The Molecular Epidemiology of Ocular Chlamydia trachomatis Infections in Western Australia: Implications for Trachoma Control

Porter, Michelle; Mak, Donna B; Chidlow, Glenys; Harnett, Gerald B.; Smith, David W.

doi:10.4269/ajtmh.2008.78.514

Cited by 10 publications

(9 citation statements)

References 13 publications

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“…It is important to note that there was strong evidence for functional tropism in C. trachomatis strains arising from the Mother–Child study. Although it is well known that UGT strains of C. trachomatis can cause conjunctivitis, primarily in adults and newborn infants, this does not have the characteristic clinical and epidemiological pattern of trachoma 48 49 50 . The ocular isolates analysed in this study are from a known trachoma endemic area, from young but not infant children exhibiting typical trachoma signs.…”

Section: Discussionmentioning

confidence: 99%

Chlamydia trachomatis from Australian Aboriginal people with trachoma are polyphyletic composed of multiple distinctive lineages

et al. 2016

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Chlamydia trachomatis causes sexually transmitted infections and the blinding disease trachoma. Current data on C. trachomatis phylogeny show that there is only a single trachoma-causing clade, which is distinct from the lineages causing urogenital tract (UGT) and lymphogranuloma venerum diseases. Here we report the whole-genome sequences of ocular C. trachomatis isolates obtained from young children with clinical signs of trachoma in a trachoma endemic region of northern Australia. The isolates form two lineages that fall outside the classical trachoma lineage, instead being placed within UGT clades of the C. trachomatis phylogenetic tree. The Australian trachoma isolates appear to be recombinants with UGT C. trachomatis genome backbones, in which loci that encode immunodominant surface proteins (ompA and pmpEFGH) have been replaced by those characteristic of classical ocular isolates. This suggests that ocular tropism and association with trachoma are functionally associated with some sequence variants of ompA and pmpEFGH.

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Section: Discussionmentioning

confidence: 99%

Chlamydia trachomatis from Australian Aboriginal people with trachoma are polyphyletic composed of multiple distinctive lineages

et al. 2016

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“…The serotype in Morocco is mainly Ba, which is predominantly seen in North Africa (Takourt et al, 2001). Australian studies have shown that serotype C is the most common serotype in children aged 1-13 years, followed by serotype Ba, whereas in children older than 14 years, even genital-type C. trachomatis (serotypes D, F, and K) may be detected in conjunctival swabs (Porter et al, 2008). Serotypes B and C are the most common serotypes in Asia, as confirmed by several studies (Naito et al, 2009;Takahashi et al, 2007;Wang et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

Molecular characteristics of the ompA gene of serotype B Chlamydia trachomatis in Qinghai Tibetan primary school students

Zhang

Liang

et al. 2016

Sci. China Life Sci.

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To study the molecular characteristics of Chlamydia trachomatis, the major outer membrane protein gene (ompA) of C. trachomatis from primary school students with trachoma residing in the Qinghai Tibetan area was sequenced and compared with the same serotype in GenBank. In Jianshetang Primary School and Galeng Central Primary School in the Galeng Tibetan Township of Qinghai Haidong Sala Autonomous County, scraped samples were collected from the upper tarsal conjunctiva and lower conjunctival sac of both eyes of 45 students with trachoma, stored at 4°C, and transported to Beijing Tongren Hospital by air within 24 h. The samples were screened for C. trachomatis by real-time PCR. The ompA gene from the C. trachomatis-positive samples was amplified by nested PCR. The serotype was confirmed by National Center for Biotechnology Information (NCBI) BLAST search and homology analysis. The entire ompA gene sequence was compared with the corresponding gene sequences of serotype B strains available in GenBank. Of the 45 students aged 6-13 years with trachoma, 26 C. trachomatis-positive students were identified by the initial real-time PCR screening (average age, (9.09±1.63) years; sex ratio, 1.0), accounting for 57.78% (26/45). The cycle threshold values for real-time PCR were 16.79-37.77. Half (13/26) of C. trachomatis-positive students had a bacterial copy number of >10 5 . The compliance rate of the ompA gene sequences with the C. trachomatis serotype B strains in GenBank was up to 99%. Two novel genetic mutations were found when the ompA gene was compared with those of the 11 serotype B strains in GenBank. The two non-synonymous mutations were located at (i) position 271 in the second constant domain, an adenine (A) to guanine (G) substitution (ACTGCT), changing the amino acid at position 91 from threonine to alanine (ThrAla) in all 26 strains; and (ii) position 887 in the fourth variable domain, a cytosine (C) to thymine (T) substitution (GCAGTA), changing the amino acid at residue 296 from alanine to valine (AlaVal) in four of the 26 strains. Six mutations were identified relative to ATCC VR-573. The strains could be divided into two gene clusters according to the mutation at nucleotide position 887: CQZ-1 (China Qinghai Tibetan-1) and CQZ-2 (China Qinghai Tibetan-2). We thus detected two novel serotype B mutant strains of C. trachomatis among study subjects with trachoma.Chlamydia trachomatis, major outer membrane protein gene, sequencing, homology analysis Citation:

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“…In trachoma studies, C serovar organisms have been identified commonly in isolated indigenous communities in western Australia, in Nepal, and elsewhere [ e.g. , 36–38]. As indicated above, this serovar indeed has been identified in genital samples, although its occurrence in genital contexts is relatively rare [ e.g.…”

Section: Discussionmentioning

confidence: 99%

Patients with Chlamydia-associated arthritis have ocular (trachoma), not genital, serovars of C. trachomatis in synovial tissue

Gérard

Stanich

Whittum-Hudson

et al. 2010

Microbial Pathogenesis

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Some individuals with a genital Chlamydia trachomatis infection develop inflammatory arthritis, but it is unknown whether particular chlamydial serovar(s) engender the disease more often than others. We defined serovar in synovial tissues from arthritis patients infected with this organism. DNA from synovial biopsies of 36 patients with PCR-confirmed synovial C. trachomatis was analyzed. Diagnoses included reactive arthritis, undifferentiated oligoarthritis, rheumatoid arthritis, and osteoarthritis. The chlamydial omp1 and trpA genes were amplified, cloned, and 10 or more clones from each sample were sequenced. The cytotoxin locus also was analyzed. omp1 sequences showed 2 patients having only C. trachomatis A serovar, 1 with only B, and 33 having only C, all ocular serovars. Analyses of trpA and the cytotoxin locus uniformly displayed standard ocular serovar characteristics for each patient. Identification of ocular chlamydial serovars in the synovia of arthritis patients is unexpected. These observations suggest that urogenital chlamydial infections, while consisting primarily of organisms of genital serovars, include some of ocular serovar(s). They further suggest that during such infections unknown selection pressures favor establishment of the latter in the synovium to the exclusion of genital serovar chlamydiae.

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The Molecular Epidemiology of Ocular Chlamydia trachomatis Infections in Western Australia: Implications for Trachoma Control

Cited by 10 publications

References 13 publications

Chlamydia trachomatis from Australian Aboriginal people with trachoma are polyphyletic composed of multiple distinctive lineages

Chlamydia trachomatis from Australian Aboriginal people with trachoma are polyphyletic composed of multiple distinctive lineages

Molecular characteristics of the ompA gene of serotype B Chlamydia trachomatis in Qinghai Tibetan primary school students

Patients with Chlamydia-associated arthritis have ocular (trachoma), not genital, serovars of C. trachomatis in synovial tissue

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