Topic
Salmonella typhi
About: Salmonella typhi is a research topic. Over the lifetime, 4549 publications have been published within this topic receiving 96464 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: The genome sequence is sequenced of a S. typhi (CT18) that is resistant to multiple drugs, revealing the presence of hundreds of insertions and deletions compared with the Escherichia coli genome, ranging in size from single genes to large islands.
Abstract: Salmonella enterica serovar Typhi (S. typhi) is the aetiological agent of typhoid fever, a serious invasive bacterial disease of humans with an annual global burden of approximately 16 million cases, leading to 600,000 fatalities. Many S. enterica serovars actively invade the mucosal surface of the intestine but are normally contained in healthy individuals by the local immune defence mechanisms. However, S. typhi has evolved the ability to spread to the deeper tissues of humans, including liver, spleen and bone marrow. Here we have sequenced the 4,809,037-base pair (bp) genome of a S. typhi (CT18) that is resistant to multiple drugs, revealing the presence of hundreds of insertions and deletions compared with the Escherichia coli genome, ranging in size from single genes to large islands. Notably, the genome sequence identifies over two hundred pseudogenes, several corresponding to genes that are known to contribute to virulence in Salmonella typhimurium. This genetic degradation may contribute to the human-restricted host range for S. typhi. CT18 harbours a 218,150-bp multiple-drug-resistance incH1 plasmid (pHCM1), and a 106,516-bp cryptic plasmid (pHCM2), which shows recent common ancestry with a virulence plasmid of Yersinia pestis.
1,211 citations
TL;DR: Results obtained with Salmonella typhimurium and the mouse as a model for human typhoid fever indicated that this mutant has the potential for use as a live, oral typhoid vaccine.
Abstract: A gal E mutant of Salmonella typhi was isolated; results obtained with Salmonella typhimurium and the mouse as a model for human typhoid fever indicated that this mutant has the potential for use as a live, oral typhoid vaccine. The mutant, Ty 21a, took up galactose from exogenous sources and accumulated sufficient quantities of galactose-1-phosphate and uridine diphosphate galactose to cause lysis of the cells, an event that resulted in the avirulence of the strain. Galactose was incorporated sufficiently into the cell wall of Ty 21a to allow the synthesis of smooth-type lipopolysaccharides, which are necessary for the proper immunogenicity. Cells of strain Ty 21a, when given intraperitoneally, protected mice against lethal challenge with strain Ty 2 of S. typhi.
517 citations
TL;DR: A phage-typing scheme for S. enteritidis is described and to date differentiates 27 types using 10 typing phages.
Abstract: For many years phage typing has proved invaluable in epidemiological studies on Salmonella typhi, S. paratyphi A and B, S. typhimurium and a few other serotypes. A phage-typing scheme for S. enteritidis is described. This scheme to date differentiates 27 types using 10 typing phages.
497 citations
TL;DR: The observed patterns of genetic isolation and drift are consistent with the proposed key role of asymptomatic carriers of Typhi as the main reservoir of this pathogen, highlighting the need for identification and treatment of carriers.
Abstract: Isolates of Salmonella enterica serovar Typhi (Typhi), a human-restricted bacterial pathogen that causes typhoid, show limited genetic variation. We generated whole-genome sequences for 19 Typhi isolates using 454 (Roche) and Solexa (Illumina) technologies. Isolates, including the previously sequenced CT18 and Ty2 isolates, were selected to represent major nodes in the phylogenetic tree. Comparative analysis showed little evidence of purifying selection, antigenic variation or recombination between isolates. Rather, evolution in the Typhi population seems to be characterized by ongoing loss of gene function, consistent with a small effective population size. The lack of evidence for antigenic variation driven by immune selection is in contrast to strong adaptive selection for mutations conferring antibiotic resistance in Typhi. The observed patterns of genetic isolation and drift are consistent with the proposed key role of asymptomatic carriers of Typhi as the main reservoir of this pathogen, highlighting the need for identification and treatment of carriers.
478 citations
TL;DR: The correlation of certain salmonella types with particular outbreaks will aid the epidemiologist in breaking chains of transmission and in preventing further spread.
Abstract: THE correlation of the numerous salmonella types with the clinical data on the infections that they cause is as important to the clinician as it is to the epidemiologist The knowledge that certain types produce a particular clinical syndrome (typhoidal, septicemic, focal, gastroenteric or carrier condition) more frequently than other types will help the clinician in his diagnosis, prognosis and therapy The correlation of certain salmonella types with particular outbreaks will aid the epidemiologist in breaking chains of transmission and in preventing further spread There is a wealth of literature on the clinical aspects of infections with Salmonella typhi and
465 citations