scholarly journals Signature-Tagged Mutagenesis of Pasteurella multocida Identifies Mutants Displaying Differential Virulence Characteristics in Mice and Chickens

2003 ◽  
Vol 71 (9) ◽  
pp. 5440-5446 ◽  
Author(s):  
Marina Harper ◽  
John D. Boyce ◽  
Ian W. Wilkie ◽  
Ben Adler
Keyword(s):  
Animal Models ◽  
Virulence Factors ◽  
Causative Agent ◽  
Pasteurella Multocida ◽  
Disease Model ◽  
Competitive Growth ◽  
Fowl Cholera ◽  
First Time ◽  
Chicken Model ◽  
Specific Virulence

ABSTRACT Pasteurella multocida is the causative agent of fowl cholera in birds. Signature-tagged mutagenesis (STM) was used to identify potential virulence factors in a mouse septicemia disease model and a chicken fowl cholera model. A library of P. multocida mutants was constructed with a modified Tn916 and screened for attenuation in both animal models. Mutants identified by the STM screening were confirmed as attenuated by competitive growth assays in both chickens and mice. Of the 15 mutants identified in the chicken model, only 5 were also attenuated in mice, showing for the first time the presence of host-specific virulence factors and indicating the importance of screening for attenuation in the natural host.

scholarly journals Investigation of Iron uptake and virulence gene factors (fur, tonB, exbD, exbB, hgbA, hgbB1, hgbB2 and tbpA) among isolates of Pasteurella multocida from Iran

2019 ◽  
Author(s):  
Motahare Feizabadi Farahani ◽  
Majid Esmaelizad ◽  
Ahmad Reza Jabbari
Keyword(s):  
Virulence Factors ◽  
Iron Uptake ◽  
Pasteurella Multocida ◽  
Iron Acquisition ◽  
Virulence Gene ◽  
Basic Information ◽  
Iron Supply ◽  
Wide Range ◽  
Pcr Method ◽  
First Time

Background and Objectives: Iron is an essential compound in metabolic pathway of wide range of organisms. Because of limited free iron supply in mammalian and avian hosts, bacteria have applied various ways to acquire iron. Materials and Methods: In this study, the frequency of 8 iron acquisition factors was examined among 63 avian and ovine Pasteurella multocida field isolates and their vaccine strains using PCR method. Results: Five candidate genes (fur, tonB, exbD, exbB and hgbA) were identified among all isolates. For the first time, 2 loci (hgbB1 and hgbB2) of the hgbB gene were identified, which were previously reported as 1 gene. Also, it was found that 5 ovine and 1 avian isolates possessed all the virulence factors, which could also be considered for evaluating the frequency of other virulence factors. Conclusion: More studies need to be conducted on the frequency of all other virulence factors among these isolates, which can provide basic information for improvement or substitution of current vaccinal strains. Overall, as the new designed sets of primers showed more potential in detecting the corresponded genes, researchers can consider them in further studies.

scholarly journals Defining the Roles of TcdA and TcdB in Localized Gastrointestinal Disease, Systemic Organ Damage, and the Host Response during Clostridium difficile Infections

mBio ◽  
2015 ◽  
Vol 6 (3) ◽  
Author(s):  
Glen P. Carter ◽  
Anjana Chakravorty ◽  
Tu Anh Pham Nguyen ◽  
Steven Mileto ◽  
Fernanda Schreiber ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Animal Models ◽  
Virulence Factors ◽  
Host Response ◽  
Organ Damage ◽  
Intestinal Damage ◽  
Content Type ◽  
Animal Infection ◽  
Antibiotic Associated Diarrhea ◽  
First Time

ABSTRACTClostridium difficileis a leading cause of antibiotic-associated diarrhea, a significant animal pathogen, and a worldwide public health burden. Most disease-causing strains secrete two exotoxins, TcdA and TcdB, which are considered to be the primary virulence factors. Understanding the role that these toxins play in disease is essential for the rational design of urgently needed new therapeutics. However, their relative contributions to disease remain contentious. Using three different animal models, we show that TcdA+TcdB−mutants are attenuated in virulence in comparison to the wild-type (TcdA+TcdB+) strain, whereas TcdA−TcdB+mutants are fully virulent. We also show for the first time that TcdB alone is associated with both severe localized intestinal damage and systemic organ damage, suggesting that this toxin might be responsible for the onset of multiple organ dysfunction syndrome (MODS), a poorly characterized but often fatal complication ofC. difficileinfection (CDI). Finally, we show that TcdB is the primary factor responsible for inducing thein vivohost innate immune and inflammatory responses. Surprisingly, the animal infection model used was found to profoundly influence disease outcomes, a finding which has important ramifications for the validation of new therapeutics and future disease pathogenesis studies. Overall, our results show unequivocally that TcdB is the major virulence factor ofC. difficileand provide new insights into the host response toC. difficileduring infection. The results also highlight the critical nature of using appropriate and, when possible, multiple animal infection models when studying bacterial virulence mechanisms.IMPORTANCEClostridium difficileis a leading cause of antibiotic-associated diarrhea and an important hospital pathogen. TcdA and TcdB are thought to be the primary virulence factors responsible for disease symptoms ofC. difficileinfections (CDI). However, the individual contributions of these toxins to disease remain contentious. Using three different animal models of infection, we show for the first time that TcdB alone causes severe damage to the gut, as well as systemic organ damage, suggesting that this toxin might be responsible for MODS, a serious but poorly understood complication of CDI. These findings provide important new insights into the host response toC. difficileduring infection and should guide the rational development of urgently required nonantibiotic therapeutics for the treatment of CDI.

scholarly journals Staphylococcal Virulence Factors on the Skin of Atopic Dermatitis Patients

mSphere ◽  
2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Mary C. Moran ◽  
Michael P. Cahill ◽  
Matthew G. Brewer ◽  
Takeshi Yoshida ◽  
Sara Knowlden ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Atopic Dermatitis ◽  
Virulence Factors ◽  
Virulence Factor ◽  
Protein Level ◽  
Content Type ◽  
Factor Production ◽  
First Time ◽  
Virulence Factor Production ◽  
Specific Virulence

ABSTRACT Staphylococcus aureus is the leading cause of skin and soft tissue infections, bacteremia, infective endocarditis, osteoarticular, pleuropulmonary, and device-related infections. Virulence factors secreted by S. aureus, including superantigens and cytotoxins, play significant roles in driving disease. The ability to identify virulence factors present at the site of infection will be an important tool in better identifying and understanding how specific virulence factors contribute to disease. Previously, virulence factor production has been determined by culturing S. aureus isolates and detecting the mRNA of specific virulence factors. We demonstrated for the first time that virulence factors can be directly detected at the protein level from human samples, removing the need to first culture isolated bacteria. Superantigens and cytotoxins were detected and quantified with a Western dot blot assay by using reconstituted skin swabs obtained from patients with atopic dermatitis. This methodology will significantly enhance our ability to investigate the complex host-microbe environment and the effects various therapies have on virulence factor production. Overall, the ability to directly quantify virulence factors present at the site of infection or colonization will enhance our understanding of S. aureus-related diseases and help identify optimal treatments. IMPORTANCE For the first time, we show that secreted staphylococcal virulence factors can be quantified at the protein level directly from skin swabs obtained from the skin of atopic dermatitis patients. This technique eliminates the need to culture Staphylococcus aureus and then test the strain’s potential to produce secreted virulence factors. Our methodology shows that secreted virulence factors are present on the skin of atopic patients and provides a more accurate means of evaluating the physiological impact of S. aureus in inflammatory diseases such as atopic dermatitis.

scholarly journals A Heptosyltransferase Mutant of Pasteurella multocida Produces a Truncated Lipopolysaccharide Structure and Is Attenuated in Virulence

2004 ◽  
Vol 72 (6) ◽  
pp. 3436-3443 ◽  
Author(s):  
Marina Harper ◽  
Andrew D. Cox ◽  
Frank St. Michael ◽  
Ian W. Wilkie ◽  
John D. Boyce ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Sequence Analysis ◽  
Magnetic Resonance ◽  
Causative Agent ◽  
Pasteurella Multocida ◽  
Full Length ◽  
Wild Type ◽  
Fowl Cholera ◽  
Insertional Inactivation

ABSTRACT Pasteurella multocida is the causative agent of fowl cholera in birds. In a previous study using signature-tagged mutagenesis, we identified a mutant, AL251, which was attenuated for virulence in mice and in the natural chicken host. Sequence analysis indicated that AL251 had an insertional inactivation of the gene waaQPM , encoding a putative heptosyl transferase, required for the addition of heptose to lipopolysaccharide (LPS) (M. Harper, J. D. Boyce, I. W. Wilkie, and B. Adler, Infect. Immun. 71:5440-5446, 2003). In the present study, using mass spectrometry and nuclear magnetic resonance, we have confirmed the identity of the enzyme encoded by waaQPM as a heptosyl transferase III and demonstrated that the predominant LPS glycoforms isolated from this mutant are severely truncated. Complementation experiments demonstrated that providing a functional waaQPM gene in trans can restore both the LPS to its full length and growth in mice to wild-type levels. Furthermore, we have shown that mutant AL251 is unable to cause fowl cholera in chickens and that the attenuation observed is not due to increased serum sensitivity.

scholarly journals Role of Enteroaggregative Escherichia coli Virulence Factors in Uropathogenesis

2013 ◽  
Vol 81 (4) ◽  
pp. 1164-1171 ◽  
Author(s):  
Erik J. Boll ◽  
Carsten Struve ◽  
Nadia Boisen ◽  
Bente Olesen ◽  
Steen G. Stahlhut ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Outbreak Strain ◽  
Content Type ◽  
E Coli ◽  
Abiotic Surfaces ◽  
Extraintestinal Disease ◽  
First Time ◽  
Specific Virulence

ABSTRACTA multiresistant clonalEscherichia coliO78:H10 strain qualifying molecularly as enteroaggregativeEscherichia coli(EAEC) was recently shown to be the cause of a community-acquired outbreak of urinary tract infection (UTI) in greater Copenhagen, Denmark, in 1991. This marks the first time EAEC has been associated with an extraintestinal disease outbreak. Importantly, the outbreak isolates were recovered from the urine of patients with symptomatic UTI, strongly implying urovirulence. Here, we sought to determine the uropathogenic properties of the Copenhagen outbreak strain and whether these properties are conferred by the EAEC-specific virulence factors. We demonstrated that through expression of aggregative adherence fimbriae, the principal adhesins of EAEC, the outbreak strain exhibited pronouncedly increased adherence to human bladder epithelial cells compared to prototype uropathogenic strains. Moreover, the strain was able to produce distinct biofilms on abiotic surfaces, including urethral catheters. These findings suggest that EAEC-specific virulence factors increase uropathogenicity and may have played a significant role in the ability of the strain to cause a community-acquired outbreak of UTI. Thus, inclusion of EAEC-specific virulence factors is warranted in future detection and characterization of uropathogenicE. coli.

scholarly journals Isolation and identification of the causative agent of fowl cholera in Iraq and preparation of vaccines against the disease 1- Isolation of the causative agent of fowl cholera and study of it’s properties.

2005 ◽  
Vol 29 (1) ◽  
pp. 11-21
Author(s):  
Hatem M . Mhanam
Keyword(s):  
Causative Agent ◽  
Pasteurella Multocida ◽  
Isolation And Identification ◽  
Antibacterial Drugs ◽  
Fowl Cholera

It was possible to obtain 17 isolates of Pasteurella multocida frominfected laying chickens with fowl cholera. Three isolates were from the chronicphases of the naturally infected chickens and other fourteen were from the acutephases. The identification of these isolates was considered. Fifteen isolatesbelong to the sub species multocida and two isolates to gallicida, ten isolatesbelong to the SE-190 isolate and one to SE-077, while six isolates were notidentified. Twelve of the isolates have a capsule. The LD50s of these isolateswere varied. The results of sensitivity to antibacterial drugs revieled that allisolates were sensitive to Penicillin and resistance to Lincomycin with variousdegrees of sensitivity to other antibacterial drugs.

scholarly journals Interaction of Pasteurella multocida with Free-Living Amoebae

2005 ◽  
Vol 71 (9) ◽  
pp. 5458-5464 ◽  
Author(s):  
Matthew J. Hundt ◽  
Carmel G. Ruffolo
Keyword(s):  
Pasteurella Multocida ◽  
Fluorescent Protein ◽  
Host Cells ◽  
Free Living ◽  
Fowl Cholera ◽  
Transmission Electron ◽  
Membrane Bound ◽  
Green Fluorescent ◽  
First Time

ABSTRACT Pasteurella multocida is a highly infectious, facultative intracellular bacterium which causes fowl cholera in birds. This study reports, for the first time, the observed interaction between P. multocida and free-living amoebae. Amoebal trophozoites were coinfected with fowl-cholera-causing P. multocida strain X-73 that expressed the green fluorescent protein (GFP). Using confocal fluorescence microscopy, GFP expressing X-73 was located within the trophozoite. Transmission electron microscopy of coinfection preparations revealed clusters of intact X-73 cells in membrane-bound vacuoles within the trophozoite cytoplasm. A coinfection assay employing gentamicin to kill extracellular bacteria was used to assess the survival and replication of P. multocida within amoebae. In the presence of amoebae, the number of recoverable intracellular X-73 cells increased over a 24-h period; in contrast, X-73 cultured alone in assay medium showed a consistent decline in growth. Cytotoxicity assays and microscopy showed that X-73 was able to lyse and exit the amoebal cells approximately 18 h after coinfection. The observed interaction between P. multocida and amoebae can be considered as an infective process as the bacterium was able to invade, survive, replicate, and lyse the amoebal host. This raises the possibility that similar interactions occur in vivo between P. multocida and host cells. Free-living amoebae are ubiquitous within water and soil environments, and P. multocida has been observed to survive within these same ecosystems. Thus, our findings suggest that the interaction between P. multocida and amoebae may occur within the natural environment.

Serological types of Pasteurella multocida isolated from turkeys and chickens in Canada

1982 ◽  
Vol 28 (9) ◽  
pp. 1078-1080 ◽  
Author(s):  
J. L. Bhasin
Keyword(s):  
Causative Agent ◽  
Pasteurella Multocida ◽  
Antigenic Determinants ◽  
Poultry Industry ◽  
Fowl Cholera ◽  
Precipitation Patterns ◽  
Precipitin Test ◽  
Type 3 ◽  
Diffusion Precipitation ◽  
Gel Diffusion

Outbreaks of fowl cholera continue to plague the Canadian poultry industry despite widespread immunization against the causative agent, Pasteurella multocida. Fowl cholera bacterins currently employed by domestic poultry growers contain three serological types, namely, serotypes 1, 3, and 4. In this study a total of 84 strains of P. multocida were isolated in Canada from outbreaks of fowl cholera in turkeys and chickens. Serotyping was accomplished using the gel diffusion precipitin test. Based on the gel diffusion precipitation patterns, 27 serotypes containing one to six antigenic determinants were recognized. The most prevalent serotype both in turkeys and chickens appeared to be type 3. Significantly, greater than 20% of P. multocida isolates failed to react with antisera raised against serotypes 1, 3, and 4.

scholarly journals Consideration of Gut Microbiome in Murine Models of Diseases

2021 ◽  
Vol 9 (5) ◽  
pp. 1062
Author(s):  
Chunye Zhang ◽  
Craig L. Franklin ◽  
Aaron C. Ericsson
Keyword(s):  
Animal Models ◽  
Mouse Models ◽  
Biomedical Research ◽  
Gut Microbiome ◽  
Close Association ◽  
Disease Model ◽  
Potential Contributor ◽  
Potential Factors ◽  
Models Of Disease ◽  
The Impact

The gut microbiome (GM), a complex community of bacteria, viruses, protozoa, and fungi located in the gut of humans and animals, plays significant roles in host health and disease. Animal models are widely used to investigate human diseases in biomedical research and the GM within animal models can change due to the impact of many factors, such as the vendor, husbandry, and environment. Notably, variations in GM can contribute to differences in disease model phenotypes, which can result in poor reproducibility in biomedical research. Variation in the gut microbiome can also impact the translatability of animal models. For example, standard lab mice have different pathogen exposure experiences when compared to wild or pet store mice. As humans have antigen experiences that are more similar to the latter, the use of lab mice with more simplified microbiomes may not yield optimally translatable data. Additionally, the literature describes many methods to manipulate the GM and differences between these methods can also result in differing interpretations of outcomes measures. In this review, we focus on the GM as a potential contributor to the poor reproducibility and translatability of mouse models of disease. First, we summarize the important role of GM in host disease and health through different gut–organ axes and the close association between GM and disease susceptibility through colonization resistance, immune response, and metabolic pathways. Then, we focus on the variation in the microbiome in mouse models of disease and address how this variation can potentially impact disease phenotypes and subsequently influence research reproducibility and translatability. We also discuss the variations between genetic substrains as potential factors that cause poor reproducibility via their effects on the microbiome. In addition, we discuss the utility of complex microbiomes in prospective studies and how manipulation of the GM through differing transfer methods can impact model phenotypes. Lastly, we emphasize the need to explore appropriate methods of GM characterization and manipulation.

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