Importance of adhesins in the recurrence of pharyngeal infections caused by Streptococcus pyogenes
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Published on: November 16, 2015
Aniela Wozniak1, Natalia Scioscia1, Enrique Geoffroy1
1Laboratorio de Microbiología, Departamento de Laboratorios Clínicos, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
Purpose:
Pharyngo-amygdalitis is the most common infection caused by Streptococcus pyogenes (S. pyogenes). Reinfection with strains of different M types commonly occurs. However, a second infection with a strain of the same M type can still occur and is referred to as recurrence. We aimed to assess whether recurrence of S. pyogenes could be associated to erythromycin resistance, biofilm formation or surface adhesins like fibronectin-binding proteins and pilus proteins, both located in the fibronectin-binding, collagen-binding, T-antigen (FCT) region.
Methodology:
We analyed clinical isolates of S. pyogenes obtained from children with multiple positive cultures of throat swabs. We analysed potential associations between M types, clonal patterns, biofilm production and FCT types with their capacity of producing a recurrent infection. We genetically defined recurrence as an infection with the same M type (same strain) and reinfection as an infection with a different M type.
Results:
No differences were observed between recurrent and reinfection isolates in relation to erythromycin resistance, presence and number of domains of prtF1 gene, and biofilm formation capacity; the only significant difference was the higher frequency of FCT-4 type among recurrent isolates. However, when all the factors that could contribute to recurrence (erythromycin resistance, biofilm production, presence of prtF1 gene and FCT-4 type) were analysed together, we observed that recurrent isolates have a higher number of factors than reinfection isolates.
Conclusions:
Recurrence seems not to be associated with biofilm formation. However, pili and fibronectin-binding proteins could be associated with recurrence because FCT-4 isolates which harbour two fibronectin-binding proteins are more frequent among recurrent isolates.
Insights
Recurrence of Streptococcus pyogenes infections is not linked to biofilm formation but may be associated with fibronectin-binding proteins and pili, particularly the FCT-4 type. This finding helps understand recurrent pharyngo-amygdalitis.
Area of Science:
- Microbiology
- Infectious Diseases
- Genetics
Background:
- Pharyngo-amygdalitis, a common infection caused by Streptococcus pyogenes, can lead to reinfection or recurrence.
- Recurrence involves a subsequent infection by the same M type (strain) of S. pyogenes.
- Understanding factors contributing to recurrence is crucial for managing this common infection.
Purpose of the Study:
- To investigate the association between S. pyogenes recurrence and factors like erythromycin resistance, biofilm formation, and surface adhesins (fibronectin-binding and pilus proteins).
- To differentiate between recurrence (same M type) and reinfection (different M type) in clinical isolates.
Main Methods:
- Analysis of clinical S. pyogenes isolates from children with multiple positive throat swab cultures.
- Assessment of M types, clonal patterns, biofilm production, and fibronectin-binding, collagen-binding, T-antigen (FCT) types.
- Genetic definition of recurrence as infection with the same M type and reinfection as infection with a different M type.
Main Results:
- No significant differences were found in erythromycin resistance, prtF1 gene domains, or biofilm formation between recurrent and reinfection isolates.
- A higher frequency of the FCT-4 type was observed among recurrent S. pyogenes isolates.
- Recurrent isolates, when analyzed collectively for contributing factors, showed a higher number of risk factors compared to reinfection isolates.
Conclusions:
- Biofilm formation does not appear to be a significant factor in S. pyogenes recurrence.
- Pili and fibronectin-binding proteins, particularly within the FCT-4 type, may be associated with S. pyogenes recurrence.
- The FCT-4 type, characterized by the presence of two fibronectin-binding proteins, is more prevalent in recurrent infections.
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