Aim: This study aimed to screen for Chlamydia trachomatis infection by direct fluorescein antibody (DFA) method in a high-risk population, registered female sex workers (FSWs) in Ankara, Turkey, to investigate the advantages and disadvantages of using this method in a routine screening program of the FSW population. Materials and Methods: All registered FSWs (n = 152) in Ankara were enrolled in the study. None of them were showing any genital signs or symptoms of sexually transmitted infections (STIs). Endocervical swabs were collected and examined for C. trachomatis by DFA method (Fluorotect Chlamydia, Omega Diagnostics, UK). Cellular adequacy of the specimens was examined for the presence of at least five columnar epithelial cells per X400 field. A positive diagnosis was made when fixed and stained specimens showed at least 10 chlamydial bodies under the fluorescein microscope. A positive control slide was also stained and examined on each study day. Results: Of the 152 specimens, only 112 (73.7%) were adequate; it was not possible to obtain adequate specimen from the remainder of the women because the cervical os was too tight to insert the swab. Of the 112 adequate specimens, 3.6% (4/112) were positive for C. trachomatis serotype-specific major outer membrane proteins (MOMP), based on DFA method. Conclusions: C. trachomatis infection rate of 3.6% was relatively low in this group of women compared to a priori expectations, yet still remarkable. A significant level of ´´inadequacy´´ in obtaining endocervical specimens (in 26.3% of FSWs) could have limited the external validity of the prevalence rate estimation in this population and the practicality of DFA use for C. trachomatis screening. C. trachomatis screening should be integrated in the STI control program for sex workers in Turkey. However, further research is warranted to optimize the method to be used in screening and/or diagnosis in such high-risk groups.

Aim: This study aimed to screen for Chlamydia trachomatis infection by direct fluorescein antibody (DFA) method in a high-risk population, registered female sex workers (FSWs) in Ankara, Turkey, to investigate the advantages and disadvantages of using this method in a routine screening program of the FSW population. Materials and Methods: All registered FSWs (n = 152) in Ankara were enrolled in the study. None of them were showing any genital signs or symptoms of sexually transmitted infections (STIs). Endocervical swabs were collected and examined for C. trachomatis by DFA method (Fluorotect Chlamydia, Omega Diagnostics, UK). Cellular adequacy of the specimens was examined for the presence of at least five columnar epithelial cells per X400 field. A positive diagnosis was made when fixed and stained specimens showed at least 10 chlamydial bodies under the fluorescein microscope. A positive control slide was also stained and examined on each study day. Results: Of the 152 specimens, only 112 (73.7%) were adequate; it was not possible to obtain adequate specimen from the remainder of the women because the cervical os was too tight to insert the swab. Of the 112 adequate specimens, 3.6% (4/112) were positive for C. trachomatis serotype-specific major outer membrane proteins (MOMP), based on DFA method. Conclusions: C. trachomatis infection rate of 3.6% was relatively low in this group of women compared to a priori expectations, yet still remarkable. A significant level of ´´inadequacy´´ in obtaining endocervical specimens (in 26.3% of FSWs) could have limited the external validity of the prevalence rate estimation in this population and the practicality of DFA use for C. trachomatis screening. C. trachomatis screening should be integrated in the STI control program for sex workers in Turkey. However, further research is warranted to optimize the method to be used in screening and/or diagnosis in such high-risk groups.