RECENT ADVANCES IN DIAGNOSIS OF SEXUALLY-TRANSMITTED DISEASES

In an effort to better diagnose, treat, and control sexually transmitted diseases (STD), a number of new diagnostic assays using molecular techniques have been developed. By incorporating molecular amplification, the sensitivity for detecting sexually transmitted infections has become markedly enhanced, and organisms that were difficult or impossible to cultivate, such as human papillomavirus (HPV) or Treponema pallidum can now be detected and monitored. By using polymerase chain reaction (PCR) or ligase chain reaction (LCR), the sensitivity of detecting some pathogens is comparable to, or in some cases better than, direct in vitro cultivation of the agent. DNA fingerprint analysis of amplified microbial DNA also has been effectively used for detailed study of the epidemiology and pathophysiology of sexually transmitted infections. In addition to direct detection, molecular techniques have been used to enhance serologic techniques by use of cloned proteins and recombinant antigens. These techniques have enabled investigators to differentiate infection caused by closely related pathogens, such as human immunodeficiency virus type 1 (HIV-1) and HIV-2 and human T-cell lymphotrophic virus type 1 (HTLV-1) and HTLV-2. As a consequence of these molecular tools, the diagnostic repertoire of the clinical laboratory for the diagnosis of STD will expand significantly, allowing investigators to better diagnose and more effectively control the spread of STD. However, with such new technology, new problems and challenges have arisen, such as the risk of sample contamination resulting in false-positive results, and the presence of inhibitors resulting in false-negative results. To effectively use these molecular diagnostic assays, a concerted international effort will be required to help evaluate these new assays and to define their place in the clinical arena.