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Serotype 19A strains have emerged as a cause of invasive pneumococcal disease after the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7), and serotype 19A has now been included in the recent 13-valent vaccine (PCV13). Genetic analysis has revealed at least three different capsular serotype 19A subtypes, and nutritional environment-dependent variation of the 19A capsule structure has been reported. Pneumococcal vaccine effectiveness and serotyping accuracy might be impaired by structural differences in serotype 19A capsules. We therefore analyzed the distribution of 19A subtypes collected within a Swiss national surveillance program and determined capsule composition under different nutritional conditions with high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR) spectroscopy. After the introduction of PCV7, a significant relative increase of subtype 19A-II and decrease of 19A-I occurred. Chemical analyses showed no difference in the composition as well as the linkage of 19A subtype capsular saccharides grown in defined and undefined growth media, which is consistent with a trisaccharide repeat unit composed of rhamnose, N -acetyl-mannosamine, and glucose. In summary, our study suggests that no structural variance dependent of the nutritional environment or the subtype exists. The serotype 19A subtype shift observed after the introduction of the PCV7 can therefore not be explained by selection of a capsule structure variant. However, capsule composition analysis of emerging 19A clones is recommended in cases where there is no other explanation for a selective advantage, such as antibiotic resistance or loss or acquisition of other virulence factors.

Consacrer un numéro de Tréma au discours sur la guerre dans les manuels scolaires et dans l’enseignement, c’est saisir l’occasion de croiser l’étude d’un sujet d’historiographie très contemporaine, aux multiples enjeux intellectuels et idéologiques, avec un travail de réflexion sur le manuel scolaire en tant qu’objet de recherche. La guerre tient en effet une place importante dans l’histoire des peuples et des nations, elle en constitue souvent un point d’ancrage mémoriel fort, parfois même l...

Heteroresistance to β-lactam antibiotics has been mainly described for staphylococci, for which it complicates diagnostic procedures and therapeutic success. This study investigated whether heteroresistance to penicillin exists in Streptococcus pneumoniae . Population analysis profile (PAP) showed the presence of subpopulations with higher penicillin resistance in four of nine clinical pneumococcal strains obtained from a local surveillance program (representing the multiresistant clones ST179, ST276, and ST344) and in seven of 16 reference strains (representing the international clones Spain 23F -1, Spain 9V -3, Spain 14 -5, Hungary 19A -6, South Africa 19A -13, Taiwan 23F -15, and Finland 6B -12). Heteroresistant strains had penicillin minimal inhibitory concentrations (MICs) (for the majority of cells) in the intermediate- to high-level range (0.19–2.0 μg/ml). PAP curves suggested the presence of subpopulations also for the highly penicillin-resistant strains Taiwan 19F -14, Poland 23F -16, CSR 19A -11, and CSR 14 -10. PAP of bacterial subpopulations with higher penicillin resistance showed a shift toward higher penicillin-resistance levels, which reverted upon multiple passages on antibiotic-free media. Convergence to a homotypic resistance phenotype did not occur. Comparison of two strains of clone ST179 showed a correlation between the heteroresistant phenotype and a higher-penicillin MIC and a greater number of altered penicillin-binding proteins (PBP1a, -2b, and -2x), respectively. Therefore, heteroresistance to penicillin occurs in international multiresistant clones of S. pneumoniae . Pneumococci may use heteroresistance to penicillin as a tool during their evolution to high penicillin resistance, because it gives the bacteria an opportunity to explore growth in the presence of antibiotics before acquisition of resistance genes.

O manual escolar se constitui em um objeto cultural complexo e é, de fato, um significativo suporte de representações sociais. Sua elaboração se dá no cruzamento de lógicas institucionais, científicas, didáticas e editoriais. Este artigo tem como tema central as representações da Guerra Fria nos manuais escolares franceses de história e geografia, utilizados no ensino secundário entre os anos de 1959 a 2006, e foi desenvolvido a partir de um método que mescla abordagens quantitativas e qualitativas. Em nosso estudo, pudemos constatar que os manuais são cada vez mais ilustrados, e as imagens, assim como o texto que estrutura a lição, propõem uma narrativa articulada em torno da noção central de "partilha do mundo", na qual se encarnam os personagens, os acontecimentos, mas também as noções e os conceitos históricos. Essas imagens, fartamente divulgadas, funcionam igualmente em rede, uma vez que, na imprensa escrita quotidiana, veiculam muito mais uma memória coletiva do que um saber histórico. A textbook is a complex object at crossroad of different approaches, institutional, scientific, didactical, editorial, which all take part in its conception. In fact, the texbook is genuine bedrock for social representations that can be scrutinized using quantitative and qualitative methods. This paper analyses the representations of the Cold war in French history and geography textbooks for secondary education, published from 1959 to 2006. We show that textbooks are more and more illustrated through years. The pictures, as well as the texts of the lesson, provide a narrative based on the central notion of "the division of the World" embodies in characters, events and historical concepts as well. These pictures act as a network, exactly as they do in the daily press, and therefore they convey a collective memory rather than a historical knowledge.

The polysaccharide capsule of Streptococcus pneumoniae defines over ninety serotypes, which differ in their carriage prevalence and invasiveness for poorly understood reasons. Recently, an inverse correlation between carriage prevalence and oligosaccharide structure of a given capsule has been described. Our previous work suggested a link between serotype and growth in vitro. Here we investigate whether capsule production interferes with growth in vitro and whether this predicts carriage prevalence in vivo. Eighty-one capsule switch mutants were constructed representing nine different serotypes, five of low (4, 7F, 14, 15, 18C) and four of high carriage prevalence (6B, 9V, 19F, 23F). Growth (length of lag phase, maximum optical density) of wildtype strains, nontypeable mutants and capsule switch mutants was studied in nutrient-restricted Lacks medium (MLM) and in rich undefined brain heart infusion broth supplemented with 5% foetal calf serum (BHI+FCS). In MLM growth phenotype depended on, and was transferred with, capsule operon type. Colonization efficiency of mouse nasopharynx also depended on, and was transferred with, capsule operon type. Capsule production interfered with growth, which correlated inversely with serotype-specific carriage prevalence. Serotypes with better growth and higher carriage prevalence produced thicker capsules (by electron microscopy, FITC-dextran exclusion assays and HPLC) than serotypes with delayed growth and low carriage prevalence. However, expression of cpsA, the first capsule gene, (by quantitative RT-PCR) correlated inversely with capsule thickness. Energy spent for capsule production (incorporation of H3-glucose) relative to amount of capsule produced was higher for serotypes with low carriage prevalence. Experiments in BHI+FCS showed overall better bacterial growth and more capsule production than growth in MLM and differences between serotypes were no longer apparent. Production of polysaccharide capsule in S. pneumoniae interferes with growth in nutrient-limiting conditions probably by competition for energy against the central metabolism. Serotype-specific nasopharyngeal carriage prevalence in vivo is predicted by the growth phenotype., Author Summary Streptococcus pneumoniae bacteria are responsible for serious human infections including meningitis, pneumonia and bacteraemia and are a common cause of otitis media (ear infection) in children. However, they most often reside harmlessly in the infant nasopharynx. An association has long been observed between the type of polysaccharide capsule surrounding the bacteria and harmless colonization versus invasive disease. Here we suggest that capsule types that are costly for the bacteria to make are produced in lower quantities and their production limits the growth of the bacteria in nutrient-restricted conditions. In contrast, bacteria with capsules that require less energy can produce more capsule and grow more successfully. This may be an explanation for why S. pneumoniae with certain capsule types can be effective long-term colonizers of the nasopharynx while others need a richer nutritional environment to flourish and so are most often associated with invasive disease. This information may be of use when considering which capsules types to target in future vaccines.

Depuis les années soixante, la Guerre Froide tient une place de choix, dans les programmes et les manuels français de terminale et de troisième. Non seulement parce que les événements du conflit Est - Ouest ont fortement marqué l’histoire (et les consciences) du second XXe siècle, mais aussi parce que le discours sur la Guerre Froide tend à recomposer une image du Monde et de l’Europe. Par le moyen d’un véritable réseau d’images, ce discours renvoie à la notion centrale de « partage du monde » et met en jeu la question de l’identité de la France et de l’Europe. Since the sixties, the Cold War takes a prominent place in the French secondary textbooks. Not only because of the importance of this the conflict in the history (and the minds) of the last XXth century, but also because the speech on the Cold War builds an image of the world and of Europe. Around the topic of the « division of the world », and by the mean of a web of images, this speech asks the question of French and European identity.

Resume Cette etude, melant approches quantitative et qualitative, porte sur 97 manuels – 60 manuels de terminale et 37 manuels de troisieme – des annees Soixante a nos jours. Le manuel scolaire, support didactique privilegie, est egalement un objet culturel complexe, porteur d’un veritable reseau de representations, qui s’expriment par le « texte-auteur », les documents de reference mais egalement par la presence aujourd’hui massive de l’iconographie. Parmi les nombreuses images de la Guerre Froide, celles du couple americano-sovietique (les « Deux Grands »), de meme que leur mise en scene, revelent le systeme de representations de la Guerre Froide vehicule par ces manuels. Si les partenaires changent, il s’agit bien toujours du meme « couple americano-sovietique ». Au gre des evenements et du renouvellement des concepts, l’image de ce couple revet des dimensions differentes (le conflit ideologique pour Kennedy et Khrouchtchev, le « condominium » pour Nixon et Brejnev, la crainte du « chaos » mondial pour Reagan et Gorbatchev), mais celles-ci coexistent et presentent autant de facettes du meme phenomene : le partage du monde, theme central des representations de la Guerre Froide dans les manuels.