Concern regarding the alleged spread of hypervirulent lymphogranuloma venereum Chlamydia trachomatis strain in Europe

A recent surveillance and outbreak report published in Eurosurveillance by Petrovay et al. on the ‘Emergence of the lymphogranuloma venereum L2c genovariant, Hungary, 2012 to 2016’ [1] provides an observation of the first European cases of a genotype of Chlamydia trachomatis associated with severe haemorrhagic proctitis. The authors of this paper diagnosed the strains as lymphogranuloma venereum (LGV)- associated and performed partial sequencing of the ompA gene (ca 1,070 bp), which is a standard typing method for C. trachomatis. The ompA gene sequence obtained was compared with those from reference isolates, and reported to be 100% concordant with the ompA sequence belonging to an L2-D recombinant strain described in 2011 [2]. This strain was named ‘L2c’, as it was found to possess a chimeric genome, not because it has a novel ompA-genotype. We would like to point out that the ompA gene sequence of this L2-D recombinant strain, and by implication those of the Hungarian isolates, is identical to that of archetypal L2 strains, for example the reference strain L2/434 [3].