Untersuchungen über das gleichzeitige Vorkommen mehrerer Pneumokokkentypen bei Gesunden und ihre Bedeutung für die Epidemiologie

Gündel, М.; Okura, G.

doi:10.1007/bf02183676

Cited by 33 publications

(9 citation statements)

References 4 publications

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“…It is however in line with historical data from studies detecting S. pneumoniae in saliva or in throat washes using a sensitive mouse inoculation method [14]. For example, in a longitudinal study conducted in Germany in 1932, Gundel and Okura [31] reported 66% (471 of 715) saliva samples from teenagers attending sex-segregated schools to be positive for S. pneumoniae with point prevalence up to 85% amongst boys and up to 71% amongst girls. Also, Rosenau et al .…”

Section: Discussionsupporting

confidence: 79%

Streptococcus pneumoniae in Saliva of Dutch Primary School Children

et al. 2014

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While nasopharyngeal sampling is the gold standard for the detection of Streptococcus pneumoniae carriage, historically seen, saliva sampling also seems highly sensitive for pneumococcal detection. We investigated S. pneumoniae carriage in saliva from fifty schoolchildren by conventional and molecular methods. Saliva was first culture-enriched for pneumococci, after which, DNA was extracted from all bacterial growth and tested by quantitative-PCR (qPCR) for pneumococcus-specific genes lytA and piaA. Next, serotype composition of the samples was determined by serotype-specific qPCRs, conventional-PCRs (cPCR) and sequencing of cPCR amplicons. Although only 2 (4%) of 50 samples were positive by conventional diagnostic culture, 44 (88%) were positive for pneumococci by qPCR. In total, we detected the presence of at least 81 pneumococcal strains representing 20 serotypes in samples from 44 carriers with 23 carriers (52%) positive for multiple (up to 6) serotypes. The number of serotypes detected per sample correlated with pneumococcal abundance. This study shows that saliva could be used as a tool for future pneumococcal surveillance studies. Furthermore, high rates of pneumococcal carriage and co-carriage of multiple pneumococcal strains together with a large number of serotypes in circulation suggests a ubiquitous presence of S. pneumoniae in saliva of school-aged children. Our results also suggest that factors promoting pneumococcal carriage within individual hosts may weaken competitive interactions between S. pneumoniae strains.

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Section: Discussionsupporting

confidence: 79%

Streptococcus pneumoniae in Saliva of Dutch Primary School Children

et al. 2014

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“…Studies in humans have shown that simultaneous carriage of multiple pneumococcal strains is common, with approximately half of carriers among children cocolonized simultaneously with two or more strains of S. pneumoniae ( 21 – 23 ). Carriage of multiple strains is also a necessary condition for these highly recombinogenic bacteria to encounter and incorporate genetic material from other members of the species, providing raw material for evolution ( 24 ).…”

Section: Introductionmentioning

confidence: 99%

Effect of Serotype on Pneumococcal Competition in a Mouse Colonization Model

Trzciński

Weinberger

et al. 2015

mBio

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Competitive interactions between Streptococcus pneumoniae strains during host colonization could influence the serotype distribution in nasopharyngeal carriage and pneumococcal disease. We evaluated the competitive fitness of strains of serotypes 6B, 14, 19A, 19F, 23F, and 35B in a mouse model of multiserotype carriage. Isogenic variants were constructed using clinical strains as the capsule gene donors. Animals were intranasally inoculated with a mixture of up to six pneumococcal strains of different serotypes, with separate experiments involving either clinical isolates or isogenic capsule-switch variants of clinical strain TIGR4. Upper-respiratory-tract samples were repeatedly collected from animals in order to monitor changes in the serotype ratios using quantitative PCR. A reproducible hierarchy of capsular types developed in the airways of mice inoculated with multiple strains. Serotype ranks in this hierarchy were similar among pneumococcal strains of different genetic backgrounds in different strains of mice and were not altered when tested under a range of host conditions. This rank correlated with the measure of the metabolic cost of capsule synthesis and in vitro measure of pneumococcal cell surface charge, both parameters considered to be predictors of serotype-specific fitness in carriage. This study demonstrates the presence of a robust competitive hierarchy of pneumococcal serotypes in vivo that is driven mainly, but not exclusively, by the capsule itself.

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“…Although multiple strains can colonize simultaneously (4,5,(7)(8)(9)(10), most surveillance studies characterize only single colonies-but how valid is this information (12)? Nasopharyngeal swabs capture more pneumococci than throat swabs (1,6,14), but throat swabs can uncover different phenotypes (13,16).…”

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confidence: 99%