Neisseria meningitidis
Margaret Meyer

Neisseria meningitidis is a gram negative diplococcal bacterium, with the adjacent sides flattened against each other.  N. meningitidis is aerobic, susceptible to drying out and growth is inhibited by free fatty acids (1).  Its natural habitat is in the nasopharyngeal tract in humans.  The cell wall had lipopolysaccharides, which acts as an endotoxin.  Other structures include a polysaccharide capsule, and fimbriae, which allow attachment to the nasopharynx (2).  It has an ATCC number of 13090 and with proper authorization, can be bought on the ATCC website for $37.00.  It has a bio safety level of 2.  It was first isolated in the spinal fluid by SE Branham (3).  It’s optimal temperature for growth is at a temperature equal to 37 °C and a pH controlled at 7.0 (4).  The medium it grows on is ATCC medium 814 GC.  There are several different strains, including; A, B, C, 29E, W-135 and Y.



Although it is not the most common cause for bacterial meningitis in the United States, N. meningitidis is certainly the most dangerous. Meningitis is an infection of the fluid surrounding the brain and spinal cord, also known as the meninges.  When the infection is caused by bacteria, the disease is much more severe. The body fights against this bacteria with anti capsular antibodies.  Infection occurs after the nasopharynx has been colonized, and the bacteria then invade the circulatory system.  This occurs when the bacteria adhere to pili and undergo endocytosis, allowing it to cross the nasopharyngeal epithelium.  Once in the blood stream the bacterial levels can rise, which results in the invasion of the meninges.  This results in inflamed meninges (7).  Several different kinds of antibiotics are used in treatment.  Although, there is treatment, it must be done very early.  With treatment, the risk of dying is reduced to below fifteen percent.  Menigngitis is contagious, the bacteria can spread by coughing, kissing, or anything that includes the exchanging of respiratory and throat secretions (8).



*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.


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