Proteomic variation and diversity in clinical Streptococcus pneumoniae isolates from invasive and non-invasive sites

Abstract

Streptococcus pneumoniae is responsible for a variety of invasive and non-invasive human infections. There are over 90 serotypes of S. pneumoniae differing in their ability to adapt to the different niches within the host. Two-dimensional gel electrophoresis was used to discriminate clinical S. pneumoniae isolates recovered from either blood cultures (invasive site isolates) or other sites, including sputum, tracheal aspirate, ear, eye and skin swabs (non-invasive site isolates). Global protein expression profiles for five invasive site and six non-invasive site isolates representing five different serotypes (serotypes 4, 6, 9, 14 and 23) were obtained for each isolate and combined into a single data set using Progenesis SameSpots™ software. One-hundred and eighty six protein spots (39% of the protein spots in the dataset) differed significantly (ANOVA, p<0.05) in abundance between the invasive site (101 upregulated protein spots) and non-invasive site (85 upregulated protein spots) isolates. Correlations between the bacterial proteomes and their sites of isolation were determined by Principal Component Analysis (PCA) using the significantly different protein spots. Out of the 186 variable protein spots, 105 exhibited a serotype-associated pattern of variability. The expression of the remaining 81 protein spots was concluded to be uniquely linked to the site of bacterial isolation. Mass spectrometry was used to identify selected protein spots that showed either constant or differential abundance levels. The identified proteins had a diverse range of functions including, capsule biogenesis, DNA repair, protein deglycation, translation, stress response and virulence as well as amino acid, carbohydrate, lipid and nucleotide metabolism. These findings provide insight on the proteins that contribute towards the adaptation of the bacteria to different sites within the host.

Exploring metal availability in the natural niche of Streptococcus pneumoniae to discover potential vaccine antigens

“…The importance of transition metals in the physiology of S. pneumoniae, as shown previously, was confirmed by our whole cell proteomics data [13,16]. In accordance with the literature, the PCA analysis in this study showed that different strains, with differences in serotype and genetic background, have unique proteomic profiles [51]. Nevertheless, the two serotypes examined in the current study responded similarly to differences in metal availability.…”

Global transcriptional responses of pneumococcus to human blood components and cerebrospinal fluid

“…In combination with a transcriptional analysis, this could reveal potential post-transcriptional regulatory mechanism important for host-niche adaptation, not discovered by a transcriptional analysis alone. Currently, a limited number of studies have investigated the proteome of pneumococci in response to invasive niches conditions ( Bae et al, 2006 ; Bittaye et al, 2017 ).…”

Adaptive response of neonatal sepsis-derived Group B Streptococcus to bilirubin

“…The bacterial cells were pelleted from the culture media by centrifugation at 2500 × g for 10 min and washed with sterile water, to lyse blood cells, then with sterile PBS. Preparation of protein extracts and analysis by 2D gel electrophoresis was undertaken within the University of Aberdeen Proteomics facility following protocols described previously 17 .…”