New Variant Of Chlamydia Trachomatis Research Articles

Changes in the Trend of Sexually Acquired Chlamydia Infections in Sweden and the Role of Testing: A Time Series Analysis.

We investigated the notification trends of sexually acquired chlamydia (chlamydia) and its association with testing in Sweden before (1992-2004) and after (2009-2018) the discovery of a new variant of Chlamydia trachomatis (nvCT). We applied monthly time series analysis to study chlamydia trends and annual time series to study chlamydia rates adjusted for testing. We analyzed incidence nationally and by county group (based on able and unable to detect nvCT at time of discovery). We present data on 606,000 cases of chlamydia and 9.9 million persons tested. We found a U-shaped chlamydia trend during the period 1992-2004, with an overall increase of 83.7% from 1996 onward. The period 2009-2018 began with a stable trend at a high incidence level followed by a decrease of 19.7% during the period 2015-2018. Peaks were seen in autumn and through during winter and summer. Similar results were observed by groups of county, although with varying levels of increase and decrease in both periods. Furthermore, increased testing volume was associated with increased chlamydia rates during the first period (P = 0.019) but not the second period. Our results showed that chlamydia trends during the period 2009-2018 were not driven by testing, as they were during the period 1992-2004. This suggests less biased notified chlamydia rates and thus possibly a true decrease in chlamydia incidence rates. It is important to adjust case rates for testing intensity, and future research should target other potential factors influencing chlamydia rates.

A Chlamydia trachomatis 23S rRNA G1523A variant escaping detection in the Aptima Combo 2 assay (Hologic) was widespread across Denmark in July-September 2019.

Chlamydia trachomatis infection is the most common bacterial sexually transmitted infection globally, and nucleic acid amplification tests (NAATs) are recommended for highly sensitive and specific diagnosis. In early 2019, the Finnish new variant of Chlamydia trachomatis (FI-nvCT) was identified. The FI-nvCT has a C1515T mutation in the 23S rRNA gene, making it escaping detection in the Aptima Combo 2 (AC2; Hologic) NAAT, and the FI-nvCT has been subsequently reported in Sweden and Norway. In the present study, we investigated the presence of the FI-nvCT and other AC2 diagnostic-escape CT mutants in July-September 2019 in Denmark. The FI-nvCT was present but rare in Denmark. However, another AC2 diagnostic-escape CT mutant (with a 23S rRNA G1523A mutation) was found to be widespread across Denmark, accounting for 95% (76/80) of AC2 diagnostic-escape nvCT samples from five Danish CT-diagnostic laboratories. This nvCT-G1523A has previously only been detected in one single sample in the United Kingdom and Norway, respectively. It is vital to monitor the continued stability of the NAAT targets in local, national and international settings and monitor as well as appropriately analyse incidence, unexplained shifts in diagnostics rates and/or annual collections of samples diagnosed as negative/equivocal using NAATs with different target(s). Furthermore, diagnostic CT NAATs with dual target sequences are crucial, and fortunately, an updated Hologic AC2 assay including one additional target sequence is in advanced development.

Validation of an Aptima-format Finnish new variant of Chlamydia trachomatis (FI-nvCT) surveillance assay, 2019.

The Finnish new variant of Chlamydia trachomatis (FI-nvCT) is escaping diagnostics in Finland, Norway and Sweden. We have developed and validated an Aptima-format nucleic acid amplification test (NAAT) designed specifically to detect the FI-nvCT. This NAAT has high sensitivity (100%) and specificity (100%) for the FI-nvCT strain, enabling further investigation of the geographic distribution, prevalence and transmission of this diagnostic-escape mutant in screening populations in Europe.

The 'Finnish new variant of Chlamydia trachomatis' escaping detection in the Aptima Combo 2 assay is widespread across Norway, June to August 2019.

The ‘Finnish new variant of Chlamydia trachomatis’ (FI-nvCT), escaping detection in the Aptima Combo 2 assay (AC2), is widespread across Norway. From June to August 2019, 84% (81/97) of available AC2/Aptima CT discordant samples from five laboratories were confirmed as FI-nvCT. Two additional CT variants (CT 23S rRNA C1514T and G1523A) also escaped AC2 detection. The high FI-nvCT proportion might indicate a long-term national spread and it cannot be excluded that FI-nvCT emerged in Norway.

Rise and fall of the new variant of Chlamydia trachomatis in Sweden: mathematical modelling study

ObjectivesA new variant of Chlamydia trachomatis (nvCT) was discovered in Sweden in 2006. The nvCT has a plasmid deletion, which escaped detection by two nucleic acid amplification tests (Abbott-Roche, AR),...

The Finnish New Variant of Chlamydia trachomatis with a Single Nucleotide Polymorphism in the 23S rRNA Target Escapes Detection by the Aptima Combo 2 Test.

In 2019, more than 200 cases of Chlamydia trachomatis negative/equivocal by the Aptima Combo 2 assay (AC2, target: 23S rRNA) with slightly elevated relative light units (RLUs), but positive by the Aptima Chlamydia trachomatis assay (ACT, target: 16S rRNA) have been detected in Finland To identify the cause of the AC2 CT false-negative specimens, we sequenced parts of the CT 23S rRNA gene in 40 specimens that were AC2 negative/equivocal but ACT positive. A single nucleotide polymorphism (SNP; C1515T in the C. trachomatis 23S rRNA gene) was revealed in 39 AC2/ACT discordant specimens. No decrease in the number of mandatorily notified C. trachomatis cases was observed nationally in Finland in 2010–2019. When RLUs obtained for AC2 negative specimens were retrospectively evaluated in 2011–2019, a continuous increase in the proportion of samples with RLUs 10–19 was observed since 2014, and a slight increase in the proportion of samples with RLUs 20–84 in 2017–2019, indicating that the Finnish new variant of C. trachomatis might have been spreading nationally for several years. This emphasizes that careful surveillance of epidemiology, positivity rate and test performance are mandatory to detect any changes affecting detection of infections.

Finnish new variant of Chlamydia trachomatis escaping detection in the Aptima Combo 2 assay also present in Örebro County, Sweden, May 2019.

We identified the first two cases of the Finnish new variant of Chlamydia trachomatis (F-nvCT) beyond Finland in two clinical urogenital specimens in Örebro County, Sweden. These Aptima Combo 2 assay-negative specimens were Aptima Chlamydia trachomatis (CT) assay positive and had the characteristic C1515T mutation in the 23S rRNA gene. From 22 March to 31 May 2019, 1.3% (2/158) of the CT-positive cases in Örebro County were missed because of the F-nvCT. International awareness, investigations and actions are essential.

Identification of a new variant of Chlamydia trachomatis in Mexico

IntroductionChlamydia trachomatis is one of the main etiological agents of sexually transmitted infections worldwide. In 2006, a Swedish variant of C. trachomatis (Swedish-nvCT), which has a deletion of 377bp in the plasmid, was reported. In Latin America, Swedish-nvCT infections have not been reported. We investigated the presence of Swedish-nvCT in women with infertility in Mexico. MethodsSwedish-nvCT was searched in 69C. trachomatis positive samples from 2339 endocervical specimens. We designed PCR primers to identify the deletion in the plasmid in the ORF1, and the presence of a repeated 44bp in the ORF3. The sample with the deletion was genotyped with the genes of the major outer membrane protein A (ompA) and the polymorphic membrane protein (pmpH). ResultsThe deletion was detected in one of the 69 samples positive C. trachomatis of 2339 endocervical exudates. The nucleotide sequence analysis of the ompA shows a high degree of similarity with the Swedish nvCT (98%), however the variant found belongs to serovar D. The nucleotide sequence of the pmpH gene associates to the variant found in the genitourinary pathotype of the Swedish-nvCT but in different clusters. ConclusionsOur results revealed the presence of a new variant of C. trachomatis in Mexican patients. This variant found in Mexico belongs to serovar D based on the in silico analysis of the ompA and pmpH genes and differs to the Swedish-nvCT (serovars E). For these variants of C. trachomatis that have been found it is necessary to carry out a more detailed analysis, although the role of this mutation has not been demonstrated in the pathogenesis.

Identification of a new variant of Chlamydia trachomatis in Mexico

IntroductionChlamydia trachomatis is one of the main etiological agents of sexually transmitted infections worldwide. In 2006, a Swedish variant of C. trachomatis (Swedish-nvCT), which has a deletion of 377bp in the plasmid, was reported. In Latin America, Swedish-nvCT infections have not been reported. We investigated the presence of Swedish-nvCT in women with infertility in Mexico. MethodsSwedish-nvCT was searched in 69C. trachomatis positive samples from 2339 endocervical specimens. We designed PCR primers to identify the deletion in the plasmid in the ORF1, and the presence of a repeated 44bp in the ORF3. The sample with the deletion was genotyped with the genes of the major outer membrane protein A (ompA) and the polymorphic membrane protein (pmpH). ResultsThe deletion was detected in one of the 69 samples positive C. trachomatis of 2339 endocervical exudates. The nucleotide sequence analysis of the ompA shows a high degree of similarity with the Swedish nvCT (98%), however the variant found belongs to serovar D. The nucleotide sequence of the pmpH gene associates to the variant found in the genitourinary pathotype of the Swedish-nvCT but in different clusters. ConclusionsOur results revealed the presence of a new variant of C. trachomatis in Mexican patients. This variant found in Mexico belongs to serovar D based on the in silico analysis of the ompA and pmpH genes and differs to the Swedish-nvCT (serovars E). For these variants of C. trachomatis that have been found it is necessary to carry out a more detailed analysis, although the role of this mutation has not been demonstrated in the pathogenesis.

Ten years transmission of the new variant of Chlamydia trachomatis in Sweden: prevalence of infections and associated complications

ObjectivesIn 2006, a new variant of Chlamydia trachomatis (nvCT) was discovered in Sweden. It has a deletion in the plasmid resulting in failed detection by the single target systems from...

Comparing swabs for diagnosing chlamydia and gonorrhea in women: recent findings

Journal of Comparative Effectiveness ResearchVol. 2, No. 5 EditorialComparing swabs for diagnosing chlamydia and gonorrhea in women: recent findingsCatherine MW Stewart, Sarah A Schoeman & Janet D WilsonCatherine MW StewartThe Goodman Centre, Lance Burn Health Centre, Churchill Way, Salford, M6 5QX, UKSearch for more papers by this author, Sarah A SchoemanDepartment of Genitourinary Medicine, Leeds General Infirmary, Leeds, LS1 3EX, UKSearch for more papers by this author & Janet D Wilson* Author for correspondenceDepartment of Genitourinary Medicine, Leeds General Infirmary, Leeds, LS1 3EX, UK. Search for more papers by this authorEmail the corresponding author at janet_d.wilson@leedsth.nhs.ukPublished Online:11 Sep 2013https://doi.org/10.2217/cer.13.52AboutSectionsView ArticleView Full TextPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinkedInRedditEmail View articleReferences1 Stewart CM, Schoeman SA, Booth RA, Smith SD, Wilcox MH, Wilson JD. Assessment of self taken swabs versus clinician taken swab cultures for diagnosing gonorrhoea in women: single centre, diagnostic accuracy study. BMJ345,e8107 (2012).Crossref, Medline, Google Scholar2 Schoeman SA, Stewart CM, Booth RA, Smith SD, Wilcox MH, Wilson JD. Assessment of best single sample for finding chlamydia in women with and without symptoms: a diagnostic test study. BMJ345,e8013 (2012).Crossref, Medline, Google Scholar3 LaMontagne DS, Fenton KA, Randall S, Anderson S, Carter P. Establishing the National Chlamydia Screening Programme in England: results from the first full year of screening. Sex. Transm. Infect.80(5),335–341 (2004).Crossref, Medline, CAS, Google Scholar4 Gaydos CA, Dwyer K, Barnes M et al. Internet-based screening for Chlamydia trachomatis to reach non-clinic populations with mailed self-administered vaginal swabs. Sex. Transm. Dis.33,451–457 (2006).Crossref, Medline, Google Scholar5 Blake DR, Maldeis N, Barnes MR et al. Cost–effectiveness of screening strategies for Chlamydia trachomatis using cervical swabs, urine and self-obtained vaginal swabs in a sexually transmitted disease clinic setting. Sex. Transm. Dis.35,649–655 (2008).Crossref, Medline, Google Scholar6 Marions L, Rotzen-Ostlund M, Grillner L et al. High occurrence of a new variant of Chlamydia trachomatis escaping diagnostic tests among STI clinic patients in Stockholm, Sweden. Sex. Transm. Dis.35,61–64 (2008).Crossref, Medline, Google Scholar7 Ison CA, Golparian D, Saunders P, Chisholm S, Unemo M. Evolution of Neisseria gonorrhoeae is a continuing challenge for molecular detection of gonorrhoea: false negative gonococcal porA mutants are spreading internationally. Sex. Transm. Infect.89(3),197–201 (2013).Crossref, Medline, Google Scholar8 CDC. CDC grand rounds: the growing threat of multidrug-resistant gonorrhoea. MMWR Morb. Mortal Wkly Rep.62,103–106 (2013).Medline, Google Scholar9 Carne CA, McClean H, Sullivan AK et al. National audit of asymptomatic screening in UK genitourinary medicine clinics: clinic policies audit. Int. J. STD AIDS21,512–515 (2010).Crossref, Medline, CAS, Google Scholar10 Van Der Pol B, Taylor SN, Liesenfeld O, Williams JA, Hook EW 3rd. Vaginal swabs are the optimal specimen for detection of genital Chlamydia trachomatis or Neisseria gonorrhoeae using the Cobas 4800 CT/NG test. Sex. Transm. Dis.40(3),247–250 (2013).Crossref, Medline, Google Scholar101 Health Protection Agency. GRASP 2011 report: the Gonococcal Resistance to Antimicrobials Surveillance Programme (2012). www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1317136030908Google Scholar102 General Medical Council. Good medical practice (2013). www.gmc-uk.org/Good_medical_practice___English_0313.pdf_51527435.pdfGoogle ScholarFiguresReferencesRelatedDetails Vol. 2, No. 5 Follow us on social media for the latest updates Metrics Downloaded 27 times History Published online 11 September 2013 Published in print September 2013 Information© Future Medicine LtdFinancial & competing interests disclosureThe authors were coapplicants in an unconditional research grant from Gen-Probe. JD Wilson is the lead applicant of a National Institute for Health Research for Patient Benefit grant. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.No writing assistance was utilized in the production of this manuscript.PDF download

The new variant of Chlamydia trachomatis was present as early as 2003 in Örebro County, Sweden, but remained undetected until 2006

ObjectivesIn 2006, a new variant of Chlamydia trachomatis (nvCT) was reported in Sweden. Because of a cryptic plasmid deletion, the nvCT was undetectable in several of the genetic diagnostic systems...

Decline of the new Swedish variant of Chlamydia trachomatis after introduction of appropriate testing

ObjectiveThe longitudinal epidemiological development of the new variant of Chlamydia trachomatis was studied after appropriate testing procedures had been introduced when the strain was detected in 2006.MethodsThe number of cases...

First Reported Case of the Swedish New Variant of Chlamydia trachomatis (nvCT) in Eastern Europe (Russia), and Evaluation of Russian Nucleic Acid Amplification Tests Regarding Their Ability to Detect nvCT

First Reported Case of the Swedish New Variant of Chlamydia trachomatis (nvCT) in Eastern Europe (Russia), and Evaluation of Russian Nucleic Acid Amplification Tests Regarding Their Ability to Detect nvCT

Prevalence Trends of the New Variant of Chlamydia trachomatis in Four Counties of Sweden in 2007–2011

A new variant of Chlamydia trachomatis (nvCT) was discovered in Sweden in 2006, and it could not be detected by diagnostic systems from Abbott and Roche, whereas the third system used, from Becton Dickinson (BD), detects nvCT. We analyzed 3648 samples from 2 counties that used Roche and 2 counties that used BD methods from 2007 to 2011. After implementation of a Roche method that detects nvCT, its proportion has decreased and converged in the 4 counties but are still at different levels in Roche and BD counties. Future studies are needed to see if nvCT will decline further.

P1-S1.34 First report of the Swedish new variant of Chlamydia trachomatis (nvCT) in Russia

BackgroundThe new variant of Chlamydia trachomatis (nvCT), first reported in Sweden in late 2006, has so far rarely been reported outside the Nordic countries. However, knowledge of the presence of...

Prevalence trends in Sweden for the new variant of Chlamydia trachomatis

In 2006, a new variant of Chlamydia trachomatis (nvCT) was discovered in Sweden that was not detectable with Abbott m2000 (Abbott) and Amplicor/COBAS Amplicor/TaqMan48 (Roche). The proportion of nvCT was 20–64% of the detected Chlamydia cases in counties using Abbott/Roche test systems. Although the ProbeTec system from Becton Dickinson (BD) could detect nvCT, the proportion of nvCT in counties using BD was 7–19%. The objective of the current study was to follow the nvCT proportions from 2007 to 2009 in two counties that used Roche and had introduced test systems able to detect nvCT in late 2006. The nvCT was also followed in two counties that used BD, and in all four counties the effect of nvCT on the serotype distribution of C. trachomatis wild‐type strains was analysed. A total of 2576 specimens positive for C. trachomatis were collected in the four counties at three time points, and analysed for nvCT and serotype E. The proportion of nvCT declined significantly in the two counties using Roche, from 65% and 48% in 2007 to 24% for both counties in 2009 (p <0.001). The nvCT proportion increased in Norrbotten county, which used BD, from 9% in 2007 to 19% in 2009 (p 0.03). In Uppsala county, which also used BD but was surrounded by counties using detection systems from Roche, the proportion of nvCT declined from 24% in 2007 to 18% in 2009 (p <0.03). No major difference in the level of serotype E was seen. The proportion of nvCT seems to rapidly converge in the Swedish counties after the selective diagnostic advantage for nvCT has been lost in the Abbott/Roche counties.

The Swedish new variant of Chlamydia trachomatis

This review focuses on the anatomy of the Swedish new variant of Chlamydia trachomatis (nvCT). This information provides an interesting insight into the emergence of new strains (how, where, and when), and the important lessons learned are discussed. In late 2006, the nvCT was first reported in Sweden; it carries a 377 bp deletion within its plasmid which covers the single targets originally used by Roche and Abbott diagnostic systems. The nvCT spread rapidly with thousands of falsely negative diagnoses. Genome sequencing and phenotypic characterization showed that the biological fitness of nvCT when compared with wild-type CT in vitro is unaltered. Therefore, the rapid transmission of nvCT was due to the selective advantage gained from failed diagnosis and the introduction of nvCT into a high-frequency transmitting population. The proportions of nvCT cases are now converging toward equilibrium with the wild-type CT strains. Interestingly, the nvCT remains rarely reported beyond the Nordic countries. The spread of nvCT had a substantial impact on C. trachomatis identification, epidemiology, and public health in Sweden. Lessons learned from this experience include the importance of investigating the incidence and epidemiology of infection in detail, the frequent participation in appropriate quality assurance schemes, and the careful design of diagnostic assays. The nvCT presents a unique opportunity to study the spread of a single C. trachomatis strain within both the human and bacterial populations; this may substantially increase our knowledge of epidemiology and transmission of chlamydial infections, and other sexually transmitted infections.

Is the new variant of Chlamydia trachomatis present in South Africa?

An investigation was conducted to determine the prevalence of the new variant of Chlamydia trachomatis (nvCT) in South Africa (SA). Four hundred and fifty-nine C. trachomatis-positive clinical specimens, tested by in-house multiplex polymerase chain reaction (PCR), were screened for the presence of the 377 bp deletion in the ORF1 of the cryptic plasmid, documented in nvCT, by means of nested PCR. All specimens generated a 630 bp amplicon in the nested PCR, indicative of wild-type CT, and no nvCT strains were identifed. Even though there was no evidence of the presence of nvCT in South Africa, continuous screening for emerging mutant strains is of epidemiological importance.

Emergence of the new variant of Chlamydia trachomatis in a defined area of Sweden before 2002?

ObjectivesTo compare the proportions of Chlamydia trachomatis-positive specimens detected by Cobas Amplicor CT/NG (CA PCR) with C trachomatis positives in cell culture from 1999 to 2006 in order to estimate...