Microbiology

General Structure of a Bacteria Cell Plasmid DNA: small circular DNA that is separate from the rest of the bacteria’s genome Nucleioid DNA: large circular DNA found in the nucleiod region. Provides instructions for critical life functions. Capsule: a layer of polysaccarides; provides extra protection for the cell and helps prevent drying out Pila: helps the cell attach to surfaces Flagellum: helps the cell move WHAT IS LACKING FROM A BACTERIA CELL? Cell Wall: made of peptidglycans (polymer consisting of sugars and amino acids) 1

Bacterial Reproduction BINARY FISSION: the division of a cell into two genetically identical cells. A form of asexual reproduction. If the conditions are just right, one bacterium could become one billion bacteria in just ten hours. 2

Bacterial Shapes and Grouping Patterns Individual Shapes   Grouping Patterns 3

Diplococcus

Spirillum volutans

Streptococcus pneumoniae

Lactobacillus acidophilus

Staphylococcus aureus

Size of Bacteria Cells Bacteria cells are smaller than eukaryotic cells. Bacteria cells are larger than viruses. 4

Streptococcus Strep throat If the infection gets into the blood stream it could cause life threatening conditions 5

Methicillin-resistant Staphyloccus aureus (MRSA) Skin infections Resistant to antibiotic medication In medical facilities, causes life-threatening blood infections, pneumonia and surgical site infections. 5

Lyme borreliosis Transmitted by an infected tick Causes fatigue, chills, fever, headache, muscle and joint aches, and swollen lymph nodes If left untreated, neurological damage may occur 5

Escherichia coli Harmless version is found in your intestines and helps digestion. Harmful version will cause food poisoning. 5

Benefits of Bacteria Nutrient Cycling Bacteria are decomposers, returning nutrients like carbon and phosphate to the environment Nitrogen gas cannot be absorbed by plants. Nitrogen-fixing bacteria convert the nitrogen gas into compounds that plants can use. Nitrogen is important for the making of DNA, RNA and amino acids. 6

Benefits of Bacteria Probiotics (Flora) Bacteria that live inside organisms that help promote healthy digestion & reduce growth of harmful bacteria. E.coli and humans have a symbiotic relationship: E.coli provide Vitamin K and humans provide a “home” for the bacteria to live in. 6

Benefits of Bacteria Food Bacteria can be used to help manufacture certain foods: Cheese Yogurt Pickles Chocolate?! 6

Benefits of Bacteria Medicine Bacteria can be genetically modified to make medicine (ex. insulin) Some antibiotics are made with bacteria: Streptomycin Bacitracin Tetracycline Vancomycin 6

Treatments for Bacterial Infections ANTIBIOTIC DRUGS: chemicals produced artificially or naturally by other microbes that kill SPECIFIC bacteria by 4 possible methods: 1. Damages cell walls  2. Damages cell membrane  3. Inhibits gene copying  4. Inhibits protein synthesis  7 prevents synthesis of new cells cell will rupture prevents DNA replication and transcription (DNA to RNA) prevents RNA to proteins, enzymes for metabolic activity is stopped

Overuse and Misuse of Antibiotics OVERUSE: 1. Someone takes old antibiotics or was someone else’s prescription. 2. Excessive use of antibacterial soap and cleaning products. 3. Livestock feed includes antibiotics. MISUSE: 1. A doctor prescribes a patient antibiotics when they have a viral infection instead. Viruses are not affected by antibiotics (no cell wall, cell membrane or enzymes to act upon). 2. The patient skips dosages of the prescription. 8

How Antibiotic Resistance Occurs… 9

Strategies to Prevent Antibiotic Resistance Patients Can: Take an antibiotic exactly as the healthcare provider tells you. Don’t pressure your doctor for antibiotics. Speak out. Urge Congress to fund more research into antibiotic resistance and alternatives to antibiotics. Healthcare Providers Can: Include microbial cultures before deciding what to do. Keep track of antibiotic outbreaks in hospitals. Develop prevention and control programs. 9

Structure of Viruses Viruses are a non-living structures that come in various shapes. All viruses have the following 2 things: 1. Genetic Material: DNA or RNA 2. Capsid: the outer layer of the virus made of protein 10

Poliovirus Transmitted by fecal matter or saliva. 90% patients don’t show symptoms, if the virus invades the nervous system it will cause paralysis. Polio is almost eradicated around the world. 11

Ebola Transmitted by bodily fluids. 90% of patients die. Bleeding from the eyes is a late symptom of the disease. 11

Common Cold Transmitted by airborne droplets or nasal secretions. Could be caused by 1 of more than 100 types of viruses. Treatments only provide symptomatic relief. 11

HIV Human Immunodeficiency Virus Transmitted through blood, semen & vaginal fluids. Attacks and destroys human immune cells called, CD4 T-cells. When T-cell counts are extremely low, the person is diagnosed with AIDS. 11

Viral Replication Viruses need a host cell in order to replicate. LYTIC CYCLE active infection Influenza Common Cold LYSOGENIC CYCLE latent infection Herepes 12

Treatment for Viral Infections ANTIVIRAL DRUGS: Designed specifically to target certain viruses. Disables the proteins on the capsule of the virus and inhibits further development. 13