腸凝集性大腸桿菌（Enteroaggregative Escherichia coli, EAggEC）為造成嬰兒下痢之病原性大腸桿菌之一。體外試驗顯示腸凝集性大腸桿菌以堆疊方式附著於組織培養細胞表面，稱為凝集吸附。本研究目的係比較聚合壜鏈鎖反應（polymerase chain reaction, PCR）、HeLa細胞吸附試驗、血球凝集試驗與細菌團形成試驗等方法檢測EAggEC之結果。自不同下痢患者分離之340 株大腸桿菌中，先經PCR篩選疑似EAggEC菌株，再利用另外三種活性試驗法測定結果，僅3 株確定為EAggEC，顯示340 株收集自下痢患者臨床分離大腸桿菌菌株中，EAggEC僅佔0.88 ﹪。至於PCR為負反應者，亦利用HeLa細胞吸附試驗與細菌團形成試驗方法檢測，發現並無正反應菌株。而上述篩選方法中，以體外HeLa細胞吸附試驗結果最為明顯，其次為細菌團形成試驗；而血球凝集試驗篩選方法所得結果，則不易判定。依本研究結果，建議在篩檢EAggEC菌株時，先以PCR方法，再配合HeLa細胞吸附方法，應可以準確鑑定EAggEC菌株。

Enteroaggregative Escherichia coli (EAggEC) is one of the pathogenic E. coli strains which may cause diarrhoea. In vitro studies have
shown that EAggEC strains could establish a “stacked-brick” like adherence pattern on the surface of tissue culture cells and such a pattern
is termed as aggregative adherence (AA). The purpose of this study is to compare the methods of polymerase chain reaction (PCR),
HeLa cell adhesion, hemagglutination, and bacteria clumping tests for the specific detection of EAggEC suspected strains. This study isolated
340 E. coli strains from clinical samples of diarrhea cases which were firstly screened with the PCR method for the presence of suspected
EaggEC strains. Strains of negative PCR results were also confirmed with HeLa cell adhesion and bacteria clumping tests for the
EAggEC activity. Results showed that of these 340 clinical isolates, only three are EAggEC strains. Thus, EAggEC strains accounted for
0.88% in total strains. Also, for the above described methods, the in vitro HeLa cells adhesion test gave the clearest results followed by the
bacteria clumping test. The hemagglutination tests might generate ambiguous results.