title: Streptococcus sinensis may react with Lancefield group F antiserum.
abstract: Lancefield group F streptococci have been found almost exclusively as members of the 'Streptococcus milleri' group, although they have been reported very occasionally in some other streptococcal species. Among 302 patients with bacteraemia caused by viridans streptococci over a 6-year period, three cases were caused by Streptococcus sinensis (type strain HKU4T, HKU5 and HKU6). All three patients had infective endocarditis complicating their underlying chronic rheumatic heart diseases. Gene sequencing showed no base differences between the 16S rRNA gene sequences of HKU5 and HKU6 and that of HKU4T. All three strains were Gram-positive, non-spore-forming cocci arranged in chains. All grew on sheep blood agar as alpha-haemolytic, grey colonies of 0.5-1 mm in diameter after 24 h incubation at 37 degrees C in ambient air. Lancefield grouping revealed that HKU5 and HKU6 were Lancefield group F, but HKU4T was non-groupable with Lancefield groups A, B, C, D, F or G antisera. HKU4T was identified by the Vitek system (GPI), API system (20 STREP) and ATB system (ID32 STREP) as 99 % Streptococcus intermedius, 51.3 % S. intermedius and 99.9 % Streptococcus anginosus, respectively. Using the same tests, HKU5 was identified as 87 % Streptococcus sanguinis/Streptococcus gordonii, 59 % Streptococcus salivarius and 99.6 % S. anginosus, respectively, and HKU6 as 87 % S. sanguinis/S. gordonii, 77 % Streptococcus pneumoniae and 98.3 % S. anginosus, respectively. The present data revealed that a proportion of Lancefield group F streptococci could be S. sinensis. Lancefield group F streptococci should not be automatically reported as 'S. milleri'.
authors.affiliation: Department of Microbiology, The University of Hong Kong, University Pathology Building, Queen Mary Hospital, Hong Kong.
authors.forename: Patrick Cy
authors.initials: PC
authors.lastname: Woo
authors.affiliation: Department of Microbiology, The University of Hong Kong, University Pathology Building, Queen Mary Hospital, Hong Kong.
authors.forename: Jade Ll
authors.initials: JL
authors.lastname: Teng
authors.affiliation: Department of Microbiology, The University of Hong Kong, University Pathology Building, Queen Mary Hospital, Hong Kong.
authors.forename: Kit-Wah
authors.initials: KW
authors.lastname: Leung
authors.affiliation: Department of Microbiology, The University of Hong Kong, University Pathology Building, Queen Mary Hospital, Hong Kong.
authors.forename: Susanna Kp
authors.initials: SK
authors.lastname: Lau
authors.affiliation: Department of Microbiology, The University of Hong Kong, University Pathology Building, Queen Mary Hospital, Hong Kong.
authors.forename: Herman
authors.initials: H
authors.lastname: Tse
authors.affiliation: Department of Microbiology, The University of Hong Kong, University Pathology Building, Queen Mary Hospital, Hong Kong.
authors.forename: Beatrice Hl
authors.initials: BH
authors.lastname: Wong
authors.affiliation: Department of Microbiology, The University of Hong Kong, University Pathology Building, Queen Mary Hospital, Hong Kong.
authors.forename: Kwok-Yung
authors.initials: KY
authors.lastname: Yuen
mesh_terms: D016470:Bacteremia / Q000382:microbiology; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000737:chemistry / Q000302:isolation & purification; D004697:Endocarditis, Bacterial / Q000382:microbiology; D020459:Genes, rRNA / Q000235:genetics; D005840:Gentian Violet; D006095:Gram-Positive Cocci; D006461:Hemolysis; D006801:Humans; D008969:Molecular Sequence Data; D010619:Phenazines; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012703:Serotyping; D013171:Spores, Bacterial; D013290:Streptococcal Infections / Q000175:diagnosis / Q000382:microbiology*; D034363:Viridans Streptococci / Q000145:classification* / Q000166:cytology / Q000276:immunology / Q000502:physiology*
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; C035863:Gram's stain; D010619:Phenazines; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D005840:Gentian Violet