Background: The biology of recurrent or long-term infections of humans by Chlamydia trachomatis is poorly understood. Because repeated or persistent infections are correlated with serious complications in humans, understanding these processes may improve clinical management and public health disease control.
Methods: We conducted whole-genome sequence analysis on C. trachomatis isolates collected from a previously described patient set in which individuals were shown to be infected with a single serovar over a lengthy period.
Results: Data from 5 of 7 patients showed compelling evidence for the ability of these patients to harbor the same strain for 3-5 years. Mutations in these strains were cumulative, very uncommon, and not linked to any single protein or pathway. Serovar J strains isolated from 1 patient 3 years apart did not accumulate a single base change across the genome. In contrast, the sequence results of 2 patients, each infected only with serovar Ia strains, revealed multiple same-serovar infections over 1-5 years.
Conclusions: These data demonstrate examples of long-term persistence in patients in the face of repeated antibiotic therapy and show that pathogen mutational strategies are not important in persistence of this pathogen in patients.