A 28 year old sexually active male presents with burning micturation. On clinical examination no ulcer in the genitals. Urine examination shows 50 WBCs/HPF, no RBCs, leucocyte esterase positive, gonococcal culture negative. What could be the most probable causative organism ?
Treponema pallidum
Neisseria
Chlamydia trachomatis
H. ducreyi