A 20 years old male patient presents to the STD clinic with a genital ulcer. The gram stain of the smear from the ulcer shows gram negative coccobacilli. Which of the following is the most appropriate culture medium for diagnosing the organism?
Patient is suffering from chancroid caused by Hemophilus ducreyi. Hemophilus ducreyi is a pleomorphic gram negative bacillus that causes chancroid, painful genital ulcers and lymphadenitis. It is grown best from scrapings of the ulcer base on chocolate agar containing 1% IsoVitaleX and vancomycin. A painful erythematous papule appears at the site of infection after an incubation period of 4 to 10 days. One to two days later, the lesion becomes eroded, ulcerated, and often pustular. The ulcers are usually 1 to 2 cm in diameter with sharp, undermined margins and are very painful. The friable base of the ulcer is covered with yellow-gray necrotic exudates. Multiple lesions are present in up to 50% of patients and "kissing lesions" are frequent. Painful inguinal lymphadenopathy develops 1 to 2 weeks after primary infection. It is treated with intramuscular ceftriaxone, oral trimethoprim-sulfamethoxazole, or oral erythromycin often results in healing in 2 weeks. Ref: Tintinalli's Emergency Medicine, Chapter 44 ; Jawetz, Melnick and Adelberg's Medical Microbiology, Chapter 18 ; Microbiology By Richard A. Harvey, Page 104 ; District Laboratory Practice in Tropical Countries, Volume 2 By Monica Cheesbrough, Page 202 ; Textbook of Microbiology and Immunology By Parija, Page 222
Thayer-Main Medium
Blood agar with X & V factors
Chocolate agar with isovitale X
Tellurite blood agar