Leprosy (Hansen disease) is a heterogeneous, curable infection caused by Mycobacterium leprae that primarily affects the upper airway, skin, and peripheral nerves. Disease manifestations are mainly determined by the host's immunologic response to infection, resulting in a wide clinical spectrum.…
Tuberculosis has caused human disease for more than 4,000 yr and is one of the most important infectious diseases worldwide. Etiology There are 5 closely related mycobacteria in the Mycobacterium tuberculosis complex: M. tuberculosis, M. bovis, M. africanum, M. microti, and…
The treatment of mycobacterial infection and disease can be challenging. Patients require therapy with multiple agents, the offending pathogens commonly exhibit complex drug resistance patterns, and patients often have underlying conditions that affect drug choice and monitoring. Several of the…
Anaerobic bacteria are among the most numerous organisms colonizing humans. Anaerobes are present in soil and are normal inhabitants of all living animals, but infections caused by anaerobes are relatively uncommon. Obligate anaerobes are markedly or entirely intolerant of exposure…
Clostridium difficile infection ( CDI ), also known as pseudomembranous colitis or C. difficile –associated diarrhea, refers to gastrointestinal (GI) colonization with C. difficile resulting in a diarrheal illness. It is a common cause of antibiotic-associated diarrhea and the most…
Etiology Tetanus is an acute, spastic paralytic illness caused by a neurotoxin produced by Clostridium tetani. Thus, tetanus can be considered more as a toxin-mediated process than an acute infectious process, since there are few, if any, symptoms elicited by…
There are 3 naturally occurring forms of human botulism, characterized by mode of acquisition: infant botulism (intestinal toxemia), foodborne botulism , and wound botulism . Infant botulism is the most common form in the United States. Under rare circumstances of…
The spectrum of disease resulting from human infection with Bartonella species includes the association of bacillary angiomatosis and cat-scratch disease with Bartonella henselae. There are more than 30 validated species of Bartonella , but 6 major species are responsible for…
Legionellosis comprises legionnaires disease ( Legionella pneumonia), other invasive extrapulmonary Legionella infections, and an acute flulike illness known as Pontiac fever. In contrast to the syndromes associated with invasive disease, Pontiac fever is a self-limited illness that develops after aerosol…
Human brucellosis is caused by organisms of the genus Brucella and continues to be a major public health problem worldwide. Humans are accidental hosts and acquire this zoonosis from direct contact with an infected animal (cattle, sheep, camels, goats, and…