The advent of pneumococcal conjugate vaccines led to the near disappearance of most of the included serotypes in high-income settings but also the rise of nonvaccine-type colonization and disease.... Show moreThe advent of pneumococcal conjugate vaccines led to the near disappearance of most of the included serotypes in high-income settings but also the rise of nonvaccine-type colonization and disease. Alternative strategies, using genetically conserved proteins as antigens, have been evaluated preclinically and clinically for years, so far unsuccessfully. One possible explanation for the failure of these efforts is that the choice of antigens may not have been sufficiently guided by an understanding of the gene expression pattern in the context of infection. Here, we present a targeted transcriptomic analysis of 160 pneumococcal genes encoding bacterial surface-exposed proteins in mouse models, human colonization, and human meningitis. We present the overlap of these different transcriptomic profiles. We identify two bacterial genes that are highly expressed in the context of mouse and human infection: SP_0282, an IID component of a mannose phosphotransferase system (PTS), and SP_1739, encoding RNase Y. We show that these two proteins can confer protection against pneumococcal nasopharyngeal colonization and intraperitoneal challenge in a murine model and generate opsonophagocytic antibodies. This study emphasizes and confirms the importance of studies of pneumococcal gene expression of bacterial surface proteins during human infection and colonization and may pave the way for the selection of a protein-based vaccine candidate. Show less
Colonization of the upper respiratory tract with Streptococcus pneumoniae is the precursor of pneumococcal pneumonia and invasive disease. Following exposure, however, it is unclear which human... Show moreColonization of the upper respiratory tract with Streptococcus pneumoniae is the precursor of pneumococcal pneumonia and invasive disease. Following exposure, however, it is unclear which human immune mechanisms determine whether a pathogen will colonize. We used a human challenge model to investigate host-pathogen interactions in the first hours and days following intranasal exposure to Streptococcus pneumoniae. Using a novel home sampling method, we measured early immune responses and bacterial density dynamics in the nose and saliva after volunteers were experimentally exposed to pneumococcus. Here, we show that nasal colonization can take up to 24 h to become established. Also, the following two distinct bacterial clearance profiles were associated with protection: nasal clearers with immediate clearance of bacteria in the nose by the activity of pre-existent mucosal neutrophils and saliva clearers with detectable pneumococcus in saliva at 1 h post challenge and delayed clearance mediated by an inflammatory response and increased neutrophil activity 24 h post bacterial encounter. This study describes, for the first time, how colonization with a bacterium is established in humans, signifying that the correlates of protection against pneumococcal colonization, which can be used to inform design and testing of novel vaccine candidates, could be valid for subsets of protected individuals.IMPORTANCE Occurrence of lower respiratory tract infections requires prior colonization of the upper respiratory tract with a pathogen. Most bacterial infection and colonization studies have been performed in murine and in vitro models due to the current invasive sampling methodology of the upper respiratory tract, both of which poorly reflect the complexity of host-pathogen interactions in the human nose. Self-collecting saliva and nasal lining fluid at home is a fast, low-cost, noninvasive, highfrequency sampling platform for continuous monitoring of bacterial encounter at defined time points relative to exposure. Our study demonstrates for the first time that, in humans, there are distinct profiles of pneumococcal colonization kinetics, distinguished by speed of appearance in saliva, local phagocytic function, and acute mucosal inflammatory responses, which may either recruit or activate neutrophils. These data are important for the design and testing of novel vaccine candidates. Show less
Gut microbiota composition in patients with Clostridioides difficile colonization is not well investigated. We aimed to identify bacterial signatures associated with resistance and susceptibility... Show moreGut microbiota composition in patients with Clostridioides difficile colonization is not well investigated. We aimed to identify bacterial signatures associated with resistance and susceptibility to C. difficile colonization (CDC) and infection (CDI). Therefore, gut microbiota composition from patients with CDC (n = 41), with CDI (n = 41), and without CDC (controls, n = 43) was determined through 16S rRNA gene amplicon sequencing. Bacterial diversity was decreased in CDC and CDI patients (p < 0.01). Overall microbiota composition was significantly different between control, CDC, and CDI patients (p = 0.001). Relative abundance of Clostridioides (most likely C. difficile) increased stepwise from controls to CDC and CDI patients. In addition, differential abundance analysis revealed that CDI patients' gut microbiota was characterized by significantly higher relative abundance of Bacteroides and Veillonella than CDC patients and controls. Control patients had significantly higher Eubacterium hallii and Fusicatenibacter abundance than colonized patients. Network analysis indicated that Fusicatenibacter was negatively associated with Clostridioides in CDI patients, while Veillonella was positively associated with Clostridioides in CDC patients. Bacterial microbiota diversity decreased in both CDC and CDI patients, but harbored a distinct microbiota. Eubacterium hallii and Fusicatenibacter may indicate resistance against C. difficile colonization and subsequent infection, while Veillonella may indicate susceptibility to colonization and infection by C. difficile. Show less
Nasopharyngeal colonization of potential respiratory pathogens such as Streptococcus pneumoniae is the major source of transmission and precursor of invasive disease. Swabbing deeply the... Show moreNasopharyngeal colonization of potential respiratory pathogens such as Streptococcus pneumoniae is the major source of transmission and precursor of invasive disease. Swabbing deeply the nasopharynx, which is currently recommended by World Health Organization, provides accurate pneumococcal detection but is unpleasant. We showed that nasal lining fluid filter strips offer equal detection sensitivity. Show less
This paper is about Kete Krachi. It discusses the various historical changes that took place after the area had contact with Germans. The paper points out the profound impact that colonialism had... Show moreThis paper is about Kete Krachi. It discusses the various historical changes that took place after the area had contact with Germans. The paper points out the profound impact that colonialism had on KeteKrachi. The author argues that chieftaincy, boundaries, allegiances trade and agricultural systems were reshaped by colonial policies and institutions under German rule in Kete Krachi. Show less
Tussen 1831 en 1872 wierf Nederland ongeveer 3085 mannen in West-Afrika, grotendeels uit het grondgebied van het huidige Ghana en Burkina Faso, voor de militaire dienst in Nederlands-Indië. De... Show moreTussen 1831 en 1872 wierf Nederland ongeveer 3085 mannen in West-Afrika, grotendeels uit het grondgebied van het huidige Ghana en Burkina Faso, voor de militaire dienst in Nederlands-Indië. De Afrikaanse soldaten werden na hun opleiding op Java ingezet in koloniale expedities op Sumatra, Borneo, Celebes, Bali, Timor en in de Atjeh-oorlog. Met hun Indonesische vrouwen stichtten deze Afrikaanse soldaten kleine Indo-Afrikaanse gemeenschappen in de garnizoenssteden op Java. Hun afstammelingen wonen in Nederland, Ghana en Indonesië en elders op de wereld. Dit boek gaat over de lotgevallen van deze 'Belanda Hitam' (Zwarte Hollanders). Het is een groepsportret, gebaseerd op archiefonderzoek en mondelinge overlevering, dat zich uitstrekt over anderhalve eeuw. [Samenvatting ASC Leiden] Show less
Between 1831 and 1872, the Dutch government recruited 3,000 Africans from the Gold Coast and Ashanti (Ghana) for service in the colonial army in the Netherlands East Indies. The majority of them... Show moreBetween 1831 and 1872, the Dutch government recruited 3,000 Africans from the Gold Coast and Ashanti (Ghana) for service in the colonial army in the Netherlands East Indies. The majority of them were ex-slaves but were promised that their conditions of service would be the same as those of Europeans. With the 'equal treatment' clause, the Dutch government defended itself against British accusations that the recruitment operation amounted to a covert form of slave trading. While this policy made sense in the context of the precolonial relations prevailing in the Gold Coast, its merits were less obvious in the East Indies. The colonial army here was the instrument of empire building but mutinies among African troops stationed on Java and Sumatra caused it to rethink its policy concerning African soldiers. This chapter explores the background to these rebellions. Ref., sum. [Book abstract] Show less
The contributions to this volume commemorating three hundred years of diplomatic relations between Ghana and the Netherlands are grouped under three headings - merchants and merchandise,... Show moreThe contributions to this volume commemorating three hundred years of diplomatic relations between Ghana and the Netherlands are grouped under three headings - merchants and merchandise, missionaries, and voluntary and involuntary migrants - reflecting the three most important areas of contact between Dutch and Ghanaians over the centuries. The first part opens with a paper on a mission carried out in 1701-1702 by David van Nyendael, envoy of the Dutch West India Company (WIC), to Kumasi, which forms the starting point for the tercentenary celebrations. It also includes papers on the slave trade, the cocoa trade, and the role of Dutch 'schnapps' in Ghanaian ritual. The contributions on missionary activity deal with the tragic life of Jacobus Capitein (1717-1747), the first black minister stationed in Elmina, and the significance of Pentecostal churches for Ghanaians in the present-day Netherlands. The contributions on migration include stories of individual people who migrated back and forth between the Netherlands and Ghana, such as two Euro-African women from Elmina, as well as chapters on the Ghanaian diaspora, covering Suriname, Indonesia and the Netherlands. The contributions are by Ineke van Kessel, Michel R. Doortmont, Akosua Perbi, Henk den Heijer, Emmanuel Akyeampong, Victor K. Nyanteng, Henri van der Zee, David N.A. Kpobi, Rijk van Dijk, Natalie Everts, Jean Jacques Vrij, Andr‚ R.M. Pakosie, Endri Kusruri and Daniel Kojo Arhinful Show less
Between 1831 and 1872 some 3,000 African recruits sailed from Elmina (Gold Coast, now Ghana) to Batavia, the capital of the Netherlands East Indies. They had been recruited to serve in the Dutch... Show moreBetween 1831 and 1872 some 3,000 African recruits sailed from Elmina (Gold Coast, now Ghana) to Batavia, the capital of the Netherlands East Indies. They had been recruited to serve in the Dutch colonial army, which throughout most of the 19th century experienced a chronic shortage of European manpower. The Africans counted as part of the European contingent of the army. After expiry of their contracts, some Africans returned to the Gold Coast, while others opted to settle in the East Indies. They became the founding fathers of the Indo-African communities in the Javanese towns of Purworedjo, Semarang, Salatiga and Solo. On Java, the African soldiers and their descendants became known as 'Belanda Hitam' - black Dutchmen. This chapter outlines the background to the recruitment of Africans for the Dutch colonial army and describes three phases in the recruitment process: a slow start (1831-1836), a massive influx (1837-1841), and smaller-scale recruitment from the late 1850s onwards. After Indonesia's independence in 1949, most Indo-Africans opted for repatriation to the Netherlands. Bibliogr., ref Show less
This article deals with the partitioning of Central Africa between 1875 and 1885. The first part presents a brief summary of the process and the rivalries between the actors involved, the ensuing... Show moreThis article deals with the partitioning of Central Africa between 1875 and 1885. The first part presents a brief summary of the process and the rivalries between the actors involved, the ensuing territorial conflicts and the diplomacy which led to the treaties between the European powers. The second part discusses thirteen theories, all dealing with the causes of the partition of Africa (or late 19th-century European imperialism in general). The theories are grouped under four headings - economic explanations, political explanations, ‚litist explanations, and explanations rooted in local African circumstances. The author concludes that none of these theories is able to explain why, at the end of the 1870s, a process of European territorial expansion started in Central Africa. However, the theories are useful in explaining the outcome of this imperialistic process. By analysing the processes of European territorial expansion, moreover, political geographers can make a useful contribution to the understanding of late 19th-century imperialism, in particular in those cases where territorial rivalries were involved. Show less
Deze studie beschrijft een politiek-historisch proces en vormt een bijdrage aan de systematische studie van internationale territoriale conflicten vanuit het gezichtspunt van de politieke... Show moreDeze studie beschrijft een politiek-historisch proces en vormt een bijdrage aan de systematische studie van internationale territoriale conflicten vanuit het gezichtspunt van de politieke geografie. Tevens worden aspecten van het Europese imperialisme van de late 19e eeuw nader verklaard. De conflicten tussen Frankrijk en de Association Internationale du Congo (AIC) en tussen Portugal en de AIC over de opdeling van Centraal-Afrika, een proces dat plaatsvond in de periode 1875-1885, dienen als voorbeelden. Het boek bestaat uit drie delen. In deel 1 komen de theoretische en methodologische aspecten aan de orde. Deel 2 bestaat uit de case-study. Hoofdstuk 3 behelst de beleidsbepaling. De hoofdstukken 4, 5 en 6 behandelen de beleidsuitvoering van de factoren die rechtstreeks bij de territoriale conflicten betrokken waren: Leopold II, Frankrijk en Portugal. In hoofdstuk 7 staat de conflictoplossing centraal. Deel 3 bestaat uit ‚‚n hoofdstuk. Eerst wordt nagegaan in hoeverre de theorie‰n van toepassing zijn op dit onderdeel van de opdeling van Afrika. De conclusie is dat ze meer zeggen over de afloop van dit stukje opdelingsgeschiedenis dan over het ontstaan ervan. Die afloop betreft het gehele proces van de opdeling van Centraal-Afrika, en wordt geanalyseerd met behulp van de begrippen en modellen uit hoofdstuk 2. Show less
This book concerns the early years of German colonial rule in Cameroon. It focuses on the North-Western Province. When Cameroon was declared a German protectorate in 1884 a systematic effort was... Show moreThis book concerns the early years of German colonial rule in Cameroon. It focuses on the North-Western Province. When Cameroon was declared a German protectorate in 1884 a systematic effort was made to penetrate the hinterlands and to impose German rule. The gradual penetration was closely monitored by the Governor's office in Buea, and reports on this process were either published in the 'Deutsches Kolonialzeitung' or in 'Das Deutsche Kolonialblatt' (DKB) or in other German papers. The author concentrates on DKB, which for 29 years (1890-1919) covered the events in the German colonies. Part I is the author's analytic assessment of the articles published in DKB on the western Grassfields. It reviews the data on its peoples, the penetration strategies and the effective establishment of the 'Bamenda Bezirk'. Part II concentrates on the Zintgraff years (1889-1892). Zintgraff's move into the region is documented by the DKB. Part III presents the various exploratory and punitive expeditions that were carried out against the so-called 'rebel tribes' from 1901-1913. An annex carries five articles in German. Show less
