Frequency of adhesive factors and enterotoxins in strains of Escherichia coli isolated from piglets with diarrhea.

Neonatal colibacillosis is one of the most prevalent illnesses in pig farms. In order to examine the frequency of adherence factors and the production of enterotoxins in strains of E. coli, we collected stool specimens from 500 piglets between 1 and 10 days of age with diarrhea, including piglets from several different farms on the periphery of Mérida, Yucatán. One thousand and eighty (1080) strains of E. coli were isolated, of which 127 (11.76%) produced STa, and 62 (5.74%) produced adherence factors. Of these, 30 (48.39%) produced factor K88, 18 (29.03%) produced factor 987P, 12 (19.35%) produced K99, and 2 (3.23%) produced F41. Of the 62 strains which produced adherence factors, 42 (67.74%) also produced STa, and of these, 17 (40.84%) produced factor K88, 13 (30.95%) produced 987P, 10 (23.81%) produced K99, and 2 (4.76%) produced F41. In summary, of the 1080 strains isolated, 42 (3.89%) produced both STa toxin and adherence factors, 85 (7.87%) produced STa but did not produce adherence factors, and 933 (86.39%) produced neither STa or adherence factors. No LT-producing E. coli was detected in this study.