Spread of a new Chlamydia trachomatis variant from men who have sex with men to the heterosexual population after replacement and recombination in ompA and pmpH genes.

OBJECTIVES: Sexually transmitted infections are frequently related to outbreaks in high-risk populations due to the dense sexual networks. We wanted to determine the dissemination of a Chlamydia trachomatis variant characterized by the pmpH-recombinant gene between L and G genotypes, which was previously described in a high-risk population. METHODS: A total of 449 samples were analysed in two periods ranging from 2009 to 2015 for detection of the pmpH-recombinant gene. For those samples yielding positive amplification, a sampling was selected for phylogenetic reconstructions based on sequencing of five chromosomal genes. RESULTS: Globally this variant was found in 113 of the 449 samples (25%). During the first years (2009-13), this variant was found almost exclusively in rectal samples (30/112 samples) of men who have sex with men and in only one non-rectal sample (1/63). In 2014, this variant was also found in urethral and pharyngeal samples (1/24 and 1/7, respectively). However, in 2015, an epidemiological change was observed as the proportion of this variant had increased in rectal samples (20/51; 39%) and non-rectal samples, including cervical samples (51/142; 36.4%). The molecular characterization revealed the replacement of the ompA gene belonging to subtype G in samples recovered from 2009 to 2013 by the ompA gene belonging to subtype J after 2013. CONCLUSIONS: Our data would support the evidence that subtype J could be a 'subtype bridge' between different sexual networks, as subtype J has been found in men who have sex with men and heterosexual populations in similar proportions. This work reveals the necessity of implementing molecular surveillance in extra-rectal samples to help us understand the gaps in transmission.

Clinical and epidemiological characterization of a lymphogranuloma venereum outbreak in Madrid, Spain: co-circulation of two variants.

The lymphogranuloma venereum (LGV) outbreak described in the Netherlands in 2003, increased the interest in the genotyping of Chlamydia trachomatis. Although international surveillance programmes were implemented, these studies slowly decreased in the following years. Now data have revealed a new accumulation of LGV cases in those European countries with extended surveillance programmes. Between March 2009 and November 2011, a study was carried out to detect LGV cases in Madrid. The study was based on screening of C. trachomatis using commercial kits, followed by real-time pmpH-PCR discriminating LGV strains, and finally ompA gene was sequenced for phylogenetic reconstruction. Ninety-four LGV infections were identified. The number of cases increased from 10 to 30 and then to 54 during 2009-2011. Incidence of LGV was strongly associated with men who have sex with men; but in 2011, LGV cases were described in women and heterosexual men. Sixty-nine patients were also human immunodeficiency virus (HIV) positive, with detectable viral loads at the moment of LGV diagnosis, suggesting a high-risk of co-transmission. In fact, in four patients the diagnosis of HIV was simultaneous with LGV infection. The conventional treatment with doxycycline was prescribed in 75 patients, although in three patients the treatment failed. The sequencing of the ompA gene permitted identification of two independent transmission nodes. One constituted by 25 sequences identical to the L2b variant, and a second node including 37 sequences identical to L2. This epidemiological situation characterized by the co-circulation of two LGV variants has not been previously described, reinforcing the need for screening and genotyping of LGV strains.

Multicentric reference values for some quantities measured with Tina-Quant reagents systems and RD/Hitachi analysers.

Ten clinical laboratories in different regions of Spain have shared the search for reference individuals and the production of reference values for quantities concerning ferritin, transferrin, rheumatoid factors, C-reactive protein and antistreptolysin O, using Tina-Quant reagents systems and RD/Hitachi analysers. All the logistic work has been done in co-operation with the supplier of the reagents and analysers (Roche Diagnostics España, S.L., Barcelona). The reference limits produced in the virtual laboratory are derived from the blend of reference values obtained by each laboratory. The multicentric reference limits were estimated according to the recommendations of the International Federation of Clinical Chemistry. The work done is a model of co-operation between the in vitro diagnostic industry and clinical laboratories for the production of reference values.

Annual rhythmic and non-rhythmic biological variation of magnesium and ionized calcium concentrations.

The annual inter- and intra-individual biological variation, including the circannual rhythmic variation, of the serum concentrations of magnesium and ionized calcium has been investigated in a group of 51 apparently healthy volunteers. Venous blood specimens were collected on intervals of once a month within a one-year period, using a standardized protocol. The inter-individual coefficients of variation were 5.12% for magnesium and 1.58% for ionized calcium. The medians of the intra-individual coefficients of variation were 1.93% for magnesium and 2.18% for ionized calcium. These data were used to determine the allowable imprecision, the allowable systematic error, the critical difference for significant change detection, and the usefulness of population reference values (index of individuality). Of the quantities studied, only the serum concentration of ionized calcium shows a significant annual rhythmic variation (amplitude 1.3%), although this result may be due to the between-run metrological variance, considering that the concentration of ionized calcium of the control material used during the study possesses a similar significant rhythmic variation.

Multicentric reference values for some quantities measured with the Elecsys 2010 analyser.

Several clinical laboratories in different regions of Spain have shared the search for reference individuals and the production of reference values for quantities concerning thyrotropin, non-protein bound thyroxine, triiodothyronine, cobalamines and folates, using an Elecsys 2010 analyser. All the logistic work has been done in co-operation with the supplier of the analyser (Roche Diagnostics España, S.L., Barcelona). The reference limits produced in the virtual laboratory are in fact derived from the blend of reference values obtained by each laboratory. The multicentric reference limits were estimated according to the recommendations of the International Federation of Clinical Chemistry. The work done represents a model of co-operation between the in vitro diagnostic industry and clinical laboratories for the production of reference values.