Men and Women Have an Equal Oropharyngeal and Anorectal Chlamydia trachomatis Bacterial Load: A Comparison of 3 Anatomic Sites

Abstract

Background The Chlamydia trachomatis bacterial load could have impact on transmission and sequelae. This is the first study providing comparison of C. trachomatis load at 3 anatomic sites estimated by cycle quantification (Cq) values. Methods Data from 7900 C. trachomatis-positive samples were included (2012–2018). Cq value was used as an inversely proportional measure for C. trachomatis load. Multivariable linear regression analyses assessed differences in mean Cq values. Results Vaginal swabs had the lowest Cq values (31.0) followed by urine (32.5), anorectal swabs (34.0), and oropharyngeal swabs (36.8) (P < .001). Men and women had similar oropharyngeal (36.4 vs 37.3; P = .13) and anorectal (34.2 vs 33.9; P = .19) Cq values. Men (32.2) and women (30.7) aged <25 years had lower urogenital Cq values than men (32.8) and women (31.9) aged ≥25 years (P < .001). HIV-positive patients had higher urogenital Cq values than HIV-negative patients (33.8 vs 32.6; P < .03). Conclusions Men and women have a similar C. trachomatis load at extragenital locations arguing for similar transmission potential and clinical relevance. Older patients and HIV-coinfected patients had lower C. trachomatis load, suggesting exposure to previous C. trachomatis infections potentially leading to partial immunity reducing load.

Routine universal testing versus selective or incidental testing for oropharyngeal Neisseria gonorrhoeae in women in the Netherlands: a retrospective cohort study

“…12,25 Spontaneous pharyngeal C trachomatis clearance has been estimated to be 36-57% within a median time of 9-10 days, 14,12,25 and this proportion seems to be higher than for genital or rectal infections. 12,[26][27][28] The percentage viable in pharyngeal C trachomatis samples (26%) has been much lower than in genital (94-96%) or rectal (58-67%) positive samples. 14.23 Regarding the public health effect, some evidence suggests that pharyngeal C trachomatis might contribute to ongoing transmission to sexual partners.…”

Analytical Evaluation of the Abbott RealTime CT/NG Assay for Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in Rectal and Pharyngeal Swabs

“…14 One recent large study found higher bacterial loads in rectal infections compared with pharyngeal infections and no differences between men and women tested but reported only cycle threshold levels. 15 Although it is difficult to define the precise number of bacteria needed to cause infections at these sites, the limit of detection for the Abbott RealTime CT/NG assay reported here would be expected to detect infections for the bacterial loads in those reports. The clinical performance of the Abbott RealTime CT/NG in rectal and pharyngeal specimens was recently evaluated in a multicenter study of 2598 symptomatic and asymptomatic patients, alongside two other assays that have now been FDA approved for detection of C. trachomatis and N. gonorrhoeae at rectal and pharyngeal sites.…”

Oropharyngeal Chlamydia trachomatis in women; spontaneous clearance and cure after treatment (FemCure)

“…6 The proportion of spontaneous clearance of oropharyngeal CT is much higher than we observed for vaginal CT (6.0%, 95% CI 4.2% to 8.4%) and rectal CT (15.8%, 95% CI 10.8% to 21.8%). 16 A possible explanation is the lower initial CT bacterial load at the oropharyngeal site compared with the vaginal and the rectal site, 7 because lower initial load is associated with oropharyngeal CT clearance. 6 8 Of those women who remained CT positive at the oropharyngeal site at week 0, three quarters had non-viable CT only.…”

“…6 Data on oropharyngeal CT in women are scarce as women are not routinely tested for oropharyngeal CT, while in MSM oropharyngeal testing is an emerging practice. 5 Oropharyngeal CT infections have been considered low bacterial load infections 7 that are frequently self-limiting. 6 8 Concerns were raised that oropharyngeal CT infection may initiate a reservoir of infection, that is, via the gastrointestinal tract.…”