Identification and Discrimination of Chlamydia trachomatis Ocular and Urogenital Strains and Major Phylogenetic Lineages by CtGEM Typing, A Double-Locus Genotyping Method

Holt, Deborah C.; Andersson, Patiyan; Buckley, Cameron; Whiley, David M.; Giffard, Philip M.

doi:10.1007/978-1-4939-9694-0_8

Cited by 1 publication

(1 citation statement)

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“…In the last decades other more discriminating typing techniques were also developed, leading to even more CT genotypes, which could be clustered in specific lineages [4,5]. Ocular ompA types are A, B, Ba and C and are still found only in non-Western countries but sometimes also occur in urogenital infections [4,[6][7][8][9][10]. The urogenital genovars B and D to K, infect cervical and vaginal sites in women and anal sites in men and can all also be detected in urine samples.…”

Section: Introductionmentioning

confidence: 99%

Reduction of non-typeable results using a plasmid oriented Lymfogranuloma venereum PCR for typing of Chlamydia trachomatis positive samples

Smit¹,

Cornelissen²,

Bruisten³

2020

PLoS ONE

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Typing of Chlamydia trachomatis (CT) is traditionally performed by characterising the ompA gene, resulting in more than a dozen different genovars, A to L. Type L is associated with Lymphogranuloma venereum (LGV) and commonly screened for using PCR, targeting the chromosomal pmpH gene. We aimed to develop and validate a new CT/LGV plasmidbased typing assay targeting the pgp3 gene, to increase sensitivity and thus reduce the number of non-typeable results. Methods The new pgp3 PCR assay using LNA probes to detect point mutations was analytically and prospectively validated in a routine diagnostic laboratory setting. For the analytical tests, quantified nucleotide constructs (gBlocks) were used to perform limit of detection analyses. Quality control panel samples from 2018 and 2019 for CT were also tested. For the clinical study patient samples which were collected in two months in 2018 were tested simultaneously using the pmpH PCR and the pgp3 PCR. Results Analytically, the assay proved to be 100% specific relative to the previously used LGV typing assay targeting the single copy pmpH gene but it was much more sensitive to detect non-LGV CT. In the quality control panel 2 nonLGV samples and 7 LGV samples were solely positive with the pgp3 PCR and not with the pmpH PCR. None of the samples from analytical specificity panels were positive, indicating 100% specificity. In a prospective panel of 152 clinical samples, 142 (93%) were successfully typed with the pgp3 PCR compared to 78% with the pmpH PCR. The pgp3 PCR was fully concordant with the pmpH PCR to

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