What kind of organisms does Barbour-Stoenner-Kelly (BSK) agar primarily culture?

Barbour-Stoenner-Kelly (BSK) agar is specifically designed for the cultivation of Borrelia species, which are known to be spirochete bacteria and are primarily associated with human diseases such as Lyme disease and relapsing fever. This medium provides the necessary nutrients and conditions that support the growth of these fastidious organisms, which require a particular environment that is typically not found in standard culture media.

The formulation of BSK agar includes specific additives that help to facilitate the growth of Borrelia, such as serum and complex carbohydrates, which mimic the natural habitat of these bacteria found in the hosts they infect. The ability of BSK agar to support the growth of Borrelia species has been critical for their isolation and study in laboratory settings, aiding in the understanding of their biology and pathogenesis.

In contrast, the other options pertain to organisms that have different cultivation requirements and are not specifically cultured using BSK agar. Streptococcus species prefer different types of media that support lactic acid fermentation, while Mycobacterium species often require enriched media, such as acid-fast bacilli media. Legionella species typically grow on specialized media like charcoal yeast extract agar, which contains specific nutrients and conditions suitable for their growth. Thus