Genome Sequence and Comparative Pathogenomics Analysis of a Salmonella enterica Serovar Typhi Strain Associated with a Typhoid Carrier in Malaysia

Yap, Kien-Pong; Gan, Han Ming; Teh, Cindy Shuan Ju; Baddam, Ramani; Chai, Lay Ching; Kumar, Narender; Tiruvayipati, Suma; Ahmed, Niyaz; Thong, Kwai Lin

doi:10.1128/jb.01416-12

Cited by 23 publications

(24 citation statements)

References 27 publications

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“…Epidemiological studies are complicated by the fact that the majority of chronic carriers in endemic settings are asymptomatic [35], and up to 25% have no clinical history of typhoid [36]. Additionally, potential risk factors may be confounded by the fraction of the population with gallbladder abnormalities [37]. For instance, the risk of becoming a chronic carrier following an acute infection increases with age, is greater for women than for men, and is particularly associated with cholelithiasis and cholecystitis [10, 38].…”

Section: Epidemiology and Treatment Of Chronic Carriagementioning

confidence: 99%

Salmonella chronic carriage: epidemiology, diagnosis, and gallbladder persistence

Gunn

Marshall

Baker

et al. 2014

Trends in Microbiology

246

242

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Typhoid (enteric fever) remains a major cause of morbidity and mortality worldwide, causing over 21 million new infections annually, with the majority of deaths occurring in young children. As typhoid fever-causing Salmonella have no known environmental reservoir, the chronic, asymptomatic carrier state is thought to be a key feature of continued maintenance of the bacterium within human populations. In spite of the importance of this disease to public health, our understanding of the molecular mechanisms that catalyze carriage, as well as our ability to reliably identify and treat the Salmonella carrier state, have only recently begun to advance.

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Section: Epidemiology and Treatment Of Chronic Carriagementioning

confidence: 99%

Salmonella chronic carriage: epidemiology, diagnosis, and gallbladder persistence

Gunn

Marshall

Baker

et al. 2014

Trends in Microbiology

246

242

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“…The strain BL196 was associated with a large outbreak in Kelantan, Malaysia in 2005 23 . Strains CR0044 and CR0063 were isolated from carrier individuals in 2007 after an outbreak and were reported to share PFGE profiles with the strain BL196 24 25 . Strain ST0208 was associated with a sporadic case in Kuala Lumpur, Malaysia 26 .…”

mentioning

confidence: 99%

Genome dynamics and evolution of Salmonella Typhi strains from the typhoid-endemic zones

Baddam

Kumar

Shaik

et al. 2014

Sci Rep

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Typhoid fever poses significant burden on healthcare systems in Southeast Asia and other endemic countries. Several epidemiological and genomic studies have attributed pseudogenisation to be the major driving force for the evolution of Salmonella Typhi although its real potential remains elusive. In the present study, we analyzed genomes of S. Typhi from different parts of Southeast Asia and Oceania, comprising of isolates from outbreak, sporadic and carrier cases. The genomes showed high genetic relatedness with limited opportunity for gene acquisition as evident from pan-genome structure. Given that pseudogenisation is an active process in S. Typhi, we further investigated core and pan-genome profiles of functional and pseudogenes separately. We observed a decline in core functional gene content and a significant increase in accessory pseudogene content. Upon functional classification, genes encoding metabolic functions formed a major constituent of pseudogenes as well as core functional gene clusters with SNPs. Further, an in-depth analysis of accessory pseudogene content revealed the existence of heterogeneous complements of functional and pseudogenes among the strains. In addition, these polymorphic genes were also enriched in metabolism related functions. Thus, the study highlights the existence of heterogeneous strains in a population with varying metabolic potential and that S. Typhi possibly resorts to metabolic fine tuning for its adaptation.

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“…The sequence data were assembled de novo in the same way as described previously [40-45] into 538 contigs using Velvet [46] at optimal hash length 39. SSPACE [47] was used for scaffolding the pre-assembled contigs using paired-end data.…”

Section: Methodsmentioning

confidence: 99%

Genome sequencing and analysis of Salmonella enterica serovar Typhi strain CR0063 representing a carrier individual during an outbreak of typhoid fever in Kelantan, Malaysia

et al. 2012

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Salmonella Typhi is a human restricted pathogen with a significant number of individuals as asymptomatic carriers of the bacterium. Salmonella infection can be effectively controlled if a reliable method for identification of these carriers is developed. In this context, the availability of whole genomes of carrier strains through high- throughput sequencing and further downstream analysis by comparative genomics approaches is very promising. Herein we describe the genome sequence of a Salmonella Typhi isolate representing an asymptomatic carrier individual during a prolonged outbreak of typhoid fever in Kelantan, Malaysia. Putative genomic coordinates relevant in pathogenesis and persistence of this carrier strain are identified and discussed.

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Genome Sequence and Comparative Pathogenomics Analysis of a Salmonella enterica Serovar Typhi Strain Associated with a Typhoid Carrier in Malaysia

Cited by 23 publications

References 27 publications

Salmonella chronic carriage: epidemiology, diagnosis, and gallbladder persistence

Salmonella chronic carriage: epidemiology, diagnosis, and gallbladder persistence

Genome dynamics and evolution of Salmonella Typhi strains from the typhoid-endemic zones

Genome sequencing and analysis of Salmonella enterica serovar Typhi strain CR0063 representing a carrier individual during an outbreak of typhoid fever in Kelantan, Malaysia

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