Rarely occurring Shigella serovars.

In addition to the predominant Shigella sonnei, also rarely occurring Shigella serovars have been found in Czechoslovakia: 4 serovars of subgroup A (S. dysenteriae 3, 4, 7 and 12) and 11 serovars of subgroup C (S. boydii 2, 3, 5, 7, 9 lactose-positive, 10, 13, 14 aerogenic, mannitol-negative, 15, 16 and the provisional serovar E 16553). First isolations of these serovars were mostly connected with cases imported from abroad. Some serovars were isolated repeatedly. Newly recognized serovars of S. flexneri (3b, 5a) as well as biochemically aberrant strains of subgroup B (S. flexneri), C (S. boydii) and D (S. sonnei) were isolated. Frequency and importance of some S. flexneri serovars have been changing in the course of time, e.g. S. flexneri 2b, that had evidently been frequent in central Europe 40 years ago, disappeared completely.