Sponsored by
11. Walter Gilbert (1932 -), Frederick Sanger (1918 – 2013) and Paul Berg (1926 -): Gilbert, an American molecular biologist, Sanger, a British biochemist, and Berg, an American biochemist, shared the 1980 Nobel Prize for Chemistry. Berg received half the award for his work with recom- binant DNA. Gilbert and Sanger shared the other half for their work with DNA base sequences.
12. Robert Gallo (1937 -) and Luc Montag- nier (1932 -): Dr. Gallo, an America bio- medical researcher, and Dr. Montagnier, a French virologist, shared credit for the discovery of the human immunodefi- ciency virus (HIV) in 1984.
13. Raymond Kralovic (1940 – 2013): An American microbiologist, Kralovic con- ceived and developed the first process for low-temperature liquid sterilization, which was needed for delicate medical instruments that could not tolerate the standard steam sterilization process.
14. Bayer (Established 1863): Founded in 1863 in Barmen, Germany, this company’s microbiologists developed ciprofloxacin hydrochloride, which was cleared by FDA in 2000 for use in treating biological-agent induced infections such as anthrax.
How we relate to microbes The interaction between microorganisms and humans can be described as a love-hate relationship. We love them when they’re nonpathogenic (don’t cause disease), but hate them when they cause us harm (patho- genic). Resident microbes are those that live with us daily. For the most part, we get along because they aid with food diges- tion and protect us from diseases. They are often referred to as normal flora. In contrast, transient microorganisms are passed from person to person, surface to person or envi- ronment to person. They are picked up from surfaces and environments, or pass through our bodies. One could say that all microorganisms have a competitive nature. Under certain conditions, both resident and transient mi- croorganisms can have a negative effect on humans. For example, in individuals with a compromised, weakened or disrupted immune system (such as someone with HIV-AIDS), normal flora can become oppor- tunistic or pathogenic. They take advantage of the situation and grow in number until they overtake the person and cause harm. Transient microorganisms will try to colonize in or on the human body, but are typically controlled by the person’s immune
system, the competition of normal resident flora, or by physical or chemical action on the skin surface (washing).
Categories of microorganisms Microorganisms can be organized into four major classes: 1. Bacteria 2. Viruses 3. Fungi 4. Protozoa
Important characteristics that impact their function and effect on humans include their cell structure, their DNA/RNA composi- tion, their means of reproduction, and their size. Bacteria are the most abundant and impactful microorganism found in the en- vironment. They are single-cell structures that self-replicate. They contain DNA and range in size from 0.3 to 2.0 micrometers. To provide a size reference; a medium- sized grain of sand is one thousand times larger than one bacterium. Bacteria are easily viewed under a microscope using the Gram-staining technique. Some strains are beneficial to humans, and are normally found in the human digestive tract. All bacteria can exist in an actively growing or “vegetative” state, but certain special groups of bacteria are “spore-formers” (able to form a protective shell that’s very resistant to environmental stress). When environmental conditions for reproduction are present, bacterial spores become veg- etative cells. Some examples of pathogenic bacteria are: • Mycobacterium tuberculosis (Tuberculosis) • Staphylococcus aureus (Impetigo) • Bordetella pertussis (Whooping Cough) • Salmonella enteritis (Food Poisoning) Viruses, on the other hand, do not have a cellular structure. Some viruses have a lipid envelope, and this envelope makes them harder to kill. They contain either DNA or RNA, but not both. Instead of replicating themselves, they use the host cell to re- produce. Some, like Herpes simplex virus and Varicella zoster, may remain dormant (inactive) within the host cell. When they are environmentally stimulated, they re- activate and take over the host cell’s DNA or RNA by copying or reprogramming it. In the reproduction process the host cell may be killed. Viruses range in size from two (2) to 300 micrometers and can only be seen under an electron microscope. Viral infections can occur not only in humans but in plants and bacteria as well. They are common in humans, and in some situations,
SELF-STUDY SERIES
can be life-threatening. Some examples of pathogenic viruses are: • Influenza (flu). The individual’s immune system works to eliminate the viral infec- tion. (Swine flu, an H1N1 type, mutated from a combination of animal and hu- man strains. In 2009, it was the cause of a pandemic that led to 16,000 deaths worldwide.)
• Rhinovirus (common cold) • Hepatitis B (liver disease). A vaccine is available to immunize this virus.
• Human Immunodeficiency Virus (HIV)- can lead to Acquired Immune Deficiency Syndrome (AIDS)
Fungi (yeasts and molds) are saprophytic (obtain nutrients from dead organic matter) in nature. They are parasites (an organism that is living in, on or with another organ- ism), which are either single (yeasts) or multi-cellular (mold) in structure. They contain DNA, are self-replicating and range in size from two (2) micrometers to one (1) millimeter. Some can be seen without the aid of a microscope. Some examples of pathogenic fungi are: • Candida albicans (Thrush): this occurs in the mouth and gastrointestinal tract. Unless the person is immunocompromised, it is easily treated with medication.
• Trichophyton mentagrophytes (Athletes Foot): causes scaling, itching, and flaking. Over-the-counter antifungal treatments are available, and good hygiene practices can help prevent it from occurring.
• Aspergillus fumigatus (Lung Disease): Found in nature, this fungus aids in the de- cay of organic matter. Most people breathe in several of these spores daily. Individuals who are not immunocompromised are able to eliminate the spores from their body with no problem. However, weak- ened patients who contract Aspergillosis may cough up blood and suffer kidney and liver failure. Protozoa are single-celled organisms that have DNA and are self-replicating. Some are capable of animal-like movements. They range in size from 1.5 to 80 micrometers. Some protozoa cause parasitic infections in humans or animals. Examples of pathogenic protozoa are: • Entamoeba histolytica (Amoebic Dysentery), which takes hold in the large intestine and causes diarrhea and colitis. Dysentery is treatable with proper oral medication.
• Giardia lamblia (Gastroenteritis) affects the large intestine and causes diarrhea.
• Cryptosporidium Sp. (Diarrhea) also affects the large intestine and causes diarrhea.
Page 34
hpnonline.com • HEALTHCARE PURCHASING NEWS • July 2017 33
Self-Study Test Answers: 1. B, 2. C, 3. B, 4. A, 5. B, 6. D, 7. C, 8. A, 9. A, 10. A
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58
