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GRAM1 - μ m which puts them at or below the limits of...

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GRAM-POSITIVE BACTERIA Listeria monocytogenes  occasionally contaminates food, especially dairy products. It has the  ability to grow at refrigerator temperatures, and there have been recent outbreaks of the disease  listeriosis traced to hotdogs and luncheon meats. The disease is particularly serious in pregnant  women, since it can cause severe damage to the fetus.  Listeria  can survive inside phagocytic  cells.   5. MYCOPLASMATALES---these are highly pleomorphic and lack a cell wall. (They really  don’t have a gram-reaction, but are placed in the gram-positive group anyway.) When first  discovered, this group could not be grown on artificial media, but after the discovery that media  must contain sterols and meet some other unusual requirements that is no longer true.  a.  Mycoplasma---m ost are aerobic or facultative anaerobes. The cells are very small (0.1 to .025 
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Unformatted text preview: μ m), which puts them at or below the limits of resolution of a light microscope. Even their colonies are so tiny that a magnifying glass is used to observe them. Because their plasma membranes must be stronger than those of other bacteria, they must incorporate sterols in the membrane, so their growth media must include sterols, which most bacteriological media do not. They also are grown in tissue cultures. Mycoplasma pneumoniae —causes atypical primary pneumonia (walking pneumonia) b. Spiroplasma species, which are pathogens of plants and insects that feed on plants. Cells have a corkscrew shape. c. Ureaplasma species—sometimes associated with urinary tract infections. They produce an enzyme that can split urea....
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