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101 Cards in this Set
- Front
- Back
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microbiology |
the study of microscopic living things |
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pathogens |
is a biological agent that causes disease or illness to its host. |
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normal flora |
are bacteria which are found in or on our bodies on a semi-permanent basis without causing disease. |
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opportunistic infections |
an infection caused by bacterial, viral, fungal, or protozoan pathogens take advantage of a host with a weakened immune system. They do not cause disease in a healthy host that has a normal immune system. |
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binary fission ("division in half") |
is a kind of asexual reproduction. It is the most common form of reproduction in prokaryotes and occurs in some single-celled eukaryotes. |
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binary fission process |
1. organism replicates its genetic material, 2. the cell divides into two nearly equal sized daughter cells. The genetic material is also equally split. |
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types of eukaryotes |
plants, animals, humans, fish, insects, fungi, algae, protozoa |
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Eukaryotic cells |
any organism whose cells contain a nucleus and other organelles enclosed within membranes |
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prokaryotic cells |
A prokaryote is a single-celled organism that lacks a membrane-bound nucleus (karyon), mitochondria, or any other membrane-bound organelles. eg. bacteria |
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microbial colony |
a visible cluster of microorganisms growing on the surface of or within a solid medium, presumably cultured from a single cell. |
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rules foor nomenclature |
Genus / species (Capital letter) Family surname (lower-case letter) Italics or underlines |
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Reservoir examples |
soil water people plants |
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what is a reservoir? |
Any person, animal, plant, soil or substance in which an infectious agent normally lives and multiplies. |
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transient flora |
bacterial flora on us which do not establish themselves permanently |
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structure of typical bacteria (CCCFPRIPE) |
Cell wall Cytoplasmic membrane Chromosome Flagella Plasmid Ribosome Inclusion body Pili Endospore |
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Function of bacterial cell wall |
Protect cells against osmotic shock and physical damage |
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Function of bacterial cytoplasmic membrane |
Regulation of substance transport into and out of cells |
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Function of bacterial DNA (Nuclear area) |
contain genome The chromosomal DNA carries most of the genetic information. Plasmid DNA forms small loops and carries extra information. |
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Function of bacterial plasmid |
Contain supplemental genetic information that can be passed on between bacteria such as: resistance to antibiotics, production of toxins tolerance to toxic environment. |
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function of bacterial ribosomes |
Take part in protein synthesis. |
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function of bacterial capsule |
stops white blood cells engulfing them stops bacteria from drying out helps them stick onto walls & eachother |
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function of bacterial frimbrae |
helps them stick to eachother and walls cause slime layers to help them stick have high levels of disinfection (hard to remove) |
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function of bacterial flagella |
helps bacteria move around |
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function of inclusion body |
Mineral storage of cells. |
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function of bacterial pilli |
for attachment to host & bacterial mating. |
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endospores |
spore within the cell Tough, heat resistance structure that help bacteria survive in adverse conditions. Dormant until conditions are just right |
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Two endospore forming bacteria: |
Clostridium and Bacillus |
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requirements for bacterial growth |
•Temperature •Moisture •Time •Phlevel •Oxygen •Suitable medium (eg. Food, people) |
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Bacteria: psychophiles Mesophiles Thermophiles |
cold loving (10°C or lower) warm loving (20 and 45 °C) Hot loving (45°C and higher) |
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Bacteria: facultative anaerobes anaerobic aerobic |
Can grow in high or low oxygen environments Grow best without oxygen Grow best with oxygen |
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Bacteria: how can Moisture be removed from food |
(food containing water) -Dehydration (dried milk) -High sugar (jam) - high salt (bacon) - Freezing |
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Bacteria: What is their optimum pH? |
grow best in neutral pH (6.6-7.5) cannot survive below 4.5 Vinegar (pH 3.5) can be used to preserve food |
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Bacteria Shape: Baccilus (baccili) |
Rod-shaped eg. Escherichia coli, Bacillus cereus |
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Bacterial shape: Coccus (cocci) |
Spherical have an arrangement in clusters (staphlycocci) chains (streplycocci) eg. Staphylococcus epiderminis |
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Bacterial shape: Spirochaete |
curved / spiral eg. Vibrio cholera, Rhodospirilium rubrum |
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Bacterial shape: Arcula |
square-shaped |
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Bacterial shape: Stella |
Star-shaped |
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Meaning of pink and purple gram stains.... |
purple bacteria = gram positive thick cell wall & hang on to the purple stain pink bacteria = gram negative Thin cell wall & removable purple stain |
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beneficial use of gram stains? |
- helps stain WBC to see presence of infection - quick to do - helps show shape of bacteria - can see clusters or chains of cocci |
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The Zeihl- Nilson stain |
The only procedure designed to stain mycobacteria, mycobacteria = cause of tuberculosis |
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Examples of Diseases caused by bacteria: |
1. syphilis (gram negative) 2. staphlycoccal 3. Impetigo & Necrotising fascilitis (from Group A Streplycocci) 5. Gas Gang green |
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viruses |
Not living cells , No metabolic activity Have either RNA or DNA (never both) protein coat protects its DNA/RNA very host specific (human virus, affect humans) Some are mutogenic (can change/adapt) Some can have multiple hosts |
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envelope viruses |
cannot live long outside body envelope is fragile envelope is made of material taken from its host |
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Shapes of viruses |
Cubic Helical complex |
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attachment of virus |
- Find the attachment site (like lock and key) - Releases its DNA/RNA - Viral nucleic acid replicates using host - New viral nucleic acids are packed into viral particles and released from the cell. |
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what 2 things can antivirals do? |
1. block the binding of the virus particle onto the host cell 2. stop the RNA/DNA from being incorporated into the hosts DNA |
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Viral infection indications |
usually no symptoms antibodies to the virus can indicate if there was trace of virus in the body |
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latent viral infections |
if the virus is not eliminated once identified, it can go away and hide in the body. Once it comes back it can be dangerous eg. chickenpox, HIV, Hep.C |
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Chronic viral infections |
are always present body cannot eliminate it on their own |
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oncogenic viruses |
can cause cancer eg. hep B & C = liver cancer HIV = skin cancer |
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How are viral diseases transmitted? |
- airborne - faecal - oral - body fluid - vector (bites from insects) - Foetal/neonatal (through placenta/birth canal) |
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Treatment of viruses |
antibiotics dont kill virus antiviral drugs sometimes can be used but are virustatic (stops or slows down replication) Vaccination can prevent many viralinfections. |
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Yeast cells |
Yeasts are eukaryotic organisms living organisms are a type of fungi |
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fungi |
mainly on the skin live off dead organic matter aerobic (like oxygen) make antibiotics often grows where bacteria cant |
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Skin infections |
caused by Dermatophytes doesn't go any deeper than the skin can infect the nails (harder to treat) can infect the hair & kill follicles (bald patches) |
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systemic infections |
means affecting the entire body, rather than a single organ or body part. eg. Influenza infection that is in the bloodstream is called a systemic infection. high mortality rate (drugs are too slow acting) |
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opportunistic infections |
are infections that occur more frequently and are more severe in individuals with weakened immune systems, eg. -in pregnancy, HIV pos people, neonates |
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protozoa |
tranferred through contaminated water/food or an insect bite can be in a resistant state (dormant), or when injested, turn into trophozoate (feeding/replicating state) |
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flagellate (protozoa) |
causes vomiting and diarrhoea |
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Ciliate (protozoa) |
very few cause human infection move with fine cilia |
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amoeba (protozoa) |
move like a slug (stretch out) cause sever diarrhoea and vomiting |
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toxoplasmosis (porzoa) |
can move (without cilia or flagella) pregnant woman can get infected from ingesting infected undercooked meat or cat faeces systemic infection |
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parasites |
an organism which lives in or on another organism (its host) and benefits by deriving nutrients at the other's expense. |
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worms |
can be up to meters in length or microscopic they are parasites that feed off nutrition in intestines sometimes cause no ill effect Sometimes cause sever illness flat worms & round worms |
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4 types of worms |
round worms (lays eggs to reproduce) flat worms (attach into the intestines, grow long in length and feed off our nutrition) hook worm (gets stood on, travels inside you, gets into respiratory tract then GI tract) Giant round worm (cause eodema) |
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Ectoparasites |
a parasite, such as a flea, that lives on the outside of its host. Highly contagious eg. scabies , lice |
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mycosis |
Mycoses is a fungal infection Inhalation of fungal spores or localized colonization of the skin may initiate persistent infections; mycoses often start in the lungs or on the skin |
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Where are microorganisms not present in the body? |
Trachea, Bronchi Lungs uterus - womb Bladder (sterile) |
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Where are the most bacteria located in the body && why is it there? |
Intestines (mainly E.Coli) Helps break down food for absorption of nutrients |
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helicobacter pylori |
causes diseases of GI tract and stomach ulcers |
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importance of ciliated epithelial cells in trachea |
traps bacteria, dust and microorganisms. Moves it into the stomach to hopefully get destroyed |
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pneumonia : cause & source? |
caused by bacteria infecting the lungs. hospital enquired pneumonia are common from ventilated patients |
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why are UTI's more common in females? |
Female anus and urethra are close rectal bacteria can move from one area to another and stick to walls of bladder. |
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why is it dangerous for pregnant women to get a UTI? |
can lead to prem. labour increase in WBC in urine >10^8cells/litre presence of epithelial cells high presence of bacteria in urine |
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why should pregnant women be continuously tested for UTI? |
pregnant women may be asymptomatic |
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Types of microorganisms: |
- Bacteria - Fungi - Algae - Protozoa - Parasites - Viruses |
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Where can normal flora be found in the body? |
- skin - mouth - upper respiratory tract - gastrointestinal - uro genital tracts |
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Benefits of microorganisms in body? |
- Protection - Breakdown of ingested food - |
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Where is normal flora not typically found in body? |
- bladder - upper genital tract - lungs |
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how can microorganisms be controlled in the body? |
- changing body temp - changing body pH levels |
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where does a neonates first normal flora come from? |
its mother |
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why is lactobacilli in the vagina? |
help increase the pH of the vagina to avoid urinary tract infections |
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why are women more susceptible to UTI's? |
because their anus and fecal bacteria is closer to their urethra |
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what is the risk of a UTI? |
renal infections and kidney damage |
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risk of UTI in pregnancy? |
Premature labour |
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Signs of a UTI present in a urine specimen are: |
Increased WBC Might have elevated RBC presence of bacteria (10^8/L) |
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how to indicate contamination of urine specimen for UTI test? |
check for epithelial cells |
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whether or not disease occurs in a person, depends on: |
- the individual's susceptibility - pathogenicity of the pathogen - The ineffective dose |
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Streptococcus pyogenes can infect the bloodstream and cause: |
haemolysis : where RBC are ruptured/destroyed |
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clinical signs of infection? |
fever pus swelling redness in skin organ shutdown |
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reservoirs of infection |
food people (**main) medical waste equipment |
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Endogenous infections |
infections caused by microorganisms from the individuals own body eg. UTI's , thrush |
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exogenous infections |
caused by microorganisms from a source external to the body eg. lysteria |
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fomites |
inanimate objects capable pf transmitting disease eg. medical equipment |
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what is "a carrier"? |
someone who harbours and continuously sheds a pathogen without showing and symptoms of disease eg, disease such as typhoid |
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systemic infection |
in the blood, carries through whole body |
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localised infection |
In one area of the body |
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secondary infection |
an infection that occurs during or after treatment of another pre-existing infection. It may result from the treatment itself or from changes in the immune system. eg, a vaginal yeast infection that occurs after antibiotic treatment of a bacterial infection |
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subclinical infection |
is an infection that is nearly or completely asymptomatic (no signs or symptoms). |
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portals of entry and exit for microorganisms? |
Blood GI tract upper Respiratory tract Urogenital tract congenital (existing since birth) skin |
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What is a morbidity rate and a mortality rate? |
Morbidity rate = number of people infected Mortality rate = number of deaths from infection |
