title: Frequency of aggregation substance and cytolysin genes among enterococcal endocarditis isolates.
abstract: Enterococcus faecalis blood isolates were probed for the serine protease activator of cytolysin (cylA) and aggregation substance (asa1), traits that generally reside on pheromone-responsive plasmids, to determine how commonly these genotypes were associated with disease. In dot blot assays, no significant difference was found in the frequency of asa1 for blood isolates [55 of 103 (54%)] and isolates recovered from stool [9 of 14 (60%); P > 0.1, chi 2 test]. In contrast, cylA occurred more frequently among bacteremia isolates [34 of 68 (50%)] than endocarditis [4 of 35 (11%)] or stool isolates (0 of 14; P < 0.001; chi 2 test). However, when the clonality of isolates was accounted for, the frequency of asa1 and cylA among unrelated strains was not significantly different among the three sets of strains (P > 0.2, chi 2 test). The lack of enrichment for asa1 or cylA among clonally unrelated E. faecalis bloodstream isolates fails to support a role for plasmid-encoded aggregation substance or cytolysin in the transition from bacteremia to endocarditis. Clonally related, cytolytic strains, however, demonstrated an increased propensity to cause bloodstream infection.
authors.affiliation: Department of Veterans Affairs Medical Center, University of Oklahoma Health Sciences Center, Oklahoma City 73104, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Huycke
authors.forename: M S
authors.initials: MS
authors.lastname: Gilmore
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D003603:Cytotoxins / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D004697:Endocarditis, Bacterial / Q000382:microbiology*; D013293:Enterococcus faecalis / Q000235:genetics* / Q000302:isolation & purification* / Q000472:pathogenicity; D005798:Genes, Bacterial; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology*; D006801:Humans; D008969:Molecular Sequence Data; D012724:Sex Attractants / Q000235:genetics*; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D003603:Cytotoxins; D017931:DNA Primers; D012724:Sex Attractants; C065937:aggregation substance, Enterococcus faecalis