Mini (pinpoint) koloni oluşturan beta-hemolitik streptokoklar: Streptococcus milleri grubu ve çeşitli özellikleri

Koloni çapı % 50), S.intermedius nadiren, S.anginosus çok nadiren beta-hemoliz yapar; beta-hemoliz yapanların bazıları Lancefield grup antijenlerine (A, C, G, F) sahip olabilir ve bu nedenle saptanan antijene göre yapılan tanımlama yanlış olur. Genel özellikleri klasik beta-hemolitik streptokoklar ile ortaktır ve çeşitli invaziv infeksiyonlara neden olurlar. Steril mataryelden izole edildiklerinde patojen kabul edilirler. Ancak, normal flora bakterileri içinde bulunan ve Lancefield grup A, C, G, F antijenlerine sahip mini koloni oluşturan beta-hemolitik streptokokların patojenlikleri kuşkulu olduğundan doğru idantifiye edilmelidirler. Ayırıcı tanıda koloni morfolojisi ve VP (Voges-Proskauer) pozitifliği iki önemli göstergedir. Bununla beraber rutin tanıda biyokimyasal özellikler ve Lancefield antijenlerinin varlığı yeterli olmadığından mini koloni oluşturan suşların ileri incelemeye alınması gerekmektedir.

Anahtar Kelimeler:

Streptococcus, Streptococcus milleri grubu, Viridans streptokok

Different spesifications of small colony forming (pinpoint) beta-hemolytic streptococci (S. milleri)

A group of streptococci with a colony diameter of <0.5 mm and with a hemolysis zone two or three times larger the colony diameter is called S.milleri group. The group mainly has alpha- or gamma-hemolysis and has three species called S.anginosus, S.intermedius and S.constellatus. S.constellatus has two subspecies called S.constellatus subsp constellatus and S.constellatus subsp pharyngis. S.constellatus generally (> 50 %), S.intermedius rarely, S.anginosus very rarely have beta-hemolysis; the species with beta-hemolysis sometimes have Lancefield group antigens (A, C, G, F). Because of that, the identification performed by antigen examination can be misidentified. The general specification is the same as classical beta-hemolytic streptococci and they can cause some invasive infections. Because the pathogenicity of this group is disputable when they are isolated from specimens with bacterial flora and they may have Lancefield A, C, G, F groups antigens, such isolates should be identified correctly. Two indicators such as colony morphology and VP (Voges-Proskauer) are important in their identification. Biochemical analysis and the presence of Lancefield antigens sometimes are not enough for correct identifica-tion and small colony forming strains should be evaluated for advanced examinations.

Keywords:

Streptococcus, Streptococcus milleri Group, Viridans Streptococci,

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