Investigating the Epidemiology of Repeat Chlamydia trachomatis Detection after Treatment by Using C. trachomatis OmpA Genotyping

Abstract

Repeat Chlamydia trachomatis detection frequently occurs within months after C. trachomatis infection treatment. The origins of such infection (persistence versus reinfection from untreated or new partners) are varied and difficult to determine. C. trachomatis strains can be differentiated by sequencing the ompA gene encoding the outer membrane protein A (OmpA). We used OmpA genotyping to investigate the epidemiology of repeat C. trachomatis detection after treatment in C. trachomatis-infected subjects seen at a sexually transmitted diseases clinic. Subjects were enrolled, tested for C. trachomatis, treated with azithromycin, and scheduled for a 6-month follow-up for repeat C. trachomatis testing. OmpA genotyping was performed on C. trachomatis-positive urogenital specimens obtained from patients at enrollment and follow-up. The enrollment visit OmpA genotypes for C. trachomatis were determined for 162 subjects (92% female, 94% African American). C. trachomatis was detected at follow-up in 39 subjects (24%). The OmpA genotype distribution at enrollment did not differ in those with versus those without repeat C. trachomatis detection. Of the 35 subjects with C. trachomatis strains genotyped at enrollment and follow-up, 7 (20%) had the same ompA sequence at both visits, while 28 (80%) had discordant sequences. A new sexual partner was reported more often in subjects with discordant C. trachomatis strains than in those with concordant strains (13 [46%] versus 1 [14%]; P ‫؍‬ 0.195). Half of the subjects with discordant C. trachomatis strains who reported sexual activity since treatment denied a new sexual partner; 62% of these subjects reported that their partner was treated. Our study demonstrates that most repeat C. trachomatis detections after treatment were new infections with a different C. trachomatis strain rather than reinfection with the same strain. OmpA genotyping can be a useful tool in understanding the origins of repeat C. trachomatis detection after treatment.R epeat detection of Chlamydia trachomatis within months of an initial chlamydia diagnosis and treatment is common, occurring in up to 20% of patients, or more in some studies (1-3). The origins of such repeat C. trachomatis detection (infection persistence versus reinfection from an untreated or new partner) are complex, as are the host and organism characteristics that may predispose humans to have repeat C. trachomatis detection after treatment. C. trachomatis strains can be differentiated by nucleotide sequence analysis of the ompA gene, which encodes an antigenically diverse and abundant outer membrane protein A (OmpA). Of the more than 15 C. trachomatis OmpA genotypes identified, the most common ones isolated from the urogenital tract are genotypes D through K (4). Within the OmpA genotypes, further nucleotide variation occurs, permitting strain-to-strain variation within isolates of the same C. trachomatis genotype; hence, C. trachomatis strains may be differentiated by their ompA sequence, and there may be different C. trachomatis strains...

Time to clearance of Chlamydia trachomatis RNA and DNA after treatment in patients coinfected with Neisseria gonorrhoeae – a prospective cohort study

“…Sena et al reported 12 % RNA persistence after 4 weeks in men, while Dukers et al reported 42 % intermittent positive results up to 51 days [ 9 , 19 ]. In addition, a recent study reported 24 % positivity in 180 patients after 6 months, but no data on re-exposure or reinfections were reported [ 26 ]. Since none of these previous studies reported results from consecutive days, the exact time to clearance could not be determined, and prolonged persistence could not be distinguished from blips.…”

“…Due to the small sample size we could not identify characteristics associated with the occurrence of blips. However, the occurrence of blips, as well as reinfections, could explain the higher positivity rates reported by some studies, especially in those with very long follow-up and limited sampling [ 9 , 15 , 18 , 19 , 26 ].…”

Azithromycin versus Doxycycline for UrogenitalChlamydia trachomatisInfection

“…Participants who tested negative for chlamydia at the first follow-up and who were still in a youth correctional facility on day 67 attended a second follow-up on that day for repeat nucleic acid amplification testing (to evaluate for persisting chlamydia that was not identified at the first follow-up) and for an interview in which the same information was collected as at the day 28 follow-up. Participants who tested positive for chlamydia at the first or second follow-up had OmpA genotyping performed on their urine specimens with the use of reported methods 21 to assess for concordant strains (identical ompA sequences); participants with suspected treatment failure had genotyping performed on urine specimens from both the enrollment visit and the follow-up visit.…”

Study of infectious conjunctivitis among children in rural areas of Qinghai province

“…Reagent kits (genomic DNA from tissue kits, Macherey-Nagel, Germany) were used to extract the DNA of C. trachomatis. DNA from the C. trachomatis endogenous plasmid was PCR-amplified using primers designed from those referenced in the literature (Kapil et al, 2015).…”