COMPARISON OF THE LACTOCOCCUS-LACTIS DIFFERENTIAL MEDIUM (DCL) AND SDS-PAGE OF WHOLE-CELL PROTEINS FOR THE IDENTIFICATION OF LACTOCOCCI TO SUBSPECIES LEVEL

Citation
P. Descheemaeker et al., COMPARISON OF THE LACTOCOCCUS-LACTIS DIFFERENTIAL MEDIUM (DCL) AND SDS-PAGE OF WHOLE-CELL PROTEINS FOR THE IDENTIFICATION OF LACTOCOCCI TO SUBSPECIES LEVEL, Systematic and applied microbiology, 17(3), 1994, pp. 459-466
Citations number
25
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology,"Biothechnology & Applied Migrobiology
ISSN journal
0723-2020
Volume
17
Issue
3
Year of publication
1994
Pages
459 - 466
Database
ISI
SICI code
0723-2020(1994)17:3<459:COTLDM>2.0.ZU;2-9
Abstract
In order to evaluate the practical usefulness of the DCL differential medium and highly standardised SDS-PAGE fingerprinting of whole-cell p roteins for the identification of Lactococcus strains to subspecies le vel, a total of 99 Lactococcus lactis subsp. lactis and subsp. cremori s strains were analysed by both techniques. The SDS-PAGE protein patte rns were compared to reference strains of lactic acid bacteria of the genera Aerococcus, Carnobacterium, Enterococcus, Lactobacillus, Lactoc occus, Leuconostoc, Pediococcus, Tetragenococcus, and Vagococcus. Nume rical analysis of the SDS-PAGE protein patterns clearly discriminated all species investigated. Seventy two Lactococcus lactis strains were assigned to their respective Lactococcus lactis subspecies. Twelve str ains were originally incorrectly identified to subspecies level and tw o strains were identified as Lactococcus garvieae. Four Lactococcus la ctis strains did not belong to the genus Lactococcus; one strain remai ned unidentified. For eight Lactococcus lactis strains identification to subspecies level was not possible by SDS-PAGE. Identification of La ctococcus lactis subsp. lactis var. diacetilactis strains could not be achieved by SDS-PAGE. One strain received as Lactobacillus sp. and tw o Lactococcus sp. strains were also identified as Lactococcus lactis. Due to a very high electrophoretic similarity observed between Lactoco ccus lactis subsp. lactis and Lactococcus lactis subsp. cremoris strai ns, subspecies discrimination required a high reproducibility level of the electrophoretic procedures used. The DCL differential medium fail ed for four Lactococcus lactis subsp. cremoris strains on solid medium but was correct when tested in broth. For three Lactococcus lactis su bsp. lactis strains, including the type strain, the reaction was not c onclusive. For 80 out of the 85 Lactococcus lactis strains identified to subspecies level by SDS-PAGE, the DCL differential medium was corre ct. One Lactococcus lactis strain, on repetition, displayed DCL test r esults contradictory to the SDS-PAGE identification. For four Lactococ cus lactis strains no conclusion could be drawn from the DCL test resu lts, while a good reaction was obtained (identified as Lactococcus lac tis subsp. lactis) for four non-lactococcal strains as well as for two Lactococcus garvieae strains. The test results for one unidentified i solate were not conclusive. Ten strains were identified as Lactococcus lactis subsp. lactis var. diacetilactis.