Analysis of the F Antigen-Specific papA Alleles of Extraintestinal Pathogenic Escherichia coli Using a Novel Multiplex PCR-Based Assay

作者：James R. Johnson, Adam L. Stell, Flemming Scheutz, Timothy T. O’Bryan, Thomas A. Russo, Ulrike B. Carlino, Claudine E. Fasching, Justine A. Kavle, Linda van Dijk, Wim Gaastra · 发表于：Infection and Immunity · 年份：2000 · DOI：10.1128/iai.68.3.1587-1599.2000 · 被引用次数：81 · 研究领域：Escherichia coli research studies、Antibiotic Resistance in Bacteria、Enterobacteriaceae and Cronobacter Research

Polymorphisms in PapA, the major structural subunit and antigenic determinant of P fimbriae of extraintestinal pathogenic Escherichia coli, are of considerable epidemiological, phylogenetic, and immunotherapeutic importance. However, to date, no method other than DNA sequencing has been generally available for their detection. In the present study, we developed and rigorously validated a novel PCR-based assay for the 11 recognized variants of papA and then used the new assay to assess the prevalence, phylogenetic distribution, and bacteriological associations of the papA alleles among 75 E. coli isolates from patients with urosepsis. In comparison with conventional F serotyping, the assay was extremely sensitive and specific, evidence that papA sequences are highly conserved within each of the traditionally recognized F serotypes despite the diversity observed among F types. In certain strains, the assay detected serologically occult copies of papA, of which some were shown to represent false-negative serological results and others were shown to represent the presence of nonfunctional pap fragments. Among the urosepsis isolates, the assay revealed considerable segregation of papA alleles according to O:K:H serotype, consistent with vertical transmission within clones, but with exceptions which strongly suggested horizontal transfer of papA alleles between lineages. Sequencing of papA from two strains that were papA positive by probe and PCR but F negative in the new PCR assay...