The Good, the Bad, and the Ugly Bacteria and Viruses And their Treatments

How is this different from our cells?

Microbiology The study of single cell organisms too small to see with the unaided eye. The study of single cell organisms too small to see with the unaided eye. Includes BACTERIA, Archaea, Fungi, Protists, and VIRUSES. Includes BACTERIA, Archaea, Fungi, Protists, and VIRUSES.

How Big are Bacteria compared to a cell in your body? A BACTERIUM is the size of a PITCHER’S MOUND, A BACTERIUM is the size of a PITCHER’S MOUND, And, ONE CELL from your BODY is the size of the BALLPARK!!! And, ONE CELL from your BODY is the size of the BALLPARK!!!

BACTERIA 1. Bacteria are independent organisms able to grow & reproduce as single cells 1. Bacteria are independent organisms able to grow & reproduce as single cells 2. Multiple shapes: rod, sphere, or spiral 2. Multiple shapes: rod, sphere, or spiral

BACTERIA, cont. They can be found at extreme temperatures (boiling to freezing). They can be found at extreme temperatures (boiling to freezing). They “eat” everything from sugar to chemicals. They “eat” everything from sugar to chemicals. Classified as PROKARYOTES because they do NOT have a nucleus. Classified as PROKARYOTES because they do NOT have a nucleus. DNA is the genetic material DNA is the genetic material

Bacteria Structure and Parts They are prokaryotes (means NO nucleus) Characteristics of Bacteria 1. NO nucleus & NO membrane bound organelles 2. Have cell membrane 3. DNA in chromosome(s) 4. Have ribosomes but NOT the same as in our cells 5. Have a CELL WALL! (but DIFFERENT from the one in plants) 6. For some bacteria, capsule provides protection

How is this different from our cells?

What is the main way bacteria are grouped? By the way they stain: One group is Gram Positive (+) Second group is Gram Negative (-)

How do we treat (kill) bad bacteria? ANTIBIOTICS ANTIBIOTICS ANTIBIOTICS ANTIBIOTICS!! ANTIBIOTICS ANTIBIOTICS ANTIBIOTICS ANTIBIOTICS!! The first antibiotic was discovered by Alexander Fleming in He noticed a mold (penicillium) inhibited growth of bacteria he was studying. The first antibiotic was discovered by Alexander Fleming in He noticed a mold (penicillium) inhibited growth of bacteria he was studying. He isolated the chemical from the mold and named it Penicillin. He isolated the chemical from the mold and named it Penicillin.

Diseases caused by Bacteria: Lyme Disease (Borellia) Lyme Disease (Borellia) Necrotizing Fasciitis (“Flesh eating” bacteria; Streptococcus pyogenes) Necrotizing Fasciitis (“Flesh eating” bacteria; Streptococcus pyogenes) Strep Throat (Streptococcus) Strep Throat (Streptococcus) Food poisoning (Salmonella sp., Staphylococcus aureus) Food poisoning (Salmonella sp., Staphylococcus aureus) Meningitis (Neisseria) Meningitis (Neisseria)

How do bacteria reproduce? Primarily by Binary fission! Primarily by Binary fission!  The chromosome (DNA) is copied  The cell & cell wall divide in the middle to form 2 identical ‘daughter’ cells.  Under optimal conditions, bacteria divide every 20 – 30 minutes. Bacteria occasionally use a form of sexual reproduction called conjugation Bacteria occasionally use a form of sexual reproduction called conjugation  DNA is exchanged between cells through sex pilus  This increases the genetic diversity of bacteria to improve survival

If antibiotics are so effective at killing living bacterial cells, why don’t they hurt our cells? Remember the organization of bacteria- are their cells the same as ours? NO Cell wall (very different from plant cell wall) Different type of ribosomes for making proteins (different translation equipment) Many enzymes different from the ones found in our cells

Antibiotics are SPECIFIC for the bacteria they can kill- A different type of antibiotic is prescribed for a respiratory infection and an urinary tract infection (UTI) because they are caused by DIFFERENT types of bacteria.

Problems with antibiotics: The main difficulties with antibiotics are; The main difficulties with antibiotics are;  1. Allergies  2. Killing off the “good” bacteria in our bodies

GOOD BACTERIA: Bacteria aren’t all bad! 1. Some bacteria turns MILK into YOGURT (Lactobacillus acidophilus) and CHEESE. 2. Some bacteria help us digest our FOOD and produce Vitamin K (Escherichia coli). 3. Clean wastes from sewage water at water treatment plants (Pseudomonas putida).

Good Bacteria, cont. 4. A natural pest killer in gardens and on crops (Bacillus thuringiensis). 5. Clean up chemicals at hazardous waste dumps and landfills (Methanotrophs). 6. Make medicines, like ANTIBIOTICS or using biotechnology, Human Insulin.

VIRUSES- tiny parasites depending entirely on a host to survive Composed of: Composed of:  1. Genetic material (DNA or RNA)  2. Protein coat (capsid) enclosing the DNA/RNA  3. In some, a lipid envelope surrounds the protein

VIRUSES, cont. Straddle between living and not living. Straddle between living and not living. Inert (not active) when outside of cells. Inert (not active) when outside of cells. Thousands of different viruses in a variety of shapes. Thousands of different viruses in a variety of shapes.

Viruses, cont. Viruses only “live” when inside a eukaryotic cell (one of ours!). Viruses only “live” when inside a eukaryotic cell (one of ours!). They use that cell as their own factory to make millions of new viruses. They use that cell as their own factory to make millions of new viruses.

VIRAL DISEASES AIDS (Human Immunodeficiency Virus) AIDS (Human Immunodeficiency Virus) Flu (Influenza virus) Flu (Influenza virus) Chicken Pox Chicken Pox “Kissing Disease” (Mononucleosis; EBV) “Kissing Disease” (Mononucleosis; EBV) Hepatitis (Hepatitis A, B, C, etc) Hepatitis (Hepatitis A, B, C, etc) Colds Colds Measles Measles

Q. How do we treat viruses? A. With an antiviral. A. With an antiviral. 1. This is a drug that will stop a virus from replicating in our cells. 2. There are VERY few antivirals. 3. Antivirals are more toxic to our normal cells. If antivirals aren’t the answer, how do we protect ourselves from viral infections? If antivirals aren’t the answer, how do we protect ourselves from viral infections?

With Vaccines!! 1. What is it? 1. What is it?  Part of a bacteria OR virus (or a weakened version of the organism) is injected into a person. To be most protective, a person is injected multiple times months apart. 2. How does it work? 2. How does it work?  The vaccine does NOT give the person the disease, BUT the immune system of the person “SEES” the bacteria or virus as an invader and REACTS to it by preparing the weapons to fight it off.

Vaccination, cont Normally, it takes our immune system several days to a week to “see” a foreign invader (bacteria or virus) and mount a response against it. (that’s why we feel sick!) Normally, it takes our immune system several days to a week to “see” a foreign invader (bacteria or virus) and mount a response against it. (that’s why we feel sick!) If you’ve been vaccinated, your body will immediately “see” the bacteria or virus as an invader and it already has the weapons to immediately fight it off. You may NEVER know you were infected. If you’ve been vaccinated, your body will immediately “see” the bacteria or virus as an invader and it already has the weapons to immediately fight it off. You may NEVER know you were infected.

How does the immune response react? One way the immune response reacts is to make ANTIBODIES specific for that virus or bacteria. IF you are infected with that virus or bacteria, the antibodies in your body will bind to the specific virus or bacteria to stop it from infecting you. One way the immune response reacts is to make ANTIBODIES specific for that virus or bacteria. IF you are infected with that virus or bacteria, the antibodies in your body will bind to the specific virus or bacteria to stop it from infecting you.

How else do we prevent disease? Excellent Sanitation Practices! Wash hands frequently! Wash hands frequently! Wash foods before eating Wash foods before eating Careful food storage and preparation Careful food storage and preparation Treatment of human excrement to kill infectious agents Treatment of human excrement to kill infectious agents Clean water supplies for drinking Clean water supplies for drinking Clean cuts & wounds immediately after getting them Clean cuts & wounds immediately after getting them Sterile practices in hospitals Sterile practices in hospitals

HOW DO BACTERIA AND VIRUSES DIFFER? SIZE: Bacteria are much larger. SIZE: Bacteria are much larger. STRUCTURE: Bacteria are much more complex. Bacteria have a thick cell wall, a chromosome, & ribosomes. A virus has a small amount of nucleic acid and a protein coat. STRUCTURE: Bacteria are much more complex. Bacteria have a thick cell wall, a chromosome, & ribosomes. A virus has a small amount of nucleic acid and a protein coat. Antibiotics kill bacteria. Antibiotics do NOT kill viruses. Only antivirals kill viruses. Antibiotics kill bacteria. Antibiotics do NOT kill viruses. Only antivirals kill viruses.

HOW DO BACTERIA AND VIRUSES DIFFER? Bacteria are free living- they contain ALL they need to grow and reproduce themselves. One cell divides into 2 ‘daughter’ cells. Bacteria are free living- they contain ALL they need to grow and reproduce themselves. One cell divides into 2 ‘daughter’ cells. Viruses are moochers- they only contain limited genetic information. They invade a cell and hijack its machinery to turn it into a VIRUS FACTORY! Viruses are moochers- they only contain limited genetic information. They invade a cell and hijack its machinery to turn it into a VIRUS FACTORY!