Bacteria and Viruses

All you ever (didn’t really) want to know!

Did you know…

You are breathing in bacteria right now

Your body is crawling with bacteria Right now…

Your skin

Your mouth

Your stomach

Your intestines(about 500 different species)

Bacteria can grow anywhereOn Earth

Cheese, yogurt and beer are madeWith bacteria

Garlic, onion, allspice, hot peppersAnd ginger are considered

Anti-bacterial agents

One bacteria cell can becomeMore than 8 million in 24 hours

A little background on Bacteria

•Bacteria are the only prokaryotes- What kingdoms?

•They live in soil, water, air, hot and cold temps

• Bacteria have a cell membrane that is surrounded by a tough cell wall

• DNA is not inside a nucleus, it floats in the cytoplasm

• DNA is called a plasmid• Glycocalyx- polysacc. on

the outside of bacteria to protect the cell- slimy feel

A square centimeter of your skin has Thousands of bacteria

A teaspoon of soil contains more thanA billion bacteria

How big are bacteria?

• Bacteria are measured in micrometers- one millionth of a meter

• Ranging from 1 to 5 micrometers• Eukaryotic cells tend to be about

10 times larger than a bacterial cell

Bacteria are described according to their shape

Bacilli-Rod shaped

Cocci- circular shape

Spirilla- spiral shape

Bacterial Nutrition

• Heterotrophic- feed on dead, decaying organic matter

• Photoautotroph-use sunlight as source of energy

• Chemoautotroph- use chemical reactions as a source of energy

• Some bacteria can live with ( aerobic) or without (anaerobic) oxygen

Production of Toxins

-Bacteria can give off toxins. Toxins are poisonous substances that disrupt the metabolism of the infected organism

- endotoxins- found in the cell wall

- exotoxins- secreted into the areas

around the bacteria

Common Bacterial Infections

• Strep throat

• Pneumonia

• Urinary tract infections

• Ear infections

• Salmonella and E.coli

Antibiotics

• Inhibit the growth of some bacteria

• They are only used for bacteria, they will not kill viruses ( common cold) For example, an antibiotic might inhibit a bacterium's ability to turn glucose into energy, or its ability to construct its cell wall. When this happens, the bacterium dies instead of reproducing. At the same time, the antibiotic acts only on the bacterium's cell-wall-building mechanism, not on a normal body cells.

• Disadvantages- over use can lead to bacterial resistance and kill good bacteria in our body

Leading causes of Antibiotic Resistance

• Antibiotic resistanceAlthough the survival tactics of bacteria contribute to antibiotic resistance, humans bear most of the responsibility for the problem. Leading causes of antibiotic resistance include:

Leading causes of Antibiotic Resistance

• Unnecessary antibiotic use. Like other superbugs, MRSA is the result of decades of excessive and unnecessary antibiotic use. For years, antibiotics have been prescribed for colds, flu and other viral infections that don't respond to these drugs, as well as for simple bacterial infections that normally clear on their own.

Leading causes of Antibiotic Resistance

• Antibiotics in food and water. Prescription drugs aren't the only source of antibiotics. In the United States, antibiotics can be found in livestock. These antibiotics find their way into municipal water systems when the runoff from feedlots contaminates streams and groundwater

Leading causes of Antibiotic Resistance

• Germ mutation. Even when antibiotics are used appropriately, they contribute to the rise of drug-resistant bacteria because they don't destroy every germ they target. Bacteria live on an evolutionary fast track, so germs that survive treatment with one antibiotic soon learn to resist others. And because bacteria mutate much more quickly than new drugs can be produced, some germs end up resistant to just about everything. That's why only a handful of drugs are now effective against most forms of staph.

Life Threatening BacteriaAnthrax

• Anthrax is an acute disease in humans and animals caused by the bacterium Bacillus anthracis, which is highly lethal in some forms. There are effective vaccines against anthrax, and some forms of the disease respond well to antibiotic treatment.

• The anthrax bacillus is one of only a few that can form long-lived spores: in a hostile environment, caused perhaps by the death of an infected host or extremes of temperature, the bacteria become inactive dormant spores which can remain viable for many decades and perhaps centuries. Spores are found on all continents except Antarctica. When spores are inhaled, ingested, or come into contact with a skin lesion on a host they reactivate and multiply rapidly

Anthrax skin lesion

MRSA

• MRSA infection is caused by Staphylococcus aureus bacteria — often called "staph." MRSA stands for methicillin-resistant Staphylococcus aureus. It's a strain of staph that's resistant to the broad-spectrum antibiotics commonly used to treat it. MRSA can be fatal.

Symptoms of MRSA• Staph skin infections, including MRSA, generally start as small red bumps that

resemble pimples, boils or spider bites. These can quickly turn into deep, painful abscesses that require surgical draining. Sometimes the bacteria remain confined to the skin. But they can also penetrate into the body, causing potentially life-threatening infections in bones, joints, surgical wounds, the bloodstream, heart valves and lungs.

Flesh Eating Bacteria

• Necrotizing fasciitis is a rare bacterial infection that can destroy skin and the soft tissues beneath it, including fat and the tissue covering the muscles (fascia). Because these tissues often die rapidly, a person with necrotizing fasciitis is sometimes said to be infected with "flesh-eating" bacteria. The most common type of bacteria causing necrotizing fasciitis is Streptococcus pyogenes.

Flesh Eating Bacteria

• To eradicate necrotizing faciitis, all of the affected soft tissue must be removed down to facia, bone or muscle. Then, the area must be free of any bacteria before skin grafting. The black line down my shin is the exposed tibia. The outer layer of the bone was killed by the bacteria, giving it the dark appearance.

Viruses

• Not considered living!

• They are a biological particle composed of genetic material and protein

• Consist of RNA or DNA

• Virulent- disease causing

• Temperate- doesn’t cause disease immediately

• Requires a host cell for reproduction

The Capsid

• Outer shell of the virus particle to protect the DNA or RNA inside

• Made out of protein

• Can be Icosahedral or Rod Shaped

- A virus is a thousand timesSmaller than a bacteria- Viruses are found in the Environment until they find theirWay to a host cell digestive tractOr respiratory system- They take over the host cell replicationMachinery and make more virus

How do they replicate?

• The Lytic Cycle• A virus particle attaches to a host cell. • The particle releases its genetic instructions into the

host cell. • The injected genetic material recruits the host cell's

enzymes. • The enzymes make parts for more new virus

particles. • The new particles assemble the parts into new

viruses. • The new particles break free from the host cell

Why We Feel Sick• An infected person sneezes near you.

• You inhale the virus particle, and it attaches to cells lining the sinuses in your nose.

• The virus attacks the cells lining the sinuses and rapidly reproduces new viruses.

• The host cells break, and new viruses spread into your bloodstream and also into your lungs. Because you have lost cells lining your sinuses, fluid can flow into your nasal passages and give you a runny nose.

• Viruses in the fluid that drips down your throat attack the cells lining your throat and give you a sore throat.

• Viruses in your bloodstream can attack muscle cells and cause you to have muscle aches.

Our Bodies Response

• Your immune system responds to the infection, and in the process of fighting, it produces chemicals called pyrogens that cause your body temperature to increase

• This fever actually helps you to fight the infection by slowing down the rate of viral reproduction, because most of your body's chemical reactions have an optimal temperature of 98.6 degrees F. If your temperature rises slightly above this, the reactions slow down.

• This immune response continues until the viruses are eliminated from your body. However, if you sneeze, you can spread thousands of new viruses into the environment to await another host.

The Lysogenic Cycle

• Once inside the host cell, some viruses, such as herpes and HIV, do not reproduce right away. Instead, they mix their genetic instructions into the host cell's genetic instructions.

• When the host cell reproduces, the viral genetic instructions get copied into the host cell's offspring. The host cells may undergo many rounds of reproduction, and then some environmental or predetermined genetic signal will stir the "sleeping" viral instructions.

• The viral genetic instructions will then take over the host's machinery and make new viruses as described above

HIV

• HIV infection is a viral infection caused by the human immunodeficiency virus (HIV) that gradually destroys the immune system, resulting in infections that are hard for the body to fight

• People who become infected with HIV may have no symptoms for up to 10 years, but they can still transmit the infection to others.

• Meanwhile, their immune system gradually weakens until they are diagnosed with AIDS.

• HIV infects T-cells- normally the T-cell would kill the virus, but the virus ends up killing the cell

Vaccines

• Disease prevention is the key to public health. It is always better to prevent a disease than to treat it. Vaccines prevent disease in the people who receive them and protect those who come into contact with unvaccinated individuals.

• Vaccines help prevent infectious diseases and save lives. Vaccines are responsible for the control of many infectious diseases that were once common in this country, including

• polio, measles, diphtheria, pertussis (whooping cough), rubella (German measles), mumps, tetanus, and Haemophilus influenzae type b (Hib), chicken pox.

How they Work?

• Vaccines are preparations that contain a small portion of a killed or weakened organism (often a virus) that we want to avoid.

• The vaccine is designed to trigger an immune response to produce neutralizing antibodies to the disease normally caused by this organism.

• This process then protects us in the future if exposed to the genuine bug

Vaccine for Viruses

• Weaken the virus - viruses become unable to reproduce sufficiently to cause disease, but well enough to protect against infection in the future. Measles, Mumps and Chickenpox vaccines are made this way.

• Inactivate the virus - viruses are completely killed with a chemical so it cannot reproduce or cause disease. Polio, Hepatitis A, Influenza and Rabies vaccines are made this way

Vaccine for Bacteria

• Use a bacterial process - bacteria that cause disease by producing a toxic protein are neutralized by inactivating the toxins with a chemical. Diptheria, Tetanus and Whooping Cough vaccines are made this way.

• Use part of the bacteria - the vaccine confers immunity to the sugar coating of the bacteria, sometimes combined with a harmless protein, rather than to the bacteria itself. Pneumococcal and Meningococcal vaccines are made this way.

??Bacteria or Virus??

• Peptidoglycan• Bacteriophage• Sheath• Capsid• Capsule• Glycocalyx

• Plasmid• Bacilli• Icosahedral• Spirilla• Cocci• DNA• DNA & RNA