Comparison of sonicated and nonsonicated specimens for the isolation of Chlamydia trachomatis

Cultures of sonicated and nonsonicated chlamydial specimens were compared using a Heat Systems sonicator with a cup-horn attachment for sonication. Chlamydial inclusions were detected in 71 of 780 cultures tested; 44 (62%) were positive from both, while 12 (16.9%) were positive in nonsonicated only, and 15 (21.1%) in sonicated specimens only. The mean number of inclusions from sonicated specimens was more than double that from nonsonicated specimens. The cultures of sonicated specimens could be screened more quickly because of statistically significant higher inclusion counts, less toxicity, and the absence of overlying epithelial cells.