Anal infections with concomitant Chlamydia trachomatis genotypes among men who have sex with men in Amsterdam, the Netherlands
- Equal contributors
1 DDL Diagnostic Laboratory, Voorburg, the Netherlands
2 Department of Dermatology, Leiden University Medical Centre, Leiden, the Netherlands
3 Public Health Laboratory, Cluster for Infectious Diseases, Public Health Service of Amsterdam (GGD Amsterdam), Amsterdam, The Netherlands
4 Centre for Immunity and Infectious Diseases Amsterdam (CINIMA), Academic Medical Centre, University of Amsterdam, the Netherlands
5 The Department of Pathology, Laboratory of Immunogenetics, VU University Medical Centre, Amsterdam, the Netherlands
6 Department of Dermatology, Academic Medical Centre, University of Amsterdam, the Netherlands
7 STI Outpatient Clinic, Cluster for Infectious Diseases, Public Health Service of Amsterdam (GGD Amsterdam), Amsterdam, the Netherlands
BMC Infectious Diseases 2011, 11:63 doi:10.1186/1471-2334-11-63Published: 14 March 2011
Lymphogranuloma venereum (LGV) proctitis is caused by Chlamydia trachomatis (Ct) genotype L and is endemic among men who have sex with men (MSM) in western society. Genotype L infections need to be distinguished from non-LGV (genotypes A-K) Ct infections since they require prolonged antibiotic treatment. For this purpose, an in-house developed pmpH based LGV polymerase chain reaction (PCR) test is used at the Amsterdam STI outpatient clinic. We investigated retrospectively the anal Ct genotype distribution, and the frequency of concomitant genotype infections in MSM infected with LGV and non-LGV Ct infections. To detect concomitant Ct genotype infections, the pmpH LGV PCR and genoTyping Reverse Hybridization Assay (Ct-DT RHA) were used.
A total of 201 Ct positive rectal swabs from MSM were selected, which were previously diagnosed as either LGV (n = 99) or non-LGV Ct infection (n = 102) according to the algorithm of Ct detection by the commercially available Aptima Combo 2 assay followed by an in-house pmpH LGV PCR. The samples were retested with the commercially available Ct-DT RHA, which differentiates between 14 major genotypes and is able to detect concomitant Ct genotypes.
Excellent genotyping agreement was observed between the Ct-DT RHA and the pmpH LGV PCR (Kappa = 0.900, 95%CI = 0.845-0.955, McNemar's p = 1.000). A concomitant non-LGV genotype was detected in 6/99 (6.1%) LGV samples. No additional LGV infections were observed with the Ct-DT RHA among the non-LGV Ct group. In the non-LGV group genotype G/Ga (34.3%) was seen most frequent, followed by genotype D/Da (22.5%) and genotype J (13.7%). All LGV infections were caused by genotype L2.
Concomitant non-LGV genotypes do not lead to missed LGV proctitis diagnosis. The pmpH LGV PCR displayed excellent agreement with the commercially available Ct-DT genotyping RHA test. The genotypes G/Ga, D/Da and J were the most frequent non-LGV Ct strains in MSM.