Evidence of evolving extraintestinal enteroaggregative Escherichia coli ST38 clone

BACKGROUND: Several clones of extended-spectrum β-lactamase (ESBL)–producing extraintestinal pathogenic Escherichia coli (ExPEC) have globally expanded their distribution. ExPEC infections often originate from the patient’s own intestinal flora, although the degree of overlap between diarrheagenic E. coli and ExPEC pathotypes is unclear. Relatively little is known about antimicrobial drug resistance in the most common diarrheagenic E. coli groups, including enteroaggregative E. coli (EAEC), and bacterial gastroenteritis is generally managed without use of antimicrobial drugs. APPROACHES: We conducted this study to establish the presence and characteristics of ESBL-producing EAEC in a well-defined collection of ESBL-producing isolates. The isolates were from human and animal sources in Germany, the Netherlands, and the United Kingdom. DNA from 359 ESBL isolates was screened for the presence of the EAEC transport regulator gene (aggR), located on the EAEC plasmid, using a real-time PCR assay and the phylogroup was determined for each positive isolate. A microarray was used to detect ESBL genes, such as blaCTX-M, at the group level, as previously described. The antimicrobial drug susceptibilities of EAEC isolates were determined and virulence factors associated with intestinal and extraintestinal infection and with EAEC were investigated . RESULTS AND CONCLUSIONS: We assigned a virulence score (total number of virulence factor genes detected; maximum possible score 22) and a resistance score (total number of drug classes; maximum score 11) to each isolate. We isolated 11 EAEC from humans. Eight of the EAEC were isolated from urine specimens, and 1 was isolated from a blood culture; 63% belonged to phylogroup D (Table). EAEC ST38, the most common (55%) ST, was significantly associated with extraintestinal sites in the subset of 140 human isolates (Fisher exact test, p<0.0001)

Libraries and networks of influence in the Roman world

This paper is concerned with the ways in which libraries – in this case public libraries in Rome and the Roman world – acted as points of connectivity and communication.

Ultimate attainment in the use of collocations among heritage speakers of Turkish in Germany and Turkish-German returnees

In this paper we show that heritage speakers and returnees are fundamentally different from the majority of adult second language learners with respect to their use of collocations (Laufer & Waldman, 2011). We compare the use of lexical collocations involving yap- “do” and et- “do” among heritage speakers of Turkish in Germany (n=45) with those found among Turkish returnees (n=65) and Turkish monolinguals (n=69). Language use by returnees is an understudied resource although this group can provide crucial insights into the specific language ability of heritage speakers. Results show that returnees who had been back for one year avoid collocations with yap- and use some hypercorrect forms in et-, whilst returnees who had been back for seven years upon recording produce collocations that are quantitatively and qualitatively similar to those of monolingual speakers of Turkish. We discuss implications for theories of ultimate attainment and incomplete acquisition in heritage speakers.