scholarly journals Analysis of virulence factors and emm typing of Streptococcus pyogenes clinical isolates.

2019 ◽  
Author(s):  
Gustavo Enck Sambrano ◽  
Gustavo P Riboldi ◽  
Keli C Reiter ◽  
Thiago Galvão da Silva Paim ◽  
Neidmar Correa Tolfo ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Streptococcus Pyogenes ◽  
Virulence Genes ◽  
Clinical Isolates ◽  
Pcr Analysis ◽  
Tissue Tropism ◽  
Factors Analysis ◽  
Wide Range ◽  
Group A ◽  
Micro Organisms

Background: Streptococcus pyogenes, a Group A streptococci (GAS), is an important human pathogen that causes a wide range of infections. Methods: Twenty five clinical isolates of S. pyogenes were submitted to an emm typing and to a Real-time PCR analysis for 23 important virulence factors. Results: Fourteen emm types were found and the emm1 type was the most prevalent. The majority of the isolates were classified as emm pattern E, followed by A-C3. No pattern D was found. Among the virulence factors, the most prevalent were SpeG, Slo, C5a-peptidase and SPNA. Phage encoded virulence genes were also found among the strains, such as mf-2, SpeJ and SpeL. Discussion: The emm1 type was the most prevalent while the 13 others M types were distributed along the strains. No tissue tropism was found on the isolates. The virulence factors analysis demonstrated that chromosomally and phage-encoded genes were found, which confers a potential for high virulent micro-organisms.

scholarly journals Analysis of virulence factors and emm typing of Streptococcus pyogenes clinical isolates.

2019 ◽  
Author(s):  
Gustavo Enck Sambrano ◽  
Gustavo P Riboldi ◽  
Keli C Reiter ◽  
Thiago Galvão da Silva Paim ◽  
Neidmar Correa Tolfo ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Streptococcus Pyogenes ◽  
Virulence Genes ◽  
Clinical Isolates ◽  
Pcr Analysis ◽  
Tissue Tropism ◽  
Factors Analysis ◽  
Wide Range ◽  
Group A ◽  
Micro Organisms

Background: Streptococcus pyogenes, a Group A streptococci (GAS), is an important human pathogen that causes a wide range of infections. Methods: Twenty five clinical isolates of S. pyogenes were submitted to an emm typing and to a Real-time PCR analysis for 23 important virulence factors. Results: Fourteen emm types were found and the emm1 type was the most prevalent. The majority of the isolates were classified as emm pattern E, followed by A-C3. No pattern D was found. Among the virulence factors, the most prevalent were SpeG, Slo, C5a-peptidase and SPNA. Phage encoded virulence genes were also found among the strains, such as mf-2, SpeJ and SpeL. Discussion: The emm1 type was the most prevalent while the 13 others M types were distributed along the strains. No tissue tropism was found on the isolates. The virulence factors analysis demonstrated that chromosomally and phage-encoded genes were found, which confers a potential for high virulent micro-organisms.

Distribution of virulence genes and the molecular epidemiology of Streptococcus pyogenes clinical isolates by emm and multilocus sequence typing methods

2020 ◽  
Author(s):  
Siti Nur Adila Hamzah ◽  
Mohd Nasir Mohd Desa ◽  
Azmiza Syawani Jasni ◽  
Niazlin Mohd Taib ◽  
Siti Norbaya Masri ◽  
...  
Keyword(s):  
Molecular Epidemiology ◽  
Virulence Factors ◽  
Streptococcus Pyogenes ◽  
Multilocus Sequence Typing ◽  
Virulence Genes ◽  
Clinical Samples ◽  
Pcr Analysis ◽  
Gold Standard Method ◽  
Non Invasive ◽  
Typing Methods

Abstract Background: Streptococcus pyogenes has a variety of virulence factors and the predominant invasive strains differ according to specific emm types and geographical orientation. Although emm typing is commonly used as the gold standard method for the molecular characterization, multilocus sequence typing (MLST) has become an important tool for comparing the genetic profiles globally. This study aimed to screen selected virulence genes from invasive and non-invasive clinical samples and to characterize the molecular epidemiology by emm typing and MLST methods. Methods: A total of 42 S. pyogenes isolates from invasive and non-invasive samples collected from 2014 to 2015 from two different tertiary hospitals were investigated for the distribution of virulence factors and their molecular epidemiology by emm and multilocus sequence typing methods. Detection of five virulence genes (speA , speB , speJ , ssa and sdaB) was performed using multiplex polymerase chain reaction (PCR) using the standard primers and established protocol. Results: Multiplex PCR analysis revealed that sdaB/speF (78.6%) and speB (61.9%) were the predominant virulence genes. Regardless of the type of invasiveness, diverse distribution of emm types/subtypes was noted which comprised of 27 different emm types/subtypes. The predominant emm types/subtypes were emm63 and emm18 with each gene accounted for 11.8% whereas 12% for each gene was noted for emm28, emm97.4 and emm91. The MLST revealed that the main sequence type (ST) in invasive samples was ST402 (17.7%) while ST473 and ST318 (12% for each ST) were the major types in non-invasive samples. Out of 18 virulotypes, Virulotype A (five genes, 55.6%) and Virulotype B (two genes, 27.8%) were the major virulotypes found in this study. Phylogenetic analysis indicated the presence of seven different clusters of S. pyogenes. Interestingly, Cluster VI showed that selected emm/ST types such as emm71/ST318 (n=2), emm70.1/ST318 (n=1), emm44/ST31 (n=1) and emm18/ST442 (n=1) have clustered within a common group (Virulotype A) for both hospitals studied. Conclusion: The present study showed that group A streptococci (GAS) are genetically diverse and possess virulence genes regardless of their invasiveness. Majority of the GAS exhibited no restricted pattern of virulotypes except for a few distinct clusters. Therefore, it can be concluded that virulotyping is partially useful for characterizing a heterogeneous population of GAS in hospitals.

scholarly journals Age as a Factor Influencing Diversity of Commensal E. coli Microflora in Pigs

2013 ◽  
Vol 62 (2) ◽  
pp. 165-171 ◽  
Author(s):  
EWA BOK ◽  
JUSTYNA MAZUREK ◽  
PAWEŁ PUSZ ◽  
MICHAŁ STOSIK ◽  
KATARZYNA BALDY-CHUDZIK
Keyword(s):  
Virulence Factors ◽  
Virulence Genes ◽  
Phylogenetic Group ◽  
Pcr Analysis ◽  
Weaned Piglets ◽  
Phylogenetic Groups ◽  
Phylogenetic Structure ◽  
E Coli ◽  
Phylogenetic Grouping ◽  
Group A

Commensal, intestinal E. coli microflora plays a role in maintenance of intestinal balance of the host, is responsible for defending against pathogenic E. coli. This study encompasses the analysis of BOX-PCR fingerprinting patterns, phylogenetic grouping and virulence genes prevalence among commensal E. coli isolates derived from healthy pigs. Altogether, 274 unique E. coli isolates were identified, 110 from weaned piglets (Piglets I and Piglets II) and 164 from adult sows (Sows I and Sows II). BOX-PCR analysis distinguished isolates from pigs in different age and indicated that during maturation the changes in E. coli microflora occurred. Phylogenetic grouping revealed significant differences between distribution of four phylogenetic groups among isolates derived from piglets and sows. In phylogenetic structure of isolates from the piglets group B1 prevailed significantly, while among isolates derived from the sows the majority of them were classified into phylogenetic group A. The identification of 17 virulence factors in E. coli isolates derived from healthy pigs was performed. Three of 13 intestinal (escV, ehxA, estII) and four extra-intestinal virulence genes (VGs) (hlyA, fimH, papA, sfaS) were detected in the porcine isolates. The percentage of VGs positive isolates among piglets is higher than among sows, moreover, the VGs occurring in E. coli isolates from piglets revealed greater diversity than that detected among isolates from sows.

scholarly journals Wide Distribution of Virulence Genes amongEnterococcus faeciumandEnterococcus faecalisClinical Isolates

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Sara Soheili ◽  
Sobhan Ghafourian ◽  
Zamberi Sekawi ◽  
Vasanthakumari Neela ◽  
Nourkhoda Sadeghifard ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Virulence Genes ◽  
Wide Distribution ◽  
Clinical Isolates ◽  
Nosocomial Pathogen ◽  
High Concentration ◽  
The Third ◽  
Wide Range ◽  
Facultative Anaerobic ◽  
Enterococcal Species

Enterococcus, a Gram-positive facultative anaerobic cocci belonging to the lactic acid bacteria of the phylum Firmicutes, is known to be able to resist a wide range of hostile conditions such as different pH levels, high concentration of NaCl (6.5%), and the extended temperatures between 5°C and 65°C. Despite being the third most common nosocomial pathogen, our understanding on its virulence factors is still poorly understood. The current study was aimed to determine the prevalence of different virulence genes inEnterococcus faecalisandEnterococcus faecium. For this purpose, 79 clinical isolates of Malaysian enterococci were evaluated for the presence of virulence genes.pilB, fms8, efaAfm, andsgrAgenes are prevalent in all clinical isolates. In conclusion, the pathogenicity ofE. faecalisandE. faeciumcould be associated with different virulence factors and these genes are widely distributed among the enterococcal species.

scholarly journals Biochemical and biological activity of arginine deiminase from Streptococcus pyogenes M22

2016 ◽  
Vol 94 (2) ◽  
pp. 129-137 ◽  
Author(s):  
Eleonora A. Starikova ◽  
Alexey V. Sokolov ◽  
Anna Yu. Vlasenko ◽  
Larisa A. Burova ◽  
Irina S. Freidlin ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Endothelial Cells ◽  
Streptococcus Pyogenes ◽  
Group A Streptococcus ◽  
Bacterial Pathogen ◽  
Arginine Deiminase ◽  
Dependent Manner ◽  
Group A ◽  
Micro Organisms ◽  
Dose Dependent

Streptococcus pyogenes (group A Streptococcus; GAS) is an important gram-positive extracellular bacterial pathogen responsible for a number of suppurative infections. This micro-organism has developed complex virulence mechanisms to avoid the host’s defenses. We have previously reported that SDSC from GAS type M22 causes endothelial-cell dysfunction, and inhibits cell adhesion, migration, metabolism, and proliferation in a dose-dependent manner, without affecting cell viability. This work aimed to isolate and characterize a component from GAS type M22 supernatant that suppresses the proliferation of endothelial cells (EA.hy926). In the process of isolating a protein possessing antiproliferative activity we identified arginine deiminase (AD). Further study showed that this enzyme is most active at pH 6.8. Calculating Km and Vmax gave the values of 0.67 mmol·L–1 and 42 s−1, respectively. A distinctive feature of AD purified from GAS type M22 is that its optimum activity and the maximal rate of the catalytic process is close to neutral pH by comparison with enzymes from other micro-organisms. AD from GAS type M22 suppressed the proliferative activity of endothelial cells in a dose-dependent mode. At the same time, in the presence of AD, the proportion of cells in G0/G1 phase increased. When l-Arg was added at increasing concentrations to the culture medium containing AD (3 μg·mL–1), the enzyme’s capacity to inhibit cell proliferation became partially depressed. The proportion of cells in phases S/G2 increased concomitantly, although the cells did not fully recover their proliferation activity. This suggests that AD from GAS type M22 has potential for the suppression of excessive cell proliferation.

Detection of virulence genes of APEC (avian pathogenic Escherichia coli) isolated from poultry in Noakhali, Bangladesh

2021 ◽  
Vol 7 (1) ◽  
pp. 967-972
Author(s):  
Farzana Ehetasum Hossain ◽  
Saiful Islam ◽  
Md Aminul Islam ◽  
Shariful Islam ◽  
Firoz Ahmed
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Economic Loss ◽  
Point Of View ◽  
Pcr Analysis ◽  
Avian Pathogenic Escherichia Coli ◽  
Gene Profiles ◽  
Pathogenic Escherichia Coli ◽  
Wide Range

Avian colibacillosis, caused by avian pathogenic Escherichia coli (APEC), is one of the major infectious diseases of poultry that bring about great economic loss for the Bangladesh poultry industry. The present study aimed to determine the virulence genes of avian pathogenic Escherichia coli (APEC) from cases of colibacillosis in poultry at the Noakhali district of Bangladesh. Currently, virulence-associated gene profiles of APEC isolates were investigated by polymerase chain reaction (PCR). A total of 24 (twenty-four) Escherichia coli isolates were collected and presumptively identified from 8 (eight) colibacillosis cases from 4 commercial broiler poultry farms (2 broilers per farm) in Noakhali, Bangladesh. The pathogenesis of Escherichia coli involves a wide range of different virulence genes. At this point, four virulence genes, iutA, hlyF, iroN, and iss were detected by PCR analysis. It has been observed that iutA, iss, hlyF, and iroN genes were found in 7(29.16%), 20(83.33%), 22(91.66%), and 24(100%) APEC isolates respectively. Furthermore, out of the twenty-four APEC isolates, six (25%) isolates had four virulence genes, fourteen (58.33%) isolates carried at least three virulence genes, three (12.5%) isolates carried two genes and one (4.16%) isolates had one virulence gene. Most importantly. six types of virulence gene profiles existed within the APEC isolates from which profile number 3 (hlyF, iroN, iss) having 13 (54.16%) isolates were predominant. The occurrence of APEC isolates of this region which is responsible for avian colibacillosis cases can be a matter of concern from the public health point of view. Future investigations will be able to utilize these virulence genes to identify APEC in Bangladesh helping in the diagnosis and prevention of colibacillosis in poultry. Bioresearch Commu. 7(1): 967-972, 2021 (January)

scholarly journals CovRS-Regulated Transcriptome Analysis of a Hypervirulent M23 Strain of Group A Streptococcus pyogenes Provides New Insights into Virulence Determinants

2015 ◽  
Vol 197 (19) ◽  
pp. 3191-3205 ◽  
Author(s):  
Yun-Juan Bao ◽  
Zhong Liang ◽  
Jeffrey A. Mayfield ◽  
Shaun W. Lee ◽  
Victoria A. Ploplis ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Broad Spectrum ◽  
Virulence Genes ◽  
Expression Profiles ◽  
Altered Expression ◽  
Content Type ◽  
Metabolic Genes ◽  
A Genome ◽  
Group A ◽  
Regulated Gene Expression

ABSTRACTThe two-componentcontrolofvirulence (Cov) regulator (R)-sensor (S) (CovRS) regulates the virulence ofStreptococcus pyogenes(group AStreptococcus[GAS]). Inactivation of CovS during infection switches the pathogenicity of GAS to a more invasive form by regulating transcription of diverse virulence genes via CovR. However, the manner in which CovRS controls virulence through expression of extended gene families has not been fully determined. In the current study, the CovS-regulated gene expression profiles of a hypervirulentemm23GAS strain (M23ND/CovS negative [M23ND/CovS−]) and a noninvasive isogenic strain (M23ND/CovS+), under different growth conditions, were investigated. RNA sequencing identified altered expression of ∼349 genes (18% of the chromosome). The data demonstrated that M23ND/CovS−achieved hypervirulence by allowing enhanced expression of genes responsible for antiphagocytosis (e.g.,hasABC), by abrogating expression of toxin genes (e.g.,speB), and by compromising gene products with dispensable functions (e.g.,sfb1). Among these genes, several (e.g.,parEandparC) were not previously reported to be regulated by CovRS. Furthermore, the study revealed that CovS also modulated the expression of a broad spectrum of metabolic genes that maximized nutrient utilization and energy metabolism during growth and dissemination, where the bacteria encounter large variations in available nutrients, thus restructuring metabolism of GAS for adaption to diverse growth environments. From constructing a genome-scale metabolic model, we identified 16 nonredundant metabolic gene modules that constitute unique nutrient sources. These genes were proposed to be essential for pathogen growth and are likely associated with GAS virulence. The genome-wide prediction of genes associated with virulence identifies new candidate genes that potentially contribute to GAS virulence.IMPORTANCEThe CovRS system modulates transcription of ∼18% of the genes in theStreptococcus pyogenesgenome. Mutations that inactivate CovR or CovS enhance the virulence of this bacterium. We determined complete transcriptomes of a naturally CovS-inactivated invasive deep tissue isolate of anemm23strain ofS. pyogenes(M23ND) and its complemented avirulent variant (CovS+). We identified diverse virulence genes whose altered expression revealed a genetic switching of a nonvirulent form of M23ND to a highly virulent strain. Furthermore, we also systematically uncovered for the first time the comparative levels of expression of a broad spectrum of metabolic genes, which reflected different metabolic needs of the bacterium as it invaded deeper tissue of the human host.

scholarly journals Virulence Factors Associated with Pediatric Shigellosis in Brazilian Amazon

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Carolinie Batista Nobre da Cruz ◽  
Maria Carolina Scheffer de Souza ◽  
Paula Taquita Serra ◽  
Ivanildes Santos ◽  
Antonio Balieiro ◽  
...  
Keyword(s):  
Human Health ◽  
Virulence Factors ◽  
Health Problem ◽  
Virulence Genes ◽  
Bacillary Dysentery ◽  
Brazilian Amazon ◽  
Clinical Isolates ◽  
Pathogenic Potential ◽  
Factors Associated ◽  
Etiologic Study

Shigellosis is a global human health problem and the incidence is highest among children. In the present work, mainShigellavirulence genes was examined by PCR and compared to symptoms of pediatric shigellosis. ThirtyShigellaisolates were identified from an etiologic study at which 1,339 children ranging 0–10 years old were enrolled.S. flexneriwas the most frequent species reaching 60.0% of isolates, 22.2% wereS. sonnei, and 6.6% were bothS. dysenteriaeandS. boydii. AllShigellainfected children had diarrhea, but not all were accompanied by others symptoms of bacillary dysentery. Among major virulence genes, the PCR typing revealedipaBCDwas present in all isolates, followed byIpaH7.8,set-1A,set-1B, sen/ospD3, virF,andinvE. The pathogenic potential of the ShET-1B subunit was observed in relation to dehydration (P<0.001) and ShET-2 related to the intestinal injury (P=0.033) evidenced by the presence of bloody diarrhea. Our results show associations among symptoms of shigellosis and virulence genes of clinical isolates ofShigellaspp.

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.

Lipid Peptide Core Nanoparticles as Multivalent Vaccine Candidates against Streptococcus pyogenes

2012 ◽  
Vol 65 (1) ◽  
pp. 35 ◽  
Author(s):  
Mariusz Skwarczynski ◽  
Bibi Hamideh Parhiz ◽  
Fatemeh Soltani ◽  
Saranya Srinivasan ◽  
Khairul A. Kamaruzaman ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Subunit Vaccine ◽  
Click Reaction ◽  
Group A Streptococcus ◽  
Vaccine Candidates ◽  
Wide Range ◽  
Group A ◽  
Core Peptide ◽  
Aqueous Conditions ◽  
Peptide Core

Traditional vaccine approaches for Group A streptococcus (GAS) infection are inadequate owing to the host’s production of cross-reactive antibodies that recognize not only the bacteria but also human tissue. To overcome this problem a peptide subunit-based vaccine was proposed, which would incorporate only minimal non-cross reactive epitopes. However, special delivery systems/adjuvants were required because short peptides are not immunogenic. In this study we have incorporated two epitopes from two different GAS proteins into a lipid core peptide (LCP) self-adjuvanting delivery system to achieve better protection against a wide range of GAS serotypes. Multivalent and monovalent constructs were synthesized with the help of an azide alkyne cycloaddition (click) reaction and their ability to self-assemble under aqueous conditions was examined. The compounds significantly differed in their ability to form small size nanoparticles, which are believed to be most appropriate for peptide-based subunit vaccine delivery. The LCP conjugates possessing two different epitopes, in contrast to monoepitopic constructs, formed small nanoparticles (5–15 nm) presumably owing to a suitable hydrophilic-hydrophobic balance of the molecules.

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