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.

Virulence Gene Pattern of Pasteurella multocida Isolates of Buffalo in Association to Capsule Biosynthesis Genes

2020 ◽  
Author(s):  
N. Sujatha ◽  
K. Lakshmi Kavitha ◽  
K.V. Subramanyam ◽  
T. Srinivasa Rao ◽  
R.N. Ramani Pushpa
Keyword(s):  
Virulence Factors ◽  
Pasteurella Multocida ◽  
Virulence Genes ◽  
Systemic Disease ◽  
Virulence Gene ◽  
Disease Status ◽  
Host Cells ◽  
Wide Range ◽  
Serotype B ◽  
Apparently Healthy

Background: Pasteurella multocida is the causative agent of many economically important diseases in a wide range of hosts. The mechanisms by which these bacteria can invade the mucosa, evade innate immunity and cause systemic disease are slowly being elucidated. Many key virulence factors are yet to be identified, including those required for initial attachment and invasion of host cells and for persistence in a relatively nutrient poor and hostile environment. This has led to intensive research to understand host adaptation mechanisms and virulence factors in order to develop effective vaccines. Methods: The present study was carried out to know the distribution of virulence genes viz., haemoglobin binding proteins (hgbA and hgbB), outer membrane protein (ompH), fimbrial antigen (ptfA), filamentous haemagglutinin (pfhA) and transferrin binding protein (tbpA) by PCR in P. multocida CapA isolates from apparently healthy or carrier animals and CapB isolates from field Haemorrhagic septicemia (HS) cases to monitor the epidemiological associations of virulence genes in Cap A and Cap B isolates.Result: The study revealed that all the six virulence associated genes were present in Cap B isolates. None of the Cap A isolates harboured tbpA and pfhA genes. These two genes were closely related to serotype B causing Haemorrhagic septicemia and were epidemiologically associated with disease status.

scholarly journals Molecular Characterization of Shiga Toxin-Producing Escherichia coli Strains Isolated in Poland

2016 ◽  
Vol 65 (3) ◽  
pp. 261-269 ◽  
Author(s):  
Aleksandra Januszkiewicz ◽  
Waldemar Rastawicki
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Shiga Toxin ◽  
Virulence Gene ◽  
Virulence Determinants ◽  
E Coli ◽  
Heat Stable ◽  
Food Borne ◽  
Wide Range ◽  
Uremic Syndrome

Shiga toxin-producing Escherichia coli (STEC) strains also called verotoxin-producing E. coli (VTEC) represent one of the most important groups of food-borne pathogens that can cause several human diseases such as hemorrhagic colitis (HC) and hemolytic – uremic syndrome (HUS) worldwide. The ability of STEC strains to cause disease is associated with the presence of wide range of identified and putative virulence factors including those encoding Shiga toxin. In this study, we examined the distribution of various virulence determinants among STEC strains isolated in Poland from different sources. A total of 71 Shiga toxin-producing E. coli strains isolated from human, cattle and food over the years 1996 – 2010 were characterized by microarray and PCR detection of virulence genes. As stx1a subtype was present in all of the tested Shiga toxin 1 producing E. coli strains, a greater diversity of subtypes was found in the gene stx2, which occurred in five subtypes: stx2a, stx2b, stx2c, stx2d, stx2g. Among STEC O157 strains we observed conserved core set of 14 virulence factors, stable in bacteria genome at long intervals of time. There was one cattle STEC isolate which possessed verotoxin gene as well as sta1 gene encoded heat-stable enterotoxin STIa characteristic for enterotoxigenic E. coli. To the best of our knowledge, this is the first comprehensive analysis of virulence gene profiles identified in STEC strains isolated from human, cattle and food in Poland. The results obtained using microarrays technology confirmed high effectiveness of this method in determining STEC virulotypes which provides data suitable for molecular risk assessment of the potential virulence of this bacteria.

scholarly journals Virulence and antibiotic resistance profile of avian Escherichia coli strains isolated from colibacillosis lesions in central of Algeria

2019 ◽  
Vol 12 (11) ◽  
pp. 1840-1848 ◽  
Author(s):  
Nacima Meguenni ◽  
Nathalie Chanteloup ◽  
Angelina Tourtereau ◽  
Chafika Ali Ahmed ◽  
Saliha Bounar-Kechih ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Virulence Factors ◽  
Virulence Genes ◽  
Iron Acquisition ◽  
Virulence Gene ◽  
Resistance Profile ◽  
E Coli ◽  
Antibiotic Resistance Profile ◽  
Embryo Lethality

Background and Aim: Avian pathogenic Escherichia coli cause extensive mortality in poultry flocks, leading to extensive economic losses. To date, in Algeria, little information has been available on virulence potential and antibiotics resistance of avian E. coli isolates. Therefore, the aim of this study was the characterization of virulence genes and antibiotic resistance profile of Algerian E. coli strains isolated from diseased broilers. Materials and Methods: In this study, 43 avian E. coli strains isolated from chicken colibacillosis lesions at different years were analyzed to determine their contents in 10 virulence factors by polymerase chain reaction, antimicrobial susceptibility to 22 antibiotics belonging to six different chemical classes and genomic diversity by pulsed-field gel electrophoresis (PFGE). Results: Mainly E. coli isolates (58.1%) carried two at six virulence genes and the most frequent virulence gene association detected were ompT (protectin), hlyF (hemolysin) with 55.8% (p<0.001), and iroN, sitA (iron acquisition/uptake systems), and iss (protectin) with 41.8% (p<0.001). Some strains were diagnosed as virulent according to their virulence gene profile. Indeed, 23.25% of the isolates harbored iroN, ompT, hlyF, iss, and sitA combination, 14% ompT, hlyF, and frzorf4 (sugar metabolism), and 11,6% iroN, hlyF, ompT, iss, iutA (iron acquisition/uptake systems), and frzorf4. The chicken embryo lethality assay performed on five isolates confirmed the potential virulence of these strains. All isolates submitted to PFGE analysis yielded different genetic profiles, which revealed their diversity. Overall, 97.2% of the isolates were resistant to at least one antibiotic and 53.5% demonstrated multi-antimicrobial resistance to three different antimicrobial classes. The highest resistance levels were against nalidixic acid (83.4%), amoxicillin and ampicillin (83.3%), ticarcillin (80.5%), pipemidic acid (75%), and triméthoprim-sulfamethoxazole (66.6%). For beta-lactam class, the main phenotype observed belonged to broad-spectrum beta-lactamases. However, extended-spectrum beta-lactamase associated with three at six virulence factors was also detected in 13 isolates. Two of them were attested virulent as demonstrated in the embryo lethality test which constitutes a real public threat. Conclusion: It would be imperative in avian production to discourage misuse while maintaining constant vigilance guidelines and regulations, to limit and rationalize antimicrobial use.

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 Role for sagA and siaA in Quorum Sensing and Iron Regulation in Streptococcus pyogenes

2007 ◽  
Vol 75 (10) ◽  
pp. 5011-5017 ◽  
Author(s):  
Kowthar Y. Salim ◽  
Joyce C. de Azavedo ◽  
Darrin J. Bast ◽  
Dennis G. Cvitkovitch
Keyword(s):  
Quorum Sensing ◽  
Streptococcus Pyogenes ◽  
Iron Acquisition ◽  
Virulence Gene ◽  
Wild Type ◽  
Virulence Gene Expression ◽  
Streptolysin S ◽  
Wide Range ◽  
Cell Densities ◽  
The Many

ABSTRACT Streptococcus pyogenes is a ubiquitous and versatile pathogen that causes a variety of infections with a wide range of severity. The versatility of this organism is due in part to its capacity to regulate virulence gene expression in response to the many environments that it encounters during an infection. We analyzed the expression of two potential virulence factors, sagA and siaA (also referred to as pel and htsA, respectively), in response to conditions of varying cell densities and iron concentrations. The sagA gene was up-regulated in conditioned medium from a wild-type strain but not from sagA-deficient mutants, and the gene was also up-regulated in the presence of streptolysin S (SLS), the gene product of sagA, thus indicating that this gene or its product is involved in density-dependent regulation of S. pyogenes. By comparison, siaA responded in a manner consistent with a role in iron acquisition since it was up-regulated under iron-restricted conditions. Although siaA expression was also up-regulated in the presence of SLS and in conditioned media from both wild-type and sagA-deficient mutants, this up-regulation was not growth phase dependent. We conclude that sagA encodes a quorum-sensing signaling molecule, likely SLS, and further support the notion that siaA is likely involved in iron acquisition.

scholarly journals Pasteurella multocida Gene Expression in Response to Iron Limitation

2001 ◽  
Vol 69 (6) ◽  
pp. 4109-4115 ◽  
Author(s):  
Michael L. Paustian ◽  
Barbara J. May ◽  
Vivek Kapur
Keyword(s):  
Gene Expression ◽  
Pasteurella Multocida ◽  
Molecular Mechanisms ◽  
Iron Acquisition ◽  
Expression Profiles ◽  
Growth Conditions ◽  
Whole Genome ◽  
Altered Expression ◽  
Expression Of Genes ◽  
Wide Range

ABSTRACT Pasteurella multocida is the causative agent of a wide range of diseases in avian and mammalian hosts. Gene expression in response to low iron conditions was analyzed in P. multocida using whole-genome microarrays. The analysis shows that the expression of genes involved in energy metabolism and electron transport generally decreased 2.1- to 6-fold while that of genes used for iron binding and transport increased 2.1- to 7.7-fold in P. multocida during the first 2 h of growth under iron-limiting conditions compared with controls. Notably, 27% of the genes with significantly altered expression had no known function, illustrating the limitations of using publicly available databases to identify genes involved in microbial metabolism and pathogenesis. Taken together, the results of our investigations demonstrate the utility of whole-genome microarray analyses for the identification of genes with altered expression profiles during varying growth conditions and provide a framework for the detailed analysis of the molecular mechanisms of iron acquisition and metabolism in P. multocida and other gram-negative bacteria.

scholarly journals Analysis of RogB-Controlled Virulence Mechanisms and Gene Expression in Streptococcus agalactiae

2003 ◽  
Vol 71 (9) ◽  
pp. 5056-5064 ◽  
Author(s):  
Heike Gutekunst ◽  
Bernhard J. Eikmanns ◽  
Dieter J. Reinscheid
Keyword(s):  
Gene Expression ◽  
Reporter Gene ◽  
Virulence Factors ◽  
Streptococcus Agalactiae ◽  
Virulence Gene ◽  
Pcr Analysis ◽  
Significant Similarity ◽  
Virulence Gene Expression ◽  
Fibrinogen Receptor ◽  
Wide Range

ABSTRACT Streptococcus agalactiae is the leading cause of bacterial sepsis and meningitis in neonates and also the causative agent of different serious infections in immunocompromised adults. The wide range of diseases that are caused by S. agalactiae suggests regulatory mechanisms that control the formation of specific virulence factors in these bacteria. The present study describes a gene from S. agalactiae, designated rogB, encoding a protein with significant similarity to members of the RofA-like protein (RALP) family of transcriptional regulators. Disruption of the rogB gene in the genome of S. agalactiae resulted in mutant strain RGB1, which was impaired in its ability to bind to fibrinogen and fibronectin. Mutant RGB1 also exhibited a reduced adherence to human epithelial cells but did not show an altered invasion of eukaryotic cells. By real-time PCR analysis, mutant RGB1 revealed an increased expression of the cpsA gene, encoding a regulator of capsule gene expression. However, strain RGB1 exhibited a reduced expression of the rogB gene and of two adjacent genes, encoding putative virulence factors in S. agalactiae. Furthermore, mutant RGB1 was impaired in the expression of the fbsA gene, coding for a fibrinogen receptor from S. agalactiae. The altered gene expression in mutant RGB1 could be restored by plasmid-mediated expression of rogB, confirming a RogB deficiency as the cause for the observed changes in virulence gene expression in S. agalactiae. Reporter gene studies with a promotorless luciferase gene fused to fbsA allowed a growth-dependent analysis of fbsA expression in S. agalactiae. These reporter gene studies also suggest that RogB exerts a positive effect on fbsA expression in S. agalactiae.

Safety assessment of biological raw materials in the system of medicines quality assurance

2020 ◽  
pp. 63-72
Author(s):  
Yu. Olefir ◽  
E. Sakanyan ◽  
I. Osipova ◽  
V. Dobrynin ◽  
M. Smirnova ◽  
...  
Keyword(s):  
Raw Materials ◽  
State Level ◽  
The State ◽  
Spongiform Encephalopathy ◽  
Safety Standards ◽  
Wide Range ◽  
The Russian Federation ◽  
Key Aspects ◽  
First Time ◽  
Medicines Quality

The entry of a wide range of biotechnological products into the pharmaceutical market calls for rein-forcement of the quality, efficacy and safety standards at the state level. The following general monographs have been elaborated for the first time to be included into the State Pharmacopoeia of the Russian Federation, XIV edition: "Viral safety" and "Reduction of the risk of transmitting animal spongiform encephalopathy via medicinal products". These general monographs were elaborated taking into account the requirements of foreign pharmacopoeias and the WHO recommendations. The present paper summarises the key aspects of the monographs.

Innovation in Byzantine Medicine

2020 ◽  
Author(s):  
Petros Bouras-Vallianatos
Keyword(s):  
Human Physiology ◽  
Medical Literature ◽  
Cultural Exchange ◽  
Significant Degree ◽  
Medieval Medicine ◽  
Medieval Latin ◽  
Main Thesis ◽  
Wide Range ◽  
Comprehensive Examination ◽  
First Time

Byzantine medicine is still a little-known and misrepresented field not only in the wider arena of debates on medieval medicine but also among Byzantinists. Byzantine medical literature is often viewed as ‘stagnant’ and mainly preserving ancient ideas; and our knowledge of it continues to be based to a great extent on the comments of earlier authorities, which are often repeated uncritically. This book presents the first comprehensive examination of the medical corpus of, arguably, the most important late Byzantine physician John Zacharias Aktouarios (c.1275–c.1330). The main thesis is that John’s medical works show an astonishing degree of openness to knowledge from outside Byzantium combined with a significant degree of originality, in particular, in the fields of uroscopy, pharmacology, and human physiology. The analysis of John’s edited (On Urines and On Psychic Pneuma) and unedited (Medical Epitome) works is supported for the first time by the consultation of a large number of manuscripts. The study is also informed by evidence from a wide range of medical sources, including previously unpublished ones, and texts from other genres, such as epistolography and merchants’ accounts. The contextualization of John’s works sheds new light on the development of Byzantine medical thought and practice, and enhances our understanding of the late Byzantine social and intellectual landscape. Finally, John’s medical observations are also examined in the light of examples from the medieval Latin and Islamic worlds, placing his medical theories in the wider Mediterranean milieu and highlighting the cultural exchange between Byzantium and its neighbours.

Rebels, Believers, Survivors

2020 ◽  
Author(s):  
Noel Malcolm
Keyword(s):  
Catholic Church ◽  
Religious Conversion ◽  
Late Nineteenth Century ◽  
Napoleonic Wars ◽  
Conversion To Islam ◽  
Wide Range ◽  
History Of ◽  
External Powers ◽  
First Time ◽  
Modern Myth

This book of essays covers a wide range of topics in the history of Albania and Kosovo. Many of the essays illuminate connections between the Albanian lands and external powers and interests, whether political, military, diplomatic or religious. Such topics include the Habsburg invasion of Kosovo in 1689, the manoeuvrings of Britain and France towards the Albanian lands during the Napoleonic Wars, the British interest in those lands in the late nineteenth century, and the Balkan War of 1912. On the religious side, essays examine ‘crypto-Christianity’ in Kosovo during the Ottoman period, the stories of conversion to Islam revealed by Inquisition records, the first theological treatise written in Albanian (1685), and the work of the ‘Apostolic Delegate’ who reformed the Catholic Church in early twentieth-century Albania. Some essays bring to life ordinary individuals hitherto unknown to history: women hauled before the Inquisition, for example, or the author of the first Albanian autobiography. The longest essay, on Ali Pasha, tells for the first time the full story of the role he played in the international politics of the Napoleonic Wars. Some of these studies have been printed before (several in hard-to-find publications, and one only in Albanian), but the greater part of this book appears here for the first time. This is not only a contribution to Albanian and Balkan history it also engages with many broader issues, including religious conversion, methods of enslavement within the Ottoman Empire, and the nature of modern myth-making about national identity.

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