scholarly journals High virulence gene diversity in Streptococcus pyogenes isolated in Central Italy

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6613 ◽  
Author(s):  
Daniela Bencardino ◽  
Maria Chiara Di Luca ◽  
Dezemona Petrelli ◽  
Manuela Prenna ◽  
Luca Agostino Vitali
Keyword(s):  
Streptococcus Pyogenes ◽  
Virulence Genes ◽  
Gene Diversity ◽  
Central Italy ◽  
Virulence Gene ◽  
T Antigen ◽  
Gene Profiling ◽  
Pathogenic Potential ◽  
Important Species ◽  
Multiple Loci

Globally, Streptococcus pyogenes poses a continuous burden on human health, causing both self-limiting and life-threatening diseases. Therefore, studying the profile of virulence genes and their combinations is essential to monitor the epidemiology and pathogenic potential of this important species. Thus, the aim of this study was to analyze related genetic features of clinical strains collected in Italy in 2012 in order to obtain a valid picture of their virulence profile that could be compared to similar studies made in other countries approximately in the same period. We conducted emm typing and fibronectin-collagen-T antigen (FCT) region typing in 122 Streptococcus pyogenes strains. Furthermore, several additional virulence genes were screened by polymerase chain reaction. We found correlations between emm types and FCT region profiles. emm1 strains were mainly associated with FCT2 and FCT6, while emm89 and emm12 strains were associated with FCT4. FCT5 was mainly represented in emm4, emm6, and emm75 strains. Significantly, we defined subtypes for each FCT type based on the differences in single and double loci compared to the reference scheme used for the classification of the FCT region. In addition, new FCT-region variants with differences in multiple loci were also recorded. Cluster analysis based on virulence gene profiling showed a non-random distribution within each emm type. This study added new data to existing studies conducted worldwide and revealed new variability scores in circulating Streptococcus pyogenes strains and new assortments in well-established virulence gene signatures.

scholarly journals High degree of virulence gene diversity in Streptococcus pyogenes isolated in Central Italy

2017 ◽  
Author(s):  
Daniela Bencardino ◽  
Maria Chiara Di Luca ◽  
Dezemona Petrelli ◽  
Manuela Prenna ◽  
Luca Agostino Vitali
Keyword(s):  
Streptococcus Pyogenes ◽  
Virulence Genes ◽  
Gene Diversity ◽  
Central Italy ◽  
Virulence Gene ◽  
T Antigen ◽  
Gene Profiling ◽  
Important Species ◽  
Multiple Loci ◽  
Genetic Features

AbstractGlobally, Streptococcus pyogenes poses a continuous burden on human health, causing both self-limiting and life-threatening diseases. Therefore, studying the profile of virulence genes and their combinations is essential to monitor the epidemiology and pathogenetic potential of this important species. Thus, the aim of this study was to analyze some genetic features of clinical strains collected in Italy in 2012.We conducted fibronectin-collagen-T antigen (FCT) region typing and emm typing in 122 S. pyogenes strains. Furthermore, several additional virulence genes were screened by polymerase chain reaction.We found correlations between emm types and FCT region profiles. emm1 strains were mainly associated with FCT2 and FCT6, while emm89 and emm12 strains were associated with FCT4. FCT5 was mainly represented in emm4, emm6, and emm75 strains. Noteworthy, we defined subtypes for each FCT type based on the differences in single and multiple loci compared to the reference scheme used for the classification of the FCT region. In addition, new FCT types were identified. Cluster analysis based on virulence gene profiling showed a non-random distribution within each emm type.This study showed the high variability of S. pyogenes strains and the great diversification that this pathogen has undergone during its evolution in the human host.

scholarly journals Colonization of healthy children by Moraxella catarrhalis is characterized by genotype heterogeneity, virulence gene diversity and co-colonization with Haemophilus influenzae

Microbiology ◽  
2011 ◽  
Vol 157 (1) ◽  
pp. 169-178 ◽  
Author(s):  
Suzanne J. C. Verhaegh ◽  
Martine L. Snippe ◽  
Foster Levy ◽  
Henri A. Verbrugh ◽  
Vincent W. V. Jaddoe ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Moraxella Catarrhalis ◽  
Virulence Genes ◽  
Gene Diversity ◽  
Bacterial Species ◽  
Genotypic Variation ◽  
Virulence Gene ◽  
Single Species ◽  
Healthy Children ◽  
Genotypic Analysis

The colonization dynamics of Moraxella catarrhalis were studied in a population comprising 1079 healthy children living in Rotterdam, The Netherlands (the Generation R Focus cohort). A total of 2751 nasal swabs were obtained during four clinic visits timed to take place at 1.5, 6, 14 and 24 months of age, yielding a total of 709 M. catarrhalis and 621 Haemophilus influenzae isolates. Between January 2004 and December 2006, approximate but regular 6-monthly cycles of colonization were observed, with peak colonization incidences occurring in the autumn/winter for M. catarrhalis, and winter/spring for H. influenzae. Co-colonization was significantly more likely than single-species colonization with either M. catarrhalis or H. influenzae, with genotypic analysis revealing no clonality for co-colonizing or single colonizers of either bacterial species. This finding is especially relevant considering the recent discovery of the importance of H. influenzae–M. catarrhalis quorum sensing in biofilm formation and host clearance. Bacterial genotype heterogeneity was maintained over the 3-year period of the study, even within this relatively localized geographical region, and there was no association of genotypes with either season or year of isolation. Furthermore, chronological and genotypic diversity in three immunologically important M. catarrhalis virulence genes (uspA1, uspA2 and hag/mid) was also observed. This study indicates that genotypic variation is a key factor contributing to the success of M. catarrhalis colonization of healthy children in the first years of life. Furthermore, variation in immunologically relevant virulence genes within colonizing populations, and even within genotypically identical M. catarrhalis isolates, may be a result of immune evasion by this pathogen. Finally, the factors facilitating M. catarrhalis and H. influenzae co-colonization need to be further investigated.

scholarly journals Genes de virulencia en Aeromonas spp. (Aeromonadales: Aeromonadaceae) aisladas de Oreochromis spp. (Perciformes: Cichlidae) para consumo humano en México

2018 ◽  
Vol 66 (4) ◽  
Author(s):  
JESSICA LIZBETH Ortega Balleza ◽  
Alejandro Sánchez-Varela ◽  
Isabel C. Rodríguez-Luna ◽  
Xianwu Guo
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Geographical Area ◽  
Virulence Gene ◽  
Gastrointestinal Diseases ◽  
Human Consumption ◽  
Emerging Pathogens ◽  
Pathogenic Potential ◽  
Aeromonas Caviae ◽  
And Control

The genus Aeromonas are widely distributed in aquatic ecosystems are Gram-negative rods, oxidase-positive, and glucose-fermenting, considered emerging pathogens in humans. Aeromonas belongs to the fish microbiota, these microorganisms have a diversity of virulence factors responsible for a variety of infections in humans mainly gastrointestinal diseases. The presence of Aeromonas in products intended for consumption with high commercial demand such as tilapia generates sanitary concern due to the pathogenic potential of this bacteria. In this context, identification of virulence genes in strains of Aeromonas isolated in Oreochromis spp. intended for human consumption in Reynosa, Tamaulipas, Mexico is important due to the lack of molecular studies in this geographical area. In the present study the pathogenic potential of 15 strains of Aeromonas (A. veronii, A. hydrophila and A. schubertii) from Oreochromis spp. for human consumption were analyzed. Through PCR six virulence genes were analyzed (alt, ast, aerA, hlyA, gcat and stx1) and the strains used as control were: Aeromonas hydrophila subsp. hydrophila ATCC 7966, Aeromonas caviae 429865 INP, Escherichia coli O157: H7 and Escherichia coli K12. El 100 % (n = 15) of the strains harbored at least one virulence gene, aerA gene was detected in 86.66% of the analyzed strains, while ast and stx1 genes were not identified. Moreover, Aeromonas strains had associated genes in the same strain: aerA / gcat, alt / aerA, alt / aerA / gcat / hlyA and alt / aerA / gcat, of which aerA / gcat were observed mostly in A. veronii, while A. hydrophila had the highest associations. These findings indicate that the strains of Aeromonas isolated in Oreochromis spp. have the potential to cause human diseases, and therefore, this species used as food, could be a vehicle for infections caused by Aeromonas. It also allows to provide information on this emerging microorganism to effectively treat and control any epidemiological event caused by Aeromonas spp. in the future.

scholarly journals Occurrence, distribution and virulence factors of clinically important Acinetobacter species recovered from selected freshwater resources in the Eastern Cape Province, South Africa

2019 ◽  
Author(s):  
Mary Ayobami Adewoyin ◽  
Anthony Ifeanyi Okoh
Keyword(s):  
South Africa ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Molecular Techniques ◽  
Reca Gene ◽  
Eastern Cape Province ◽  
Eastern Cape ◽  
Freshwater Resources ◽  
Important Species ◽  
Acinetobacter Species

Abstract Background : Several Acinetobacter species live in different ecosystems such as soil, freshwater, wastewater, and solid wastes. In this study, we assessed the occurrence of A. baumannii and A. nosocomialis , which are the major two clinically important species of the genus Acinetobacter , in three freshwater resources (Great Fish, Keiskemma, and Tyhume rivers) in the Eastern Cape Province, South Africa over a one year sampling regime (April 2017 - March 2018). Presumptive Acinetobacter species were subjected to molecular identification by using Acinetobacter genus-specific primers targeting the recA gene. The confirmed Acinetobacter species were further delineated into A. baumannii and A. nosocomialis using species-specific primer sets. Similarly, virulence genes, namely; afa/draBC, epsA, fimH, OmpA, PAI, sfa/focDE , and traT in the two Acinetobacter species were also determined using molecular techniques. Result : A total of 1107 presumptive Acinetobacter isolates were recovered from the freshwater resources of which 844 was confirmed positive for the Acinetobacter genus. Of the 844 Acinetobacter isolates, 285 (77%), 219 (70.9%) and 340 (79%) were recovered from Great Fish, Keiskemma and Tyhume rivers respectively. Our finding revealed that 410 (48.58%) and 23 (2.7%) of the isolates were confirmed to be A. baumannii and A. nosocomalis , respectively. The presence of these clinically-important Acinetobacter species in the freshwater studied suggests possible contamination of the selected rivers and also that A. baumannii and A. nosocomialis can thrive in aquatic environments. Besides, 308 (75.12%) A. baumannii and 3 (13.04%) A. nosocomialis isolates exhibited one or more virulence genes out of the seven tested, whereas 102 (24.88%) and 20 (86.95%) of the A. baumannii and A. nosocomialis isolates did not harbour any virulence gene. Additionally, OmpA was the most prevalent (p<0.05) virulence gene in A. baumannii with 69 (45.10%), 52 (50.98%) and 77 (49.68%) isolates in Great Fish, Keiskamma and Tyhume rivers respectively. Conclusion : The occurrence of these pathogens in rivers which are consumed by humans and livestock, as well as being used for irrigation system constitutes a risk to public health. Keywords: Freshwater resources, Molecular characterisation, Acinetobacter species, virulence gene s.

scholarly journals Role of Streptococcus pyogenes Two-Component Response Regulators in the Temporal Control of Mga and the Mga-Regulated Virulence Gene emm

2004 ◽  
Vol 72 (6) ◽  
pp. 3668-3673 ◽  
Author(s):  
Deborah A. Ribardo ◽  
Thomas J. Lambert ◽  
Kevin S. McIver
Keyword(s):  
Streptococcus Pyogenes ◽  
Virulence Genes ◽  
Stationary Phases ◽  
Virulence Gene ◽  
Temporal Control ◽  
Wild Type ◽  
Response Regulators ◽  
Two Component

ABSTRACT We examined the role of Streptococcus pyogenes two-component response regulators (SptR) in expression of Mga and the Mga-regulated gene emm. Both serotype M6 and serotype M1 mutants in 12 of the 13 identified sptR genes exhibited levels of emm transcripts and Mga protein comparable to those of the wild type during exponential and stationary phases of growth. Thus, temporal control of these virulence genes does not require Spt response regulators.

scholarly journals VIRULENCE GENE PROFILING AND PATHOGENICITY OF Streptococcus agalactiae ISOLATED FROM TILAPIA, Oreochromis niloticus FARMS IN INDONESIA

2021 ◽  
Vol 16 (2) ◽  
pp. 119
Author(s):  
Sukenda Sukenda ◽  
Achmad Suhermanto ◽  
Muhammad Zairin Jr. ◽  
Angela Mariana Lusiastuti ◽  
Sri Nuryati ◽  
...  
Keyword(s):  
Streptococcus Agalactiae ◽  
Virulence Genes ◽  
Disease Outbreaks ◽  
Virulence Gene ◽  
Gene Profiling ◽  
Pathogenicity Test ◽  
Post Injection ◽  
Gap Genes ◽  
Virulent Gene ◽  
Template Dna

Streptococcosis caused by Streptococcus agalactiae has become a major disease problem in tilapia culture in Indonesia. This study aimed to detect virulence genes of S. agalactiae during streptococcosis disease outbreaks in several tilapia farms in Indonesia and evaluate the correlation between biotype and virulence genes to bacterial virulence. The presence of virulence genes was determined in 10 strains of S. agalactiae isolated from farm-raised tilapia. Polymerase chain reaction (PCR) protocol was used to determine genes for cylE, hylB, lmb, bib A, PI-2b, fbs A, fbs B, gap, PI-1, and cfb in the template DNA. Pathogenicity test was carried out by intraperitoneal injection of 24 hour-cultured S. agalactiae to tilapia with 108 CFU/fish. Four isolates have seven of virulence genes (cylE, hylB, bibA, PI-2b, fbs A, fbs B, and gap genes), three isolates have six virulence genes (hylB, bib A, fbs A, fbs B, gap, cfb genes), one isolate has four virulence gene (hyl B, bib A, fbs, and cfb genes), and one isolate has one virulence gene (PI-2b gene). None of the isolates has lmb or PI-1 genes. Bacteria with more virulence genes showed higher pathogenicity post injection. Mortality of tilapia injected with b-hemolytic bacteria was 100% within the period of 14-19 hours, while non-hemolytic bacteria was 53.3%-86.6% on 14 days post-injection. Pathological changes associated with the infection by either isolate included melanosis, slow response, anorexia, ocular opacity, gasping, erratic, C-shape, and whirling. It can be concluded that S. agalactiae with more virulence genes show a higher level of pathogenicity. The presence of a virulent gene has the potential to be used as a basis for selecting candidate isolates and designing vaccine compositions as an effort to prevent streptococcosis infection in tilapia in Indonesia.

scholarly journals Identification of Residues Responsible for the Defective Virulence Gene Regulator Mga Produced by a Natural Mutant of Streptococcus pyogenes

2005 ◽  
Vol 187 (17) ◽  
pp. 5955-5966 ◽  
Author(s):  
Cheryl M. Vahling ◽  
Kevin S. McIver
Keyword(s):  
Streptococcus Pyogenes ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Binding Activity ◽  
Human Pathogen ◽  
Mobility Shift ◽  
Dna Binding Activity ◽  
Naturally Occurring ◽  
Electrophoretic Mobility Shift Assays ◽  
Regulated Promoters

ABSTRACT Mga is a transcriptional regulator in the pathogen Streptococcus pyogenes that positively activates several important virulence genes involved in colonization and immune evasion in the human host. A naturally occurring mutant of Mga that is defective in its ability to activate transcription has been identified in the serotype M50 strain B514-Sm. Sequence alignment of the defective M50 Mga with the fully functional Mga from serotypes M4 and M49 revealed only three amino acid changes that might result in a defective protein. Electrophoretic mobility shift assays using purified M50 and M4 maltose binding protein-Mga found that both exhibited DNA-binding activity towards regulated promoters. Thus, the significance of each residue for the functionality of M50 Mga was explored through introduction of “gain-of-function” mutations based on M4 Mga. Transcriptional studies of the mutant alleles under both constitutive (PrpsL) and autoactivated (Pmga4) promoters illustrated that an arginine-to-methionine change at position 461 of M50 Mga protein fully restored activation of downstream genes. Western blot analyses of steady-state Mga levels suggest that the M461 residue may play a role in overall conformation and protein stability of Mga. However, despite the conservation of the M461 protein among all other Mga proteins, it does not appear to be necessary for activity in a divergent M6 Mga. These studies highlight the potential differences that exist between divergent Mga proteins in this important human pathogen.

scholarly journals Phenotypic and molecular characterization of Salmonella enterica serovar Sofia, an avirulent species in Australian poultry

Microbiology ◽  
2011 ◽  
Vol 157 (4) ◽  
pp. 1056-1065 ◽  
Author(s):  
Emily Gan ◽  
Fiona J. Baird ◽  
Peter J. Coloe ◽  
Peter M. Smooker
Keyword(s):  
Salmonella Enterica ◽  
Virulence Genes ◽  
Meat Products ◽  
Virulence Gene ◽  
Cleavage Sites ◽  
Pathogenic Potential ◽  
Serovar Typhimurium ◽  
Restriction Cleavage

Salmonella enterica serovar Sofia (S. Sofia) is often isolated from chickens in Australia. However, despite its high frequency of isolation from chicken and chicken meat products, S. Sofia is rarely associated with animal or human salmonellosis, presumably because this serovar is avirulent in nature. The objective of this work was to investigate the phenotypic and molecular properties of S. Sofia in order to assess its pathogenic potential. Our in vivo studies support the observation that this serovar can colonize tissues, but does not cause disease in chickens. This was further confirmed with tissue culture assays, which showed that the ability of S. Sofia to adhere, invade and survive intracellularly is significantly diminished compared with the pathogenic Salmonella enterica serovar Typhimurium (S. Typhimurium) 82/6915. Molecular analysis of Salmonella pathogenicity islands (SPIs) showed that most of the differences observed in SPI1 to SPI5 of S. Sofia could be attributed to minor changes in the sequences, as indicated by a loss or gain of restriction cleavage sites within these regions. Sequence analysis demonstrated that the majority of virulence genes identified were predicted to encode proteins sharing a high identity (75–100 %) with corresponding proteins from S. Typhimurium. However, a number of virulence genes in S. Sofia have accumulated mutations predicted to affect transcription and/or translation. The avirulence of this serovar is probably not the result of a single genetic change but rather of a series of alterations in a large number of virulence-associated genes. The acquisition of any single virulence gene will almost certainly not be sufficient to restore S. Sofia virulence.

scholarly journals Virulence Gene Regulation by CvfA, a Putative RNase: the CvfA-Enolase Complex in Streptococcus pyogenes Links Nutritional Stress, Growth-Phase Control, and Virulence Gene Expression

2010 ◽  
Vol 78 (6) ◽  
pp. 2754-2767 ◽  
Author(s):  
Song Ok Kang ◽  
Michael G. Caparon ◽  
Kyu Hong Cho
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Nutritional Status ◽  
Streptococcus Pyogenes ◽  
Growth Phase ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Nutritional Stress ◽  
Altered Expression ◽  
Virulence Gene Expression

ABSTRACT Streptococcus pyogenes, a multiple-auxotrophic human pathogen, regulates virulence gene expression according to nutritional availability during various stages in the infection process or in different infection sites. We discovered that CvfA influenced the expression of virulence genes according to growth phase and nutritional status. The influence of CvfA in C medium, rich in peptides and poor in carbohydrates, was most pronounced at the stationary phase. Under these conditions, up to 30% of the transcriptome exhibited altered expression; the levels of expression of multiple virulence genes were altered, including the genes encoding streptokinase, CAMP factor, streptolysin O, M protein (more abundant in the CvfA− mutant), SpeB, mitogenic factor, and streptolysin S (less abundant). The increase of carbohydrates or peptides in media restored the levels of expression of the virulence genes in the CvfA− mutant to wild-type levels (emm, ska, and cfa by carbohydrates; speB by peptides). Even though the regulation of gene expression dependent on nutritional stress is commonly linked to the stringent response, the levels of ppGpp were not altered by deletion of cvfA. Instead, CvfA interacted with enolase, implying that CvfA, a putative RNase, controls the transcript decay rates of virulence factors or their regulators according to nutritional status. The virulence of CvfA− mutants was highly attenuated in murine models, indicating that CvfA-mediated gene regulation is necessary for the pathogenesis of S. pyogenes. Taken together, the CvfA-enolase complex in S. pyogenes is involved in the regulation of virulence gene expression by controlling RNA degradation according to nutritional stress.

scholarly journals The utility of multiple molecular methods including whole genome sequencing as tools to differentiate Escherichia coli O157:H7 outbreaks

2015 ◽  
Vol 20 (47) ◽  
Author(s):  
Byron M Berenger ◽  
Chrystal Berry ◽  
Trevor Peterson ◽  
Patrick Fach ◽  
Sabine Delannoy ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Core Genome ◽  
Virulence Genes ◽  
Variable Number Tandem Repeat ◽  
Virulence Gene ◽  
Variable Number ◽  
Gene Profiling ◽  
Whole Genome

A standardised method for determining Escherichia coli O157:H7 strain relatedness using whole genome sequencing or virulence gene profiling is not yet established. We sought to assess the capacity of either high-throughput polymerase chain reaction (PCR) of 49 virulence genes, core-genome single nt variants (SNVs) or k-mer clustering to discriminate between outbreak-associated and sporadic E. coli O157:H7 isolates. Three outbreaks and multiple sporadic isolates from the province of Alberta, Canada were included in the study. Two of the outbreaks occurred concurrently in 2014 and one occurred in 2012. Pulsed-field gel electrophoresis (PFGE) and multilocus variable-number tandem repeat analysis (MLVA) were employed as comparator typing methods. The virulence gene profiles of isolates from the 2012 and 2014 Alberta outbreak events and contemporary sporadic isolates were mostly identical; therefore the set of virulence genes chosen in this study were not discriminatory enough to distinguish between outbreak clusters. Concordant with PFGE and MLVA results, core genome SNV and k-mer phylogenies clustered isolates from the 2012 and 2014 outbreaks as distinct events. k-mer phylogenies demonstrated increased discriminatory power compared with core SNV phylogenies. Prior to the widespread implementation of whole genome sequencing for routine public health use, issues surrounding cost, technical expertise, software standardisation, and data sharing/comparisons must be addressed.

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