DNA-based diagnostic tests for Salmonella species targeting agfA, the structural gene for thin, aggregative fimbriae

Doran, James L.; Collinson, S. Karen; Burian, Ján; Sarlós, Géza; Todd, Ewen C. D.; Munro, C.; Kay, Cyril M.; Banser, P. A.; Peterkin, Pearl I.; Kay, William W.

doi:10.1128/jcm.31.9.2263-2273.1993

Cited by 95 publications

(31 citation statements)

References 44 publications

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“…The presence of this type of fimbria has been reported in clinical human and animal isolates of Salmonella a The following loci: invA, safC, bcfC, fimA and ssaQ were present in all the strains; the genes gipA, gogB, sspH2, sodC1, gtgE, spvC, stfE, ipfD and pefA were not found in any of these strains. [19,20]. The data presented here suggest that agfA might increase bacterial pathogenicity.…”

Section: Frequency Of Association (%)mentioning

confidence: 64%

Diversity of Salmonella spp. serovars isolated from the intestines of water buffalo calves with gastroenteritis

et al. 2012

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BackgroundSalmonellosis in water buffalo (Bubalus bubalis) calves is a widespread disease characterized by severe gastrointestinal lesions, profuse diarrhea and severe dehydration, occasionally exhibiting a systemic course. Several Salmonella serovars seem to be able to infect water buffalo, but Salmonella isolates collected from this animal species have been poorly characterized. In the present study, the prevalence of Salmonella spp. in water buffalo calves affected by lethal gastroenteritis was assessed, and a polyphasic characterization of isolated strains of S. Typhimurium was performed.ResultsThe microbiological analysis of the intestinal contents obtained from 248 water buffalo calves affected by lethal gastroenteritis exhibited a significant prevalence of Salmonella spp. (25%), characterized by different serovars, most frequently Typhimurium (21%), Muenster (11%), and Give (11%). The 13 S. Typhimurium isolates were all associated with enterocolitis characterized by severe damage of the intestine, and only sporadically isolated with another possible causative agent responsible for gastroenteritis, such as Cryptosporidium spp., Rotavirus or Clostridium perfringens. Other Salmonella isolates were mostly isolated from minor intestinal lesions, and often (78% of cases) isolated with other microorganisms, mainly toxinogenic Escherichia coli (35%), Cryptosporidium spp. (20%) and Rotavirus (10%). The S. Typhimurium strains were characterized by phage typing and further genotyped by polymerase chain reaction (PCR) detection of 24 virulence genes. The isolates exhibited nine different phage types and 10 different genetic profiles. Three monophasic S. Typhimurium (B:4,12:i:-) isolates were also found and characterized, displaying three different phage types and three different virulotypes. The molecular characterization was extended to the 7 S. Muenster and 7 S. Give isolates collected, indicating the existence of different virulotypes also within these serovars. Three representative strains of S. Typhimurium were tested in vivo in a mouse model of mixed infection. The most pathogenic strain was characterized by a high number of virulence factors and the presence of the locus agfA, coding for a thin aggregative fimbria.ConclusionsThese results provide evidence that Salmonella is frequently associated with gastroenteritis in water buffalo calves, particularly S. Typhimurium. Moreover, the variety in the number and distribution of different virulence markers among the collected S. Typhimurium strains suggests that within this serovar there are different pathotypes potentially responsible for different clinical syndromes.

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Section: Frequency Of Association (%)mentioning

confidence: 64%

Diversity of Salmonella spp. serovars isolated from the intestines of water buffalo calves with gastroenteritis

et al. 2012

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“…Neither CsgA nor CsgB contains the sequence motif found in the C-terminus of P-pili subunit proteins and related pilins known to be required for interaction with periplasmic chaperones (Kuehn et aL, 1991), suggesting that the biogenesis pathway for curli is different from that of chaperone-dependent pill. CsgA shows no homology to any proteins in the database except for AgfA, the subunit protein in Salmonella enteritidis thin, aggregative fimbriae (Doran et aL, 1993). Sequencing upstream of agfA in Salmonella typhimurium has revealed an open reading frame showing high homology to csgB suggesting that the genetic arrangement for curli and thin aggregative fimbriae may be very similar (M. Rhen, personal communication).…”

Section: Discussionmentioning

confidence: 99%

Expression of two csg operons is required for production of fibronectin‐ and Congo red‐binding curli polymers in Escherichia coli K‐12

Hammar

Arnqvist

Zhao

et al. 1995

Molecular Microbiology

472

541

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Two divergently transcribed operons in Escherichia coli required for the expression of fibronectin- and Congo red-binding curli polymers were identified and characterized by transposon mutagenesis, sequencing and transcriptional analyses, as well as for their ability to produce the curli subunit protein. The csgBA operon encodes CsgA, the major subunit protein of the fibre, and CsgB, a protein with sequence homology to CsgA. A non-polar csgB mutant is unaffected in its production of CsgA, but the subunit protein is not assembled into insoluble fibre polymers. A third open reading frame, orfC, positioned downstream of csgA may affect some functional property of curli since an insertion in this putative gene abolishes the autoagglutinating ability typical of curliated cells without affecting the production of the fibre. The promoter for the oppositely transcribed csgDEFG operon was identified by primer extension and shown, like the csgBA promoter, to be dependent upon the alternate stationary phase-specific sigma factor sigma s in wild-type cells, but not in mutants lacking the nucleoid associated protein H-NS. Insertions in csgD abolish completely trancription from the csgBA promoter. Therefore, any regulatory effect on the csgBA promoter might be secondary to events controlling the csgDEFG promoter and/or activation of CsgD. Insertions in csgE, csgF and csgG abolish curli formation but allow CsgA expression suggesting that one or more of these gene products are involved in secretion/assembly of the CsgA subunit protein. No amino acid sequence homologies were found between the CsgE, CsgF and CsgG proteins and secretion/assembly proteins for other known bacterial fibres, suggesting that the formation of curli follows a novel pathway.

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“…and, possibly, Shigella spp.) also encode curli genes [26][27][28] . Whether amyloid fibrils are more widespread within the bacterial domain is not yet known.…”

Section: Amyloids and Bacteriamentioning

confidence: 99%

Amyloids — a functional coat for microorganisms

et al. 2005

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Amyloids are filamentous protein structures approximately 10 nm wide and 0.1-10 mum long that share a structural motif, the cross-beta structure. These fibrils are usually associated with degenerative diseases in mammals. However, recent research has shown that these proteins are also expressed on bacterial and fungal cell surfaces. Microbial amyloids are important in mediating mechanical invasion of abiotic and biotic substrates. In animal hosts, evidence indicates that these protein structures also contribute to colonization by activating host proteases that are involved in haemostasis, inflammation and remodelling of the extracellular matrix. Activation of proteases by amyloids is also implicated in modulating blood coagulation, resulting in potentially life-threatening complications.

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DNA-based diagnostic tests for Salmonella species targeting agfA, the structural gene for thin, aggregative fimbriae

Abstract: SalmoneUla enteritidis 27655-3b and a few diarrheagenic Escherichia coli strains produce morphologically and antigenically related, thin, aggregative fimbriae, collectively named GVVPQ fimbriae (S. K. Collinson, L.

Cited by 95 publications

References 44 publications

Diversity of Salmonella spp. serovars isolated from the intestines of water buffalo calves with gastroenteritis

Diversity of Salmonella spp. serovars isolated from the intestines of water buffalo calves with gastroenteritis

Expression of two csg operons is required for production of fibronectin‐ and Congo red‐binding curli polymers in Escherichia coli K‐12

Amyloids — a functional coat for microorganisms

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