AIMS: Bacteriophages infect bacteria, and they are present everywhere in the world including the intestinal tracts of animals. Yersiniosis is a common foodborne infection caused by Yersinia ...enterocolitica and Yersinia pseudotuberculosis. As these bacteria are frequently isolated from pigs, we wanted to know whether Yersinia‐specific bacteriophages are also present in the pig stools and, if so, whether there is a positive or negative association between the prevalence of the Yersinia phages and the pathogenic Yersinia in the stool samples. METHODS AND RESULTS: Altogether 793 pig stool samples collected between November 2010 and March 2012 from 14 Finnish pig farms were screened for the presence of bacteriophages able to infect Y. enterocolitica serotype O:3, O:5,27 or O:9 strains, or Y. pseudotuberculosis serotype O:1a, O:1b or O:3 strains. Yersinia phages were isolated from 90 samples from eight farms. Yersinia enterocolitica O:3 was infected by 59 phages, 28 phages infected serotypes O:3 and O:5,27, and eight phages infected serotypes O:3, O:5,27 and O:9, and Y. pseudotuberculosis O:1a by eight phages. Many phages originating from pigs in the same farm were identical based on their restriction enzyme digestion patterns; 20 clearly different phages were selected for further characterization. Host ranges of these phages were tested with 94 Yersinia strains. Six of the phages infected eight strains, 13 phages infected three strains, and one phage infected only one strain, indicating that the phages had a relatively narrow host range. CONCLUSIONS: There was a clear association between the presence of the host bacteria and specific phages in the stools. SIGNIFICANCE AND IMPACT OF THE STUDY: The isolated bacteriophages may have potential as biocontrol agents for yersiniosis in both humans and pigs in future, and as alternatives or in addition to antibiotics. To our knowledge, this is the first reported isolation of Yersinia‐specific phages from pig stool samples.
What is next after antibiotics? Oduor, J.M.O.; Kadija, E.; Kiljunen, S. ...
International journal of infectious diseases,
December 2020, 2020-12-00, 2020-12-01, Letnik:
101
Journal Article
ABSTRACT
Bacteriophage φYeO3-12 is a lytic phage of
Yersinia enterocolitica
serotype O:3. The phage receptor is the lipopolysaccharide O chain of this serotype that consists of the rare sugar ...6-deoxy-
l
-altropyranose. A one-step growth curve of φYeO3-12 revealed eclipse and latent periods of 15 and 25 min, respectively, with a burst size of about 120 PFU per infected cell. In electron microscopy φYeO3-12 virions showed pentagonal outlines, indicating their icosahedral nature. The phage capsid was shown to be composed of at least 10 structural proteins, of which a protein of 43 kDa was predominant. N-terminal sequences of three structural proteins were determined, two of them showing strong homology to structural proteins of coliphages T3 and T7. The phage genome was found to consist of a double-stranded DNA molecule of 40 kb without cohesive ends. A physical map of the phage DNA was constructed using five restriction enzymes. The phage infection could be effectively neutralized using serum from a rabbit immunized with whole φYeO3-12 particles. The antiserum also neutralized T3 infection, although not as efficiently as that of φYeO3-12. φYeO3-12 was found to share, in addition to the N-terminal sequence homology, several common features with T3, including morphology and nonsubjectibility to F exclusion. The evidence conclusively indicated that φYeO3-12 is the first close relative of phage T3 to be described.
SUMMARY
Two new examples of amino acid homology between HLA B27 and microbes triggering HLA B27‐associated diseases are described. An outer membrane protein YadA (Yersinia adhesin, previously called ...Yop1) of Yersinia enterocolitica and Y. pseudotuberculosis shares a linear tetrapeptide with HLA B27. A cationic outer membrane protein OmpH of Salmonella typhimurium shares homology with five amino acids of HLA B27 in a non‐linear fashion. The four amino acids of YadA are also notably included in the hexapeptide identical between Klebsiella pneumoniae nitrogenase and HLA B27, and three of them occur in the pentapeptide shared by a Shigella flexneri protein and HLA B27. Antibodies against synthetic peptides including HLA B27 homologous sequences of YadA and OmpH were observed in one‐third of the patients with HLA B27 associated diseases. Antibodies were directed against a flanking sequence next to the amino acid sequences shared by arthritis‐triggering microbes and HLA B27. The area of identity in each example of this molecular mimicry (Yersinia, Salmonella, Shigella and Klebsiella) is located in the same place on the H LA B27 molecule: between amino acids 70 to 78 in the variable region of α1‐helix. This area of HLA B27 molecule includes sites predicted to be important for binding processed antigens.
The lipopolysaccharide (LPS) of strains representing various serotypes of
Yersinia enterocolitica
and
Y. enterocolitica
-like bacteria was studied by deoxycholate-PAGE and silver staining analysis. ...Four main types of LPS were detected based on the O-polysaccharide (O-PS): (i) LPS with homopolymeric O-PS, (ii) LPS with ladder-forming heteropolymeric O-PS, (iii) LPS with single-length O-PS, and (iv) semi-rough LPS without O-PS. Within the first three types, several subvariants were detected. Selected serotypes representing all above LPS types are sensitive to bacteriophage ϕR1-37 indicating that they share the phage receptor, a hexasaccharide called outer core in
Y. enterocolitica
O:3. Whereas phage ϕR1-37-resistant mutants of homopolymeric O-PS have lost only the outer core, those of ladder-forming or single-length O-PS have lost also the O-PS suggesting that in the latter ones the outer core is bridging between O-PS and lipid A-core. This work forms a basis of further structural, biochemical and genetic studies of these LPSs.
Gut barrier function is key in maintaining a balanced response between the host and its microbiome. The microbiota can modulate changes in gut barrier as well as metabolic and inflammatory responses. ...This highly complex system involves numerous microbiota-derived factors. The gut symbiont Akkermansia muciniphila is positively correlated with a lean phenotype, reduced body weight gain, amelioration of metabolic responses and restoration of gut barrier function by modulation of mucus layer thickness. However, the molecular mechanisms behind its metabolic and immunological regulatory properties are unexplored. Herein, we identify a highly abundant outer membrane pili-like protein of A. muciniphila MucT that is directly involved in immune regulation and enhancement of trans-epithelial resistance. The purified Amuc_1100 protein and enrichments containing all its associated proteins induced production of specific cytokines through activation of Toll-like receptor (TLR) 2 and TLR4. This mainly leads to high levels of IL-10 similar to those induced by the other beneficial immune suppressive microorganisms such as Faecalibacterium prausnitzii A2-165 and Lactobacillus plantarum WCFS1. Together these results indicate that outer membrane protein composition and particularly the newly identified highly abundant pili-like protein Amuc_1100 of A. muciniphila are involved in host immunological homeostasis at the gut mucosa, and improvement of gut barrier function.
This report describes the development of in-house real-time PCR assays using minor groove binding probes for simultaneous detection of the Bacillus anthracis pag and cap genes, the Francisella ...tularensis 23 KDa gene, as well as the Yersinia pestis pla gene. The sensitivities of these assays were at least 1 fg, except for the assay targeting the Bacillus anthracis cap gene, which showed a sensitivity of 10 fg when total DNA was used as a template in a serial dilution. The clinical value of the Bacillus anthracis- and Francisella tularensis-specific assays was demonstrated by successful amplification of DNA from cases of cow anthrax and hare tularemia, respectively. No cross-reactivity between these species-specific assays or with 39 other bacterial species was noted. These assays may provide a rapid tool for the simultaneous detection and identification of the three category A bacterial species listed as biological threats by the Centers for Disease Control and Prevention.
Non-pathogenic
Yersinia pseudotuberculosis-like strains were recovered from Finnish food and environmental samples. These strains could not be differentiated from
Y. pseudotuberculosis strains using ...API 20E or other phenotypical tests. However, all of the strains were
inv-, and
virF-negative with polymerase chain reaction (PCR), while all
Y. pseudotuberculosis strains used as controls were
inv-positive and fresh
Y. pseudotuberculosis strains were also
virF-positive, indicating that the
Y. pseudotuberculosis-like strains were non-pathogenic. Using pulsed-field gel electrophoresis (PFGE) with
NotI enzyme and ribotyping with
EcoRI and
HindIII enzymes, the
Y. pseudotuberculosis-like strains, which grouped genetically together, could be differentiated from true
Y. pseudotuberculosis strains and from strains belonging to other sucrose-negative
Yersinia species. In addition, the O-antigen gene cluster of one
Y. pseudotuberculosis-like strain was characterized, and it differed from those of known
Y. pseudotuberculosis serotypes. This study demonstrates that identification of
Y. pseudotuberculosis from food and environmental sources using solely biochemical reactions can be incorrect, and when a strain cannot be serotyped to known
Y. pseudotuberculosis serotypes, the pathogenic potential of isolates should be determined.
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