Biography:

In the past Erhard Tietze has collaborated on articles with Elisabeth Hauser and Tobias Kerrinnes. One of their most recent publications is Short communicationRelationships among the streptothricin resistance transposons Tn1825 and Tn1826 and the trimethoprim resistance transposon Tn7. Which was published in journal Plasmid.

More information about Erhard Tietze research including statistics on their citations can be found on their Copernicus Academic profile page.

Erhard Tietze's Articles: (6)

Short communicationRelationships among the streptothricin resistance transposons Tn1825 and Tn1826 and the trimethoprim resistance transposon Tn7

AbstractThe Streptothricin resistance transposons Tn1825 and Tn1826 are closely related, based on physical and genetic characteristics, to the trimethoprim resistance transposon Tn7. These transposons may be considered to be members of a transposon family sharing in common the transposition functions and a basic streptomycin/spectinomycin resistance determinant but differing from one another with respect to particular additional resistance genes inserted to the left of the aadA gene.

Short communicationThe trimethoprim resistance transposon Tn7 contains a cryptic streptothricin resistance gene

AbstractThe transposon Tn7 codes for a trimethoprim resistance and for a streptomycin/spectinomycin resistance function of the bacterial host cells. Cloning of a restriction fragment of Tn7 into the vector plasmid pUC19 reveals the presence in Tn7 of an additional potential resistance determinant. A streptothricin resistance gene, which appears cryptic in the original Tn7 context becomes activated in the recombinant plasmid upon supplying the promoter function of the lacZ system of pUC19. These results together with previously published sequence data further disclose the modular character in the resistance gene regions of Tn7-like transposons.

Regular ArticleNucleotide Sequence and Genetic Characterization of the Novel IncQ-like Plasmid pIE1107☆☆☆

AbstractThe analysis of the complete nucleotide sequence of the small resistance plasmid pIE1107 revealed a close similarity to the well-known IncQ plasmids. Highly conserved replication proteins and nearly identical origins of replication (oriV) suggest equivalent functions in the related replication systems. However, pIE1107 contains two copies of IncQ-oriV-like DNA which are slightly different regarding the iterons. Upon deletion of a silent copy of IncQ-oriV-like DNA the resulting plasmid is fully compatible with IncQ plasmids, indicating that there is no mutual communication between the replication control of the respective replicons. Experiments with clonedoriV DNA strongly suggest that the replication initiation protein of pIE1107 has specialized into the distinct target-iterons of its ownoriV which differs only by a few nucleotides from theoriV of IncQ plasmids. Implications from the apparent highly specific protein–DNA recognition and from the incompatibility properties of pIE1107 for the evolution of a family of compatible, IncQ-like plasmids are discussed.

Diversity of Salmonella enterica serovar Derby isolated from pig, pork and humans in Germany

AbstractSalmonella enterica serovar Derby (S. Derby) is one of the most prevalent serovars in pigs in Europe and in the U.S. and ranks among the 10 most frequently isolated serovars in humans. Therefore, a set of 82 epidemiologically unrelated S. Derby strains isolated between 2006 and 2008 from pigs, pork and humans in Germany was selected and investigated in respect to the transmission of clonal groups of the serovar along the food chain. Various phenotypic and genotypic methods were applied and the pathogenicity and resistance gene repertoire was determined. Phenotypically 72% of the strains were susceptible to all 17 antimicrobials tested while the others were monoresistant to tetracycline or multi-resistant with different resistance profiles. Four major clonal groups were identified based on PFGE, sequence data of the virulence genes sopA, sopB and sopD, VNTR-locus STTR5 and MLST revealing also the new sequence type ST774. Thirty different PFGE profiles were detected resulting in four clusters representing the four groups. The pathogenicity gene repertoire of 32 representative S. Derby strains analyzed by microarray showed six types with differences in the Salmonella pathogenicity islands, pathogenicity genes on smaller islets or prophages and fimbriae coding genes. The pathogenicity gene repertoire of the predominant types PAT DE1 and DE2 were most similar to the ones of S. Paratyphi B (dT+, O5−) and to a minor degree to S. Infantis and S. Virchow PATs. Overall this study showed that in Germany currently one major S. Derby clone is frequently isolated from pigs and humans. Contaminated pork was identified as one vehicle and consequently is a risk for human health. To prevent this serovar from entering the food chain, control measurements should be applied at the farm level.

CsrA and CsrB are required for the post-transcriptional control of the virulence-associated effector protein AvrA of Salmonella enterica

AbstractThe virulence-associated effector protein AvrA of Salmonella enterica is an ubiquitin-like acetyltransferase/cysteine protease, which interferes with the first line of immune response of the target organism. In contrast to translation of the AvrA protein in S. enterica strains, which takes place either constitutively (class 1 strains), or after acid induction (class 2 strains), or not at all (class 3 strains); the constitutive transcription of the respective avrA genes occurs regardless of these defined expression classes. When the number of avrA genes and mRNA molecules is raised experimentally using plasmids carrying the respective cloned avrA genes together with their promoter regions, the translation of avrA mRNA takes place very strongly in all respective AvrA expression classes. This kind of copy-dependent, post-transcriptional control of AvrA was shown to be dependent on the regulatory action of the CsrA/CsrB system since the deletion of both genes completely abolished the translation in the tested S. enterica strains, whereas the transcription remained unaffected. Moreover, AvrA production in strains carrying the cloned avrA genes on plasmids remained dependent on the presence of CsrA but unaffected in csrB mutant strains. On the other hand, overproduction of the regulatory molecules CsrA and CsrB in S. enterica strains carrying cloned csrA and csrB genes on plasmids ceased the expression of AvrA again. Therefore, the expression of avrA is suggested to be regulated in a post-transcriptional manner by critical and effective concentrations of CsrA (see-saw regulation), which is achieved through the sequestering activity of CsrB.

Molecular epidemiological view on Shiga toxin-producing Escherichia coli causing human disease in Germany: Diversity, prevalence, and outbreaks

AbstractInfections by intestinal pathogenic Escherichia coli (E. coli) are among those causing a high mortality and morbidity due to diarrheal disease and post infection sequelae worldwide. Since introduction of the Infection Protection Act in Germany 2001, these pathogens rank third among bacterial infections of the gastrointestinal tract. As a major pathovar Shiga toxin-producing E. coli (STEC) which include enterohemorrhagic E. coli (EHEC) play a leading role in occurrence of sporadic cases and disease outbreaks. An outstanding example is the large outbreak in spring 2011 caused by EHEC/EAEC O104:H4. To monitor and trace back STEC infections, national surveillance programs have been implemented including activities of the German National Reference Centre for Salmonella and other Enteric Bacterial Pathogens (NRC). This review highlights advances in our understanding of STEC in the last 20 years of STEC surveillance by the NRC. Here important characteristics of STEC strains from human infections and outbreaks in Germany between 1997 and 2013 are summarized.

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