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Prevention and control of bacterial disease

Although bacteria were first seen and depicted with remarkable accuracy by Anthony van Leeuwenhoek in the late 17-th century, they were not generally recognized as a cause of disease until 100 years ago. Recognition of microbes as disease agents led directly and swiftly to control measures. Among them were: physicians, surgeons, nurses, and hospitals. Some organisms make chemicals that prevent the growth of bacteria. These chemicals are called antibiotics. The first antibiotics where discovered in 1929 by Alexander Fleming. They are used to kill pathogenic bacteria. Bacteria, produce most antibiotics; fungi, especially the actinomycetes, form few. These antibacterial agents act by interfering with metabolic reactions essential to the bacteria but not to the cells. Penicillin, for example, inhibits bacterial growth by interfering with the cross-linking of the peptide chains in the bacterial cell walls.

The battlefields of World War II were the proving grounds for new antimicrobial drugs, such as sulfa and penicillin. Penicillin is a well-known antibiotic that cures strep throat and other diseases by killing the bacteria, which cause it. Penicillin was the first discovered antibiotic – by definition, a chemical that is produced by a living organism and is capable of inhibiting the growth of microorganisms.

Immunization, which involves the stimulation of the body’s natural defenses against a disease-causing agent, is also responsible for the prevention of many bacterial diseases, including diphtheria, whooping cough and tetanus.

Bacteria Examples Form Motility Mode of nutrition Distribu-tion Ecologi-cal role Diseases
Eubac-teria Escherichia Coli, Strep-tococcus, Mycobacte-rium tuberculosis Rod-shaped (Bacillus), spherical (coc cus), spirillum (curves), vib-rio (one curve) Gliding, flagella Chemo-autotrophs, Photosyn-thetic auto-trophs, heterotrophs Soil, water, parasites Decompo-sers, sym-bionts, pathogens Lockjaw, diphtheria, tuberculosis
Myxo-bacteria Myxococ-cus, Cyto-phage, Chondro-myces Rod-shaped, flexible, in slime Gliding Heterotrophs Soil, some aquatic bacteria Decompo-sers of complex polysacharides None
Spiroche-tes Spirocheta, Treponema, Leptospira Extremely long, helical Twisting (axial filament) Heterotrophs Aquatic (polluted water), parasitres Symbionts in mollusk, pathogens, decompo-sers Syphilis, infectious jaundice, relapsing fever
Ric-kettsiae Rickettsia Small, 0,3 – 0,5 micrometers None Heterotrophs (parasites) Intracellular parasites Pathogens Typhus, spotted fever
Myco-plasma PPLO Smallest free-living cells, no cell walls None Heterotrophs Intracellular parasites, soil Pathogens Mycoplasm pneumonia

Table 3.1

 

 


Date: 2014-12-22; view: 882


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