Description of the Pathogens The family Anaplasmataceae is classified in the order Rickettiales and currently contains five genera and two candidate genera of obligate intracellular bacteria. Four of the genera contain members that are known to infect humans: Anaplasma ,…
The Pathogen Q fever (or “query” fever) is caused by the intracellular bacterium Coxiella burnetii, which belongs to the order Legionellales, family Coxiellaceae. C. burnetii primarily is a zoonotic pathogen. The organism can be present in high concentrations in the…
The Pathogen Chlamydia psittaci (also known as Chlamydophila psittaci ) is a gram-negative obligate intracellular zoonotic bacterium that causes both systemic infection and pneumonia, often referred to as psittacosis or ornithosis ( Fig. 168.1 ). Originally named parrot fever because…
The Pathogen and Pathogenesis Chlamydiae are obligate, intracellular, nonmotile, gram-negative bacteria with a unique biphasic developmental cycle consisting of extra- and intracellular forms. Chlamydiae have an outer membrane that contains lipopolysaccharide (LPS) and membrane proteins. Peptidoglycan is present in the…
The Pathogen Chlamydiae are obligate intracellular pathogens, which former genus Chlamydia pneumoniae has been reclassified (somewhat controversially ) through genome sequencing and comparative analysis of the ribosomal operon to Chlamydophila pneumoniae, with three biovars—human (TWAR), koala, and equine. Still controversial,…
Capnocytophaga is a genus in the family Flavobacteriaceae encompassing a group of slow-growing, capnophilic (carbon dioxide−loving), facultative anaerobic, gram-negative fusiform bacilli. Species are divided into two groups, the “human” group (formerly classified as Centers for Disease Control and Prevention [CDC]…
The genus Campylobacter includes approximately 26 species and 9 subspecies. Of the Campylobacter species that are associated with human disease, C. jejuni is the prototype for enteric infections, and C. fetus is the prototype for extraintestinal infections. Campylobacter species other…
Campylobacter spp. are one of the most common causes of culture-proven bacterial gastroenteritis in resource-rich and resource-limited countries. In the US, the annual incidence is 19.5 cases per 100,000 persons and is highest in children aged <5 years. , Although…
Pertussis is an acute respiratory tract infection that was well described in the 1500s and endemic in Europe by the 1600s; its current worldwide prevalence is dampened only by continuous use of active immunization. Sydenham first used the term pertussis…
Acknowledgements Ed Young was a true gentleman and scholar who was a continuous source of education for all who crossed his path. Brucellosis is a disease of animals that can be transmitted to humans (zoonosis). The genus Brucella belongs to…