Microbial cultures history

In this chapter, by using the examples of -lactams we have briefly examined how microbial cultures may be used to produce sufficient antibiotics to meet market demands. We have also explained how enzymes (or cells) may be used to biotransform, and thereby diversify, antibiotics. By outlining the history of penicillin production, we explained how analysis and manipulation of culture regimes may be used to enhance the yields of antibiotics (and other secondary products). These studies led to die concept of directed biosynthesis by precursor feeding. 

Differentiate between microbial colonization and infection based on patient history, physical examination, and laboratory and culture results. 

Treatment of microbial keratitis is started immediately irrespective of whether microbiologic evaluation has been performed. The best antimicrobial agent or agents to use initially is debated in the ophthalmic literature. The two main choices for initial antibiotic treatment are the combination of two fortified antibiotics, such as cefazolin and tobramycin, or monotherapy with topical fluoroquinolones. Just as with the decision to culture, the choice of antibiotic is often influenced by history and clinical presentation. Milder presentations, in low-risk... 

Foods that include the incorporation of microbial metabolites as part of their production are an intricate component of the world s food supply and for ethical and sensory-nutritional reasons it is essential for all the world s population to have access to this form of food. It is a process that has been in use since the early history of mankind. An Egyptian pot dating from 2300 BC (McGee, 1984) was found to contain residues of cheese and in passages in the Bible the use of some kind of fermentative starter culture is indicated. It is, therefore, possible that the use of bacteria such as the lactic acid bacteria (LAB) dates back at least four to five thousand years, although the exact principle behind the process may not have been known to the civilizations of those times (Davidson et al., 1995). Production of fermented foods, where organisms such as the LAB are involved, is a technological process that has been used for centuries at least (Herreros et al., 2005). 

There are a number of factors that influence heat resistance, for example, history of microorganisms, composition of foods, pH, salt, and growth phase of microorganisms (Hansen and Riemann, 1963). It is known that cells from cultures in the logarithmic phase are less heat resistant than cells in the lag or stationary phase (Lemcke and White, 1959). Substrate or food composition has a very important effect on heat resistance. Decrease in moisture content can increase the heat resistance of microbial cells. Moist heat is much more effective in terms of microbial inactivation than dry heat since proteins, which may be destroyed during thermal processing, are more stable in a dry state (Hansen and Riemann, 1963). 

One of the most profound developments in the history of modem medicine has been the discovery of antibiotics to control infections. The realization that microbial products could cure infectious diseases spanned approximately sixty-five years of discoveries (8). One of the first modem scientific demonstrations was the observation by Louis Pasteur in 1877 that common bacteria inhibited the growth of a pure anthrax culture. Other observations followed. Then in 1928 it was noted by Alexander Fleming that a culture of a green inhibited the growth of bacteria on an agar plate... 

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