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?
Thayer-Main Medium
Blood agar with X & V factors
Chocolate agar with isovitale X
Tellurite blood agar
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