Bacteria disease control

Reviews of the extensive biochemistry of selenium in bacteria are available 108,109 ug fenler for Disease Control summaries for Se toxicology are also available110 A more recent review of the processes of biomethylation of selenium and tellurium in microorganisms and plants is also available.111... 

Large populations of rhizobacteria are usually present in file rhizosphere, mainly because of die ideal environmental conditions they encounter there due to a constant supply of nutrients provided through root exudates and lysates [58]. Many of the present strains exert a disease controlling activity simply by directly antagonizing soil-borne pathogens [59,60]. In order to investigate disease suppression conditioned by ISR, it is therefore important to spatially separate the bacteria fiom the roots. 

Pathogenic bacteria are responsible for the majority of food-related outbreaks in the United States. Opportunity for contamination exists at every stage in the food chain. Actual incidence of food-borne disease is unknown, even in countries with fairly sophisticated monitoring systems, because the number of cases are severely underreported. The newly installed PulseNET system by the Centers for Disease Control and Prevention (CDC) in Atlanta is an attempt to have better tracking and obtain better data regarding certain microorganisms. 

In March 2003, smallpox scabs were found tucked inside an envelope in a book on Civil War medicine in Santa Fe, New Mexico [260]. The envelope was labeled as containing the scabs and listed the names of the patients that were vaccinated with them. Assuming the contents could be dangerous, the librarian who found them did not open the envelope. This was fortunate, as unlike bacteria (with the exception of those that produce spores), viruses can theoretically survive for many years. The scabs ended up with employees from the National Center for Disease Control, who responded quickly once in-formed of the discovery. The discovery raised concerns that smallpox DNA could be extracted from these and other scabs and used for a bioterrorism attack. 

The ability to produce antibiotics is common among the actinomycetes and much of the interest in these filamentous bacteria in recent years may be attributed to this fact. This interest has been manifest chiefly in research connected directly or indirectly with medicine. Soil samples from all over the world have been examined in the search for new species and strains that may produce a new antibiotic suitable for medical use. Hundreds of these antibiotics have been isolated but only a few have been found to be sufficiently non-toxic and specific for use in disease control. Among the best known of these that are in use are streptomycin, terramycin, aureomycin, cycloheximide, chlortetracycline, oxytetracycline, chloramphenicol and neomycin. Some of these have been used to a limited extent in disease control in plants. Their use for this purpose is limited by cost, by difficulty in getting the antibiotic into the plant, and by toxicity when used at concentrations adequate to be effective. The limited time that they are effective is also an important factor (Brian, 1957 Zaumeyer, 1958 Pramer, 1959). The role of antibiotics in soils and their effect on microbial ecology is considered in Chapter 18. 

Crop rotation bears a close relationship to the title of this book since the crops grown, and the disposal made of them, affect the quality and quantity of organic matter in soils, and the extent of disease control. Nevertheless, the subject is in a sense a side issue and involves such a mass of research that no attempt will be made here to discuss it at length. Fortunately, Curl (1963), in a 67-page paper with 479 references has done an excellent job of assembling and analyzing the data. In addition, Kincaid (1960) has reviewed the information on the diseases of tobacco and states that some of those caused by nematodes, fungi, bacteria and viruses are amenable to control by crop rotation. 

In a Centers for Disease Control and Prevention (CDC) study spanning the years 1980-1990, 62% of all nosocomial infections were attributed to bacterial pathogens [3]. An undefined number are due to bacteria transferred by and from the hands and skin. Products such as preoperative skin preparations and surgical scrubs have been used in hospital settings for the reduction of nosocomial infections. Products designed for these uses rapidly and dramatically reduce the levels of resident bacteria on the hands or skin immediately prior to invasive surgical procedures. By definition, they should exhibit a persistent effect. Persistence is prolonged or extended antimicrobial activity which acts to prevent or inhibit the... 

Indeed a variety of interactions of polysaccharisurface charge than on detailed structure, and a much broatfcr study of the activity of polyelectrolytes and their possible application to disease control might be fruitful. 

---