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High toxinogenic potential of Staphylococcus aureus from wild ungulates in Brandenburg, Germany with a low level of antibiotic resistance
No full textIntroduction Data regarding the occurrence and virulence of Staphylococcus ( S .) aureus in wild living animals is rare. However, S. aureus may carry a multitude of virulence factors and express resistance to several antimicrobial substances. Handling game meat may thus lead to serious infections or food poisoning. The aim of this study was to provide insights into the occurrence and characteristics of S. aureus in wild ungulates from Brandenburg, Germany. Methods Nasal swabs of externally healthy-looking wild boars, roe, fallow and red deer were collected in hunts during season 2021/2022 and analyzed for S. aureus by selective enrichment. Species were determined using matrix assisted laser desorption ionization mass spectrometry and tested for phenotypic antimicrobial resistance. Whole-genome sequencing was conducted for genotyping, determination of virulence associated genes and analysis of phylogenetic relationships. Results S. aureus were recovered from approximately 8% of nasal swabs. However, the strains were only obtained from the sampled wild ruminants. S. aureus isolates were associated with sequence types (ST) 1, ST30, ST133, ST425, ST582 and ST6238. Isolates of ST1 clustered closely together in the phylogenetic analysis. Genes encoding staphylococcal enterotoxin (SE) or SE-like (SEl) were found in 14/17 isolates. In particular, a seh gene was present in 12/17 isolates. Moreover, two isolates harbored a multiplicity of genes encoding SE or SEl. In addition, the toxic shock syndrome toxin encoding tst gene was detected in one isolate. This isolate was resistant to penicillin and cefoxitin and accordingly harbored the blaZ gene. Discussion Wild ungulates intended for human consumption may carry potentially virulent S. aureus . In one case, the close phylogenetic relationship of S. aureus isolates indicates a possible intraspecific spread within a common territory. However, for others, the origin or the spread pattern can only be inferred. Handling of animals or their carcasses might contribute to staphylococcal infections in humans. Moreover, food poisoning due to SE producing strains may occur, if recommended hygiene practices are not applied during processing of game meat
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Quality assurance for genotyping and resistance testing of Clostridium (Clostridioides) difficile isolates - Experiences from the first inter-laboratory ring trial in four German speaking countries
No full textRobert Koch Institute, German
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Host-dependent factors in the pathogenicity and persistence of Salmonella serovars in animals and man
No full textSalmonella enterica führt deutschlandweit zu den zweithäufigsten
lebensmittelbedingten Infektionskrankheiten. Auffällig sind diesbezüglich die
Heterogenität des Wirtsspektrums und die Variabilität der Krankheitsverläufe.
Zur Aufklärung möglicher Wirts- und Serovar-abhängiger Faktoren, die zur
unterschiedlichen Adaptation und Pathogenese von Salmonella beitragen, wurden
systematisch vergleichende Infektionsstudien mit Salmonella Serovaren
unterschiedlichen Wirtsspektrums in intestinalen Epithel- und
Makrophagenzellen porcinen, aviären und humanen Ursprungs als repräsentative
Zelltypen der frühen Infektionsphase durchgeführt. Die Wirts-Pathogen-
Interaktionen wurden hinsichtlich Invasivität und Persistenz der Serovare,
daraus resultierender zytotoxischer und inflammatorischer Effekte sowie der
genomweiten Genexpressionsänderung des Wirtes untersucht. Unter
Berücksichtigung aller Faktoren ergaben sich Phänotypen, die wichtige Hinweise
auf Mechanismen zur Wirtsadaptation und Pathogenese liefern. Die Spezies- und
Zelltyp-übergreifend hohen Invasionsraten der Breitspektrum Serovare S.
Typhimurium und S. Enteritidis verursachten eine starke proinflammatorische
Antwort sowie im verhältnismäßig hohen Maße zytotoxische Effekte, was in vivo
zu einer starken Inflammation und örtlichen Begrenzung der Infektion führen
würde, wie sie etwa bei der humanen Gastroenteritis durch Breitspektrum-
Serovare zu beobachten ist. Dagegen stellte sich S. Choleraesuis insbesondere
in den porcinen Zelllinien als schwach invasiv dar, persistierte jedoch in den
meisten Zelllinien ähnlich gut wie die Breitspektrum-Serovare und führte
dementsprechend zu einer mittleren NF-κB Aktivierung und Zytotoxizität.
Diesbezüglich stellten sich die verwendeten porcinen Zelllinien auch bei hohen
MOIs als sehr robust heraus, die zudem auf verschiedene synthetische pathogen-
associated molecular patterns (PAMPs) wie Flagellin, PGN-Fragmenten und LPS
nur schwach bis mäßig reagierten. In vivo würde die beobachtete schwache
Invasivität und NF-κB Aktivierung von S. Choleraesuis vor allem in porcinen
Zellen und die relativ gute Persistenz, die durch das robuste Verhalten der
porcinen Zelllinien jedoch weitestgehend toleriert wird, auf eine „sanfte“
Infektion ohne starke Inflammation hindeuten, die damit eine systemische
Ausbreitung ermöglicht, wie sie für S. Choleraesuis im Schwein beschrieben
wurde. Die Geflügel-beschränkten Serovare S. Gallinarum und S. Pullorum
invadierten und persistierten dagegen insgesamt verhältnismäßig schlecht.
Dementsprechend verursachten sie kaum zytotoxische Effekte. Auffällig war
diesbezüglich auch die hohe Sensibilität der Hühnermakrophagen, die bereits
bei einer moderaten MOI um 5 bei höher invasiven Serovaren abstarben. Demnach
begünstigen die Charakterisitka von S. Gallinarum und S. Pullorum trotz eines
relativ hohen inflammatorischen Potentials das Überleben in sehr sensibel
reagierenden Hühnermakrophagen, die für eine systemische Infektion, wie sie
für S. Gallinarum und S. Pullorum im Huhn beschrieben sind, notwendig wären.
Untersuchungen mit synthetischen PAMPs sowie entsprechenden Salmonella
Deletions-mutanten mit beeinträchtigter Flagellensynthese und
Peptidoglycanrecycling deuteten zudem vor allem auf die initiale Interaktion
mit Epithelzellen eher als die mit Makrophagen als diskriminierenden Faktor
für eine Spezies-spezifische Anpassung und Pathogenität hin. Zusammenfassend
verdeutlichen die Ergebnisse dieser Arbeit, dass die Wirtsadaptation von
Salmonella neben einer möglichen bakteriellen Adaptation insbesondere aus
immunologischen oder anatomischen Eigenschaften resultiert, die einem Serovar,
das im Vergleich zu Breitspektrum-Serovaren Einschränkungen der Virulenz oder
des Metabolismus aufweist, in bestimmten Spezies eine erfolgreiche Infektion
und Persistenz ermöglichen.Salmonella enterica is the second most prevalent causative agent of foodbourne
diseases in Germany. With regard to their host range and pathogenicity,
Salmonella is a group of strong heterogenicity. To identify possible host- and
serovar-specific determinants involved in adaptation and different
pathogenicities of Salmonella, we systematically compared infections with
Salmonella serovars of different host-ranges in intestinal epithelial and
macrophage-like cells of porcine, avian and human origin as representative of
the early affected cell types during infection. Host-pathogen interactions
were analyzed with regard to invasiveness and persistence of the serovars,
cytotoxic effects and host immune responses as well as whole genome expression
patterns of the host. The outcomes of these assays revealed certain phenotypes
suggesting possible mechanisms for host adaptation and pathogenicity. The high
invasion rates observed for broad host-range serovars S. Typhimurium and S.
Enteritidis correlated with a strong proinflammation und resulted in
relatively strong cytotoxic effects, which suggest a strong inflammation and a
local limitation of the infection in vivo, consistent with observations of
human gastroenteritis due to broad host-range serovars. In contrast, S.
Choleraesuis strains were weakly invasive, especially in porcine cells, but
showed similar levels of persistence in most cell lines as the broad host-
range serovars. The resulting innate immune responses were correspondingly
intermediate, with average NF-κB activation levels and associated
cytotoxicity. The porcine cell lines were found to be even at high infective
doses extremely robust and responded to synthetic pathogen-associated
molecular patterns (PAMPs) with only average or weak NF-kB activation. The
lower invasiveness and NF-κB activation of the swine-adapted serovar S.
Choleraesuis in porcine cells but the fairly high-level persistence which is
tolerated by these host cells would result in a “soft” infection without a
strong inflammation in vivo that allows this serovar to spread systemically as
has been described for S. Choleraesuis infections in pigs. The poultry-
restricted Salmonella serovars Gallinarum and Pullorum showed the lowest
invasion rates and persisted poorly, independent of the cell type or species.
This correlated with no or only very weak cytotoxic effects. In this context
we observed a strong sensitivity of chicken macrophages with early onset of
cell cytoxicity at even moderate MOI of 5 with the more highly invasive
serovars. These observations suggest the characteristics for Salmonella
serovars Gallinarum and Pullorum enabling them to survive despite a relatively
high inflammatory potential. This conclusion would also be consistent with the
patterns of systemic infections reported for S. Gallinarum / S. Pullorum
infections in chickens. In addition, screening of the cell lines of different
species with synthetic PAMPs like flagellin, PGN-fragments or LPS as well as
Salmonella mutants with disrupted synthesis of flagella and recycling of
peptidogylcan indicate the epithelial cell layer rather than interactions with
macrophages as discriminating factor enabling a species-specific host
adaptation and pathogenicity. Rather than an adaptation to a particular host,
this study suggests host adaptation is the result of a particular host
providing the necessary prerequisites, anatomical or immunological, which
permit successful infection and persistence of serovars which may have
virulence or metabolic disadvantages compared to broad host-range serovars
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