Microevolution and Patterns of Transmission ofShigella sonneiwithin Cyclic Outbreaks Shigellosis, Israel

Abstract

Whole-genome sequencing unveiled host and environment-related insights to Shigella sonnei transmission within cyclic epidemics during 2000–2012 in Israel. The Israeli reservoir contains isolates belonging to S. sonnei lineage III but of different origin, shows loss of tetracycline resistance genes, and little genetic variation within the O antigen: highly relevant for Shigella vaccine development.

Evidence for re-infection and persistent carriage of Shigella species in adult males reporting domestically acquired infection in England

“…This suggests much shorter re-infection time intervals for Shigella are possible within this population than might be expected based on immunity data from endemic regions. Evidence from regions of high incidence of S. sonnei reveals a 3-year cycle of infection indicating that immunity from re-infection with S. sonnei is approximately 3 years [28,29]. Based on the phylogenetic analysis greater than two-thirds of isolate pairs were most plausibly explained by persistent carriage and approximately one third by re-infection.…”

Emergence of novel strains of Shigella flexneri associated with sexual transmission in adult men in England, 2019–2020

“…The different clades of Shigella contributing to the highest levels of transmission continue to fluctuate, although the drivers of the rise and fall of the dominant types remains unclear. Host immunity may be one factor influencing the change in dominant types observed over the last decade [16, 17]. Herd immunity may reduce circulation of specific serotypes, preventing epidemic strains from being sustained in the population, providing the opportunity for novel types, such as S.…”

“…sonnei , and outbreaks of extended-spectrum beta-lactamase-producing S. sonnei have been described [1, 11, 17–22]. Overuse of certain antimicrobials is likely to be a contributing factor in driving increasing resistance to the same class of antimicrobials.…”

“…sonnei clades 2 and 5 emerging in successive waves between 2009 and 2018 [11, 13]. The emergence of each clade corresponded with the acquisition of the pK100 plasmid conferring resistance to azithromycin [12, 17, 18]. Since 2019, the three clades of S.…”

Accessory Genome Dynamics and Structural Variation of Shigella from Persistent Infections

“…In addition, coinfection with HIV is common among shigellosis-affected MSM (with 75% being HIV infected) ( 13 ), and this could be a risk factor for sustaining prolonged infection among MSM ( 17 , 18 ). Although Shigella infection is typically self-limiting, with infection times ranging between 1 and 4 weeks and followed by immunity against the homologous serotype ( 19 ) for a period of approximately 5 months to 2 years ( 20 – 22 ), this may not be the case in MSM. Serial isolation of the same Shigella serotype from an individual for up to 1,862 days has been reported among UK MSM ( 16 ).…”