'Dodgy 6As': differentiating pneumococcal serotype 6C from 6A by use of the Quellung reaction.

摘要

The Quellung reaction has long been the standard method for pneumococcal serotyping (7); however, the new serotype 6C is reportedly indistinguishable from serotype 6A using this method (8). We report an anomalous Quellung reaction associated with serotype 6C, which may aid in diagnostic interpretation.The 7-valent pneumococcal conjugate vaccine was introduced in Australia for indigenous and other high-risk infants in 2001. In 2002, a serotyping anomaly was noted in a subset of carriage isolates. These isolates appeared negative for all nine pool antisera A to I (covering 90 pneumococcal serotypes) but reacted positively with Omni serum