Opportunistic screening for Chlamydia trachomatis cervicitis: the value of cytobrush specimens for detection by PCR...

Endocervical sampling for microbiological and pathological screening is laborious and expensive due to different sampling devices and techniques. The purpose of this study was to examine if the routine procedure could be simplified by using a cytobrush for concurrent cytology and sampling for Chlamydia trachomatis detection using the PCR method or cell culture. As a sampling device control we used a conventional rayon swab.

Culture: Out of 873 paired endocervical specimens, C. trachomatis was isolated in 68 swab specimens and in 65 cytobrush specimens (overall detection rate 8.4%). The cytobrush proved less suitable than the swab for the isolation of C. trachomatis as 31.5% of the cytobrush samples showed cytotoxicity to the cultured cells vs 0.9% of the swab samples. PCR: In a random sample of 427 paired endocervical specimens, C. trachomatis was detected in 45 pairs without any difference between the two sampling devices. The sensitivity of PCR was 93.8% vs 89.6% and 87.5% in cultured swab and cultured cytobrush specimens, respectively. The cytobrush can therefore be recommended as a cervical sampling device if a PCR assay is used for the detection of C. trachomatis, but not if the cell culture method is used, due to high cytotoxicity. Furthermore, the same cytobrush may be used for cervical cytological sampling and thereafter placed in transport medium for subsequent C. trachomatis detection if the PCR technique is used.