Sexually transmitted infections (STI) remain a public health problem of major significance in most parts of the world. The incidence of acute STI is believed to be high in many countries and failure to diagnose and treat STI at an early stage may result in serious complications and sequelae, including infertility, foetal wastage, ectopic pregnancy, anogenital cancer and premature death, as well as neonatal and infant infections. The individual and national expenditure for STI care can be substantial.

The appearance of the human immunodeficiency virus (HIV) and the acquired immunodeficiency syndrome (AIDS) has focused greater attention on the control of STI. There is a strong correlation between the spread of conventional STI and HIV transmission and both ulcerative and non-ulcerative STI have been found to increase the risk of sexual transmission of HIV

The emergence and spread of HIV infection and AIDS complicated the management and control of some other STI. For example, the treatment of chancroid has become increasingly difficult in areas with a high prevalence of HIV infection, due to the HIV-related immunosuppression.

Antimicrobial resistance of several sexually transmitted pathogens is increasing, rendering some regimens ineffective.

New agents, such as third-generation cephalosporins and fluoroquinolones, capable of treating infections with resistant strains are available but are expensive. However, their initial high cost must be weighed against the cost of inadequate therapy, which may lead to complications, relapse, further spread and selection for antimicrobial resistance.