scholarly journals Identification and Characterization of Bicistronic speB and prsA Gene Expression in the Group A Streptococcus

2006 ◽  
Vol 188 (21) ◽  
pp. 7626-7634 ◽  
Author(s):  
Yongsheng Ma ◽  
Amy E. Bryant ◽  
Dan B. Salmi ◽  
Susan M. Hayes-Schroer ◽  
Eric McIndoo ◽  
...  
Keyword(s):  
Group A Streptococcus ◽  
Genetic Regulation ◽  
Active Form ◽  
Prolyl Isomerase ◽  
Peptidyl Prolyl Isomerase ◽  
Invasive Group ◽  
Genes Encoding ◽  
Group A ◽  
Streptococcal Pyrogenic Exotoxin B

ABSTRACT Severe, invasive group A streptococcal infections have reemerged worldwide, and extracellular toxins, including streptococcal pyrogenic exotoxin B (SpeB), have been implicated in pathogenesis. The genetic regulation of SpeB is not fully understood, and the mechanisms involved in the processing of the protoxin to its enzymatically active form have not been definitively established. The present work demonstrated that the genes encoding SpeB (speB) and a peptidyl-prolyl isomerase (prsA) constitute an operon with transcription initiated from two promoters upstream of speB. Further, the speB-prsA operon was transcribed as a bicistronic mRNA. This finding is in contrast to the generally accepted notion that speB is transcribed only as a monocistronic gene. In addition, prsA has its own promoter, and transcription from this promoter starts in early log phase, prior to the transcription of speB. Genomic disruption of prsA decreased the production of enzymatically active SpeB but not the level of the pro-SpeB zymogen. Taken together, these results demonstrate that prsA is required for production of fully mature, enzymatically active SpeB.

scholarly journals Prevalence and Characterization of Invasive Isolates of Streptococcus pyogenes with Reduced Susceptibility to Fluoroquinolones

2005 ◽  
Vol 49 (5) ◽  
pp. 2130-2132 ◽  
Author(s):  
Jeff Powis ◽  
Allison McGeer ◽  
Carla Duncan ◽  
Ryan Goren ◽  
Joyce C. S. de Azavedo ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Susceptibility Testing ◽  
Group A Streptococcus ◽  
Invasive Group ◽  
Group A

ABSTRACT Fluoroquinolone susceptibility testing was performed on invasive group A streptococcus isolates from 1992-1993 and 2003 from Ontario, Canada. None were nonsusceptible to levofloxacin. Two of 153 (1.3%) from 1992-1993 and 7 of 160 (4.4%) from 2003 had a levofloxacin MIC of 2 μg/ml; all nine had parC mutations, and eight were serotype M6.

scholarly journals Epidemiological and Molecular Characterization of an Invasive Group A Streptococcusemm32.2 Outbreak

2017 ◽  
Vol 55 (6) ◽  
pp. 1837-1846 ◽  
Author(s):  
Jennifer E. Cornick ◽  
Anmol M. Kiran ◽  
Roberto Vivancos ◽  
Jon Van Aartsen ◽  
Jenny Clarke ◽  
...  
Keyword(s):  
Group A Streptococcus ◽  
Adult Population ◽  
Sequencing Analysis ◽  
Invasive Group ◽  
Disadvantaged Population ◽  
Specific Subset ◽  
Time Period ◽  
Case Comparison ◽  
Group A

ABSTRACTAnemm32.2 invasive group A streptococcus (iGAS) outbreak occurred in Liverpool from January 2010 to September 2012. This genotype had not previously been identified in Liverpool, but was responsible for 32% (14/44) of all iGAS cases reported during this time period. We performed a case-case comparison ofemm32.2 iGAS cases with non-emm32.2 control iGAS cases identified in the Liverpool population over the same time period to assess patient risk factors foremm32.2 iGAS infection. Theemm32.2 iGAS cases were confined to the adult population. We show that homelessness, intravenous drug use, and alcohol abuse predisposed patients toemm32.2 iGAS disease; however, no obvious epidemiological linkage between the patients withemm32.2 iGAS could be identified. Comparative whole-genome sequencing analysis ofemm32.2 iGAS and non-emm32.2 control isolates was also performed to identify pathogen factors which might have driven the outbreak. We identified 19 genes, five of which had previously been implicated in virulence, which were present in all of theemm32.2 iGAS isolates but not present in any of the non-emm32.2 control isolates. We report that a novelemm32.2 genotype emerged in Liverpool in 2010 and identified a specific subset of genes, which could have allowed this novelemm32.2 genotype to persist in a disadvantaged population in the region over a 3-year period.

scholarly journals Erratum for Cornick et al., “Epidemiological and Molecular Characterization of an Invasive Group A Streptococcus emm32.2 Outbreak”

2018 ◽  
Vol 56 (9) ◽  
Author(s):  
Jennifer E. Cornick ◽  
Anmol M. Kiran ◽  
Roberto Vivancos ◽  
Jon Van Aartsen ◽  
Jenny Clarke ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Group A Streptococcus ◽  
Invasive Group ◽  
Group A

Bilateral periorbital necrotising fasciitis associated with invasive group: a Streptococcus infection

2020 ◽  
Vol 13 (12) ◽  
pp. e236800
Author(s):  
Grace Anne McCabe ◽  
Thomas Hardy ◽  
Thomas Gordon Campbell
Keyword(s):  
Group A Streptococcus ◽  
Early Recognition ◽  
Skin Grafting ◽  
Final Diagnosis ◽  
Necrotising Fasciitis ◽  
Invasive Group ◽  
Group A ◽  
Tissue Microscopy ◽  
Periorbital Swelling ◽  
Multidisciplinary Teamwork

A previously independent 56-year-old immunocompetent woman presented with septic shock in the setting of periorbital swelling and diffuse infiltrates on chest imaging. Blood cultures were positive for growth of group A Streptococcus (GAS). Broad spectrum antimicrobials were initiated with the inclusion of the antitoxin agent clindamycin. Necrosis of periorbital tissue was noted and surgical consultation was obtained. Débridement of both eyelids with skin grafting was performed. GAS was isolated from wound cultures and also observed on periorbital tissue microscopy. The final diagnosis was bilateral periorbital necrotising fasciitis (PONF) associated with invasive GAS infection. The patient had a prolonged intensive care unit course with input from multiple specialist teams. This case demonstrates the importance of early recognition and treatment of PONF, the profound systemic morbidity caused by these infections, and illustrates successful multidisciplinary teamwork.

scholarly journals Preliminary characterization of a cloned neutral isoelectric form of the human peptidyl prolyl isomerase cyclophilin

1991 ◽  
Vol 266 (4) ◽  
pp. 2474-2479
Author(s):  
T F Holzman ◽  
D A Egan ◽  
R Edalji ◽  
R L Simmer ◽  
R Helfrich ◽  
...  
Keyword(s):  
Prolyl Isomerase ◽  
Peptidyl Prolyl Isomerase ◽  
Preliminary Characterization

scholarly journals The M Protein Is Dispensable for Maturation of Streptococcal Cysteine Protease SpeB

2005 ◽  
Vol 73 (2) ◽  
pp. 859-864 ◽  
Author(s):  
Björn Zimmerlein ◽  
Hae-Sun Park ◽  
Shaoying Li ◽  
Andreas Podbielski ◽  
P. Patrick Cleary
Keyword(s):  
Cysteine Protease ◽  
Protease Activity ◽  
Active Form ◽  
Surface Protein ◽  
M Protein ◽  
Cysteine Protease Activity ◽  
Group A ◽  
Streptococcal Pyrogenic Exotoxin B ◽  
Major Surface ◽  
Culture Supernatants

ABSTRACT The streptococcal pyrogenic exotoxin B (SpeB) is an important virulence factor of group A streptococci (GAS) with cysteine protease activity. Maturation of SpeB to a proteolytically active form was suggested to be dependent on cell-wall-anchored M1 protein, the major surface protein of GAS (M. Collin and A. Olsén, Mol. Microbiol. 36:1306-1318, 2000). Collin and Olsén showed that mutant GAS strains expressing truncated M protein secrete a conformationally different form of unprocessed SpeB with no proteolytic activity. Alternatively, we hypothesized that a truncated M protein may interfere with processing of this secreted protease, and therefore we tested cysteine protease activity in genetically defined mutant strains that express either no M protein or membrane-anchored M protein with an in-frame deletion of the AB repeat region. Measurements of SpeB activity by cleavage of a substrate n-benzoyl-Pro-Phe-Arg-p-nitroanilide hydrochloride showed that the proteolytic activities in culture supernatants of both mutants were similar to those from the wild-type strain. In addition, Western blot analysis of culture supernatants showed that SpeB expression and processing to a mature form was unaffected by either deletion mutation. Therefore, we conclude that M protein is not required for maturation of the streptococcal cysteine protease SpeB.

scholarly journals Regulation of Polysaccharide Utilization Contributes to the Persistence of Group A Streptococcus in the Oropharynx

2007 ◽  
Vol 75 (6) ◽  
pp. 2981-2990 ◽  
Author(s):  
Samuel A. Shelburne ◽  
Nnaja Okorafor ◽  
Izabela Sitkiewicz ◽  
Paul Sumby ◽  
David Keith ◽  
...  
Keyword(s):  
Parental Strain ◽  
Group A Streptococcus ◽  
Transcriptional Regulator ◽  
Human Saliva ◽  
Transcript Levels ◽  
Expression Of Genes ◽  
Rich Media ◽  
Genes Encoding ◽  
Group A ◽  
Mutant Derivative

ABSTRACT Group A Streptococcus (GAS) genes that encode proteins putatively involved in polysaccharide utilization show growth phase-dependent expression in human saliva. We sought to determine whether the putative polysaccharide transcriptional regulator MalR influences the expression of such genes and whether MalR helps GAS infect the oropharynx. Analysis of 32 strains of 17 distinct M protein serotypes revealed that MalR is highly conserved across GAS strains. malR transcripts were detectable in patients with GAS pharyngitis, and the levels increased significantly during growth in human saliva compared to the levels during growth in glucose-containing or nutrient-rich media. To determine if MalR influenced the expression of polysaccharide utilization genes, we compared the transcript levels of eight genes encoding putative polysaccharide utilization proteins in the parental serotype M1 strain MGAS5005 and its ΔmalR isogenic mutant derivative. The transcript levels of all eight genes were significantly increased in the ΔmalR strain compared to the parental strain, especially during growth in human saliva. Following experimental infection, the ΔmalR strain persistently colonized the oropharynx in significantly fewer mice than the parental strain colonized, and the numbers of ΔmalR strain CFU recovered were significantly lower than the numbers of the parental strain CFU recovered. These data led us to conclude that MalR influences the expression of genes putatively involved in polysaccharide utilization and that MalR contributes to the persistence of GAS in the oropharynx.

scholarly journals Sequential Quadriplex Real-Time PCR for Identifying 20 Common emm Types of Group A Streptococcus

2020 ◽  
Vol 59 (1) ◽  
pp. e01764-20
Author(s):  
Srinivasan Velusamy ◽  
Katherine Jordak ◽  
Madeline Kupor ◽  
Sopio Chochua ◽  
Lesley McGee ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Group A Streptococcus ◽  
High Specificity ◽  
The United States ◽  
Rapid Identification ◽  
Invasive Group ◽  
Outbreak Investigations ◽  
Group A ◽  
Culture Negative

ABSTRACTWe developed a sequential quadriplex real-time PCR-based method for rapid identification of 20 emm types commonly found in invasive group A Streptococcus (iGAS) strains recovered through the Centers for Disease Control and Prevention’s Active Bacterial Core surveillance. Each emm real-time PCR assay showed high specificity and accurately identified the respective target emm type, including emm subtypes in the United States. Furthermore, this method is useful for rapid typing of GAS isolates and culture-negative specimens during outbreak investigations.

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