[Comparison of immunochromatographic (IC) and real-time polymerase chain reaction (Rt-PCR) tests for screening Neisseria gonorrhoeae， Chlamydia trachomatis， Ureaplasma spp and Mycoplasma spp in HIV-infected men]

Laboratory testing is critical for sexually transmitted infections (STIs) as most of the infected people usually have no symptoms. It is known that having HIV and STI coinfection increases the risk of HIV transmission. Sensitive tests are required for the infection control. The aim of this study was to compare the 2 different diagnostic tests-an immunochromatographic (IC) test and a real-time polymerase chain reaction (Rt-PCR) assay-for screening Neisseria gonorrhoeae， Chlamydia trachomatis， Ureaplasma spp. and Mycoplasma spp. in HIV-infected men. The tests were evaluated in terms of sensitivity， specificity， rapidity， sample types and cost per test. Eighty HIV-infected adult men who were admitted to Hacettepe University Faculty of Medicine Hospital STIs Outpatient Clinic between October 2017-April 2018 were included in the study. Urine and urethral swab samples were collected from each patient. Urine samples were tested by BDMAX (Becton-Dickinson， Canada) assay， Chlamydia antigen cassette test (Monlab， Spain) and Mycoview test (Zeakon， France). Urethral swabs were tested by Gonorrhoeae cassette test (Monlab， Spain). In 18 (22.5%) of the 80 HIV-infected individuals， the presence of at least one of the four agents was detected by Rt-PCR method. A total of 23 agents were reported as one N.gonorrhoeae (1/80)， two C.trachomatis (2/80)， seven Mycoplasma spp. (7/80)， 13 Ureaplasma spp. (13/80). In five (27.7%) patients， Ureaplasma spp. and Mycoplasma spp. were detected simultaneously. Twelve of 23 bacteria detected by Rt-PCR were also detected by IC tests; however， the remaining 11 bacteria (one N.gonorrhoeae， two C.trachomatis， four Ureaplasma spp.， four Mycoplasma spp.) were not detected. When IC tests were compared to the gold standard test Rt-PCR， the sensitivity was 47.8% (11/23) and the positive-predictive value was 100% (11/11). Sixteen patients had STI-related signs and symptoms whereas 64 were asymptomatic. Only two of the 18 men with positive-Rt-PCR test results had STI-related symptoms. It was concluded that all individuals with risky behaviours should undergo STIs screening regardless of their symptoms. As obtaining urethral samples could create difficulty for the patients as well as for the physicians， using urine samples determined to be more convenient. In our study the sensitivity of IC tests found to be insufficiently low. It was concluded that in STI screening the use of Rt-PCR method， which has high sensitivity， specificity and ability to give results on the same day although a high cost test could be preferred on high risk groups such as HIV-infected individuals with no signs of infection.