Donovanosis

Donovanosis, also known as granuloma inguinale, is a bacterial disease that has reached endemic proportions in many underdeveloped regions. Because of the scarcity of medical treatment, the disease often goes untreated. The disease is characterized by painless genital ulcers which can be mistaken for syphilis.^[1] However, they ultimately progress to destruction of internal and external tissue, with leakage of mucus and blood. The destructive nature of donovanosis also increases the risk of superinfection by other pathogenic microbes.

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Classification

The proper clinical designation for donovanosis is granuloma inguinale.^[2] 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. Discovered by a researcher named Donovan, these intracellular inclusions represent bacteria that have been engulfed by scavenger cells called mononuclear phagocytes or histiocytes.

The causative organism, Klebsiella granulomatis, used to be called Calymmatobacterium granulomatis, 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.^[3] The species 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 (PCR) techniques using a colorimetric detection system showed a 99% similarity with other species in the Klebsiella genus.

Symptoms

  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 perianal region. Rarely, the vaginal wall or cervix is the site of the lesion.

Transmission

The microorganism spreads from one host to another through contact with the open sores. Oral, vaginal or anal intercourse are high risk behaviors to engage in with someone who is infected.

Diagnosis

The patient’s sexual history is requested. Experienced doctors are able to diagnose donovanosis by only looking at the ulcers. However, it may be necessary for the health care provider to take a sample of tissue in order to correctly diagnose the disease. He or she may decide to add a Wright-Giesmsa stain in order to better view the cells. Additionally, the presence of Donovan bodies in the tissue sample confirms donovanosis.

Treatment

Three weeks of treatment with erythromycin, streptomycin, or tetracycline, or 12 weeks of treatment with ampicillin are standard forms of therapy. Normally, the infection will begin to subside within a week of treatment, however, the full treatment period must be followed in order to minimize the possibility of relapse.

Prevention

The disease is effectively treated with antibiotics, therefore, developed countries, like the United States, have a very low incidence of donovanosis, (approximately 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 STD testing before beginning a sexual relationship are effective preventative measures for donovanosis.

References

1. ^ Murray P. et al. (2005), Medical Microbiology, fifth ed., Elsevier Mosby, p. 336.
2. ^ Murray P. et al. (2005), Medical Microbiology, fifth ed., Elsevier Mosby, p. 336.
3. ^ Murray P. et al. (2005), Medical Microbiology, fifth ed., Elsevier Mosby, p. 336.

See also

• International Journal of Systematic Bacteriology, Vol 49, 1695–1700
• N. O’Farrell, Donovanosis. Sexually Transmitted Infections December 2002; 78: 452–457.
• Gavin Hart MD, MPH Transcript of the lecture given at the Australian Society for Infectious Diseases/Australasian College of Tropical Medicine Conference at Palm Cove (Cairns), Queensland on 19 April 1999.
• 2001 National Guideline for the management of Donovanosis (granuloma inguinale) Association for Genitourinary Medicine and the Medical Society for the study of Venereal Diseases
• Sequencing of 16S rDNA of Klebsiella: taxonomic relations within the genus and to other Enterobacteriaceae. International Journal of Medical Microbiology. 2003 Feb;292(7-8):495–503.