Comparative genomic and morphological analyses of capsular and capsular-deficient pneumococcal strains simultaneously...

Area of Science:

• Microbiology
• Genomics
• Infectious Diseases

Background:

• Understanding in-vivo dynamics of pneumococci is crucial for invasive pneumococcal disease (IPD) research.
• Investigating pneumococcal carriage in IPD patients provides insights into disease progression.

Purpose of the Study:

• To compare genomic and morphological differences between pneumococcal strains from different sites within an IPD patient.
• To investigate potential in-vivo morphological changes in Streptococcus pneumoniae.

Main Methods:

• Comparative genomic and morphological analysis of two pneumococcal strains (capsular from blood, non-capsular from sputum) from an IPD patient.
• Genomic analysis focused on the wcxK gene and insertion regions.
• Biofilm-forming capacity assessment.
• Transmission electron microscopy for capsule visualization.

Main Results:

• The blood isolate was a capsular serotype 24B strain.
• The sputum isolate was non-encapsulated, with genomic analysis revealing an insertion in the wcxK gene.
• The non-encapsulated strain exhibited higher biofilm-forming capacity compared to the capsular strain.
• Electron microscopy confirmed the absence of a capsule in the sputum isolate.

Conclusions:

• Comparative analysis of Streptococcus pneumoniae strains from blood and sputum of an IPD patient suggests a possible in-vivo morphological change involving capsule loss.
• The non-encapsulated strain's enhanced biofilm formation may play a role in IPD pathogenesis.