Helena MB Seth-Smith
University Hospital Basel, Division of Clinical Bacteriology and Mycology, Basel, Switzerland
The diagnosis of sexually transmitted infections (STIs) is a prequel to treatment. Diagnosis needs to be both accurate and timely, to enable successful administration of appropriate treatment and improve patient compliance. Over the decades, diagnosis of Chlamydia trachomatis has moved from culture through antibody based methods, and nucleic acid amplification tests (NAATs) are now the most commonly used. While offering high specificity and sensitivity, NAATs is associated with problems of diagnostic escape, when genomic targets mutate and the bacterium becomes diagnostically invisible.
Typing has primarily used OmpA-serotyping and now ompA-genotyping, with higher resolution provided by multilocus sequence typing (MLST) and multiple loci variable number tandem-repeat analysis (MLVA). However, the ancestral inference of all of these are confounded by recombination, at which C. trachomatis is quite proficient. The resolution, compared to whole genome sequencing, is also suboptimal.
With the continuing global rise in chlamydial diagnoses and the observed danger of diagnostic escape, we need to understand the evolution of STIs and the selection pressures that they are under. Whole genome sequencing can contribute a great deal towards this. Genomics has given us many insights into the lifestyles and evolution of Chlamydia, over long and short term. Genomic surveillance will always be necessary to decipher population dynamics and to characterise novel strains. Application of real time sequencing technologies also provides us with future possibilities of rapid diagnosis and typing, combined with sexual contact tracing, to identify and terminate outbreaks.
34 IUSTI Congress - European Congres on Sexually transmitted Infections and HIV/AIDS
TAMING THE TIDE of STIs & HIV
Bucharest, September 3-5,