SEROTYPES AND COLONIZATION FACTORS OF ENTEROTOXIGENIC ESCHERICHIA-COLI ISOLATED IN VARIOUS COUNTRIES

One hundred and six enterotoxigenic E. coli (ETEC) isolated from many geographical areas were serotyped and investigated for the presence of colonization factor antigens CFA/I and CFA/II, the expression of mann ose-resistant haemagglutination (MRHA) and the levels of surface hydro phobicity. CFA/I was found in 6 (17%) of 36 LT+STa+ strains and in 15 (54%) of 28 STa+ strains; CFA/II was found in 16 (44%) of 36 LT+STa+ s trains. None of 42 LT+ strains showed CFA/I or CFA/II. CFA/I was found in ETEC of serotypes O63:K-:H-, O78:K80, O128:K67 and O153:K-:H45, wh ereas CFA/II was found in serotypes O6:H-, O6:K15:H16 and O6:K?:H40. O f the 69 CFA/I-CFA/II- ETEC strains, 9 (13%) showed MRHA with some of the seven erythrocyte species used and 21 (30%) were hydrophobic. Amon g the 21 hydrophobic strains CFA-negative we have detected: (i) 6 LTstrains of serogroup O25 negative for MRHA, (ii) 5 strains O159 (4 LT and 1 LT+ STa+) also negative for MRHA, and (iii) 3 STa+ strains of s erotype O27:K-:H7 that haemagglutinated calf and sheep erythrocytes wh en grown on Minca-Is. The 106 ETEC strains belonged to 20 different O serogroups. However, 77 (73%) were of one of nine serogroups (O6, O8, O25, O27, O78, O148, O153, O159 and O167). E. coli strains belonging t o O6 and O153 groups predominated among ETEC isolated in Spain, O159 s trains in the Central African Republic, O25 and O148 strains in Japan, and O15 and O78 strains in India.