Characterization of Escherichia coli serotype O12:K1:H7 isolates from an immunocompetent carrier with a history of spontaneous abortion and septicemia.

Escherichia coli isolates from an immunocompetent woman with a history of repeated amnion infections and spontaneous abortion were characterized. Escherichia coli were isolated from stool, blood and cervix swab samples taken over a 21-month period after the last abortion which followed septicemia during pregnancy. All samples except the last cervix swab contained isolates of serotype O12:K1:H7, which produced adhesins, P fimbriae, type I fimbriae and the iron-chelator aerobactin. Pulsed-field gel electrophoresis revealed identical Xbal restriction patterns of the O12:K1:H7 isolates, suggesting that one particular Escherichia coli strain was responsible for the severe extraintestinal infections during pregnancy. The strain was able to persist in the intestine of the woman despite antibiotic therapy.