Chlamydia trachomatis ompA variants in trachoma: what do they tell us?
<h4>Background</h4>Trachoma, caused by Chlamydia trachomatis (Ct), is the leading infectious cause of blindness. Sequence-based analysis of the multiple strains typically present in endemic communities may be informative for epidemiology, transmission, response to treatment, and understa...
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2008-09-01
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| Series: | PLoS Neglected Tropical Diseases |
| Online Access: | https://journals.plos.org/plosntds/article/file?id=10.1371/journal.pntd.0000306&type=printable |
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| author | Aura A Andreasen Matthew J Burton Martin J Holland Spencer Polley Nkoyo Faal David C W Mabey Robin L Bailey |
| author_facet | Aura A Andreasen Matthew J Burton Martin J Holland Spencer Polley Nkoyo Faal David C W Mabey Robin L Bailey |
| author_sort | Aura A Andreasen |
| collection | DOAJ |
| description | <h4>Background</h4>Trachoma, caused by Chlamydia trachomatis (Ct), is the leading infectious cause of blindness. Sequence-based analysis of the multiple strains typically present in endemic communities may be informative for epidemiology, transmission, response to treatment, and understanding the host response.<h4>Methods</h4>Conjunctival and nasal samples from a Gambian community were evaluated before and 2 months after mass azithromycin treatment. Samples were tested for Ct by Amplicor, with infection load determined by quantitative PCR (qPCR). ompA sequences were determined and their diversity analysed using frequency-based tests of neutrality.<h4>Results</h4>Ninety-five of 1,319 (7.2%) individuals from 14 villages were infected with Ct at baseline. Two genovars (A and B) and 10 distinct ompA genotypes were detected. Two genovar A variants (A1 and A2) accounted for most infections. There was an excess of rare ompA mutations, not sustained in the population. Post-treatment, 76 (5.7%) individuals had Ct infection with only three ompA genotypes present. In 12 of 14 villages, infection had cleared, while in two it increased, probably due to mass migration. Infection qPCR loads associated with infection were significantly greater for A1 than for A2. Seven individuals had concurrent ocular and nasal infection, with divergent genotypes in five.<h4>Conclusions</h4>The number of strains was substantially reduced after mass treatment. One common strain was associated with higher infection loads. Discordant genotypes in concurrent infection may indicate distinct infections at ocular and nasal sites. Population genetic analysis suggests the fleeting appearance of rare multiple ompA variants represents purifying selection rather than escape variants from immune pressure. Genotyping systems accessing extra-ompA variation may be more informative. |
| format | Article |
| id | doaj-art-d4feb748dc0847b2bd0ad58eb4c4208c |
| institution | OA Journals |
| issn | 1935-2727 1935-2735 |
| language | English |
| publishDate | 2008-09-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS Neglected Tropical Diseases |
| spelling | doaj-art-d4feb748dc0847b2bd0ad58eb4c4208c2025-08-20T02:39:02ZengPublic Library of Science (PLoS)PLoS Neglected Tropical Diseases1935-27271935-27352008-09-0129e30610.1371/journal.pntd.0000306Chlamydia trachomatis ompA variants in trachoma: what do they tell us?Aura A AndreasenMatthew J BurtonMartin J HollandSpencer PolleyNkoyo FaalDavid C W MabeyRobin L Bailey<h4>Background</h4>Trachoma, caused by Chlamydia trachomatis (Ct), is the leading infectious cause of blindness. Sequence-based analysis of the multiple strains typically present in endemic communities may be informative for epidemiology, transmission, response to treatment, and understanding the host response.<h4>Methods</h4>Conjunctival and nasal samples from a Gambian community were evaluated before and 2 months after mass azithromycin treatment. Samples were tested for Ct by Amplicor, with infection load determined by quantitative PCR (qPCR). ompA sequences were determined and their diversity analysed using frequency-based tests of neutrality.<h4>Results</h4>Ninety-five of 1,319 (7.2%) individuals from 14 villages were infected with Ct at baseline. Two genovars (A and B) and 10 distinct ompA genotypes were detected. Two genovar A variants (A1 and A2) accounted for most infections. There was an excess of rare ompA mutations, not sustained in the population. Post-treatment, 76 (5.7%) individuals had Ct infection with only three ompA genotypes present. In 12 of 14 villages, infection had cleared, while in two it increased, probably due to mass migration. Infection qPCR loads associated with infection were significantly greater for A1 than for A2. Seven individuals had concurrent ocular and nasal infection, with divergent genotypes in five.<h4>Conclusions</h4>The number of strains was substantially reduced after mass treatment. One common strain was associated with higher infection loads. Discordant genotypes in concurrent infection may indicate distinct infections at ocular and nasal sites. Population genetic analysis suggests the fleeting appearance of rare multiple ompA variants represents purifying selection rather than escape variants from immune pressure. Genotyping systems accessing extra-ompA variation may be more informative.https://journals.plos.org/plosntds/article/file?id=10.1371/journal.pntd.0000306&type=printable |
| spellingShingle | Aura A Andreasen Matthew J Burton Martin J Holland Spencer Polley Nkoyo Faal David C W Mabey Robin L Bailey Chlamydia trachomatis ompA variants in trachoma: what do they tell us? PLoS Neglected Tropical Diseases |
| title | Chlamydia trachomatis ompA variants in trachoma: what do they tell us? |
| title_full | Chlamydia trachomatis ompA variants in trachoma: what do they tell us? |
| title_fullStr | Chlamydia trachomatis ompA variants in trachoma: what do they tell us? |
| title_full_unstemmed | Chlamydia trachomatis ompA variants in trachoma: what do they tell us? |
| title_short | Chlamydia trachomatis ompA variants in trachoma: what do they tell us? |
| title_sort | chlamydia trachomatis ompa variants in trachoma what do they tell us |
| url | https://journals.plos.org/plosntds/article/file?id=10.1371/journal.pntd.0000306&type=printable |
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