DETECTION OF ENTEROTOXIGENICITY AND ATTACHMENT FACTORS IN ESCHERICHIA-COLI STRAINS OF HUMAN, PORCINE AND BOVINE ORIGIN - COMPARATIVE-STUDY

  • 1 January 1979
    • journal article
    • research article
    • Vol. 243  (2-3) , 245-257
Abstract
Porcine and bovine strains of E. coli suspected to be enterotoxigenic were tested for heat-labile enterotoxin (LT) production by a test measuring the stimulation of the synthesis of 3''5'' cyclic (c)AMP and rounding mouse adrenal tumor Y1 cells and for heat-stable enterotoxin (ST) production by the baby mouse test (BM test). The test results were compared with those of the ligated gut test (LG test) using pig and calf intestine. Strains (111) of human origin were tested in the cAMP test, the Y1 test and the BM test. All strains were tested for the presence of the attachment factors K88, K99, P987 and CF10407. Of 117 bovine strains, 74 produced only ST and all 74 ST-producing strains possessed K99 antigen [Ag]. None of the 43 nonenterotoxigenic strains possessed K99. The presence of K99 Ag is a reliable indicator of enterotoxigenicity in bovine strains. Porcine strains produced LT, ST or LT + ST. The K88 Ag was found in 52 of 101 enterotoxigenic strains, K99 and P987 in 7 and 6 strains, respectively, and the latter 13 strains produced only ST. P987 was only detected after subculturing in liquid medium to enhance pilus formation. Of 111 strains origin, 11 stimulated cAMP synthesis but failed to round Y1 cells, whereas 4 known LT producers were positive in both tests. Attachment factors were found in 2 of the latter 4 strains.