Streptobacillus moniliformis, S. hongkongensis, and S. notomytis of the genus Streptobacillus cause infection in humans. They are fastidious, nonmotile, gram-negative, pleomorphic, and often filamentous, beaded, facultative anaerobic bacilli. S. moniliformis can exist in two phases: the bacillary phase and the…
Rickettsia Prowazekii (Classic Louse-Borne Epidemic Typhus: Brill-Zinsser Disease Or Recrudescent Typhus; Sylvatic Or Flying Squirrel-Associated Typhus) Description of Pathogen Rickettsia prowazekii is a small, gram-negative, obligately intracellular, rod-shaped bacterium. R. prowazekii possesses a regularly arrayed surface autotransporter protein (OmpB) layer…
Description of The Pathogen Rickettsia rickettsii, the etiologic agent of Rocky Mountain spotted fever (RMSF), is a small, obligately intracellular, gram-negative, rod-shaped organism that is among the most pathogenic of all known bacteria. Although R. rickettsii can infect several different…
Investigation of an outbreak of pneumonia among attendees at an American Legion Convention in Philadelphia in 1976 revealed a previously unrecognized causative pathogen, Legionella pneumophila. , Infection with Legionella spp. occurs in sporadic and outbreak forms and is one etiology…
The genus Kingella belongs to the Neisseriaceae family in the β-subclass of the Proteobacteria, and the genus currently comprises five recognized species. Kingella potus has been isolated from an infected animal bite in an adult, the recently described K. negevensis…
Since the discovery of Helicobacter pylori and the demonstration of its causal relationship with human gastroduodenal disease, investigators have identified numerous non− Helicobacter pylori Helicobacter (NHPH) species. These other Helicobacter spp. are frequently found in domestic and wild animals and…
Helicobacter pylori infection is ubiquitous among humans. , Despite declining prevalence in developed countries, H. pylori continues to be one of the most common human infections worldwide, affecting up to 90% of the population in developing nations. Transmission primarily occurs…
Of the Haemophilus species, H. influenzae causes by far the most human disease. Several other members of this genus, however, cause clinical illness. These include H. influenzae biogroup aegyptius , H. ducreyi, H. parainfluenzae, H. pittmaniae, H. sputorum, H. haemolyticus,…
Haemophilus influenzae was first isolated by Pfieffer during the 1889 influenza pandemic. For a time, H. influenzae was believed to be the causative agent of influenza and originally was called the influenza bacillus. However, subsequent studies demonstrated the fallacy of…
Description of Pathogen and Epidemiology Francisella tularensis, the etiologic agent of tularemia, is a small, fastidious, non−spore-forming, strictly aerobic gram-negative coccobacillus, which is nonmotile and nonpiliated and has a thin capsule composed mostly of lipid. Tularemia is a zoonotic disease;…