Characterization of an emergent clone of enteroinvasive Escherichia coli circulating in Europe

Enteroinvasive Escherichia coli (EIEC) cause intestinal illness indistinguishable from that caused by Shigella, mainly in developing countries. Recently an upsurge of cases of EIEC infections has been observed in Europe, with two large outbreaks occurring in Italy and in the United Kingdom. We have characterized phenotypically and genotypically the strains responsible for these epidemics together with an additional isolate from a sporadic case isolated in Spain. The three isolates belonged to the same rare serotype O96:H19 and were of sequence type ST-99, never reported before in EIEC or Shigella. The EIEC strains investigated possessed all the virulence genes harboured on the large plasmid conferring the invasive phenotype to EIEC and Shigella while showing only some of the known chromosomal virulence genes and none of the described pathoadaptative mutations. At the same time, they displayed motility abilities and biochemical requirements resembling more closely those of the non-pathogenic E. coli rather than the EIEC and Shigella strains used as reference. Our observations suggested that the O96:H19 strains belong to an emerging EIEC clone, which could be the result of a recent event of acquisition of the invasion plasmid by commensal E. coli

A new pathogenicity island carrying an allelic variant of the Subtilase cytotoxin is common among Shiga toxin producing Escherichia coli of human and ovine origin

AbstractSubtilase (SubAB) is a cytotoxin elaborated by some Shiga Toxin (Stx)-producing Escherichia coli (STEC) strains usually lacking the locus of enterocyte effacement (LEE). Two variants of SubAB coding genes have been described: subAB1, located on the plasmid of the STEC O113 98NK2 strain, and subAB2, located on a pathogenicity island (PAI) together with the tia gene, encoding an invasion determinant described in enterotoxigenic E. coli. In the present study, we determined the entire nucleotide sequence of the PAI containing the subAB2 operon, termed Subtilase-Encoding PAI (SE-PAI), and identified its integration site in the pheV tRNA locus. In addition, a PCR strategy for discriminating the two subAB allelic variants was developed and used to investigate their presence in E. coli strains belonging to different pathotypes and in a large collection of LEE-negative STEC of human and ovine origin. The results confirmed that subAB genes are carried predominantly by STEC and showed their presence in 72% and 86% of the LEE-negative strains from human cases of diarrhoea and from healthy sheep respectively. Most of the subAB-positive strains (98%) identified possessed the subAB2 allelic variant and were also positive for tia, suggesting the presence of SE-PAI. Altogether, our observations indicate that subAB2 is the prevalent SubAB-coding operon in LEE-negative STEC circulating in European countries, and that sheep may represent an important reservoir for human infections with these strains. Further studies are needed to assess the role of tia and/or other genes carried by SE-PAI in the colonization of the host intestinal mucosa

Community-wide outbreak of haemolytic uraemic syndrome associated with Shiga toxin 2-producing Escherichia coli O26:H11 in southern Italy, summer 2013

In summer 2013, an excess of paediatric cases of haemolytic uraemic syndrome (HUS) in a southern region of Italy prompted the investigation of a community-wide outbreak of Shiga toxin 2-producing Escherichia coli (STEC) O26:H11 infections. Case finding was based on testing patients with HUS or bloody diarrhoea for STEC infection by microbiological and serological methods. A case-control study was conducted to identify the source of the outbreak. STEC O26 infection was identified in 20 children (median age 17 months) with HUS, two of whom reported severe neurological sequelae. No cases in adults were detected. Molecular typing showed that two distinct STEC O26:H11 strains were involved. The case-control study showed an association between STEC O26 infection and consumption of dairy products from two local plants, but not with specific ready-to-eat products. E.coli O26:H11 strains lacking the stx genes were isolated from bulk milk and curd samples, but their PFGE profiles did not match those of the outbreak isolates. This outbreak supports the view that infections with Stx2-producing E. coli O26 in children have a high probability of progressing to HUS and represent an emerging public health problem in Europe

The labor market effects of technology shocks

We analyze the effects of neutral and investment-specific technology shocks on hours worked and unemployment. We characterize the response of unemployment in terms of job separation and job finding rates. We find that job separation rates mainly account for the impact response of unemployment while job finding rates for movements along its adjustment path. Neutral shocks increase unemployment and explain a substantial portion of unemployment and output volatilityinvestment-specific shocks expand employment and hours worked and mostly contribute to hours worked volatility. We show that this evidence is consistent with the view that neutral technological progress prompts Schumpeterian creative destruction, while investment specific technological progress has standard neoclassical feature

Relocation to get venture capital : a resource dependence perspective

This is the author accepted manuscript. The final version is available from SAGE via the DOI in this record.Using a resource dependence perspective, we theorize and show that non-venture-capital-backed ventures founded in U.S. states with a lower availability of venture capital (VC) are more likely to relocate to California (CA) or Massachusetts (MA)—the two VC richest states—compared to ventures founded in states with a greater availability of VC. Moreover, controlling for self-selection, ventures that relocate to CA or MA subsequently have a greater probability of attracting initial VC compared to ventures that stay in their home state. We discuss the implications for theory, future research, and practice