Genetic diversity and relationships among Streptococcus pyogenes strains expressing serotype M1 protein: recent intercontinental spread of a subclone causing episodes of invasive disease.

Abstract Objectives Pharyngeal carriers such as H. influenzae seem to constitute the only reservoir and probably the only transmission vehicle of the invasive disease. The aims of this study were to estimate the prevalence of H. influenzae carriage, to characterize antibiotic susceptibility, and to explore genetic diversity of H. influenzae isolates. Sampling was carried out as nasopharynx swabs among children less than 6 years old volunteers. After traditional biochemical tests, isolates were confirmed by targeting omp6 sequence. Following the susceptibility tests, genomic diversity of strains was analyzed by Pulsed-Field Gel Electrophoresis procedure. Results Out of 328 nasopharynx swabs, 73 strains were identified as H. influenzae. Among H. influenzae isolates, resistance to chloramphenicol (42%) and ampicillin (43%) was observed. Levofloxacin is the most effective antibiotic and the least effect belonged to tetracycline. By genomic analysis of selected H. influenza, 28 PFGE patterns were achieved among which 11 patterns included at least 2 strains. All strains clustered into 25 different clones. The dendrogram analysis of the isolated H. influenzae strains showed that some of these strains had a clonal relationship and common genetic origin. According to our results, antibiotic resistance didn’t show any significant correlation with the clonality of strains.

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A Naturally Occurring Rgg Variant in Serotype M3 Streptococcus pyogenes Does Not Activate speB Expression Due to Altered Specificity of DNA Binding

Infection and Immunity ◽

10.1128/iai.00373-09 ◽

2009 ◽

Vol 77 (12) ◽

pp. 5411-5417 ◽

Cited By ~ 17

Author(s):

Kyle V. Kappeler ◽

Srivishnupriya Anbalagan ◽

Alexander V. Dmitriev ◽

Emily J. McDowell ◽

Melody N. Neely ◽

...

Keyword(s):

Amino Acid ◽

Streptococcus Pyogenes ◽

Murine Model ◽

Cysteine Protease ◽

Phenotypic Diversity ◽

Transcriptional Regulator ◽

Amino Acid Position ◽

Invasive Disease ◽

Naturally Occurring

ABSTRACT The transcriptional regulator Rgg of Streptococcus pyogenes is essential for expression of the secreted cysteine protease SpeB. Although all isolates of S. pyogenes possess the speB gene, not all of them produce the protein in vitro. In a murine model of infection, the absence of SpeB production is associated with invasive disease. We speculated that naturally occurring mutations in rgg, which would also abrogate SpeB production, may be present in invasive isolates of S. pyogenes. Examination of the inferred Rgg sequences available in public databases revealed that the rgg gene in strain MGAS315 (a serotype M3 strain associated with invasive disease) encodes a proline at amino acid position 103 (Rgg103P); in contrast, all other strains encode a serine at this position (Rgg103S). A caseinolytic assay and Western blotting indicated that strain MGAS315 does not produce SpeB in vitro. Gene-swapping experiments showed that the rgg gene of MGAS315 is solely responsible for the lack of SpeB expression. In contrast to Rgg103S, Rgg103P does not bind to the speB promoter in gel shift assays, which correlates with a lack of speB expression. Despite its inability to activate speB expression, Rgg103P retains the ability to bind to DNA upstream of norA and to influence its expression. Overall, this study illustrates how variation at the rgg locus may contribute to the phenotypic diversity of S. pyogenes.

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Transcription of the Streptococcus pyogenes Hyaluronic Acid Capsule Biosynthesis Operon Is Regulated by Previously Unknown Upstream Elements

Infection and Immunity ◽

10.1128/iai.02035-14 ◽

2014 ◽

Vol 82 (12) ◽

pp. 5293-5307 ◽

Cited By ~ 19

Author(s):

Marina Falaleeva ◽

Oliwia W. Zurek ◽

Robert L. Watkins ◽

Robert W. Reed ◽

Hadeel Ali ◽

...

Keyword(s):

Hyaluronic Acid ◽

Streptococcus Pyogenes ◽

Regulatory Region ◽

Regulatory System ◽

Invasive Disease ◽

Negative Regulator ◽

Mobility Shift ◽

Putative Promoter ◽

Transcriptional Terminator ◽

Content Type

ABSTRACTThe important human pathogenStreptococcus pyogenes(group AStreptococcus[GAS]) produces a hyaluronic acid (HA) capsule that plays critical roles in immune evasion. Previous studies showed that thehasABCoperon encoding the capsule biosynthesis enzymes is under the control of a single promoter, P1, which is negatively regulated by the two-component regulatory system CovR/S. In this work, we characterize the sequence upstream of P1 and identify a novel regulatory region controlling transcription of the capsule biosynthesis operon in the M1 serotype strain MGAS2221. This region consists of a promoter, P2, which initiates transcription of a novel small RNA, HasS, an intrinsic transcriptional terminator that inefficiently terminates HasS, permitting read-through transcription ofhasABC, and a putative promoter which lies upstream of P2. Electrophoretic mobility shift assays, quantitative reverse transcription-PCR, and transcriptional reporter data identified CovR as a negative regulator of P2. We found that the P1 and P2 promoters are completely repressed by CovR, and capsule expression is regulated by the putative promoter upstream of P2. Deletion ofhasSor of the terminator eliminates CovR-binding sequences, relieving repression and increasing read-through,hasAtranscription, and capsule production. Sequence analysis of 44 GAS genomes revealed a high level of polymorphism in the HasS sequence region. Most of the HasS variations were located in the terminator sequences, suggesting that this region is under strong selective pressure. We discovered that the terminator deletion mutant is highly resistant to neutrophil-mediated killing and is significantly more virulent in a mouse model of GAS invasive disease than the wild-type strain. Together, these results are consistent with the naturally occurring mutations in this region modulating GAS virulence.

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Molecular characterization of fourHaemophilus influenzaeserotype a strains isolated from patients in Quebec, Canada

Canadian Journal of Microbiology ◽

10.1139/w07-088 ◽

2007 ◽

Vol 53 (10) ◽

pp. 1191-1194 ◽

Cited By ~ 7

Author(s):

Michelle L. Sill ◽

Jianwei Zhou ◽

Dennis K.S. Law ◽

Manon Lorange ◽

Louise Ringuette ◽

...

Keyword(s):

Genetic Diversity ◽

Invasive Disease ◽

Sequence Type ◽

The Other ◽

Division I ◽

Common Allele ◽

Dna Fingerprints ◽

Partial Deletion ◽

Superoxide Dismutase Gene

Four epidemiologically unrelated Haemophilus influenzae serotype a (Hia) strains from patients in Quebec, Canada, were characterized and found to represent 3 distinct groups. One isolate, found to be biotype I and sequence type (ST)-62 by multilocus sequence typing, was shown to possess the copper- and zinc-containing superoxide dismutase gene, sodC, and was suspected to belong to clonal division II. The other 3 isolates were classified as clonal division I based on the absence of the sodC gene. Among the 3 sodC-negative Hia strains, 2 were biotype II and had related STs (ST-23 and ST-403) and highly similar DNA fingerprints, similar to a group of previously described Hia isolates causing invasive disease in Manitoba, Canada. The remaining sodC-negative strain belonged to biotype I and ST-4 and shared no common allele with ST-23, ST-403, or ST-62. This isolate also possessed the IS1016-bexA partial deletion, which is often associated with increased virulence. Despite the small number of isolates used in this study, our finding of 3 distinct groups shows the existence of a potential genetic diversity not previously described for Hia. Whether this genetic diversity is related to the severity and epidemiology of Hia disease requires further studies.

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Impact of immunization against SpyCEP during invasive disease with two streptococcal species: Streptococcus pyogenes and Streptococcus equi

Vaccine ◽

10.1016/j.vaccine.2009.06.042 ◽

2009 ◽

Vol 27 (36) ◽

pp. 4923-4929 ◽

Cited By ~ 47

Author(s):

Claire E. Turner ◽

Prathiba Kurupati ◽

Siouxsie Wiles ◽

Robert J. Edwards ◽

Shiranee Sriskandan

Keyword(s):

Streptococcus Pyogenes ◽

Invasive Disease ◽

Streptococcus Equi ◽

Streptococcal Species

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The M1 Protein of Streptococcus pyogenes Triggers an Innate Uptake Mechanism into Polarized Human Endothelial Cells

Journal of Innate Immunity ◽

10.1159/000358085 ◽

2014 ◽

Vol 6 (5) ◽

pp. 585-596 ◽

Cited By ~ 7

Author(s):

Anja Ochel ◽

Manfred Rohde ◽

Gursharan S. Chhatwal ◽

Susanne R. Talay

Keyword(s):

Endothelial Cells ◽

Streptococcus Pyogenes ◽

Human Endothelial Cells ◽

Uptake Mechanism ◽

M1 Protein

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Streptococcus pyogenes Pharyngeal Isolates with Reduced Susceptibility to Ciprofloxacin in Spain: Mechanisms of Resistance and Clonal Diversity

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.49.1.418-420.2005 ◽

2005 ◽

Vol 49 (1) ◽

pp. 418-420 ◽

Cited By ~ 11

Author(s):

Sebastián Albertí ◽

Guadalupe Cortés ◽

Cesar García-Rey ◽

Carmen Rubio ◽

Fernando Baquero ◽

...

Keyword(s):

Genetic Diversity ◽

Streptococcus Pyogenes ◽

Point Mutations ◽

Clonal Diversity ◽

Gene Sequences ◽

Mechanisms Of Resistance ◽

Topoisomerase Iv ◽

Subunit C ◽

Pulsed Field ◽

Ciprofloxacin Resistance

ABSTRACT A survey of emm gene sequences and an analysis of the pulsed-field electrophoretic profiles of 30 Streptococcus pyogenes isolates with reduced susceptibilities to ciprofloxacin detected the prevalence of isolates with emm type 6 and considerable genetic diversity among isolates. The mechanism of ciprofloxacin resistance in these isolates was based on point mutations in topoisomerase IV subunit C encoded by parC, mainly replacement of serine-79 by alanine.

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