Bacteria Escherichia coii

May be effective in the treatment of acute urinary tract infections caused by susceptible strains of gram-positive and gram-negative bacteria, especially Enterobacter sp. and Escherichia coii. It usually is less effective than other antimicrobial agents in the treatment of urinary tract infections caused by bacteria other than mycobacteria. Consider using only when the more conventional therapy has failed and when the organism has demonstrated sensitivity. 

Some shams of the bacterium Escherichia coii harbor a dormant virus called lambda, which consists of a long molecule of DNA enclosed in protein Exposure of such infected bacteria to ultraviolet light suddenly switches oil these inactive lambda. The viruses proliferate and some 45 minutes after irradiation the bacteria burst, yielding a crop of new virus particles. If the bacteria are not irradiated, they grow normally, and rarely give rise spontaneously to viruses. 

A FIGURE 1-2 Prokaryotic cells have a simpler internal organization than eukaryotic cells, (a) Electron micrograph of a thin section of Escherichia coii, a common intestinal bacterium. The nucleoid, consisting of the bacterial DNA, is not enclosed within a membrane. E. coii and some other bacteria are surrounded by two membranes separated by the periplasmic space. The thin cell wall is adjacent to the inner membrane. 

Binding of (3-lactam antibiotics to PBP-1A and PBP-1 B (transpeptidase) of Escherichia coii leads to cell lysis to PBP-2 (transpeptidase) leads to oval cells deficient in rigidity and to inhibition of cell division to PBP-3 (transpeptidase) leads to abnormally long, filamentous shapes by failure to produce a septum and to PBP-4 through PBP-6 (carboxypeptidases) leads to no lethal effects. Approximately 8% of a dose of benzylpenicillin binds to PCP-1, 0.7% to PCP-2, 2% to PBP-3, 4% to PBP-4, 65% to PBP-5, and 21% to PBP-6. Thus, the majority of the penicillin dose bonds to PBPs for which the function remains obscure. Binding to PBP-1 is lethal. Other (3-lactam antibiotics display different binding patterns. Amoxicillin and the cephalosporins bind more avidly to PBP-1, methicillin and cefotaxime to PBP-2, and mezlocillin and cefuroxime to PBP-3. All these drugs are lethal to susceptible bacteria. 

Escherichia coli (E. coii)—Bacteria in human intestine that aids in digestion it does not cause disease unless the bacteria escape to other organs or tissues. However, some strains of . coli produce toxins and can cause food poisoning. Strains of . coli are used in biotechnology, modified so the bacteria cannot cause disease. 

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