Pneumococcal serotype determines growth and capsule size in human cerebrospinal fluid

Abstract

Background: The polysaccharide capsule is a major virulence factor of S. pneumoniae in diseases such as meningitis. While some capsular serotypes are more often found in invasive disease, high case fatality rates are associated with those serotypes more commonly found in asymptomatic colonization. We tested whether growth patterns and capsule size in human cerebrospinal fluid depends on serotype using a clinical isolate of S. pneumoniae and its capsule switch mutants. Results: We found that the growth pattern differed markedly from that in culture medium by lacking the exponential and lysis phases. Growth in human cerebrospinal fluid was reduced when strains lost their capsules. When a capsule was present, growth was serotype-specific: high carriage serotypes (6B, 9 V, 19F and 23F) grew better than low carriage serotypes (7F, 14, 15B/C and 18C). Growth correlated with the case-fatality rates of serotypes reported in the literature. Capsule size in human cerebrospinal fluid also depended on serotype. Conclusions: We propose that serotype-specific differences in disease severity observed in meningitis patients may, at least in part, be explained by differences in growth and capsule size in human cerebrospinal fluid. This information could be useful to guide future vaccine design.

Habitat Elevation Shapes Microbial Community Composition and Alter the Metabolic Functions in Wild Sable (Martes zibellina) Guts

“…These findings led us to accept our second hypothesis, which was consistent with consistent with previous studies. For example, the ability for energy metabolism and fermentation of polysaccharides in house mice gut microbiota was enhanced with increased elevation [ 54 ], and gut microbiota of rhesus macaques living at higher altitudes had higher expression of genes related to energy metabolism and lipid metabolism [ 34 ]. A possible interpretation is that altitude usually affects other environmental factors such as temperature, oxygen levels, ultraviolet radiation, wind, etc., and it also affects biological factors such as vegetation type, canopy density and concealment level, which in turn affected the physiological characteristics of wild animals [ 64 ].…”

“…Some studies illustrate that interactions between physiological characteristics and the intestinal metagenome function of an individual are attributed to bacterial community diversity or some specific bacterial groups, e.g., species or functional clusters [ 28 , 29 ]. Previous studies have suggested associations between intestinal metagenome and environmental fluctuation, for example, the gut microbial community changes with habitat fragmentation and degradation [ 30 , 31 , 32 ], altitude [ 33 , 34 ], season [ 35 ], and climate change [ 36 , 37 ] of locations where the hosts live. Cold acclimated laboratory mice experience a dramatic change in gut microbiota composition as temperature increases [ 21 ].…”

Serotype-Dependent Inhibition of Streptococcus pneumoniae Growth by Short-Chain Fatty Acids

“…Next, the physical properties of CPS, such as thickness and density, potentially provide protection. Serotypes 3 and 7F, associated with invasive disease, have well-preserved, dense, thick capsules [ 38 - 40 ]. We found that serotypes 3 and 7F were the most resistant serotypes against SCFAs.…”

Klebsiella pneumoniae peptide hijacks a Streptococcus pneumoniae permease to subvert pneumococcal growth and colonization

“…Growth assays were done as described previously 16 and plotted in R with error bars representing SEM of 3 independent biological replicates. For growth in hCSF, bacteria were inoculated as described elsewhere 55 with twice the inoculum in PBS compared to the growth assay in CDM due to anticipated slower growth in hCSF.…”