Validation of the O15:K52:H1-specific fumC PCR assay for 162 E. coli isolates of known clonal group status

Isolate source(s)Putative O15:K52:H1 clonal group status (no.)bBasis for assignmentcfumC PCR assay result (no.)CommentdReference(s) or source
Spain, England (urine)25O:K:H serotype223All 3 isolates neg. by PCR assay were non-O15:K52:H1 by RAPD and MLST; 2 were K− or Knt21
15O:K:H serotype01521
U.S., Africa (all O15 isolates)18RAPD, ERIC, BOX153All 3 isolates neg. by PCR assay were positive for F7-2 and hly and non-O15:K52:H1 by RAPD (one also by MLST); two were serotyped as O15:K2:H1813
18RAPD, ERIC, BOX01813
Iowa clin. micro. labsa7RAPD, O15 antigen70All isolates resistant to ciprofloxacin7
ECOR collection13O antigen, phylo. gp.013ECOR strains 7, 10, 24, 30, 35, 40, 41, 44, 47, 50, 59, 62, 725,17
Pyelonephritis (U.S.)1O antigen, RAPD108
20O antigen, RAPD0208
Cystitis (Minn.)8O antigen0814
Global CGA search24Phylo. gp., RAPD023Abstractf
CGA in acute cystitis18ERIC, RAPD, PFGE01814
Total5111145117PCR assay sensitivitye 88% (or 100%); specificity, 100%
  • a Clin. micro. labs, clinical microbiology laboratories.

  • b Pos., positive; neg., negative.

  • c ERIC and BOX, ERIC2 and BOX A1R repetitive-element fingerprinting; phylo. gp., phylogenetic group; PFGE, pulsed-field gel electrophoresis.

  • d MLST, multilocus sequence typing; K−, capsule minus; Knt, K nontypeable; F7-2, papA variant (P fimbrial structural subunit); hly, hemolysin gene.

  • e Estimated sensitivity depends on whether the seven false-negative fumC reference isolates are regarded as O15:K52:H1 (see the text).

  • f A. C. Murray, T. T. O'Bryan, M. A. Kuskowski, A. R. Manges, L. W. Riley, and J. R. Johnson. Abstr. 103rd Gen. Meet. Am. Soc. Microbiol.