Characterisation of Treponema pallidum lineages within the contemporary syphilis outbreak in Australia: a genomic epidemiological analysis

Putting a twist in syphilis vaccine development

“…It has been suggested that this rapid expansion may have been due to the relaxation in sexual behaviour after the introduction of an effective antiretroviral therapy in the 1990s. This is relevant as some sublineages were found to be associated with specific sexual networks 3 , which supports the observation that sexual behaviour is one of the most important factors in syphilis transmission. Overall, syphilis genomes exhibited very limited genetic diversity across time and space, which indicates a very low evolutionary rate 1 – 3 .…”

“…This is relevant as some sublineages were found to be associated with specific sexual networks 3 , which supports the observation that sexual behaviour is one of the most important factors in syphilis transmission. Overall, syphilis genomes exhibited very limited genetic diversity across time and space, which indicates a very low evolutionary rate 1 – 3 . Interestingly, a single highly discriminative locus, TP0548, used for multi locus sequence typing, was found to correlate well with TPA sublineages identified via phylogenomics 3 .…”

“…Genome sequencing revealed that two major TPA lineages, Nichols and SS14, co-circulate across multiple continents. The genetically homogeneous SS14 lineage was the dominant lineage in most sampled regions; however, both lineages exhibited similar phylodynamics and are responsible for current epidemics 1 – 3 . Furthermore, TPA populations circulating among patients in the twentieth century may have been different from the modern populations 1 , 3 .…”

“…The genetically homogeneous SS14 lineage was the dominant lineage in most sampled regions; however, both lineages exhibited similar phylodynamics and are responsible for current epidemics 1 – 3 . Furthermore, TPA populations circulating among patients in the twentieth century may have been different from the modern populations 1 , 3 . This has been linked to a population bottleneck in the late 1990s, followed by the expansion of modern sublineages in the 2000s.…”

“…Hybridization capture using DNA or RNA probes designed based on TPA genomes has become the most popular and efficient technique for this targeted genome sequencing. Three recently published studies used this technology for large-scale sequencing of TPA, which enabled the deep exploration of modern syphilis epidemics 1 – 3 .…”