Characterization of Types of Virulent Factors of Enterotoxigenic Escherichia Coli in Some Areas, China

369 strains of ETEC isolated from seven areas were tested for LT, ST h, STp, CFA Ⅰand CFAⅡ. T he results showed that ST -ETEC was the most frequently in these areas.Of ST - ETEC strains, ST p-only strains were predomination, followed by ST h-only strains. LT -ETEC strains were common in southern areas, however rarely found in northern areas. LT - only strains were not found ex cept Guangzhou and Haikou areas. Among 260 str ains of ETEC, CFA Ⅰand CFA Ⅱ wer e found in 50. 8%. We confirmed the observations of others that ST p ETEC are more frequently associated with CFAⅠ and CFA Ⅱ ex pression, however, in contrast to others, we found LT -only ETEC also associated with CFA Ⅰand CFA Ⅱ. CFA Ⅱ was the more frequently identified colonization factor than CFAⅠ. Bearing CFA Ⅰ strains was significantly frequent in southern areas than in northern areas. No significant difference was found in enterotoxin types among strains isolated fr om patients, healthy persons and environments.But a clear association was showed between diarrheal patients and CFAⅠand CFAⅡ.