Bacteriocin production in vancomycin-resistant and vancomycin-susceptible Enterococcus isolates of different origins.
Bacteriocin production was determined for 218 Enterococcus isolates (Enterococcus faecalis [93] and E. faecium [125]) obtained from different origins (human clinical samples [87], human fecal samples [78], sewage [28], and chicken samples [25]) and showing different vancomycin susceptibility patterns (vancomycin resistant, all of them vanA positive [56], and vancomycin susceptible [162]). All enterococcal isolates were randomly selected except for the vancomycin-resistant ones. A total of 33 isolates of eight different bacterial genera were used as indicators for bacteriocin production. Forty-seven percent of the analyzed enterococcal isolates were bacteriocin producers (80.6% of E. faecalis and 21.6% of E. faecium isolates). The percentage of bacteriocin producers was higher among human clinical isolates (63.2%, 81.8% of vancomycin-resistant isolates and 60.5% of vancomycin-susceptible ones) than among isolates from the other origins (28 to 39.3%). Only one out of the 15 vancomycin-resistant isolates from human fecal samples was a bacteriocin producer, while 44.4% of fecal vancomycin-susceptible isolates were. The bacteriocin produced by the vanA-containing E. faecium strain RC714, named bacteriocin RC714, was further characterized. This bacteriocin activity was cotransferred together with the vanA genetic determinant to E. faecalis strain JH2-2. Bacteriocin RC714 was purified to homogeneity and its primary structure was determined by amino acid sequencing, showing an identity of 88% and a similarity of 92% with the previously described bacteriocin 31 from E. faecalis YI717. The presence of five different amino acids in bacteriocin RC714 suggest that this could be a new bacteriocin. The results obtained suggest that the epidemiology of vancomycin resistance may be influenced by different factors, including bacteriocin production.
del Campo
R
R
Area de Bioquímica y Biología Molecular, Universidad de La Rioja, Logroño, Spain.
Tenorio
C
C
Jiménez-Díaz
R
R
Rubio
C
C
Gómez-Lus
R
R
Baquero
F
F
Torres
C
C
D000595:Amino Acid Sequence; D000818:Animals; D001430:Bacteriocins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002645:Chickens; D013293:Enterococcus faecalis / Q000302:isolation & purification / Q000378:metabolism*; D016984:Enterococcus faecium / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D020713:Vancomycin Resistance / Q000502:physiology*
D001430:Bacteriocins