Structure and Growth
B. burgdorferi is a highly specialized, motile, two-membrane, flat-waved spirochete, ranging from about 9 to 32 micrometers in length. Because of its double-membrane envelope, it is often mistakenly described as Gram negative, though it stains weakly in Gram stain. The bacterial membranes in at least the B31, NL303 and N40 strains of B. burgdorferi do not contain lipopolysaccharide, which is extremely atypical for Gram negative bacteria; instead, the membranes contain glycolipids. However, the membranes in the B31 strain have been found to contain a lipopolysaccharide-like component. B. burgdorferi is a microaerophilic organism, requiring little oxygen to survive. Unlike most bacteria, B. burgdorferi does not use iron, hence avoiding the difficulty of acquiring iron during infection. It lives primarily as an extracellular pathogen, although in vitro it can also hide intracellularly (see Mechanisms of persistence section).
Like other spirochetes, such as Treponema pallidum (the agent of syphilis), B. burgdorferi has an axial filament composed of flagella which run lengthways between its cell wall and outer membrane. This structure allows the spirochete to move efficiently in corkscrew fashion through viscous media, such as connective tissue.
B. burgdorferi is very slow growing, with a doubling time of 12–18 hours (in contrast to pathogens such as Streptococcus and Staphylococcus, which have a doubling time of 20–30 minutes). Since most antibiotics kill bacteria only when they are dividing, this longer doubling time necessitates the use of relatively longer treatment courses for Lyme disease.
Read more about this topic: Lyme Disease Microbiology
Famous quotes containing the words structure and, structure and/or growth:
“Slumism is the pent-up anger of people living on the outside of affluence. Slumism is decay of structure and deterioration of the human spirit. Slumism is a virus which spreads through the body politic. As other “isms,” it breeds disorder and demagoguery and hate.”
—Hubert H. Humphrey (1911–1978)
“... the structure of our public morality crashed to earth. Above its grave a tombstone read, “Be tolerant—even of evil.” Logically the next step would be to say to our commonwealth’s criminals, “I disagree that it’s all right to rob and murder, but naturally I respect your opinion.” Tolerance is only complacence when it makes no distinction between right and wrong.”
—Sarah Patton Boyle, U.S. civil rights activist and author. The Desegregated Heart, part 2, ch. 2 (1962)
“The wind of change is blowing through the continent. Whether we like it or not, this growth of national consciousness is a political fact.”
—Harold MacMillan (1894–1986)