title: Molecular characterization of disease-associated streptococci of the mitis group that are optochin susceptible.
abstract: Eight optochin-susceptible (Opt(s)) alpha-hemolytic (viridans) streptococcus isolates were characterized at the molecular level. These isolates showed phenotypic characteristics typical of both viridans streptococci and Streptococcus pneumoniae. Comparison of the sequence of housekeeping genes from these isolates with those of S. pneumoniae, Streptococcus mitis, Streptococcus oralis, and Streptococcus pseudopneumoniae suggested that the Opt(s) isolates corresponded to streptococci of the mitis group. Besides, the Opt(s) streptococci were negative by a Gen-Probe AccuProbe pneumococcus test and hybridized with specific pneumococcal probes (lytA and ply) but also with ant, a gene not present in most S. pneumoniae strains. Moreover, the isolates were insoluble in 1% sodium deoxycholate but completely dissolved in 0.1% deoxycholate. Sequence analysis of the lytA gene revealed that the Opt(s) streptococci carried lytA alleles characteristic of those present in nonpneumococcal streptococci of the mitis group. The determination of the partial nucleotide sequence embracing the atp operon encoding the F(o)F(1) H(+)-ATPase indicated that the optochin susceptibility of the isolates was due to the acquisition of atpC, atpA, and part of atpB from S. pneumoniae by horizontal gene transfer.
authors.affiliation: Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain.
authors.forename: Luz
authors.initials: L
authors.lastname: Balsalobre
authors.forename: Antonia
authors.initials: A
authors.lastname: Hernández-Madrid
authors.forename: Daniel
authors.initials: D
authors.lastname: Llull
authors.forename: Antonio J
authors.initials: AJ
authors.lastname: Martín-Galiano
authors.forename: Ernesto
authors.initials: E
authors.lastname: García
authors.forename: Asunción
authors.initials: A
authors.lastname: Fenoll
authors.forename: Adela G
authors.initials: AG
authors.lastname: de la Campa
mesh_terms: D000483:Alleles; D001483:Base Sequence; D002876:Chromosomes, Bacterial; D008969:Molecular Sequence Data; D009876:Operon; D011803:Quinine / Q000031:analogs & derivatives* / Q000494:pharmacology; D034361:Streptococcus mitis / Q000187:drug effects / Q000235:genetics*
chemical_list: C017303:ethylhydrocupreine; D011803:Quinine