Characterization of a polysaccharide capsular antigen of septicemic Escherichia coli O115:K "V165" :F165 and evaluation of its role in pathogenicity

Abstract

Escherichia coli strains of serogroup 0115:K(-):F165 have been associated with septicemia in calves and piglets. These strains express a capsular antigen referred to as K"V165" which inhibits agglutination of the 0 antigen by anti-0115 serum. We used hybrid transposon TnphoA mutants M48, 18b, and 2, and a spontaneous 0-agglutinable mutant, 5131a, to evaluate the role of K"IV165" in the pathogenicity of E. coli 0115. Mutant M48 was as resistant to 90%o rabbit serum and as virulent in day-old chickens as the parent strain 5131, mutants 18b and 5131a were less resistant to serum and less virulent in chickens, and mutant 2 was serum sensitive and avirulent. Analysis of outer membrane protein and lipopolysaccharide profiles failed to show any difference between the transposon mutants and the parent strain. In contrast, the spontaneous 0-agglutinable mutant showed additional bands in the 16-kDa region of the polysaccharide ladder-like pattern. Mutants 2 and

F1651fimbriae of the P fimbrial family inhibit the oxidative response of porcine neutrophils

“…For example, an F165 1 ‐negative mutant of a pathogenic E. coli strain failed to colonize extraintestinal organs and to induce septicemia in experimentally inoculated gnotobiotic piglets. Moreover, an O‐antigen capsule‐negative spontaneous mutant of this pathogenic E. coli strain was serum‐sensitive in vitro and non‐pathogenic in young pigs [14–16].…”

“…In fact, E. coli causing septicemia produce virulence‐associated factors such as fimbrial antigen, outer membrane protein, lipopolysaccharide, capsule and O‐antigen capsule, mostly expressed on the bacterial cell membrane [16,26–29]. In addition, the bacteria may possess high molecular mass plasmids such as ColV, and produce various cytotoxins such as α‐hemolysin [30,31].…”

“…Wild‐type E. coli strain 5131 was isolated from the intestinal contents of a diarrheic and septicemic piglet at the Faculté de Médecine Vétérinaire, Université de Montréal, Saint‐Hyacinthe, Que., Canada. This strain is serum‐resistant, induces septicemia in experimentally inoculated piglets, and is resistant to phagocytic killing by pPMNLs [2–16]. Strain HB101 (pCJ7) is a transformant from plasmid pACYC184 in which was inserted a 10‐kb fragment of DNA (from an F165 1 ‐positive wild‐type septicemia‐inducing E. coli strain 4787) into the Bam HI site [15].…”

Purification and characterization of P fimbriae from an Escherichia coli strain isolated from a septicemic turkey

“…The relationship between the purified avian P fimbriae and Fll fimbriae was examined by an adaption of the enzyme-linked immunosorbent assay (ELISA) as described previously [19]. A 100 /xl volume of purified avian P fimbriae (2.5 /xg…”

Effects of DNA supercoiling and topoisomerases on the expression of genes coding for F1651, a P-like fimbriae

“…F165 1 fimbriae are produced by Escherichia coli 4787, a strain associated with septicemia in pigs, and involved in pathogenesis (Ngeleka et al , 1992, 1993). The F165 1 adhesin from E. coli , encoded by the foo operon, belongs to the family of Pap‐related fimbriae.…”