sequences revealed 100% homology of all analyzed 15 slt-IIB-related toxin genes. In addition, the nucleotide sequence of slt-IIB-related toxin genes were identical to slt-IIcB. Our findings indicate that SLT-IIc is a major variant form of SLT-II present in E. coli O157 strains.

Bacterial Toxins↗
PubMed1994

Haemolytic-uraemic syndrome in childhood: surveillance and case-control studies in Italy. Italian HUS Study Group.

Seventy-six cases of haemolytic-uraemic syndrome (HUS) were collected over a 4-year period during a surveillance and case-control study. The annual incidence of 0.2 per 100,000 children aged 0-14 years is lower than in other countries; 34% had no prodromal diarrhoea. Evidence for verocytotoxin-producing Escherichia coli (VTEC) infection was found in 72% of patients and 3% of controls; 88% of patients with bloody diarrhoea, 67% with non-bloody diarrhoea and 55% without diarrhoea were VTEC positive. Seventy-three percent of patients had creatinine clearance > or = 80 ml/min per 1.73 m2, normal blood pressure, no proteinuria and haematuria < 2+ after 1 year of follow-up. One patient died and none had non-renal sequelae. VTEC positivity was significantly correlated with a good outcome, while the absence of diarrhoea and a high total white blood cell count at onset were not predictors of a bad outcome. Household contacts of HUS patients had diarrhoea more frequently than those of the control group, supporting the hypothesis of person-to-person transmission of VTEC infection.

Adolescent↗