Background: Men who have sex with men (MSM) are disproportionally affected by sexually transmitted infections (STI). STI are often extragenital and asymptomatic. Both can delay diagnosis and treatment. Approval of HIV preexposure prophylaxis (PrEP) might have influenced sexual behaviour and STI-prevalence of HIV-MSM. We estimated STI-prevalence and risk factors amongst HIV-and HIV+ MSM in Germany to plan effective interventions. Methods: We conducted a nationwide, cross-sectional study between February and July 2018. Thirteen MSMfriendly STI-practices screened MSM for Chlamydia trachomatis (CT), Mycoplasma genitalium (MG), Neisseria gonorrhea (NG), and Trichomonas vaginalis (TV) using self-collected rectal and pharyngeal swabs, and urine samples. APTIMA™ STI-assays (Hologic™ Inc., San Diego, USA) were used for diagnostics, and samples were not pooled. We collected information on socio-demographics, HIV-status, clinical symptoms, sexual behaviour within the last 6 months, and PrEP use. We combined HIV status and PrEP use for defining risk groups, and used directed acyclic graphs and multivariable logistic regression to identify risk factors for STI. Results: Two thousand three hundred three MSM were included: 50.5% HIV+, median age 39 [18-79] years. Median number of male sex partners within the last 6 months was five. Sex without condom was reported by 73.6%, use of party drugs by 44.6%. 80.3% had a STI history, 32.2% of STI+ MSM reported STI-related symptoms. 27.6% of HIV-MSM used PrEP.

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The analytical performances of the new Abbott RealTime hepatitis C virus (HCV) and human immunodeficiency virus type 1 viral load assays were compared at nine laboratories with different competitor assays. These included the Abbott LcX, Bayer Versant bDNA, Roche COBAS Amplicor, and Roche COBAS TaqMan assays. Two different protocols used during the testing period with and without a pre-m1000 RNA isolation spin were compared. The difference proved to be nonsignificant. A uracil-N-glycosylase (UNG) contamination control option in the HCV test for previous Roche COBAS Amplicor users was evaluated. It proved to decrease amplicon carryover by 100-fold independent of the amplicon input concentration. The protocol including UNG proved to overcome problems with false-positive negative controls. Comparison with other assays revealed only minor differences. The largest difference was observed between the Abbott HCV RealTime assay and the Roche COBAS Amplicor HCV Monitor version 2.0 assay.Hepatitis C virus (HCV) and human immunodeficiency virus type 1 (HIV-1) are major causes of mortality in both developing and developed countries. For both viruses, relatively effective therapies have been available in developed countries for quite some time. HCV and HIV-1 viral loads are important parameters in patient management both before initiating therapy and during therapy. The decline of the HCV viral load during the first 3 months of therapy is, for instance, a strong indicator of the final outcome of therapy (9, 23). Moreover, in many countries, the HCV viral load in infected health care workers determines whether they are allowed to perform surgical procedures. HIV-1 viral load is monitored during therapy, and a viral load above a certain threshold, which may differ per treating physician, requires a switch in medication (6, 13).The first tests that were described for determining the viral load were based on target amplification techniques like reverse transcriptase PCR (RT-PCR) and nucleic acid sequence-based amplification (NASBA). These tests had readout on agarose gel or readout with enzymatic detection of the amplicon after amplification with biotinylated primers (1, 3, 15, 17). Subsequently, signal amplification techniques were developed for the quantitative detection of HCV and HIV-1 (5, 16). Those techniques were improved and commercialized. The suppliers of the most widely used systems at the moment are Roche and Abbott, for RT-PCR-based systems (the COBAS Amplicor and LcX systems, respectively); bioMerieux (formerly Organon Technica), with a NASBA-based technique; and Bayer, with the Versant bDNA system being a signal amplification technique (4,18,19). Each technique has its own advantages and disadvantages. The relatively small dynamic range is a disadvantage that all current assay formats have in common. All assay formats are also rather sensitive to contamination, especially at the lower limit of detection (21). Handling of the sample after target amplification is a major cause of contamination for the NASBA-and RT-PC...

High accuracy and precision at the lower end of quantification are crucial requirements of a modern HIV viral load (VL) assay, since some clinically relevant thresholds are located at 50 and 200 copies/ml. In this study, we compared the performance of two new fully automated HIV-1 VL assays, Aptima HIV-1 Quant Dx and Cobas HIV-1 (Cobas 6800), with the established RealTime m2000 assay.