Frequency of gene sequences necessary for pyelonephritis-associated pili expression among isolates of Enterobacteriaceae from human extraintestinal infections.

Bacteria representing eight genera of the Enterobacteriaceae were collected from human extraintestinal infections and examined to determine whether they contained gene sequences necessary for expression of a pili type often associated with bacteria causing human pyelonephritis. Escherichia coli isolated from most of the extraintestinal sites were frequently found to possess pap-related DNA sequences. Isolates which possessed these sequences were often found to exhibit D-mannose-resistant hemagglutination of human erythrocytes and to have surface antigens related to P pili.