|Classification and external resources|
Granuloma inguinale (also known as donovanosis) is a bacterial disease caused by Klebsiella granulomatis (formerly known as Calymmatobacterium granulomatis) characterized by ulcerative genital lesions. It is endemic in many less developed regions. It is also known as donovanosis, granuloma genitoinguinale, granuloma inguinale tropicum, granuloma venereum, granuloma venereum genitoinguinale, lupoid form of groin ulceration, serpiginous ulceration of the groin, ulcerating granuloma of the pudendum, and ulcerating sclerosing granuloma.
The disease often goes untreated because of the scarcity of medical treatment in the countries in which it is found. In addition, the painless genital ulcers can be mistaken for syphilis. The ulcers ultimately progress to destruction of internal and external tissue, with extensive leakage of mucus and blood from the highly vascular lesions. The destructive nature of donovanosis also increases the risk of superinfection by other pathogenic microbes.
The first known name for this condition was "serpiginous ulcer", which dates to 1882. The proper clinical designation for donovanosis is now "granuloma inguinale". A granuloma is a nodular type of inflammatory reaction, and inguinale refers to the inguinal region, which is commonly involved in this infection. The disease is commonly known as donovanosis, after the Donovan bodies which are a diagnostic sign.
The causative organism, Klebsiella granulomatis, was called Calymmatobacterium granulomatis, and some sources still use this classification, from the Greek kalymma (a hood or veil), referring to the lesions that contain the bacteria. Prior to this, it was called Donovania granulomatis, named after the Donovan bodies.
The specific name granulomatis refers to the granulomatous lesions. The organism was recently reclassified under the genus Klebsiella, a drastic taxonomic change since it involved changing the organism's phylum. However, polymerase chain reaction techniques using a colorimetric detection system showed a 99% similarity with other species in the Klebsiella genus.
Small, painless nodules appear after about 10–40 days of the contact with the bacteria. Later, the nodules burst, creating open, fleshy, oozing lesions. The infection spreads, mutilating the infected tissue. The infection will continue to destroy the tissue until treated. The lesions occur at the region of contact typically found on the shaft of the penis, the labia, or the perineum. Rarely, the vaginal wall or cervix is the site of the lesion. At least one case in India led to partial autoamputation of the penis. The patient tested positive for HIV-2 and had been infected for six years.
The microorganism spreads from one host to another through contact with the open sores.
The diagnosis is based on the patient's sexual history and on physical examination revealing a painless, "beefy-red ulcer" with a characteristic rolled edge of granulation tissue. In contrast to syphilitic ulcers, inguinal lymphadenopathy is generally mild or absent. Tissue biopsy and Wright-Giemsa stain are used to aid in the diagnosis. The presence of Donovan bodies in the tissue sample confirms donovanosis. Donovan bodies are rod-shaped, oval organisms that can be seen in the cytoplasm of mononuclear phagocytes or histiocytes in tissue samples from patients with granuloma inguinale.
They appear deep purple when stained with Wright's stain. These intracellular inclusions are the encapsulated Gram-negative rods of the causative organisms. They were discovered by Charles Donovan.
Recommended regimen is doxycycline 100 mg orally twice a day, alternatively with azithromycin 1 g orally once per week or ciprofloxacin 750 mg orally twice a day or erythromycin base 500 mg orally four times a day or trimethoprim-sulfamethoxazole one double-strength (160 mg/800 mg) tablet orally twice a day. All antibiotic regimens should last for at least 3 weeks and until all lesions have completely healed. Normally, the infection will begin to subside within a week of treatment, but the full treatment period must be followed to minimize the possibility of relapse.
The disease is effectively treated with antibiotics, therefore, developed countries have a very low incidence of donovanosis; about 100 cases reported each year in the United States. However, sexual contacts with individuals in endemic regions dramatically increases the risk of contracting the disease. Avoidance of these sexual contacts, and sexually transmitted disease testing before beginning a sexual relationship, are effective preventative measures for donovanosis.