RT Journal Article
SR Electronic
T1 Characterisation of <em>Chlamydia trachomatis</em> by <em>ompA</em> sequencing and multilocus sequence typing in a Swedish county before and after identification of the new variant
JF Sexually Transmitted Infections
JO Sex Transm Infect
FD BMJ Publishing Group Ltd
SP 56
OP 60
DO 10.1136/sti.2009.037572
VO 86
IS 1
A1 Margaretha Jurstrand
A1 Linus Christerson
A1 Markus Klint
A1 Hans Fredlund
A1 Magnus Unemo
A1 Björn Herrmann
YR 2010
UL http://sti.bmj.com/content/86/1/56.abstract
AB Objectives In 2006 a new variant of Chlamydia trachomatis (nvCT), with a deletion in the cryptic plasmid, was reported in Sweden. This deletion included the targets for the genetic diagnostic systems used in many clinical laboratories and resulted in thousands of false-negative results. The aim of this study was to characterise consecutive Chlamydia tissue culture-positive samples from 2006 in Örebro County, after identification of the nvCT, and to compare the results from samples collected in the same county in 1999–2000. The study also aimed to evaluate the discriminatory capacity of multilocus sequence typing (MLST) compared with ompA sequencing.Methods ompA sequencing and MLST was used to characterise 100 consecutive Chlamydia tissue culture-positive samples.Results A significant (p&lt;0.001) increase of genotype E, from 47% in 1999–2000 to 69% in 2006, was detected. All 41 nvCT isolates from 2006 displayed an identical ompA genotype E and MLST profile. Excluding the nvCT isolates, the distribution of ompA genotypes is similar to the genotyping results from 1999–2000. Among the wild-type genotype E isolates from 2006, 14 unique MLST sequence types were obtained from 26 isolates while they were identical in ompA genotyping. The discriminatory power (D) of C trachomatis strains in this material was 83.5% using the MLST system compared with 49.5% utilising ompA sequencing.Conclusion In all, MLST enables improved studies of the molecular epidemiology of C trachomatis. All nvCT isolates from 2006 displayed an identical ompA genotype E and MLST profile, which strongly indicates a clonal spread of the nvCT.