Caratterizzazione fenotipica di ceppi di Streptococcus agalactiae (streptococco di gruppo B) di origine umana e bovina isolati nel Nord Italia

Serotype, haemolytic activity and CAMP reaction of 466 strains of Streptococcus agalactiae (269 of human origin and 197 of bovine origin) isolated in the North of Italy (Lombardia, Emilia) were evaluated.The presence of the rare serotype VII was recorded in 3 human strains and in 1 bovine isolates. In human strains serotype III (32%) was the most common followed by serotypes Ia (17.1%),V (13.8%), II (9.7%), Ib (3.7%), IV (3%),VII (1.1%); 19.6% of strains resulted nontypeable. Between bovine strains the most abundant was serotype IV (22.3%), followed by Ib and III (5.6%), II (5.1%), Ia (3.6%),V (3%) and VII (0.5%), a large number was nontypeable (54.3%). Stains belonging to serotype of VI or VIII were not observed. 43 strains were anhemolytic (15 of humane origin and 28 bovine origin) and 5 strains were CAMP-negative (2 humane and 3 bovine).