New data suggest that universal rectal screening for Chlamydia trachomatis among high-risk women may be warranted to identify asymptomatic individuals.
“Although the overall personal and public health benefits of the detection of C. trachomatis remain to be elucidated, early detection and treatment are likely to be critical strategies in chlamydia control to prevent complications and reduce transmission,” the researchers wrote in Clinical Infectious Diseases. “Our study shows that most rectal infections are asymptomatic and confirm previous findings that using a history of anal intercourse to screen for rectal chlamydia is not a reliable triaging tool for anatomical site-specific testing.”
Jennifer Gratrix, MSc, of the STI Centralized Services, Alberta Health Services in Edmonton, Canada, and colleagues evaluated the prevalence of rectal chlamydia among women who received pelvic exams at two STI clinics in Calgary and Edmonton from July 20 to Dec. 31, 2012. The study included 3,055 women who underwent rectal screening, regardless of their history of anal intercourse. Almost all of the rectal screenings were accompanied by genitourinary screening. All testing was completed with nucleic acid amplification tests.
The prevalence of chlamydia, regardless of infection site, was 13% at the Calgary clinic and 17.2% at the Edmonton clinic. The prevalence of rectal chlamydia was 11.7% at Calgary and 13.5% at Edmonton.
Overall, there were 432 cases of chlamydia identified and 356 of the cases (82.4%) had positive rectal tests. At Calgary, 170 cases (89%) were rectal-positive; 42.4% of cases were positive both at the genitourinary and rectal sites and 46.6% were positive only at the rectal site. At Edmonton, 186 (77.1%) cases were rectal-positive; 59.3% were positive at both the genitourinary and rectal sites and 17.8% were positive only at the rectal site.
With the detection of 89 rectal-only cases at Calgary, the case detection increased by 87.3%, from 102 genitourinary cases to 191 total cases. In Edmonton, there were 43 rectal-only cases identified. This increased the case detection by 21.7%, from 198 genitourinary cases to 241 total cases.
“Our findings add to the growing body of evidence supporting universal rectal screening in high-risk women,” the researchers wrote. “Future studies should examine the cost effectiveness of rectal chlamydia screening in high risk women and examine the long term implications of untreated rectal chlamydia on health and transmission.”
Disclosure: The researchers report no relevant disclosures.