FIG. 1.

Gene organization of kps, sfa, pap, and hly gene clusters. (A and B) Organization of pap and sfa gene clusters. Boxes indicate genes, and uppercase letters indicate gene designation(s). (C) The kps genes in region 1 (five genes [kpsSCUDE]) and region 3 (two genes [kpsMT]) are conserved among E. coli isolates that synthesize serologically distinct capsules. The number of genes in the central region 2 (kpsDBACES) reflects the size and complexity of the polysaccharide repeating unit. (D) The alpha-hemolysin determinant from E. coli J96 is represented; it consists of four genes. Black bars below gene clusters indicate the position of DNA fragments used as probes.