Fungal Wound Infections

Fungal infections of wounds are unusual in economically developed countries, except that the yeast Candida albicans can be troublesome in severe burns and in those with wounds and underlying diseases such as diabetes and cancer. This yeast, commonly present among the normal flora and kept in check by it, becomes pathogenic when the competing microorganisms are eliminated, as in individuals receiving antibacterial therapy. Other fungal wound infections are much more common in impoverished people around the world. For example, Madura foot, a condition caused by various species of fungi, occurs in areas of the world where foot injuries are common, resulting from lack of shoes. Named after the city in India where it was first described, Madura foot is characterized by swellings and draining passageways that spit out yellow or black granules of fungal material. Only a minority of those with foot injuries contract the disease despite exposure to the same fungi, suggesting that other factors such as malnutrition may play a role. Sporotrichosis, another kind of fungal wound infection, occurs worldwide and is not poverty-related.

"Rose Gardener's Disease" (Sporotrichosis)

Sporotrichosis, also known as "rose gardener's disease," is widely distributed around the world, associated with activities that lead to puncture wounds from vegetation. Although many cases are sporadic, the disease can occur in groups of people engaged in the same occupation. Thousands of workers in the warm humid mines of South Africa have contracted the disease from splinters on mine timbers. Epidemics have occurred in the United States among handlers of sphagnum moss from Wisconsin.

Symptoms

In most cases, a hand or arm is involved, but the trunk, legs, and face can also be sites of infection. Typically, a chronic ulcer

Table 27.10 Human Bite Wound Infections

Symptoms

Rapid onset, pain, massive swelling, drainage of foul-smelling pus

Incubation period

Usually 6 to 24 hours

Causative agent

Mixed mouth flora: anaerobic streptococci, fusiforms, spirochetes, anaerobic Gram-negative rods; sometimes Staphylococcus aureus

Pathogenesis

Various mouth bacteria act synergistically to destroy tissue

Epidemiology

Alcohol-related violence; forcible restraint; poor mouth care and extensive dental disease

Prevention and treatment

No proven preventive measures except to avoid altercations. Prompt cleansing of wound and application of antiseptic is advised.Treatment is usually surgical

Sporotrichosis

Figure 27.16 Individual with "Rose Gardener's Disease" (Sporotrichosis)

Notice the multiple abscesses along the course of the lymphatic drainage from the hand.

Figure 27.16 Individual with "Rose Gardener's Disease" (Sporotrichosis)

Notice the multiple abscesses along the course of the lymphatic drainage from the hand.

forms at the wound site, followed by a slowly progressing series of ulcerating nodules that develop sequentially toward the center of the body (figure 27.16). Lymph nodes in the region of the wound enlarge, but patients generally do not become ill. If they have AIDS or other immunodeficiency, however, the disease can spread throughout the body, threatening life.

Causative Agent

Sporotrichosis is caused by the dimorphic fungus Sporothrix schenckii (figure 27.17), which lives in soil and on vegetation. ■ dimorphic fungus, p. 310

Pathogenesis

Sporothrix schenckii spores are usually introduced with an injury caused by plant material. After an incubation period that usually ranges from 1 to 3 weeks but can be much longer, the multiplying fungi cause formation of a small nodule or pimple at the site of the injury. This lesion slowly enlarges and ulcerates, producing a red, easily bleeding skin defect. Unless the ulcer becomes secondarily infected with bacteria, there is little or no pus, and the lesion is pain-free. After a week or longer, the process repeats itself, progression of the disease usually following the flow of a lymphatic vessel. In healthy individuals, the process does not proceed beyond the lymph node. Sometimes, however, satellite lesions appear irrespective of the lymphatic vessels. Without treatment, the disease can go on for years. ■ lymphatic vessel, p. 396

Epidemiology

Sporotrichosis is distributed worldwide, mostly in the warmer regions but extending into temperate climates. In the United States, most cases occur in the Mississippi and Missouri river valleys. It is an occupational disease of farmers, carpenters, gardeners, greenhouse workers, and others who deal with plant materials. Sporotrichosis is not a reportable disease, and its incidence is unknown. Risk factors for the disease besides occupation include diabetes, immunosuppression, and alcoholism. Children can contract the disease from playing in baled hay. Individuals with chronic lung disease can contract S. schenckii lung infections from inhaling dust from hay or cattle feed. Deaths from sporotrichosis are rare.

Prevention and Treatment

Protective gloves and a long-sleeved shirt can help prevent sporotrichosis, especially when handling evergreen seedlings and sphagnum moss. This chronic disease is often misdiagnosed, leading to delayed and inappropriate treatment. Surprisingly,

25 mm

25 mm

30 mm

Figure 27.17 Sporothrix schenckii, Showing the Two Forms of This Dimorphic Fungus (a) Mold form, (b) Yeast form, as seen in infected tissue.

30 mm

Figure 27.17 Sporothrix schenckii, Showing the Two Forms of This Dimorphic Fungus (a) Mold form, (b) Yeast form, as seen in infected tissue.

Summary 711

Table 27.11

"Rose Gardener's Disease" Sporotrichosis

Symptoms

Painless, ulcerating nodules appearing in sequence in a linear pattern

Incubation period

Usually 1 to 3 weeks

Causative agent

Sporothrix schenckii, a dimorphic fungus

Pathogenesis

Spores multiply at site of introduction by thorn, splinter, or other plant material, causing a small nodule that ulcerates. Spores carried by lymph flow repeat the process along the course of the lymphatic vessel. May spread beneath the skin irrespective of lymphatic vessels

Epidemiology

Distributed worldwide in tropical and temperate climates. Occupations requiring contact with sharp plant materials at particular risk

Prevention and treatment

Protective gloves and clothing. Most cases effectively treated with potassium iodide. Generalized infections require amphotericin B or itraconazole

unlike other infections, sporotrichosis can usually be cured by oral treatment with the simple chemical compound potassium iodide (KI). KI is not active against S. schenckii in vitro, but somehow enhances the body's ability to reject the fungus. Itraconazole or the antibiotic amphotericin B is used in rare cases when the disease spreads throughout the body.

Table 27.11 presents some of the main features of sporotrichosis.

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Responses

  • gebre
    Why the fungal wound form in the body?
    3 years ago
  • PRISCO
    What are the fungal infiction and causative agent?
    11 months ago
  • salla
    What is the causative agent of fungal diseases?
    11 months ago
  • Betty
    What are the causative agents of fungi?
    7 months ago
  • dennis
    What are the fungal infection and cousetive agent that are releated to immunocompromize patient?
    7 months ago

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