A German Chlamydia trachomatis screening program employing semi-automated real-time PCR: results and perspectives

Kanoi B, Kimani R, Maina M, Waweru H, Kamita M, Ndirangu I, M. Abkallo H, Oduor B, Pamme N, Dupaty J, M. Klapperich C, Raju Lolabattu S, Gitaka J. Multi-repeat sequences identification using genome mining techniques for developing highly sensitive molecular diagnostic assay for the detection of Chlamydia trachomatis

Chlamydia trachomatis ( C. trachomatis) is a common sexually transmitted infection (STI). In 2019, the World Health Organization reported about 131 million infections. The majority of infected patients are asymptomatic with cases remaining undetected. It is likely that missed C. trachomatis infections contribute to preventable adverse health outcomes in women and children. Consequently, there is an urgent need of developing efficient diagnostic methods. In this study, genome-mining approaches to identify identical multi-repeat sequences (IMRS) distributed throughout the C. trachomatis genome were used to design a primer pair that would target regions in the genome. Genomic DNA was 10-fold serially diluted (100pg/μL to 1×10 -3pg/μL) and used as DNA template for PCR reactions. The gold standard PCR using 16S rRNA primers was also run as a comparative test, and products were resolved on agarose gel. The novel assay, C. trachomatis IMRS-PCR, had an analytical sensitivity of 4.31 pg/µL, representing better sensitivity compared with 16S rRNA PCR (9.5 fg/µL). Our experimental data demonstrate the successful development of lateral flow and isothermal assays for detecting C. trachomatis DNA with potential use in field settings. There is a potential to implement this concept in miniaturized, isothermal, microfluidic platforms, and laboratory-on-a-chip diagnostic devices for reliable point-of-care testing.

High-Throughput Testing of Urogenital and Extragenital Specimens for Detection of Chlamydia Trachomatis and Neisseria Gonorrhoeae with Cobas® CT/NG

We compared the analytical and clinical performance of cobas^® CT/NG for use on the Cobas^® 6800/8800 Systems with the Cobas^® 4800 CT/NG Test from urogenital and extragenital specimens in over 12,000 specimens from both male and female subjects in Germany and the United States. The analytical sensitivity was ≤40 EB/ml for Chlamydia trachomatis (CT) and ≤1 CFU/ml for Neisseria gonorrhoeae (NG). Using clinical specimens, the overall percent agreement with the Cobas^® 4800 CT/NG Test was >98.5%. Across urogenital specimens, there were 93 discrepant specimens; 76 (93.8%) of 81 CT discrepant specimens were 6800+/4800– and 10 (83.3%) of 12 NG discrepant specimens were 6800+/4800–. Sequencing verified CT results for 45 (61.6%) of 73 samples positive by 6800 and 1 (20%) of 5 positive by 4800. Similarly, 7 (70.0%) of 10 NG samples positive by 6800 and 1 of 2 positive by 4800 were confirmed by sequencing. Among discrepant extragenital specimens (all 6800+/4800–), 7 (50%) of 14 oropharyngeal and 23 (76.7%) of 30 anorectal CT discordant samples were confirmed as CT positive by sequencing; all 8 anorectal and 20 (90.9%) of 22 oropharyngeal NG discordant results were also confirmed as NG positive. In conclusion, Cobas^® CT/NG for use on the Cobas^® 6800/8800 Systems provides high-throughput automated solutions for sexually transmitted infection (STI) screening programs.

Prevalence of Chlamydia trachomatis infection in parturient women in Gipuzkoa, Northern Spain

The prevalence of Chlamydia trachomatis infection in Southern Europe is poorly understood and its identification is essential for the design of appropriate prevention policies. The prevalence of C. trachomatis in 2011–2014 was determined through polymerase chain reaction in urine samples from 11,687 unselected parturient women from the Basque Country, Spain (San Sebastián area). The overall age-adjusted prevalence was 1.0 % (95 % CI 0.8–1.2). The prevalence of infection in women younger than 25 years was 6.4 % and decreased substantially with increasing age: 2.0 % in 25–29 year-olds and 0.5 % in older women (P < 0.001). The prevalence was higher in parturient of foreign origin (1.9 %, 95 % CI 1.3–2.5) than in Spanish parturients (0.8 %, 95 % CI 0.6–1.0), (P < 0.001). The results of this study support the need to screen young women as part of antenatal care in Spain.

Screening for Chlamydia trachomatis in Egyptian women with unexplained infertility, comparing real-time PCR techniques to standard serology tests: case control study

BACKGROUND

To study the prevalence of Chlamydia infection in women with primary and secondary unexplained infertility using ELISA technique for antibody detection and real time, fully automated PCR for antigen detection and to explore its association with circulating antisperm antibodies (ASA).

METHODS

A total of 50 women with unexplained infertility enrolled in this case control study and a control group of 44 infertile women with a known cause of infertility. Endocervical specimens were collected for Chlamydia antigen detection using PCR and serum samples for antibodies detection. Circulating anti-sperm antibodies were detected using sperm antibody Latex Agglutination tests.

RESULTS

The overall prevalence of Chlamydial infection in unexplained infertility cases as detected by both ELISA and PCR was 40 % (20/50). The prevalence of current Chlamydial genital infection as detected by real-time PCR was only 6.0 % (3/50); two of which were also IgM positive. Prevalence of ASA was 6.0 % (3/50); all were sero-negative for anti-C.trachomatis IgM and were PCR negative.

CONCLUSION

The incidence of Chlamydial infection in Egyptian patients with unexplained infertility is relatively high. In the setting of fertility investigations; screening for anti. C.trachomatis antibodies using ELISA, and treatment of positive cases should be considered. The presence of circulating ASA does not correlate with the presence of old or current Chlamydia infection in women with unexplained infertility.

Screening for Chlamydia trachomatis, Neisseria gonorrhoeae, and Mycoplasma genitalium should it be integrated into routine pregnancy care in French young pregnant women?

Chlamydia trachomatis, Neisseria gonorrhoeae, and Mycoplasma genitalium screening during pregnancy is not performed routinely in France. We conducted the first prospective study in 1004 women attending for routine antenatal care to determine the prevalence and risk factors for these bacterial infections. The overall prevalence of C. trachomatis, N. gonorrhoeae, and M. genitalium infections was 2.5%, 0%, and 0.8%, respectively. In patients aged 18-24 years, the prevalence increased to 7.9% for C. trachomatis and to 2.4% for M. genitalium. C. trachomatis infection was associated with age ≤24 years or being single or having more than 5 sexual partners in a lifetime. M. genitalium infection was more frequent in patients aged ≤24 years or who had a history of abortion or their first sexual intercourse after 20 years of age. The high prevalence of C. trachomatis in pregnant women aged ≤24 years, mostly asymptomatic, suggests that systematic screening could be beneficial.

Risk factors for Chlamydia trachomatis infection in adolescents: results from a representative population-based survey in Germany, 2003-2006

Infections with Chlamydia trachomatis (CT) can lead to severe sequelae; however, they are not notifiable in Germany. We tested urine samples from participants of KiGGS (German Health Interview and Examination Survey for Children and Adolescents) for CT infections and linked the results to demographic and behavioural data from 1,925 participants (girls aged 15-17 years and boys aged 16-17 years) to determine a representative prevalence of CT infection in adolescents in Germany and to assess associated risk factors. Prevalence of CT infection was 2.2% (95% CI: 1.4-3.5) in girls and 0.2% (95% CI: 0.1-0.7) in boys. CT infection in girls was associated with higher use of alcohol, marijuana and cigarettes, lower social status, oral contraceptive use, pregnancy, repeated lower abdominal pain and higher rates of doctors' consultations within the preceding three months and consultation of gynaecologists within the last 12 months. In multiple logistic regression, we identified two predictors for CT infection: marijuana consumption often or several times within the last 12 months (F(1,164)=7.56; p<0.05) and general health status less than 'very good' (F(1,164)=3.83; p=0.052). Given our findings, we recommend enhancing sex education before sexual debut and promoting safe sex practices regardless of the contraceptive method used. Well-informed consumption of alcohol should be promoted, the risky behaviour of people intoxicated through consumption of marijuana highlighted and doctors' awareness of CT screening enhanced.