scholarly journals Sequence type 1 group BStreptococcus, an emerging cause of invasive disease in adults, evolves by small genetic changes

2015 ◽  
Vol 112 (20) ◽  
pp. 6431-6436 ◽  
Author(s):  
Anthony R. Flores ◽  
Jessica Galloway-Peña ◽  
Pranoti Sahasrabhojane ◽  
Miguel Saldaña ◽  
Hui Yao ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Phenotypic Diversity ◽  
The United States ◽  
Invasive Disease ◽  
Sequence Type ◽  
Surface Proteins ◽  
Genome Comparison ◽  
Genetic Changes ◽  
Capsule Production ◽  
Group B

The molecular mechanisms underlying pathogen emergence in humans is a critical but poorly understood area of microbiologic investigation. Serotype V group BStreptococcus(GBS) was first isolated from humans in 1975, and rates of invasive serotype V GBS disease significantly increased starting in the early 1990s. We found that 210 of 229 serotype V GBS strains (92%) isolated from the bloodstream of nonpregnant adults in the United States and Canada between 1992 and 2013 were multilocus sequence type (ST) 1. Elucidation of the complete genome of a 1992 ST-1 strain revealed that this strain had the highest homology with a GBS strain causing cow mastitis and that the 1992 ST-1 strain differed from serotype V strains isolated in the late 1970s by acquisition of cell surface proteins and antimicrobial resistance determinants. Whole-genome comparison of 202 invasive ST-1 strains detected significant recombination in only eight strains. The remaining 194 strains differed by an average of 97 SNPs. Phylogenetic analysis revealed a temporally dependent mode of genetic diversification consistent with the emergence in the 1990s of ST-1 GBS as major agents of human disease. Thirty-one loci were identified as being under positive selective pressure, and mutations at loci encoding polysaccharide capsule production proteins, regulators of pilus expression, and two-component gene regulatory systems were shown to affect the bacterial phenotype. These data reveal that phenotypic diversity among ST-1 GBS is mainly driven by small genetic changes rather than extensive recombination, thereby extending knowledge into how pathogens adapt to humans.

scholarly journals 125Single Nucleotide Polymorphisms Drive Phenotypic Diversity Among Sequence Type 1 Group B Streptococcus, An Emerging Cause of Invasive Disease in Adult Humans

2014 ◽  
Vol 1 (suppl_1) ◽  
pp. S12-S12
Author(s):  
Jessica Galloway-Pena ◽  
Pranoti Sahasrabhojane ◽  
Immaculada Margarit ◽  
Roberto Rosini ◽  
Guido Grandi ◽  
...  
Keyword(s):  
Phenotypic Diversity ◽  
Group B Streptococcus ◽  
Invasive Disease ◽  
Sequence Type ◽  
Nucleotide Polymorphisms ◽  
Adult Humans ◽  
Group B

scholarly journals Emergence of Serotype IV Group B Streptococcus Adult Invasive Disease in Manitoba and Saskatchewan, Canada, Is Driven by Clonal Sequence Type 459 Strains

2015 ◽  
Vol 53 (9) ◽  
pp. 2919-2926 ◽  
Author(s):  
Sarah Teatero ◽  
Taryn B. T. Athey ◽  
Paul Van Caeseele ◽  
Greg Horsman ◽  
David C. Alexander ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Group B Streptococcus ◽  
The United States ◽  
Invasive Disease ◽  
Sequence Type ◽  
Polymorphism Analysis ◽  
Invasive Infection ◽  
Content Type ◽  
Total Burden ◽  
Group B

Serotype IV group BStreptococcus(GBS) is emerging in Canada and the United States with rates as high as 5% of the total burden of adult invasive GBS disease. To understand this emergence, we studied the population structure and assessed the antimicrobial susceptibility of serotype IV isolates causing adult invasive infection in Manitoba and Saskatchewan, Canada, between 2010 and 2014. Whole-genome sequencing was used to determine multilocus sequence typing information and identify genes encoding antimicrobial resistance in 85 invasive serotype IV GBS strains. Antimicrobial susceptibility testing was performed by standard methods. Strain divergence was assessed using genome-wide single-nucleotide polymorphism analysis. Serotype IV strains were responsible for 16.9% of adult invasive GBS infections in Manitoba and Saskatchewan during the period. The majority of serotype IV isolates (89%) were clonally related, tetracycline-, erythromycin-, and clindamycin-resistant sequence type 459 (ST459) strains that possessed genestetMandermTR. Genome comparisons between ST459 and serotype V ST1 GBS identified several areas of recombination in an overall similar genomic background. Serotype IV ST459 GBS strains are expanding and causing a substantial percentage of adult invasive GBS disease. This emergence may be linked to the acquisition of resistance to tetracycline, macrolides, and lincosamides.

scholarly journals Complete Genome Sequence of Streptococcus agalactiae Serotype III, Multilocus Sequence Type 283 Strain SG-M1

2015 ◽  
Vol 3 (5) ◽  
Author(s):  
Kurosh S. Mehershahi ◽  
Li Yang Hsu ◽  
Tse Hsien Koh ◽  
Swaine L. Chen
Keyword(s):  
Gastrointestinal Tract ◽  
Genome Sequence ◽  
Streptococcus Agalactiae ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Invasive Disease ◽  
Sequence Type ◽  
Human Gastrointestinal Tract ◽  
Commensal Strain ◽  
Group B

Streptococcus agalactiae (group B Streptococcus ) is a common commensal strain in the human gastrointestinal tract that can also cause invasive disease in humans and other animals. We report here the complete genome sequence of S. agalactiae SG-M1, a serotype III, multilocus sequence type 283 strain, isolated from a Singaporean patient suffering from meningitis.

scholarly journals Streptococcus pneumoniaeSerotype 3 in Mexico (1994 to 2017): Decrease of the Unusual Clonal Complex 4909 Lineage following PCV13 Introduction

2018 ◽  
Vol 57 (1) ◽  
Author(s):  
Gabriela Echániz-Aviles ◽  
Soraia I. Guerreiro ◽  
Catarina Silva-Costa ◽  
Catarina I. Mendes ◽  
João André Carriço ◽  
...  
Keyword(s):  
Clonal Complex ◽  
Geographic Origin ◽  
Case Fatality ◽  
Genomic Analysis ◽  
The United States ◽  
Invasive Disease ◽  
Sequence Type ◽  
Content Type ◽  
Case Fatality Ratio ◽  
High Virulence

ABSTRACTStreptococcus pneumoniaeexpressing serotype 3 has a high virulence and a high case fatality ratio. Most studies of serotype 3 pneumococci have focused on a single lineage, the widespread sequence type 180 (ST180). To evaluate the serotype 3 lineages causing infections in Mexico, we characterized 196 isolates recovered from 1994 to 2017. The isolates were mostly susceptible to all antimicrobials tested. A single meningitis isolate was resistant to penicillin, and the resistance to erythromycin was 5.2%. The isolates represented the widely disseminated clonal complex 180 (CC180;n= 140), the unusual CC4909 (n= 42), CC260 (n= 11), and a few singletons (n= 3). CC260 was less frequent among pneumococcal invasive disease isolates than CC180 and CC4909 (P = 0.015). There was a decrease of CC4909 (P < 0.001) following PCV13 introduction (2012 to 2017). The CC4909 isolates were represented mostly by ST1119 (n= 40), seemingly having a restricted geographic origin, with isolates in the PubMLST database having been recovered only in Mexico, the United States, and Germany. A genomic analysis of publicly available genomes showed that ST1119 isolates have less than 32% similarity with ST180 isolates, indicating that these lineages are more separated than revealed by traditional multilocus sequence typing. Considering the suggestions of a lower efficacy of the 13-valent pneumococcal conjugate vaccine against serotype 3, the different dynamics of the two major serotype 3 lineages in Mexico following the introduction of PCV13 should be closely monitored.

scholarly journals Characterization of fHbp, nhba (gna2132), nadA, porA, and Sequence Type in Group B Meningococcal Case Isolates Collected in England and Wales during January 2008 and Potential Coverage of an Investigational Group B Meningococcal Vaccine

2010 ◽  
Vol 17 (6) ◽  
pp. 919-929 ◽  
Author(s):  
Jay Lucidarme ◽  
Maurizio Comanducci ◽  
Jamie Findlow ◽  
Stephen J. Gray ◽  
Edward B. Kaczmarski ◽  
...  
Keyword(s):  
First Generation ◽  
Vaccine Coverage ◽  
Membrane Vesicle ◽  
Invasive Disease ◽  
Cross Reactivity ◽  
Surface Proteins ◽  
England And Wales ◽  
Alternative Approach ◽  
Glycoconjugate Vaccines ◽  
Group B

ABSTRACT Invasive disease caused by meningococcal capsular groups A, C, W-135, and Y is now preventable by means of glycoconjugate vaccines that target their respective polysaccharide capsules. The capsule of group B meningococci (MenB) is poorly immunogenic and may induce autoimmunity. Vaccines based on the major immunodominant surface porin, PorA, are effective against clonal epidemics but, thus far, have a limited scope of coverage against the wider MenB population at large. In an alternative approach, the first-generation, investigational, recombinant MenB (rMenB) plus outer membrane vesicle (OMV) (rMenB-OMV) vaccine contains a number of relatively conserved surface proteins, fHBP, NHBA (previously GNA2132), and NadA, alongside PorA P1.4-containing OMVs from the New Zealand MeNZB vaccine. MenB currently accounts for approximately 90% of cases of meningococcal disease in England and Wales. To assess potential rMenB-OMV vaccine coverage of pathogenic MenB isolates within this region, all English and Welsh MenB case isolates from January 2008 (n = 87) were genetically characterized with respect to fHBP, NHBA, NadA, and PorA. Alleles for fHbp, nhba, and porA were identified in all of the isolates, of which 22% were also found to harbor nadA alleles. On the basis of genotypic data and predicted immunological cross-reactivity, the potential level of rMenB-OMV vaccine coverage in England and Wales ranges from 66% to 100%.

Molecular Mechanisms of Complement System Proteins and Matrix Metalloproteinases in the Pathogenesis of Age-Related Macular Degeneration

2019 ◽  
Vol 19 (10) ◽  
pp. 705-718 ◽  
Author(s):  
Naima Mansoor ◽  
Fazli Wahid ◽  
Maleeha Azam ◽  
Khadim Shah ◽  
Anneke I. den Hollander ◽  
...  
Keyword(s):  
Matrix Metalloproteinases ◽  
Macular Degeneration ◽  
Complement System ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Age Related Macular Degeneration ◽  
Genetic Changes ◽  
Complement System Proteins ◽  
Age Related ◽  
Common Genetic Variants

: Age-related macular degeneration (AMD) is an eye disorder affecting predominantly the older people above the age of 50 years in which the macular region of the retina deteriorates, resulting in the loss of central vision. The key factors associated with the pathogenesis of AMD are age, smoking, dietary, and genetic risk factors. There are few associated and plausible genes involved in AMD pathogenesis. Common genetic variants (with a minor allele frequency of >5% in the population) near the complement genes explain 40–60% of the heritability of AMD. The complement system is a group of proteins that work together to destroy foreign invaders, trigger inflammation, and remove debris from cells and tissues. Genetic changes in and around several complement system genes, including the CFH, contribute to the formation of drusen and progression of AMD. Similarly, Matrix metalloproteinases (MMPs) that are normally involved in tissue remodeling also play a critical role in the pathogenesis of AMD. MMPs are involved in the degradation of cell debris and lipid deposits beneath retina but with age their functions get affected and result in the drusen formation, succeeding to macular degeneration. In this review, AMD pathology, existing knowledge about the normal and pathological role of complement system proteins and MMPs in the eye is reviewed. The scattered data of complement system proteins, MMPs, drusenogenesis, and lipofusogenesis have been gathered and discussed in detail. This might add new dimensions to the understanding of molecular mechanisms of AMD pathophysiology and might help in finding new therapeutic options for AMD.

scholarly journals New Insights into the Pathogenesis of Systemic Mastocytosis

2021 ◽  
Vol 22 (9) ◽  
pp. 4900
Author(s):  
Zhixiong Li
Keyword(s):  
Molecular Mechanisms ◽  
Kinase Inhibitor ◽  
Systemic Mastocytosis ◽  
Treatment Strategies ◽  
The United States ◽  
European Medicines Agency ◽  
Myeloid Neoplasm ◽  
Organ Systems ◽  
United States Food ◽  
Kit D816v

Mastocytosis is a type of myeloid neoplasm characterized by the clonal, neoplastic proliferation of morphologically and immunophenotypically abnormal mast cells that infiltrate one or more organ systems. Systemic mastocytosis (SM) is a more aggressive variant of mastocytosis with extracutaneous involvement, which might be associated with multi-organ dysfunction or failure and shortened survival. Over 80% of patients with SM carry the KIT D816V mutation. However, the KIT D816V mutation serves as a weak oncogene and appears to be a late event in the pathogenesis of mastocytosis. The management of SM is highly individualized and was largely palliative for patients without a targeted form of therapy in past decades. Targeted therapy with midostaurin, a multiple kinase inhibitor that inhibits KIT, has demonstrated efficacy in patients with advanced SM. This led to the recent approval of midostaurin by the United States Food and Drug Administration and European Medicines Agency. However, the overall survival of patients treated with midostaurin remains unsatisfactory. The identification of genetic and epigenetic alterations and understanding their interactions and the molecular mechanisms involved in mastocytosis is necessary to develop rationally targeted therapeutic strategies. This review briefly summarizes recent developments in the understanding of SM pathogenesis and potential treatment strategies for patients with SM.

scholarly journals Key Role of Capsular Polysaccharide in the Induction of Systemic Infection and Abortion by Hypervirulent Campylobacter jejuni

2017 ◽  
Vol 85 (6) ◽  
Author(s):  
Orhan Sahin ◽  
Samantha A. Terhorst ◽  
Eric R. Burrough ◽  
Zhangqi Shen ◽  
Zuowei Wu ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Campylobacter Jejuni ◽  
Capsular Polysaccharide ◽  
Systemic Infection ◽  
The United States ◽  
Content Type ◽  
Model Following ◽  
Capsule Production ◽  
Guinea Pig Model

ABSTRACT Campylobacter jejuni is a zoonotic pathogen, and a hypervirulent clone, named clone SA, has recently emerged as the predominant cause of ovine abortion in the United States. To induce abortion, orally ingested Campylobacter must translocate across the intestinal epithelium, spread systemically in the circulation, and reach the fetoplacental tissue. Bacterial factors involved in these steps are not well understood. C. jejuni is known to produce capsular polysaccharide (CPS), but the specific role that CPS plays in systemic infection and particularly abortion in animals remains to be determined. In this study, we evaluated the role of CPS in bacteremia using a mouse model and in abortion using a pregnant guinea pig model following oral challenge. Compared with C. jejuni NCTC 11168 and 81-176, a clone SA isolate (IA3902) resulted in significantly higher bacterial counts and a significantly longer duration of bacteremia in mice. The loss of capsule production via gene-specific mutagenesis in IA3902 led to the complete abolishment of bacteremia in mice and abortion in pregnant guinea pigs, while complementation of capsule expression almost fully restored these phenotypes. The capsule mutant strain was also impaired for survival in guinea pig sera and sheep blood. Sequence-based analyses revealed that clone SA possesses a unique CPS locus with a mosaic structure, which has been stably maintained in all clone SA isolates derived from various hosts and times. These findings establish CPS as a key virulence factor for the induction of systemic infection and abortion in pregnant animals and provide a viable candidate for the development of vaccines against hypervirulent C. jejuni.

scholarly journals Genome Sequencing Identifies Two Nearly Unchanged Strains of Persistent Listeria monocytogenes Isolated at Two Different Fish Processing Plants Sampled 6 Years Apart

2013 ◽  
Vol 79 (9) ◽  
pp. 2944-2951 ◽  
Author(s):  
Anne Holch ◽  
Kristen Webb ◽  
Oksana Lukjancenko ◽  
David Ussery ◽  
Benjamin M. Rosenthal ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Food Processing ◽  
Random Amplified Polymorphic Dna ◽  
The United States ◽  
Genome Comparison ◽  
Physiological Factors ◽  
Content Type ◽  
Human Pathogenic Bacterium ◽  
A Genome ◽  
Genome Analyses

ABSTRACTListeria monocytogenesis a food-borne human-pathogenic bacterium that can cause infections with a high mortality rate. It has a remarkable ability to persist in food processing facilities. Here we report the genome sequences for twoL. monocytogenesstrains (N53-1 and La111) that were isolated 6 years apart from two different Danish fish processers. Both strains are of serotype 1/2a and belong to a highly persistent DNA subtype (random amplified polymorphic DNA [RAPD] type 9). We demonstrate usingin silicoanalyses that both strains belong to the multilocus sequence typing (MLST) type ST121 that has been isolated as a persistent subtype in several European countries. The purpose of this study was to use genome analyses to identify genes or proteins that could contribute to persistence. In a genome comparison, the two persistent strains were extremely similar and collectively differed from the reference lineage II strain, EGD-e. Also, they differed markedly from a lineage I strain (F2365). On the proteome level, the two strains were almost identical, with a predicted protein homology of 99.94%, differing at only 2 proteins. No single-nucleotide polymorphism (SNP) differences were seen between the two strains; in contrast, N53-1 and La111 differed from the EGD-e reference strain by 3,942 and 3,471 SNPs, respectively. We included a persistentL. monocytogenesstrain from the United States (F6854) in our comparisons. Compared to nonpersistent strains, all three persistent strains were distinguished by two genome deletions: one, of 2,472 bp, typically contains the gene forinlF, and the other, of 3,017 bp, includes three genes potentially related to bacteriocin production and transport (lmo2774,lmo2775, and the 3′-terminal part oflmo2776). Further studies of highly persistent strains are required to determine if the absence of these genes promotes persistence. While the genome comparison did not point to a clear physiological explanation of the persistent phenotype, the remarkable similarity between the two strains indicates that subtypes with specific traits are selected for in the food processing environment and that particular genetic and physiological factors are responsible for the persistent phenotype.

scholarly journals Complete Genome Sequence of Serotype III Streptococcus agalactiae Sequence Type 17 Strain 874391

2017 ◽  
Vol 5 (42) ◽  
Author(s):  
Matthew J. Sullivan ◽  
Brian M. Forde ◽  
Darren W. Prince ◽  
Deepak S. Ipe ◽  
Nouri L. Ben Zakour ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Streptococcus Agalactiae ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Historical Context ◽  
Invasive Disease ◽  
Sequence Type ◽  
Content Type ◽  
Disproportionate Number

ABSTRACT Here we report the complete genome sequence of Streptococcus agalactiae strain 874391. This serotype III isolate is a member of the hypervirulent sequence type 17 (ST-17) lineage that causes a disproportionate number of cases of invasive disease in humans and mammals. A brief historical context of the strain is discussed.

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