Mycoplasma pneumoniae is a very small bacterium in the class Mollicutes. It is a human pathogen that causes the disease mycoplasma pneumonia, a form of atypical bacterial pneumonia related to cold agglutinin disease. M. pneumoniae is characterized by the absence of a peptidoglycan cell wall and resulting resistance to many antibacterial agents. The persistence of M. pneumoniae infections even after treatment is associated with its ability to mimic host cell surface composition.
In 1898, Nocard and Roux isolated an agent assumed to be the cause of cattle pneumonia and named it microbe de la peripneumonie Microorganisms from other sources, having properties similar to the pleuropneumonia organism (PPO) of cattle, soon came to be known as pleuropneumonia-like organisms (PPLO), but their true nature remained unknown. Many PPLO were later proven to be the cause of pneumonias and arthritis in several lower animals.
In 1944, Monroe Eaton used embryonated chicken eggs to cultivate an agent thought to be the cause of human primary atypical pneumonia (PAP), commonly known as "walking pneumonia." This unknown organism became known as the "Eaton agent". At that time, Eaton's use of embryonated eggs, then used for cultivating viruses, supported the idea that the Eaton agent was a virus. Yet it was known that PAP was amenable to treatment with broad-spectrum antibiotics, making a viral etiology suspect.
Robert Chanock, a researcher from the NIH who was studying the Eaton agent as a virus, visited the Wistar Institute in Philadelphia in 1961 to obtain a cell culture of a normal human cell strain developed by Leonard Hayflick. This cell strain was known to be exquisitely sensitive to isolate and grow human viruses. Chanock told Hayflick of his research on the Eaton agent, and his belief that its viral nature was questionable. Although Hayflick knew little about the current research on this agent, his doctoral dissertation had been done on animal diseases caused by PPLO. Hayflick knew that many lower animals suffered from pneumonias caused by PPLOs (later to be termed mycoplasmas).
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Ce cours permet aux étudiants ayant suivi Morphologie I de réviser et d'approfondir leurs connaissances par l'étude de l'anatomie radiologique et du développement. L'origine de malformations fréquente
Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and are often beneficial but others can cause infectious diseases. The number of these pathogenic species in humans is estimated to be fewer than a hundred. By contrast, several thousand species are part of the gut flora present in the digestive tract.
Bronchitis is inflammation of the bronchi (large and medium-sized airways) in the lungs that causes coughing. Bronchitis usually begins as an infection in the nose, ears, throat, or sinuses. The infection then makes its way down to the bronchi. Symptoms include coughing up sputum, wheezing, shortness of breath, and chest pain. Bronchitis can be acute or chronic. Acute bronchitis usually has a cough that lasts around three weeks, and is also known as a chest cold. In more than 90% of cases the cause is a viral infection.
An upper respiratory tract infection (URTI) is an illness caused by an acute infection, which involves the upper respiratory tract, including the nose, sinuses, pharynx, larynx or trachea. This commonly includes nasal obstruction, sore throat, tonsillitis, pharyngitis, laryngitis, sinusitis, otitis media, and the common cold. Most infections are viral in nature, and in other instances, the cause is bacterial. URTIs can also be fungal or helminthic in origin, but these are less common. In 2015, 17.
In the beginning was the metabolism. The biochemical processes that make life possible transformed the soup of chemicals into the life on Earth we know today. Since then, living organisms have evolved, and life on Earth has become more complex. Living orga ...
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Neonatal hypoxic-ischemic (HI) encephalopathy (HIE) in term newborns is a leading cause of mortality and chronic disability. Hypothermia (HT) is the only clinically available therapeutic intervention; however, its neuroprotective effects are limited. Lacto ...
The pathogenic bacterium Streptococcus pneumoniae (S. pneumoniae) can invade the cerebrospinal fluid (CSF) and cause meningitis with devastating consequences. Whether and how sensory cells in the central nervous system (CNS) become activated during bacteri ...