Growing resistance to antibiotics has complicated efforts to rein in common sexually transmitted diseases like gonorrhoea, chlamydia and syphilis, the World Health Organization warned Tuesday as it issued new treatment guidelines. Globally, more than one million people contract a sexually transmitted disease (STD) or infection (STI) every day, WHO said. "Chlamydia, gonorrhoea and syphilis are major public health problems worldwide, affecting millions of peoples' quality of life, causing serious illness and sometimes death," Ian Askew, head of WHO's reproductive health and research division, said in a statement.