Nonvenereal treponemal infections—yaws, bejel (endemic syphilis), and pinta—are caused by different subspecies of Treponema pallidum and occur in tropical and subtropical areas. The causative agents of nonvenereal treponematoses— T. pallidum pertenue, T. pallidum subspecies endemicum, and Treponema carateum —cannot be…
Syphilis is a chronic systemic sexually or vertically (mother to child) transmitted infection that can be easily treated if detected early but manifests with protean clinical symptoms and significant morbidity if left unchecked. Etiology Syphilis is caused by Treponema pallidum,…
Nontuberculous mycobacteria ( NTM ), also referred to as atypical mycobacteria and mycobacteria other than tuberculosis (MOTT), are all members of the genus Mycobacterium and include species other than Mycobacterium tuberculosis complex and Mycobacterium leprae . The NTM constitute a…
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…