Identification of Shigella flexneri subserotype 1c in rural Egypt

In a population based study of diarrhea in rural, northern Egypt, 60 Shigel la flexneri strains were identified, of which 10 could not be definitively serotyped. Serological analysis with commercial reagents suggested that the y were serotype 1, but the strains failed to react with subserotype 1a- or Ib-specific antibodies. All 10 strains reacted with MASF Ic, a monoclonal a ntibody specific for a provisional S. flexneri subserotype, Ic, first ident ified in Bangladesh and not previously detected outside of that region. Our results show that S. flexneri subserotype Ic is not unique to Bangladesh a nd that the inability to detect it may reflect both the limited use of suit able screening methods and the rarity of this subserotype.