Tags: Osteomyelitis

Aspergillus, Pseudallescheria, & Agents of Mucormycosis

Aspergillus spp. are found worldwide and grow in a variety of conditions. They commonly grow in soil and moist locations and are among the most common molds encountered on spoiled food and decaying vegetation, in compost piles, and in stored hay and grain. Aspergillus spp. often grow in houseplant soil, and such soil may be a source of Aspergillus conidia or spores in the home, office, or hospital setting. The airborne conidia are extremely heat resistant and can withstand extreme environmental conditions.

Candida Species

Candida organisms are commensal with humans and, in the absence of alterations in host defense mechanisms, usually do not cause disease. Candida exists as normal flora within the oral cavity, throughout the gastrointestinal (GI) tract, in expectorated sputum, in the vagina, and in the bladder of patients with indwelling catheters. There are >150 species within the genus Candida, although the majority are not known to cause disease in humans. C albicans, C krusei, C glabrata, C tropicalis, C pseudotropicalis, C guilliermondii, C parapsilosis, C lusitaniae, and C rugosa are known human pathogens.

Blastomyces Dermatitidis (Blastomycosis)

Blastomyces dermatitidis is an endemic fungus that causes acute and chronic infections in humans and other animals. It is found primarily in the south central, southeastern, and midwestern United States, especially in the states surrounding the Mississippi and Ohio Rivers. Outside the United States, cases have been reported from Canadian provinces bordering the Great Lakes, Africa, India, the Middle East, and Central and South America.

Mycoplasma & Ureaplasma

Mycoplasma and Ureaplasma species (mycoplasmas) are ubiquitous in nature and are commonly found in plants, animals, and humans. These bacteria contain the smallest amount of double-stranded DNA that is capable of producing a free-living microorganism; they measure between 0.15 and 0.3 um in diameter and = 2 um in length.

Treponema Pallidum

The term syphilis was first used in 1530 by the Italian physician Girolamo Fracastoro in his epic poem Syphilis Sive Morbus Gallicus. Much has been learned since then about this sexually transmitted disease caused by T pallidum.

Actinomyces

Disease occurs when mechanical insult disrupts the mucosal barrier or organisms gain access to privileged sites. For example, actinomycosis commonly occurs after dental procedures, trauma, surgery, or aspiration. Actinomyces israelii causes the majority of human disease owing to this genus, but other species, including Actinomyces naeslundii, Actinomyces viscosus, Actinomyces enksonii, Actinomyces odontolyticus, and Actinomyces meyeri have also been implicated. Actinomycosis is threefold more common in men than women.

Other Mycobacteria

The increasingly relative importance of the atypical mycobacteria, many of which are ubiquitous in the environment, was recognized with the decline in tuberculous disease. Generally, atypical mycobacteria are unusual causes of disease in patients who are immunocompetent but can in immunocompromised hosts such as AIDS and cancer patients.

Mycobacterium Avium Complex (Disseminated & Pulmonary Disease)

Mavium is the most common atypical mycobacterium to cause disease in humans. In immunocompetent patients, M avium can cause pulmonary disease (Box 1). It is the most common pulmonary pathogen of all the atypical mycobacteria. There are several risk factors for pulmonary M avium infection besides AIDS.

Brucella, Francisella, Pasteurella, Yersinia, & Hacek

Brucellosis (also called undulant fever, Mediterranean fever, Malta fever) is an infection that causes abortion in domestic animals. It is caused by one of six species of Brucella coccobacilli. It may occasionally be transmitted to humans, in whom the disease could be acute or chronic with ongoing fever and constitutional symptoms without localized findings.