Common occurrence of plasmid DNA and vancomycin resistance in Leuconostoc spp

Abstract

Resistance to vancomycin permitted detection, in a culture of Streptococcus cremoris 290PC, of a contaminant gram-positive coccus. Morphological and physiological characteristics indicated that this bacterium was a strain of Leuconostoc sp., designated P0184. This strain contained four plasmid species, which were distinct from those harbored by S. cremoris 290PC. Antibiotic disk susceptibility tests indicated that Leuconostoc sp. strain P0184 was also resistant to sulfathiazole and trimethoprim and susceptible to 17 other antimicrobials. The MIC of vancomycin for this strain was >2,000 ,ug/ml, and resistance did not depend on drug inactivation. Leuconostoc sp. strain P0184 produced a substance which was inhibitory to S. cremoris U134, but not to S. lactis ATCC 11454. Five other leuconostocs produced substances with antibacterial activity. Of 18 strains of Leuconostoc sp., 14 were resistant to at least 500 jig of vancomycin per ml, including four L. oenos strains which harbored no plasmid DNA in the 1to 76-megadalton range. Twelve Leuconostoc sp. strains contained at least one plasmid species in this mass range. These findings are discussed from the physiological, taxonomical, and ecological standpoints and with regard to their potential applications.

Conjugative transfer of the transposon Tn919 to lactic acid bacteria

“…This report extends our knowledge to streptococcal transposons. The genetics of Leuconostoc has, thus far, received less attention, although the presence of plasmid DNA has been reported [16,17]. This study has demonstrated gene transfer by conjugation in this genus.…”

Some roles of malic acid in the malolactic fermentation in wine making

“…Many of the plasmids display induction for antibiotic resistance, which can also be used to help in selection of altered cells, as was done in the example above. This was also important in one of the first demonstrations of plasmids in the leuconostocs [96], and in an intragenic conjugal transfer between streptococci and leuconostocs [97].…”

Lactic acid bacteria: starters for flavour

“…Early work [31] indicated that most leuconostocs dissimilate citrate but the property may easily be lost in strains kept in the laboratory. The fact that fast lactose metabolism and citrate utilisation in the Lactococcus species are plasmid encoded may lead to conjecture of similarly coded characters in the 'dairy' leuconostocs, particularly as Orberg and Sandine [32] have demonstrated the presence of plasmids in a number of strains and O'Sullivan [33] has found some evidence for plasmid involvement in lactose metabolism.…”