Genetic Transfer of a Mucosal Adherence Factor (R1) from an Enteropathogenic Escherichia coli Strain into a Shigella flexneri Strain and the Phenotypic Suppression of this Adherence Factor

Abstract

Escherichia coli strain RDEC-1 avidly adheres to rabbit ileal brush borders. Two separate experiments were designed to determine whether pili promote this adherence. (1) Adherence of strain RDEC-1 was phenotypically suppressed by changing the culture medium. Loss of adherence was correlated with the absence of pili. Thus, growth of strain RDEC-1 in Penassay broth (Difco Laboratories, Detroit, Mich.) promoted both adherence and expression of pili on greater than or equal to 90% of organisms, whereas growth in brain-heart infusion medium suppressed adherence and reduced the percentage of piliated organisms to less than or equal to 13%. (2) The adherence ability of strain RDEC-1 was genetically transferred to previously nonadherent and nonpiliated Shigella flexneri. The Shigella exconjugants that inherited the adherence ability were uniformly piliated, while all nonadherent Shigella exconjugants were nonpiliated. Finally, the pili on both RDEC-1 and the Shigella exconjugant strains were shown to be distinct from type 1 pili. Therefore, unique pili confer upon strain RDEC-1 the ability to adhere to rabbit intestinal brush borders.

Disparate In Vitro Inhibition of Adhesion of Enteropathogenic Escherichia coli RDEC-1 by Mucins Isolated from Various Regions of the Intestinal Tract

“…Infection of rabbits with AFJR1-piliated RDEC-1 results in greater morbidity and mortality than infection with nonpiliated mutants (20). The AF/Rl pilus is a hydrophobic adhesin ligand expressed on the surface of RDEC-1 (21,29). AFIR1 pili mediate adhesion of organisms to luminal glycoproteins was evident in the in vitro adhesion assay model system used in these experiments.…”

Surface properties of diarrhoeagenic Escherichia coli isolates

“…Similarly, the rabbit pathogen RDEC-1 , although analogous to human EPEC strains in possessing the eaeA gene, does not carry an EAF plasmid, or the bfpA gene, but is very hydrophobic. However, it does express an alternative fimbrial structure, AF/R1 [25]. Although RDEC-1 does not manifest the localised adherence phenotype, and AF/ R1 is not critical in the pathogenesis of the disease, the fimbriae do serve to promote the initial adherence of RDEC-1 to the brush border [35].…”

Increased Interleukin-1 (IL-1) and Imbalance between IL-1 and IL-1 Receptor Antagonist during Acute Inflammation in Experimental Shigellosis

“…M90T is a wild-type S. flexneri serotype 5 strain (54). BS15 is a noninvasive derivative of M90T which was cured of the 220-kb plasmid pWR100 and transformed with the recombinant plasmid pRKB15 (66) encoding AFR1, an adherence pilus of the rabbit-specific Escherichia coli strain RDEC-1 (13). Prior to experimental infection of rabbits, the bacteria were streaked on Congo red agar.…”

“…M26295) obtained on Clustal V multiple sequence alignment (61) and with the PCRare program (25). The cDNAs were synthesized after RQ 1 Dnase treatment (2U; Promega France, Charbonnières, France) in a total volume of 50 l, using 10 g of total RNAs and 0.5 g of oligo(dT) [12][13][14][15][16][17][18] (Promega France) as a primer, 1.25 mM deoxynucleoside triphosphate, 0.5 U of RNasin (Promega France), and 200 U of Moloney murine leukemia virus reverse transcriptase RNase-H minus (Promega France) in the manufacturer's buffer for 1 h at 42°C. PCRs were performed on a PHc-2 (Techne Inc., Rahway, N.J.).…”