A 45-year-old businessman presents with a unilateral tender enlarged inguinal lymph node. He travels overseas several times a year, and admits to having sex with prostitutes while away. Upon returning from his most recent business trip last month, he noticed a painless ulcer on his penis. He self-medicated with penicillin, and the ulcer resolved after several days. A few weeks later the lymphadenopathy began to develop. VDRL and HIV screening are negative. From what is the patient most likely suffering?
- Chancroid caused by H. ducreyi
- Genital herpes caused by HSV-2
- Granuloma inguinale caused by K. granulomatis
- Lymphogranuloma venereum caused by C. trachomatis
- Primary syphilis caused by T. pallidum
- Secondary syphilis caused by T. pallidum