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Shigella Diversity and Changing Landscape: Insights for the Twenty-First Century.

Anderson M, Sansonetti PJ, Marteyn BS - Front Cell Infect Microbiol (2016)

Bottom Line: Shigella is a pathovar of Escherichia coli comprising four groups, Shigella flexneri, Shigella sonnei, Shigella dysenteriae, and Shigella boydii, each of them, with the exception of S.sonnei, comprising several serotypes.Host-cell invasion is the final step of the infection process, as Shigella's virulence strategy relies also on its ability to survive hostile conditions during its journey through the gastro-intestinal tract, to compete with the host microbiota and to cross the intestinal mucus layer.The recent development of high-throughput screening and sequencing methods will facilitate these complex comparison studies.

View Article: PubMed Central - PubMed

Affiliation: Institut Pasteur, Unité de Pathogénie Microbienne MoléculaireParis, France; Institut National de la Santé et de la Recherche Médicale, Unité 786Paris, France.

ABSTRACT
Shigella is a pathovar of Escherichia coli comprising four groups, Shigella flexneri, Shigella sonnei, Shigella dysenteriae, and Shigella boydii, each of them, with the exception of S.sonnei, comprising several serotypes. Shigella accounts for the majority of dysentery causing infections occurring world-wide each year. Recent advancements in the Shigella field have led to a better understanding of the molecular mechanisms underlying host epithelial cell invasion and immune cell function manipulation, mainly using S. flexneri as a model. Host-cell invasion is the final step of the infection process, as Shigella's virulence strategy relies also on its ability to survive hostile conditions during its journey through the gastro-intestinal tract, to compete with the host microbiota and to cross the intestinal mucus layer. Hence, the diversity of the virulence strategies among the different Shigella species has not yet been deeply investigated, which might be an important step to understand the epidemiological spreading of Shigella species worldwide and a key aspect for the validation of novel vaccine candidates. The recent development of high-throughput screening and sequencing methods will facilitate these complex comparison studies. In this review we discuss several of the major avenues that the Shigella research field has taken over the past few years and hopefully gain some insights into the questions that remain surrounding this important human pathogen.

No MeSH data available.


Related in: MedlinePlus

Prevelance of Shigella species across China 2003–2013. Comparison of reported Shigella species between 2003–2004 and 2011–2013 showing the increase in S. sonnei isolations. For years 2003–2004 n = 235 cases, for 2011–2013 n = 1049 cases. Prevelance data reported in Qiu et al. (2015).
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Figure 2: Prevelance of Shigella species across China 2003–2013. Comparison of reported Shigella species between 2003–2004 and 2011–2013 showing the increase in S. sonnei isolations. For years 2003–2004 n = 235 cases, for 2011–2013 n = 1049 cases. Prevelance data reported in Qiu et al. (2015).

Mentions: Outside of outbreak settings, S. flexneri and S. sonnei account for the majority of Shigellosis cases. Recent epidemiological studies conducted around the world have discovered a rise in the proportion of S. sonnei isolates compared to S. flexneri. The expansion of S. sonnei can clearly be observed from clinical surveillance studies conducted in China which show the proportion of S. sonnei isolates increasing from 17.4% in 2003–2004 to 58.2% less than a decade later, closely following the rapid industrialization in China (Figure 2; Mao et al., 2013; Qiu et al., 2015). Noticeably, regions that had undergone significant industrialization reported decreases in S. flexneri and increasing cases of S. sonnei compared to under developed areas where flexneri levels remain high (Qiu et al., 2015). Rising cases of S. sonnei have also been detected in Bangladesh, which has historically been affected by all four species of Shigella. Between 2001 and 2011 the proportion of S. sonnei infections rose from 7 to 25% of reported cases in Bangladesh, which also corresponds with enhanced sanitation and clean water efforts throughout the country (Das et al., 2013; Hulland et al., 2013). The reasons for the counter-intuitive increase of S. sonnei in the face of better sanitation have not been determined, however several hypotheses have been put forward (Thompson et al., 2015). S. sonnei and Plesiomonas shigelloides share a common O-antigen that may lead to natural cross-protective immunity in populations that encounter high levels of P. shigelloides due to contaminated water supplies (Sack et al., 1994). Other avenues of interest include observations of increased survival and replication of S. sonnei in Acanthamoeba which may act as a reservoir and increased ability to acquire antibiotic resistances (Saeed et al., 2012). As more countries increase their level of development and sanitation it is likely that S. sonnei will become even more of a global public health concern which could have important impacts on vaccine development efforts.


Shigella Diversity and Changing Landscape: Insights for the Twenty-First Century.

Anderson M, Sansonetti PJ, Marteyn BS - Front Cell Infect Microbiol (2016)

Prevelance of Shigella species across China 2003–2013. Comparison of reported Shigella species between 2003–2004 and 2011–2013 showing the increase in S. sonnei isolations. For years 2003–2004 n = 235 cases, for 2011–2013 n = 1049 cases. Prevelance data reported in Qiu et al. (2015).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835486&req=5

Figure 2: Prevelance of Shigella species across China 2003–2013. Comparison of reported Shigella species between 2003–2004 and 2011–2013 showing the increase in S. sonnei isolations. For years 2003–2004 n = 235 cases, for 2011–2013 n = 1049 cases. Prevelance data reported in Qiu et al. (2015).
Mentions: Outside of outbreak settings, S. flexneri and S. sonnei account for the majority of Shigellosis cases. Recent epidemiological studies conducted around the world have discovered a rise in the proportion of S. sonnei isolates compared to S. flexneri. The expansion of S. sonnei can clearly be observed from clinical surveillance studies conducted in China which show the proportion of S. sonnei isolates increasing from 17.4% in 2003–2004 to 58.2% less than a decade later, closely following the rapid industrialization in China (Figure 2; Mao et al., 2013; Qiu et al., 2015). Noticeably, regions that had undergone significant industrialization reported decreases in S. flexneri and increasing cases of S. sonnei compared to under developed areas where flexneri levels remain high (Qiu et al., 2015). Rising cases of S. sonnei have also been detected in Bangladesh, which has historically been affected by all four species of Shigella. Between 2001 and 2011 the proportion of S. sonnei infections rose from 7 to 25% of reported cases in Bangladesh, which also corresponds with enhanced sanitation and clean water efforts throughout the country (Das et al., 2013; Hulland et al., 2013). The reasons for the counter-intuitive increase of S. sonnei in the face of better sanitation have not been determined, however several hypotheses have been put forward (Thompson et al., 2015). S. sonnei and Plesiomonas shigelloides share a common O-antigen that may lead to natural cross-protective immunity in populations that encounter high levels of P. shigelloides due to contaminated water supplies (Sack et al., 1994). Other avenues of interest include observations of increased survival and replication of S. sonnei in Acanthamoeba which may act as a reservoir and increased ability to acquire antibiotic resistances (Saeed et al., 2012). As more countries increase their level of development and sanitation it is likely that S. sonnei will become even more of a global public health concern which could have important impacts on vaccine development efforts.

Bottom Line: Shigella is a pathovar of Escherichia coli comprising four groups, Shigella flexneri, Shigella sonnei, Shigella dysenteriae, and Shigella boydii, each of them, with the exception of S.sonnei, comprising several serotypes.Host-cell invasion is the final step of the infection process, as Shigella's virulence strategy relies also on its ability to survive hostile conditions during its journey through the gastro-intestinal tract, to compete with the host microbiota and to cross the intestinal mucus layer.The recent development of high-throughput screening and sequencing methods will facilitate these complex comparison studies.

View Article: PubMed Central - PubMed

Affiliation: Institut Pasteur, Unité de Pathogénie Microbienne MoléculaireParis, France; Institut National de la Santé et de la Recherche Médicale, Unité 786Paris, France.

ABSTRACT
Shigella is a pathovar of Escherichia coli comprising four groups, Shigella flexneri, Shigella sonnei, Shigella dysenteriae, and Shigella boydii, each of them, with the exception of S.sonnei, comprising several serotypes. Shigella accounts for the majority of dysentery causing infections occurring world-wide each year. Recent advancements in the Shigella field have led to a better understanding of the molecular mechanisms underlying host epithelial cell invasion and immune cell function manipulation, mainly using S. flexneri as a model. Host-cell invasion is the final step of the infection process, as Shigella's virulence strategy relies also on its ability to survive hostile conditions during its journey through the gastro-intestinal tract, to compete with the host microbiota and to cross the intestinal mucus layer. Hence, the diversity of the virulence strategies among the different Shigella species has not yet been deeply investigated, which might be an important step to understand the epidemiological spreading of Shigella species worldwide and a key aspect for the validation of novel vaccine candidates. The recent development of high-throughput screening and sequencing methods will facilitate these complex comparison studies. In this review we discuss several of the major avenues that the Shigella research field has taken over the past few years and hopefully gain some insights into the questions that remain surrounding this important human pathogen.

No MeSH data available.


Related in: MedlinePlus