Optimal methods for the isolation of groups A, B, C and G streptococci.

The recovery of beta-haemolytic streptococci on laboratory media over a 48-hour period was studied from a variety of swabs held in plastic containers only, and from those held in transport media, stored either at room temperature or at 4 degrees C. The best results were obtained from swabs not held in transport medium and of these plain cotton-wool swabs consistently produced optimal results. The percentage recovery over 48 hours was maintained satisfactorily only when the swabs were kept at 4 degrees C.