Mary Woltemate Stec

Dr. Stec began her nursing career in 1973 as a graduate of Jefferson’s Nursing Diploma School. She would go on to receive her BS in Nursing from the University of Pennsylvania, her MSN from Gwynedd Mercy College, and her PhD in Nursing from Widener University. Dr. Stec has spent the majority of her career as a nursing educator, including as an instructor at Thomas Jefferson University Hospital School of Nursing, Gwynedd Mercy College, and Abington Memorial Hospital Dixon School of Nursing. She is now an Assistant Professor at Temple University. She is also a Certified Nurse Educator, an Evaluator for the National League for Nursing Accrediting Commission, and has served on a number of Boards, including the Nursing of Children Network, the National League for Nursing Accrediting Commission, and the National Coalition of Hospital Associated Schools and Colleges of Nursing.https://jdc.jefferson.edu/nursing_oral_histories/1005/thumbnail.jp

Closely related Campylobacter jejuni strains from different sources reveal a generalist rather than a specialist lifestyle

Background: Campylobacter jejuni and Campylobacter coli are human intestinal pathogens of global importance. Zoonotic transmission from livestock animals or animal-derived food is the likely cause for most of these infections. However, little is known about their general and host-specific mechanisms of colonization, or virulence and pathogenicity factors. In certain hosts, Campylobacter species colonize persistently and do not cause disease, while they cause acute intestinal disease in humans. Results: Here, we investigate putative host-specificity using phenotypic characterization and genome-wide analysis of genetically closely related C. jejuni strains from different sources. A collection of 473 fresh Campylobacter isolates from Germany was assembled between 2006 and 2010 and characterized using MLST. A subset of closely related C. jejuni strains of the highly prevalent sequence type ST-21 was selected from different hosts and isolation sources. PCR typing of strain-variable genes provided evidence that some genes differed between these strains. Furthermore, phenotypic variation of these strains was tested using the following criteria: metabolic variation, protein expression patterns, and eukaryotic cell interaction. The results demonstrated remarkable phenotypic diversity within the ST-21 group, which however did not correlate with isolation source. Whole genome sequencing was performed for five ST-21 strains from chicken, human, bovine, and food sources, in order to gain insight into ST-21 genome diversity. The comparisons showed extensive genomic diversity, primarily due to recombination and gain of phage-related genes. By contrast, no genomic features associated with isolation source or host were identified. Conclusions: The genome information and phenotypic data obtained in vitro and in a chicken infection model provided little evidence of fixed adaptation to a specific host. Instead, the dominant C. jejuni ST-21 appeared to be characterized by phenotypic flexibility and high genetic microdiversity, revealing properties of a generalist. High genetic flexibility might allow generalist variants of C. jejuni to reversibly express diverse fitness factors in changing environments

BaiCD gene cluster abundance is negatively correlated with Clostridium difficile infection

Background Clostridium difficile infection (CDI) is a major cause of hospital-acquired diarrhea. Secondary bile acids were shown to confer resistance to colonization by C. difficile. 7 alpha-dehydroxylation is a key step in transformation of primary to secondary bile acids and required genes have been located in a single bile acid-inducible (bai) operon in C. scindens as well as in C. hiranonis, two Clostridium sp. recently reported to protect against C. difficile colonization. Aim To analyze baiCD gene abundance in C. difficile positive and negative fecal samples. Material & methods A species-specific qPCR for detecting baiCD genes was established. Fecal samples of patients with CDI, asymptomatic toxigenic C. difficile colonization (TCD), non-toxigenic C. difficile colonization (NTCD), of C. difficile negative (NC) patients, and of two patients before and after fecal microbiota transplantation (FMT) for recurrent CDI (rCDI) were tested for the presence of the baiCD genes. Results The prevalence of the baiCD gene cluster was significantly higher in C. difficile negative fecal samples than in samples of patients diagnosed with CDI (72.5% (100/138) vs. 35.9% (23/64;p<0.0001). No differences in baiCD gene cluster prevalence were seen between NC and NTCD or NC and TCD samples. Both rCDI patients were baiCD-negative at baseline, but one of the two patients turned positive after successful FMT from a baiCD-positive donor. Conclusion Fecal samples of CDI patients are less frequently baiCD-positive than samples from asymptomatic carriers or C. difficile-negative individuals. Furthermore, we present a case of baiCD positivity observed after successful FMT for rCDI

Intestinal Microbiota Composition of Interleukin-10 Deficient C57BL/6J Mice and Susceptibility to Helicobacter hepaticus-Induced Colitis

The mouse pathobiont Helicobacter hepaticus can induce typhlocolitis in interleukin-10-deficient mice, and H. hepaticus infection of immunodeficient mice is widely used as a model to study the role of pathogens and commensal bacteria in the pathogenesis of inflammatory bowel disease. C57BL/6J Il10[superscript −/−] mice kept under specific pathogen-free conditions in two different facilities (MHH and MIT), displayed strong differences with respect to their susceptibilities to H. hepaticus-induced intestinal pathology. Mice at MIT developed robust typhlocolitis after infection with H. hepaticus, while mice at MHH developed no significant pathology after infection with the same H. hepaticus strain. We hypothesized that the intestinal microbiota might be responsible for these differences and therefore performed high resolution analysis of the intestinal microbiota composition in uninfected mice from the two facilities by deep sequencing of partial 16S rRNA amplicons. The microbiota composition differed markedly between mice from both facilities. Significant differences were also detected between two groups of MHH mice born in different years. Of the 119 operational taxonomic units (OTUs) that occurred in at least half the cecum or colon samples of at least one mouse group, 24 were only found in MIT mice, and another 13 OTUs could only be found in MHH samples. While most of the MHH-specific OTUs could only be identified to class or family level, the MIT-specific set contained OTUs identified to genus or species level, including the opportunistic pathogen, Bilophila wadsworthia. The susceptibility to H. hepaticus-induced colitis differed considerably between Il10[superscript −/−] mice originating from the two institutions. This was associated with significant differences in microbiota composition, highlighting the importance of characterizing the intestinal microbiome when studying murine models of IBD.National Institutes of Health (U.S.) (Grant NIH P01-CA26731)National Institutes of Health (U.S.) (Grant NIH P30ES0026731)National Institutes of Health (U.S.) (Grant NIH R01-OD011141

Systematische Simulation von Erdschlussvorgaengen in den Kabelnetzen des deutschen Steinkohlenbergbaus

Copy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Within-host evolution of Helicobacter pylori shaped by niche-specific adaptation, intragastric migrations and selective sweeps

The human pathogen Helicobacter pylori displays extensive genetic diversity. While H. pylori is known to evolve during infection, population dynamics inside the gastric environment have not been extensively investigated. Here we obtained gastric biopsies from multiple stomach regions of 16 H. pylori-infected adults, and analyze the genomes of 10 H. pylori isolates from each biopsy. Phylogenetic analyses suggest location-specific evolution and bacterial migration between gastric regions. Migration is significantly more frequent between the corpus and the fundus than with the antrum, suggesting that physiological differences between antral and oxyntic mucosa contribute to spatial partitioning of H. pylori populations. Associations between H. pylori gene polymorphisms and stomach niches suggest that chemotaxis, regulatory functions and outer membrane proteins contribute to specific adaptation to the antral and oxyntic mucosa. Moreover, we show that antibiotics can induce severe population bottlenecks and likely play a role in shaping the population structure of H. pylori

Use of UV-C Light for Surface Desinfection: Results from a Portable Sanitizing Device

Albrecht U-V, Vonberg R-P, Woltemate S, Sedlacek L. Use of UV-C Light for Surface Desinfection: Results from a Portable Sanitizing Device. In: 63. Jahrestagung der Deutschen Gesellschaft für Hygiene und Mikrobiologie (DGHM) e. V. International Journal of Medical Microbiology. Vol 301. Elsevier; 2011

Genomic evolution and transmission of Helicobacter pyloriin two South African families

Helicobacter pylori infects the stomachs of one in two humans and can cause sequelae that include ulcers and cancer. Here we sequenced the genomes of 97 H. pylori isolates from 52 members of two families living in rural conditions in South Africa. From each of 45 individuals, two H. pylori strains were isolated from the antrum and corpus parts of the stomach, and comparisons of their genomes enabled us to study within-host evolution. In 5 of these 45 hosts, the two genomes were too distantly related to be derived from each other and therefore represented evidence of multiple infections. From the remaining 40 genome pairs, we estimated that the synonymous mutation rate was 1.38 × 10(−5) per site per year, with a low effective population size within host probably reflecting population bottlenecks and immune selection. Some individuals showed very little evidence for recombination, whereas in others, recombination introduced up to 100-times more substitutions than mutation. These differences may reflect unequal opportunities for recombination depending on the presence or absence of multiple infections. Comparing the genomes carried by distinct individuals enabled us to establish probable transmission links. Transmission events were found significantly more frequently between close relatives, and between individuals living in the same house. We found, however, that a majority of individuals (27/52) were not linked by transmission to other individuals. Our results suggest that transmission does not always occur within families, and that coinfection with multiple strains is frequent and evolutionarily important despite a fast turnover of the infecting strains within-host