154 research outputs found
Molecular epidemiology of methicillin-resistant S. aureus (MRSA) in veterinary medicine
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Inhaltsverzeichnis
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Einleitung
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Diskussion
Zusammenfassung
Summary
Referenzen
Danksagung
SelbständigkeitserklärungEinige S. aureus-Populationen, die sich im hospitalassoziierten Milieu seit
vielen Jahren etabliert haben, erlangen multiple Resistenzen durch die
Akkumulation verschiedener Resistenzdeterminaten. Insbesondere Methicillin-
resistente Staphylococcus aureus (MRSA) sind heute weltweit einer der
häufigsten Verursacher von sporadischen sowie endemischen Infektionen in
Krankenhäusern, anderen Gesundheitseinrichtungen und auch in ambulanten
Bereichen. Seit den frühen 70er Jahren werden MRSA-Fälle auch bei Tieren
berichtet. In den letzten Jahren kam es jedoch zu einem deutlichen Anstieg von
Berichten ĂĽber MRSA-infizierte Tiere, insbesondere bei Kleintieren und Pferden
in klinischen Einrichtungen. Auch die Frage nach dem zoonotischen Charakter
animaler MRSA wird zunehmend diskutiert. Diese Arbeit verfolgte deshalb vier
wesentliche Ziele. Zunächst wurden vergleichend Untersuchungen zu
verschiedenen phänotypischen Nachweisverfahren für die MRSA-Diagnostik in der
Veterinärmedizin durchgeführt. Ein zweiter Punkt war die Erfassung von Daten
ĂĽber das Vorkommen, die Typisierung sowie die genetische Charakterisierung von
MRSA-Isolaten von Pferden und Kleintieren. In Zusammenarbeit mit der Klinik
und Poliklinik für kleine Haustiere der Freien Universität Berlin wurde das
dritte Ziel verfolgt, die Aufdeckung von möglichen zoonotischen
Transmissionswegen sowie die nosokomiale Verbreitung von MRSA in klinischen
Einrichtungen der Veterinärmedizin unter Einbeziehung von Tieren, Menschen und
Gegenständen. Das vierte angestrebte Ziel dieser Arbeit umfasste die Analyse
der gesammelten Daten unter epidemiologischen Gesichtspunkten und Einordnung
der untersuchten Isolate in die bislang bekannten S. aureus- Population sowie
den Vergleich zu einigen häufig auftretenden humanen Epidemiestämmen. Um alle
MRSA-Isolate zu typisieren, wurden verschiedene international gebräuchliche
Methoden eingesetzt. Durch den Einsatz einer Pulsfeld-Gel-Elektrophorese
(PFGE) nach Makrorestriktion mittels der Endonuklease SmaI war ein Vergleich
der Restriktionsmuster des Gesamtgenoms aller Isolate realisierbar. Unter
Anwendung der Multi-Locus-Sequenztypisierung (MLST) war eine Zuordnung der
hier aufgetretenen mit bereits bekannten und in einer Online-Datenbank
(www.mlst.net) hinterlegten Sequenztypen (ST) möglich. Die Typisierung des
mobilen Staphylokokken-Austauschsystems (SCCmec), welches den mec-Komplex
beinhaltet, wurde in dieser Arbeit mit einer bereits beschriebenen Multiplex-
Strategie verfolgt, die jedoch nicht in jedem Fall zu einem eindeutigen
Ergebnis fĂĽhrte. Insgesamt sind in dieser Arbeit 1544 Einzelproben (davon 144
vordifferenzierte Keimisolate aus anderen veterinärmedizinischen
diagnostischen Laboren) von Tieren, Menschen und Gegenständen untersucht
worden. Im ersten Abschnitt wurden die verschiedenen Verfahren fĂĽr den
phänotypischen Nachweis animaler MRSA vergleichend getestet, wobei
festgestellt werden konnte, dass der Agardiffusionstest mit Cefoxitin (30µg)
anderen Methoden, wie z.B. dem Agardiffusionstest mit Oxacillin 1 und 5µg
sowie dem Einsatz eines Oxacillin-Screeningagars, deutlich unterlegen ist. Der
Goldstandard fĂĽr den Nachweis der Resistenzdeterminante mecA ist jedoch noch
immer ein spezifischer Gennachweis mittels Polymerase-Kettenreaktion (PCR),
möglichst verbunden mit einem eindeutigen Speziesnachweis. Zu diesem Zweck
wurde eine Triplex-PCR erarbeitet, die neben dem fĂĽr die Ăź-Lactamresistenz
verantwortlichen Gen mecA gleichzeitig Spezies-spezifische Nachweise von S.
aureus und S. intermedius ermöglicht. Im zweiten Teil der Ergebnisse wurden
MRSA-Isolaten von Pferden und Kleintieren analysiert. In den insgesamt 135
untersuchten Proben (davon 70 S. aureus) von Pferden aus unterschiedlichen
Bundesländern von verschiedenen klinisch infizierten Tieren konnte in 11
Proben (15,7%) ein MRSA-Nachweis gefĂĽhrt werden. Die dabei aufgetretenen
Genotypen, welche in dieser Arbeit mit den GroĂźbuchstaben "A", "B", "C"
benannt wurden, erzielten in der Analyse dieser Muster aus der PFGE einen
genetischen Ăśbereinstimmungsgrad von ca. 86%, der sich auch in der engen
Verwandtschaft der mittels MLST ermittelten Sequenztypen ST8 und ST254
widerspiegelt. Diese ST unterscheiden sich tatsächlich lediglich in einem
Basenpaar im ersten Allel der fĂĽr die Bestimmung herangezogenen definierten
Abschnitte von sieben konservativen Haushaltsgenen. Leider schränkt die
begrenzte Anzahl der untersuchten Isolate von Pferden die Aussagekraft der
Daten ein. Alle Staphylokokken-Genkassetten (SCCmec) aus equinen MRSA-Isolaten
waren Vertreter der bislang kleinsten bekannten Kassette vom Typ SCCmec IV.
Weitere 6 MRSA-Isolate von Kleintieren aus anderen Bundesländern zeigten die
PFGE- Muster: "F", "D" und "H" sowie Subtypen. Die hier durch MLST ermittelten
Sequenztypen waren ST254, ST225 und ST239. Während bei fünf Isolaten ebenfalls
SCCmec IV auftrat, zeigte sich ein Isolat aus GieĂźen (ST225) positiv fĂĽr
SCCmec II. Im dritten Abschnitt dieser Arbeit wurde S. aureus in der
Kleintierklinik ĂĽber einen Zeitraum von 20 Monaten in insgesamt 6,9% (60/866)
der klinischen Proben gefunden. 26 von diesen waren mecA-positiv, darunter
auch Isolate von so exotischen Tieren wie Papagei, Schildkröte oder
Fledermaus. AuĂźerdem wurden Nasentupfer von Hunden (257 Tupfer von 191
Tieren), von Menschen (dreimal n=62, n=62 und n=88) und Objekten (20)
untersucht. Dabei wurde in 6 Fällen bei Hunden, bei 20 Personen und an 3
Objekten ein MRSA Nachweis gefĂĽhrt. Lokal dominierten hier ĂĽberwiegend zwei
verschiedene PFGE Typen, hier als "G" und "D" bezeichnet. Die MLST-Analyse
zeigte zwei genetisch unterschiedliche MRSA-Klone: PFGE-Typ "G" entspricht dem
ST22, der PFGE-Typ "D" hingegen entspricht dem ST239. Neben dem SCCmec IV, der
generell bei PFGE Typ "D" nachzuweisen war, schlug die eindeutige
Charakterisierung der Genkassette des PFGE-Typs "G" mit denen in dieser Arbeit
eingesetzten Techniken fehl. Eine Auswertung der Daten aus der Kleintierklinik
unter einigen epidemiologischen Aspekten zeigte, dass eine zeitweise
nosokomiale Verbreitung der genannten Klone innerhalb dieser Institution
angenommen werden darf. Den Abschluss dieser Arbeit bildete die Einordnung der
bei animalen MRSA-Isolaten dieser Arbeit aufgetretenen STen in einen S.
aureus-Populationszusammenhang, der hier unter Einbeziehung von Daten ĂĽber
bislang bekannte S. aureus-STen aus der Datenbank www.mlst.net durch die
Erstellung eines Minimum-Spannig-Trees. Dabei konnte gezeigt werden, dass alle
in dieser Arbeit aufgetreten STen (ST8, ST239, ST254, ST225, ST22) bereits
häufig in der Humanmedizin als MRSA in Erscheinung getreten sind und
etablierten klonalen Komplexen angehören, also keinesfalls "neue" genotypische
Linien begrĂĽnden oder vertreten. Die vorliegenden Daten belegen, dass sich
nosokomiale Infektionen, insbesondere solche durch MRSA, sich in der
Veterinärmedizin etabliert haben. Aufgrund der ständigen Anpassungsvorgänge
der Infektionserreger an ihre Umgebung und ihr hohes Adaptionsvermögen an
Wirtsorganismen anderer Spezies ist die Erarbeitung standardisierter
Hygienerichtlinien, die der Transmission von Tier zu Tier aber auch zwischen
Mensch und Tier entgegenwirken, auch für veterinärmedizinischen Praxen und
Kliniken erforderlich. Die Bedeutung von MRSA-Infektionen bei Tieren als
Quelle und / oder Reservoir fĂĽr MRSA-Erkrankungen beim Menschen ist bislang
noch vollkommen ungeklärt. Durch die nachweislich leichte Übertragbarkeit,
insbesondere in einer Umgebung mit Selektionsdruck (Praxis, Klinik), ist
jedoch davon auszugehen, dass das Risiko fĂĽr Transmissionen zwischen Mensch
und Tier bei engem Kontakt bzw. mangelnder Hygiene nicht zu unterschätzen ist.Various populations of S. aureus, which have established themselves in the
hospital environment over the last decades, have acquired different resistance
factors and are now difficult to combat, even in the field of veterinary
medicine. In particular, Methicillin-resistant Staphylococcus aureus (MRSA)
are one of the most predominant causes of sporadic and endemic infections in
hospitals as well as in hospital-adapted institutions. Since the early `70s,
infections due to MSRA have also been reported in animals. In the last years,
however, there have been increasing reports about MRSA infections in small
animals and horses. Recently published studies address the potential of
interspecies transferability, or the zoonotic character of MRSA. The aim of
this work was to compile data and knowledge about the occurrence and relevance
of MRSA in the field of veterinary medicine. Therefore, four main goals were
defined prior to this work. First of all, a comparative investigation of
different methods for phenotypical identification of MRSA of animal origin was
performed. A second point of interest was the recording of data concerning
occurrence, patterns of resistance and characterization of relevant genetic
markers. In close cooperation with the clinic and policlinic for small animals
of the Free University of Berlin, a third goal was set: To pinpoint the
zoonotic potential of some MRSA lineages and detection of potential nosocomial
transmission pathways in a clinical setting. The last intention of this
investigation was to analyze all recorded data from an epidemiological point
of view. Therefore, isolates originating from animals were compared to a set
of data from human MRSA strains and assigned to a database that provided
information about several S. aureus-genotypes. International recommended
methods were applied to characterize the MRSA isolates in this work. Clonal
analysis was performed by employing endonuclease SmaI digestion, followed by
pulsed-field gel-electrophoresis (PFGE) in order to compare the genomic
marcrorestriction patterns of all isolates. Multilocus sequence typing (MLST),
which is based on the sequence analysis of defined sections of seven
housekeeping genes, enabled the assignment of sequence types (ST) to each MRSA
and into the whole S. aureus population analysed so far (www.mlst.net). Typing
of the mobile genetic element (SCCmec), which harbours the mec-complex in
staphylococci, was carried out using a previously published Multiplex
polymerase chain reaction (PCR) strategy. Unfortunately, this PCR typing did
not always produce satisfying results. A total of 1,544 specimens (including
144 isolates from other veterinary facilities) from animals, humans and
everyday objects were examined in this work. Comparing different phenotypical
methods to diagnose MRSA from animal origin revealed that the agar diffusion
test with Cefoxitin (30ug) seems to be superior to other methods, e.g. agar
diffusion test with Oxacillin 1µg and 5µg as well as an Oxacillin screening
agar. Despite these results, the best method for MRSA verification still is
PCR, detecting the mecA gene that codes for the resistance determinant as well
as a species-specific marker like the nuc gene and/or a specific 16S rDNA
sequence. Samples from 135 S. aureus infected horses were sent in from
different veterinary microbiological institutions in Germany. Upon
examination, 70 samples proved to contain S. aureus, 11 of those turned out to
be positive for MRSA (15.7%). By applying PFGE, three clonal types were
identified and designated as "A", "B", "C". Surprisingly, these clonaltypes
showed a degree of genetic similarity of 86%. A second examination emphasized
these findings, proving this close relationship. The detected STs, determined
by MLST, turned out to be the closely-related ST8 and ST254, which differ from
each other only by substitution of a single base-pair (bp) in one of the seven
housekeeping genes sequenced (arcC, aroE, glpF, gmk, pta, tpi, ypiL).
Unfortunately, the restricted number of horse isolates investigated here is a
limiting factor in the interpretation of these results. All recorded
staphylococcal chromosomal cassettes (SCCmec) from equine MRSA isolates in
this work proved to be SCCmec IV. Additional 6 MRSA isolates of small animals
from different sources in Germany showed different PFGE types: "F", "D" and
"H" as well as subtypes. The obtained sequence types determined by MLST were
ST254, ST225 and ST239. While five isolates proved to contain SCCmec IV, one
isolate (out of those related to ST225) was positive for SCCmec II. In the
third part of this work, during an investigation period of 20 months, S.
aureus was found in 6.9% (60/866) of all clinical samples being sent to our
laboratory for diagnostic purposes from the small animal hospital. Twenty-six
of these tested positive for mecA (including isolates from exotic animals such
as parrots, turtles as well as a bat). In addition, we collected and
investigated nasal specimens from dogs (257 specimens of 191 animals) and
humans (tested three times: n=62; n=62; and n=88). Furthermore, 20 samples of
everyday objects were analysed. MRSA was detected in six canine cases, in
nasal specimens from 20 persons, and on 3 objects. Two different PFGE types
dominated in this setting during the investigation period, namely type "G" and
"D". MLST analysis showed two genetically different MRSA clones: PFGE type "G"
corresponded to ST22, and PFGE type "D" was determined to ST239. Despite the
SCCmec IV, which was found to be related to type "D", the utilized SCC-typing
techniques used in this work failed in typing SCCmec in PFGE type "G". In
regard to epidemiological aspects, evaluating data from this small animal
hospital indicated that an occasional nosocomial spread of the aforementioned
MRSA clones may have occurred within this institution. The final part of this
investigation was to classify all MRSA ST which had been identified during
this work, in an epidemical context by using additional data from www.mlst.net
in performing a Minimum spanning tree analysis. This approach could
demonstrate that all MRSA STs in this thesis (ST8, ST239, ST254, ST225, ST22)
have also been frequently observed in isolates from human MRSA infections with
an almost global occurrence. The data presented here are evidence of
nosocomial infections due to MSRA in veterinary medicine facilities. Due to
the constant adaptation processes of infectious agents to their environment
and their high adaptability to host organisms of different (animal) species,
the development of standardized hygienic guidelines for veterinary practice
and hospitals should be enforced. Especially the potential nosocomial
transmission of MRSA from animal to animal as well as between human and animal
should be the focus of hygienic measures as well as future research. The
current relevance of MRSA infections in animals as a potential source and/or
reservoir for MRSA mediated infections in humans is still unknown. The
apparent ready transferability of MRSA, in particular in an environment with a
certain selection pressure (practice, hospital), showed that the risk for
nosocomial transmission between human and animal with close contact and/or
lack of hygienic measures must be taken seriously
Complete Genome Sequence of the Livestock-Associated Methicillin-Resistant Strain Staphylococcus aureus subsp. aureus 08S00974 (Sequence Type 398)
We report here the complete genome sequence of the livestock-associated
methicillin-resistant Staphylococcus aureus strain 08S00974 from sequence type
398 (ST398 LA-MRSA) isolated from a fatting pig at a farm in Germany
Complete Genome Sequence of the Disinfectant Susceptibility Testing Reference Strain Staphylococcus aureus subsp. aureus ATCC 6538
We report here the complete genome sequence of the methicillin-sensitive
Staphylococcus aureus subsp. aureus strain ATCC 6538 (FDA 209, DSM 799, WDCM
00032, and NCTC 10788)
StationsprĂĽfbericht Schaf 2010
Ergebnisse der 15. Mast- und Schlachtleistungsprüfung beim Schaf aus der Prüfstation Köllitsch 201
Effects of a Four-Week High-Dosage Zinc Oxide Supplemented Diet on Commensal Escherichia coli of Weaned Pigs
Strategies to reduce economic losses associated with post-weaning diarrhea in pig farming include high-level dietary zinc oxide supplementation. However, excessive usage of zinc oxide in the pig production sector was found to be associated with accumulation of multidrug resistant bacteria in these animals, presenting an environmental burden through contaminated manure. Here we report on zinc tolerance among a random selection of intestinal Escherichia coli comprising of different antibiotic resistance phenotypes and sampling sites isolated during a controlled feeding trial from 16 weaned piglets: In total, 179 isolates from “pigs fed with high zinc concentrations” (high zinc group, [HZG]: n = 99) and a corresponding “control group” ([CG]: n = 80) were investigated with regard to zinc tolerance, antimicrobial- and biocide susceptibilities by determining minimum inhibitory concentrations (MICs). In addition, in silico whole genome screening (WGSc) for antibiotic resistance genes (ARGs) as well as biocide- and heavy metal tolerance genes was performed using an in-house BLAST-based pipeline. Overall, porcine E. coli isolates showed three different ZnCl2 MICs: 128 μg/ml (HZG, 2%; CG, 6%), 256 μg/ml (HZG, 64%; CG, 91%) and 512 μg/ml ZnCl2 (HZG, 34%, CG, 3%), a unimodal distribution most likely reflecting natural differences in zinc tolerance associated with different genetic lineages. However, a selective impact of the zinc-rich supplemented diet seems to be reasonable, since the linear mixed regression model revealed a statistically significant association between “higher” ZnCl2 MICs and isolates representing the HZG as well as “lower ZnCl2 MICs” with isolates of the CG (p = 0.005). None of the zinc chloride MICs was associated with a particular antibiotic-, heavy metal- or biocide- tolerance/resistance phenotype. Isolates expressing the 512 μg/ml MIC were either positive for ARGs conferring resistance to aminoglycosides, tetracycline and sulfamethoxazole-trimethoprim, or harbored no ARGs at all. Moreover, WGSc revealed a ubiquitous presence of zinc homeostasis and – detoxification genes, including zitB, zntA, and pit. In conclusion, we provide evidence that zinc-rich supplementation of pig feed selects for more zinc tolerant E. coli, including isolates harboring ARGs and biocide- and heavy metal tolerance genes – a putative selective advantage considering substances and antibiotics currently used in industrial pork production systems
In situ characterization of polycaprolactone fiber response to quasi-static tensile loading in scanning electron microscopy
Microstructural responses to the mechanical load of polymers used in tissue engineering is notably important for qualification at in vivo testing, although insufficiently studied, especially regarding promising polycaprolactone (PCL). For further investigations, electrospun PCL scaffolds with different degrees of fiber alignment were produced, using two discrete relative drum collector velocities. Development and preparation of an adjusted sample geometry enabled in situ tensile testing in scanning electron microscopy. By analyzing the microstructure and the use of selected tracking techniques, it was possible to visualize and quantify fiber/fiber area displacements as well as local fractures of single PCL fibers, considering quasi-static tensile load and fiber alignment. The possibility of displacement determination using in situ scanning electron microscopy techniques for testing fibrous PCL scaffolds was introduced and quantified
In situ characterization of polycaprolactone fiber response to quasi-static tensile loading in scanning electron microscopy
Microstructural responses to the mechanical load of polymers used in tissue engineering is notably important for qualification at in vivo testing, although insufficiently studied, especially regarding promising polycaprolactone (PCL). For further investigations, electrospun PCL scaffolds with different degrees of fiber alignment were produced, using two discrete relative drum collector velocities. Development and preparation of an adjusted sample geometry enabled in situ tensile testing in scanning electron microscopy. By analyzing the microstructure and the use of selected tracking techniques, it was possible to visualize and quantify fiber/fiber area displacements as well as local fractures of single PCL fibers, considering quasi-static tensile load and fiber alignment. The possibility of displacement determination using in situ scanning electron microscopy techniques for testing fibrous PCL scaffolds was introduced and quantified. © 2021 by the authors. Licensee MDPI, Basel, Switzerland
Men’s Use of Cosmetic Surgery and the Role of Traditional Masculinity Ideologies
Background: In western countries, men are increasingly using cosmetic surgery. However, despite this trend, there remains a dearth of information on the prevalence, acceptance, and motivations behind men's use of cosmetic surgery. Furthermore, the potential association between men's use of cosmetic surgery and in particular male-specific cosmetic surgery procedures such as head hair transplant or penis enlargement and traditional masculinity ideologies (TMI) has not been investigated so far.
Methods: A cross-sectional anonymous online survey was conducted among 241 self-identifying men aged 18 years or older from the German-speaking part of Europe. Participants responded to questions about cosmetic surgery use and experiences, and completed the Conformity to Masculine Ideologies - Short Form (CMNI-SF) and Male Role Norms Inventory - Short Form (MRNI-SF) questionnaires to assess conformity with and endorsement of TMI.
Results: Of the 241 men, 47 (19.5%) have undergone cosmetic surgery. The most common types of cosmetic surgeries reported were wrinkle treatment, eyelid correction, and head-hair transplant. Penis enlargement procedures were reported by three (6.4%) of the 47 men that have performed cosmetic surgery procedures. The main reasons for undergoing surgery were to feel better (72.3%) and look better (55.3%), while to increase sexual success (17.0%) and to increase manliness (14.9%) were also reported. Logistic regression models showed that higher conformity to TMI (CMNI-SF) was associated with higher odds of having undergone cosmetic surgery. Specifically, an increase of one standard-deviation in the CMNI-SF increased the odds of having undergone cosmetic surgery by a factor of 2.29, and the odds of having undergone head-hair transplant surgery by a factor of 3.84.
Conclusion: The results highlight overall increased use and specific characteristics of men’s cosmetic surgery use. The significant positive association between conformity to TMI and men's use of cosmetic surgery points towards men’s use of cosmetic surgery as increasingly used mean to assert power, success, dominance and sexual success
Sharing more than friendship - nasal colonization with coagulase-positive staphylococci (CPS) and co-habitation aspects of dogs and their owners
Background Since the relationship between dogs and their owners has changed,
and dogs moved from being working dogs to family members in post-industrial
countries, we hypothesized that zoonotic transmission of opportunistic
pathogens like coagulase positive staphylococci (CPS) is likely between dogs
and their owners. Methodology/Principal Findings CPS- nasal carriage,
different aspects of human-to-dog relationship as well as potential
interspecies transmission risk factors were investigated by offering nasal
swabs and a questionnaire to dog owners (108) and their dogs (108) at a dog
show in 2009. S. aureus was found in swabs of 20 (18.5%) humans and two dogs
(1.8%), and spa types which correspond to well known human S. aureus lineages
dominated (e.g. CC45, CC30 and CC22). Multilocus sequence typing (MLST) of the
two canine strains revealed ST72 and ST2065 (single locus variant of ST34).
Fifteen dogs (13.9%) and six owners (5.6%) harboured S. pseudintermedius,
including one mecA-positive human isolate (MRSP). Pulsed field gel
electrophoresis (PFGE) revealed that one dog/owner pair harboured
indistinguishable S. pseudintermedius- isolates of ST33. Ten (48%) of the 21
S. pseudintermedius-isolates showed resistance towards more than one
antimicrobial class. 88.9% of the dog owners reported to allow at least one
dog into the house, 68.5% allow the dog(s) to rest on the sofa, 39.8% allow
their dogs to come onto the bed, 93.5% let them lick their hands and 52.8% let
them lick their face. Bivariate analysis of putative risk factors revealed
that dog owners who keep more than two dogs have a significantly higher chance
of being colonized with S. pseudintermedius than those who keep 1–2 dogs
(p<0.05). Conclusions/Recommendations In conclusion, CPS transmission between
dog owners and their dogs is possible. Further investigation regarding
interspecies transmission and the diverse adaptive pathways influencing the
epidemiology of CPS (including MRSA and MRSP) in different hosts is needed
High-Zinc Supplementation of Weaned Piglets Affects Frequencies of Virulence and Bacteriocin Associated Genes Among Intestinal Escherichia coli Populations
To prevent economic losses due to post-weaning diarrhea (PWD) in industrial pig production, zinc (Zn) feed additives have been widely used, especially since awareness has risen that the regular application of antibiotics promotes buildup of antimicrobial resistance in both commensal and pathogenic bacteria. In a previous study on 179 Escherichia coli collected from piglets sacrificed at the end of a Zn feeding trial, including isolates obtained from animals of a high-zinc fed group (HZG) and a corresponding control group (CG), we found that the isolate collection exhibited three different levels of tolerance toward zinc, i.e., the minimal inhibitory concentration (MIC) detected was 128, followed by 256 and 512 mu g/ml ZnCl2. We further provided evidence that enhanced zinc tolerance in porcine intestinal E. coli populations is clearly linked to excessive zinc feeding. Here we provide insights about the genomic make-up and phylogenetic background of these 179 E. coli genomes. Bayesian analysis of the population structure (BAPS) revealed a lack of association between the actual zinc tolerance level and a particular phylogenetic E. coli cluster or even branch for both, isolates belonging to the HZG and CG. In addition, detection rates for genes and operons associated with virulence (VAG) and bacteriocins (BAG) were lower in isolates originating from the HZG (41 vs. 65% and 22 vs. 35%, p < 0.001 and p = 0.002, resp.). Strikingly, E. coli harboring genes defining distinct pathotypes associated with intestinal disease, i.e., enterotoxigenic, enteropathogenic, and Shiga toxin-producing E. coli (ETEC, EPEC, and STEC) constituted 1% of the isolates belonging to the HZG but 14% of those from the CG. Notably, these pathotypes were positively associated with enhanced zinc tolerance (512 mu g/ml ZnCl2 MIC, p < 0.001). Taken together, zinc excess seems to influence carriage rates of VAGs and BAGs in porcine intestinal E. coli populations, and high-zinc feeding is negatively correlated with enteral pathotype occurrences, which might explain earlier observations concerning the relative increase of Enterobacterales considering the overall intestinal microbiota of piglets during zinc feeding trials while PWD rates have decreased
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