Frequency of aggregation substance and cytolysin genes among enterococcal endocarditis isolates.
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.
Huycke
M M
MM
Department of Veterans Affairs Medical Center, University of Oklahoma Health Sciences Center, Oklahoma City 73104, USA.
Gilmore
M S
MS
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
D001426:Bacterial Proteins; D003603:Cytotoxins; D017931:DNA Primers; D012724:Sex Attractants; C065937:aggregation substance, Enterococcus faecalis