Application of Congo Red agar for detection of Streptococcus dysgalactiae isolated from diseased fish

作者：Abdelsalam M; Nakanishi K; Yonemura K; Itami T; Chen S C; Yoshida T^*

来源：Journal of Applied Ichthyology, 2009, 25(4): 442-446.

DOI：10.1111/j.1439-0426.2009.01226.x

P>The strong clinical similarity between Lancefield group C Streptococcus dysgalactiae subsp. dysgalactiae (GCSD) and Lactococcus garvieae infections, characterized by development of necrotic lesions in the caudal peduncle of infected fish, has hindered differentiation of these two strains, making rapid and accurate diagnosis of diseased fish in fish farms difficult. GCSD from diseased fish were presumptively identified and isolated using Todd-Hewitt agar containing 30 mu g ml(-1) of Congo Red dye (TH-CR). TH-CR agar was also used to detect and presumptively identify the GCSD obtained from artificially or naturally infected fish. Orange GCSD colonies distinct from the L. garvieae colonies were observed on the TH-CR agar; thus, TH-CR agar can be used to detect and identify GCSD isolated from infected fish.

• 出版日期2009-8