Studies on Novel Pili from <i>Shigella flexneri</i>

Utsunomiya, Akiyoshi; Naito, Toshiki; Ehara, Masahiko; Ichinose, Yuki; Hamamoto, Ayami

doi:10.1111/j.1348-0421.1992.tb02082.x

Cited by 13 publications

(3 citation statements)

References 13 publications

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“…Despite this null adherence factor hypothesis, a limited number of reports have detected adherence factor expression in S. flexneri (27–29), but, unfortunately, in-depth genetic analyses have not been performed. Furthermore, we have previously demonstrated that tryptic soy broth (TSB) media supplemented with bile salts induce the adherence of S.…”

Section: Introductionmentioning

confidence: 99%

Shigella flexneri Adherence Factor Expression in In Vivo -Like Conditions

Chanin

Nickerson

Llanos-Chea

et al. 2019

mSphere

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Bacterial pathogens have evolved to regulate virulence gene expression at critical points in the colonization and infection processes to successfully cause disease. The Shigella species infect the epithelial cells lining the colon to result in millions of cases of diarrhea and a significant global health burden. As antibiotic resistance rates increase, understanding the mechanisms of infection is vital to ensure successful vaccine development. Despite significant gains in our understanding of Shigella infection, it remains unknown how the bacteria initiate contact with the colonic epithelium. Most pathogens harbor multiple adherence factors to facilitate this process, but Shigella was thought to have lost the ability to produce these factors. Interestingly, we have identified conditions that mimic some features of gastrointestinal transit and that enable Shigella to express adherence structural genes. This work highlights aspects of genetic regulation for Shigella adherence factors and may have a significant impact on future vaccine development.

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Section: Introductionmentioning

confidence: 99%

Shigella flexneri Adherence Factor Expression in In Vivo -Like Conditions

Chanin

Nickerson

Llanos-Chea

et al. 2019

mSphere

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“…Since Shigella evolved from various strains of E. coli (Pupo et al, 2000;Townsend et al, 2001) and given the fact that fimbriae are prevalent among the Enterobacteriaceae (Bloch et al, 1992), we hypothesize that Shigella utilize fimbriae or other adhesins during initial colonization of the colon. Two reports have identified the presence of fimbriae on the surface of Shigella, including type 1 fimbriae (Utsunomiya et al, 1992;Snellings et al, 1997). In addition, comparative genomic studies have identified novel open reading frames in S. flexneri that have been annotated as adhesins (Wei et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Shigella flexneri effectors OspE1 and OspE2 mediate induced adherence to the colonic epithelium following bile salts exposure

Faherty

Redman

Rasko

et al. 2012

Molecular Microbiology

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Summary Shigella flexneri is a Gram-negative pathogen that invades the colonic epithelium. While invasion has been thoroughly investigated, it is unknown how Shigella first attaches to the epithelium. Previous literature suggests that Shigella utilizes adhesins that are induced by environmental signals, including bile salts, encountered in the small intestine prior to invasion. We hypothesized that bile would induce adherence factors to facilitate attachment to colonic epithelial cells. To test our hypothesis, S. flexneri strain 2457T was subcultured in media containing bile salts, and the ability of the bacteria to adhere to the apical surface of polarized T84 epithelial cells was measured. We observed a significant increase in adherence, which was absent in a virulence plasmid-cured strain and a type-III secretion system mutant. Microarray expression analysis indicated that the ospE1/ospE2 genes were induced in the presence of bile, and bile-induced adherence was lost in a ΔospE1/ΔospE2 mutant. Further studies demonstrated that the OspE1/OspE2 proteins were localized to the bacterial outer membrane following exposure to bile salts. The data presented are the first demonstration that the OspE1/OspE2 proteins promote initial adherence to the intestinal epithelium. The adhesins required for Shigella attachment to the colonic epithelium may serve as ideal targets for vaccine development.

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“…This study demonstrates definitively that Shigella expresses type 1 fimbrial adhesins. Recent reports have also documented the presence of type 3 and type 4 fimbrial adhesins and of afimbrial adhesins in Shigella strains (29,32). The difficulty in obtaining fimbriated Shigella cultures could be partly explained by inappropriate growth conditions as well as by a low frequency of switching from the afimbriated to the fimbriated phase.…”

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confidence: 99%

Characterization of Shigella type 1 fimbriae: expression, FimA sequence, and phase variation

1997

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This study documents the presence of type 1 fimbriae on Shigella and confirms these mannose-sensitive adherence structures to be bona fide components of the Shigella surface. While laboratory-passaged Shigella strains and lyophilized clinical isolates failed to express type 1 fimbriae, 6 of 20 recent clinical isolates, including 4 Shigella flexneri strains, 1 Shigella boydii strain, and 1 Shigella dysenteriae strain, produced type 1 fimbriae as detected by mannose-sensitive hemagglutination (MSHA) and electron microscopy. Optimal production of a predominantly Fim ؉ population required serial passage every 48 to 72 h in unshaken brain heart infusion broth at 37°C. Fim ؉ Shigella cultures were capable of reversibly switching to a non-MSHA, afimbriated phase during serial aerobic cultivation on tryptic soy agar plates. The amino acid sequence of S. flexneri type 1 FimA contained 18 substitutions compared to that of Escherichia coli fimbrillin. Indirect immunoelectron microscopy suggested the presence of both shared and unique epitopes on E. coli and S. flexneri type 1 fimbriae. Random phase variation between fimbriated and afimbriated states in Shigella was accompanied by the genomic rearrangement associated with phase variation in E. coli.

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Studies on Novel Pili from Shigella flexneri

Cited by 13 publications

References 13 publications

Shigella flexneri Adherence Factor Expression in In Vivo -Like Conditions

Shigella flexneri Adherence Factor Expression in In Vivo -Like Conditions

Shigella flexneri effectors OspE1 and OspE2 mediate induced adherence to the colonic epithelium following bile salts exposure

Characterization of Shigella type 1 fimbriae: expression, FimA sequence, and phase variation

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