Genetic changes associated with the temporal shift in invasive non-typhoidal Salmonella serovars in Bamako Mali

Bornstein, Kristin; Tennant, Sharon M.; Hazen, Tracy H.; Sorkin, John D.; Tapia, Milagritos D.; Sow, Samba O.; Onwuchekwa, Uma; Levine, Myron M.; Rasko, David A.

doi:10.1371/journal.pntd.0007297

Cited by 5 publications

(6 citation statements)

References 37 publications

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“…All Enteritidis isolates recovered during this period were isolated within the Basse area with similar virulence and antimicrobial resistance patterns. A study in Mali highlighted that, in contrast to Salmonella Typhimurium, iNTS disease caused by Salmonella Enteritidis started to increase from 2008 with the highest peak seen in 2010 and 2011 [ 16 ]. The finding in Mali corresponds with our observed increase in Enteritidis in 2010 and 2011, suggesting the potential combination of a regional increase in Enteritidis exacerbated by the impact of the flood in our setting.…”

Section: Discussionmentioning

confidence: 99%

“…Surveillance in the same location from 2000 to 2004 documented Enteritidis and Typhimurium as the dominant iNTS serovars [ 14 ]. Although shifts in Salmonella serovar prevalence and dominance have been documented in The Gambia and elsewhere in the world [ 14 15 , 16 ], the genomic characteristics and epidemiological factors responsible for this shift are unclear. We used whole genome sequencing and bioinformatic analyses to investigate changes in pathogen characteristics between 2008 and 2016.…”

Section: Introductionmentioning

confidence: 99%

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Invasive atypical non-typhoidal Salmonella serovars in The Gambia

et al. 2021

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Invasive non-typhoidal Salmonella (iNTS) disease continues to be a significant public health problem in sub-Saharan Africa. Common clinical misdiagnosis, antimicrobial resistance, high case fatality and lack of a vaccine make iNTS a priority for global health research. Using whole genome sequence analysis of 164 invasive Salmonella isolates obtained through population-based surveillance between 2008 and 2016, we conducted genomic analysis of the serovars causing invasive Salmonella diseases in rural Gambia. The incidence of iNTS varied over time. The proportion of atypical serovars causing disease increased over time from 40 to 65 % compared to the typical serovars Enteritidis and Typhimurium that decreased from 30 to 12 %. Overall iNTS case fatality was 10%, but case fatality associated with atypical iNTS alone was 10 %. Genetic virulence factors were identified in 14/70 (20 %) typical serovars and 45/68 (66 %) of the atypical serovars and were associated with: invasion, proliferation and/or translocation (Clade A); and host colonization and immune modulation (Clade G). Among Enteritidis isolates, 33/40 were resistant to four or more of the antimicrobials tested, except ciprofloxacin, to which all isolates were susceptible. Resistance was low in Typhimurium isolates, but all 16 isolates were resistant to gentamicin. The increase in incidence and proportion of iNTS disease caused by atypical serovars is concerning. The increased proportion of atypical serovars and the high associated case fatality may be related to acquisition of specific genetic virulence factors. These factors may provide a selective advantage to the atypical serovars. Investigations should be conducted elsewhere in Africa to identify potential changes in the distribution of iNTS serovars and the extent of these virulence elements.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Invasive atypical non-typhoidal Salmonella serovars in The Gambia

et al. 2021

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“…The use of organoids derived from livestock animals like chickens (STm host) and non-human primate or pig could be generated to draw an overview of STm interaction with IECs of various species concerned by STm infection. We also propose that it will be an interesting tool to better understand serovar evolution and switch in population like those observed in Africa ( Feasey et al, 2012 ; Bornstein et al, 2019 ). The organoid technology becoming more sophisticated, the method for quantitative gene expression analysis (RNA-seq) has rapidly been adapted to organoid models and more recently at the single cell level.…”

Section: Discussionmentioning

confidence: 97%

Cross-Talk Between the Intestinal Epithelium and Salmonella Typhimurium

et al. 2022

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Salmonella enterica serovars are invasive gram-negative bacteria, causing a wide range of diseases from gastroenteritis to typhoid fever, representing a public health threat around the world. Salmonella gains access to the intestinal lumen after oral ingestion of contaminated food or water. The crucial initial step to establish infection is the interaction with the intestinal epithelium. Human-adapted serovars such as S. Typhi or S. Paratyphi disseminate to systemic organs and induce life-threatening disease known as typhoid fever, whereas broad-host serovars such as S. Typhimurium usually are limited to the intestine and responsible for gastroenteritis in humans. To overcome intestinal epithelial barrier, Salmonella developed mechanisms to induce cellular invasion, intracellular replication and to face host defence mechanisms. Depending on the serovar and the respective host organism, disease symptoms differ and are linked to the ability of the bacteria to manipulate the epithelial barrier for its own profit and cross the intestinal epithelium.This review will focus on S. Typhimurium (STm). To better understand STm pathogenesis, it is crucial to characterize the crosstalk between STm and the intestinal epithelium and decipher the mechanisms and epithelial cell types involved. Thus, the purpose of this review is to summarize our current knowledge on the molecular dialogue between STm and the various cell types constituting the intestinal epithelium with a focus on the mechanisms developed by STm to cross the intestinal epithelium and access to subepithelial or systemic sites and survive host defense mechanisms.

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“…Outbreaks of Salmonella Enteritidis as a result of consumption of contaminated food or animal products have been reported elsewhere 44 . Although this theory could be true, a study in Mali highlighted that, in contrast to Salmonella Typhimurium, iNTS disease caused by Salmonella Enteritidis started to increase from 2008 with the highest peak seen in 2010 and 2011 16 . The finding in Mali corresponds with our observed increase in Enteritidis in 2010 and 2011 suggesting the potential combination of a regional increase in Enteritidis exacerbated by the impact of the flood in our setting.…”

Section: Discussionmentioning

confidence: 99%

“…Surveillance in the same location from 2000 to 2004 documented Enteritidis and Typhimurium as the dominant iNTS serovars 14 . Although shifts in Salmonella serovar prevalence and dominance have been documented in The Gambia and elsewhere in the world 14,15,16 , the genomic characteristics and epidemiological factors responsible for this shift are unclear. We used whole genome sequencing and bioinformatic analyses to investigate changes in pathogen characteristics between 2008 and 2016.…”

Section: Introductionmentioning

confidence: 99%

Invasive atypical non-typhoidalSalmonellaserovars in The Gambia

Kanteh

Sesay

Alikhan

et al. 2021

Preprint

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Background Invasive non-typhoidal Salmonella (iNTS) disease continues to be a significant public health problem in sub-Saharan Africa. Common clinical misdiagnosis, frequent antimicrobial resistance, high case fatality, and lack of a vaccine make iNTS a priority for global health research. Consequently, we conducted a detailed genomic analysis of the different serovars causing invasive Salmonella diseases in rural Gambia by performing whole genome sequence analysis on 164 invasive Salmonella isolates obtained between 2008 and 2016. Results Overall, we observed changes in the incidence of invasive Salmonella disease over time and an increase in the proportion of atypical serovars causing invasive disease to 40% - 65%, relative to serovars Enteritidis and Typhimurium. Overall case fatality was rate of 10% while atypical iNTS was associated with 40% case fatality. Previously undetected genetic virulence factors, xxx, yyy, and zzz, were identified in two clades (Clade A and G), in n/N (%) of the atypical serovars. Conclusion The increase in the proportion of iNTS disease caused by atypical serovars and the high associated case fatality may be related to acquisition of specific genetic virulence factors. These factors may provide a a selective advantage to these atypical serovars. Investigations should be conducted to determine potential changes in the distribution iNTS serovars elsewhere in Africa and the extent of these virulence elements.

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Genetic changes associated with the temporal shift in invasive non-typhoidal Salmonella serovars in Bamako Mali

Cited by 5 publications

References 37 publications

Invasive atypical non-typhoidal Salmonella serovars in The Gambia

Invasive atypical non-typhoidal Salmonella serovars in The Gambia

Cross-Talk Between the Intestinal Epithelium and Salmonella Typhimurium

Invasive atypical non-typhoidalSalmonellaserovars in The Gambia

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