Lab exam 2 Flashcards
What is the effect of temperature on bacterial growth?
- 37 C- body temp
- 24 C- room temperature
Growth rates for a given species grown at 37oC (normal human body temperature)
positive
Growth rates for a given species grown at 24oC (room temperature)
positive
Growth rates for a given species grown at 4oC (refrigerated temperature)
positive
Hand washing- What three species inhabits human skin?
- Staphylococcus aureus
- Staphylococcus epidermidis
- Micrococcus luteus
Hand washing- What are the distinct colony morphologies (color) of these species?
- S. aureus- small, round gold or pale yellow
- S. epidermis- small round cream colonies
- M. luteus- Small, round bright yellow
Compare and contrast clinical and routine hand-washing
Primary weapon in infection control policies that removes all microbes from skin.
What is the function and mechanism of action of hibiclens?
Contains chlorhexidine, which binds to negatively charged microbial surfaces to inhibit or lysis
What is the function and mechanism of action of betadine?
- Contains iodine in an alcohol-based solution to kill 90% of microbes in 90 seconds, including spores
- Iodine binds to tyrosine and or histidine to denature proteins
What is the function and mechanism of action of ethanol as antiseptic? (same as hand sanitizer)
Is an antiseptic at concentrations of 70% by denaturing: -surface-bound proteins -lipids Found in: -bacterial cell wall -viral envelopes -capsids
-Spores are resistant
Define: pyrimidine dimer
Dimers represent non-strandard DNA configurations and inhibit both replication and transcription
Explain how UV light damages DNA
- Functions as a mutagen
- Physically and chemically changing the genetic material of DNA
What are the cause of pyrimidine dimers and how they are formed? (Diagram the process)
- It excites electrons in DNA
- Forms extra covalent bonds
- Give rise to pyrimidine dimer
- This inhibits replication and transcription
Explain failure of excision repair
A high mutation load in microsatellite repeat sequences.
What is the clinical application of UV light?
- Black light is used
- Sterilizing surfaces contaminated with bacteria
- Surgical rooms for infectious control
What are the benefits of using UV in a clinical setting?
What are the limitations of using UV light in a clinical setting?
- UV can can rid of bacteria on inanimate surfaces
- Can not be used directly on patients as it will cause skin cancer
Define: gastroenteritis
- When your stomach and intestines are irritated and inflamed:
- Diarrhea
- Vomiting
- Abdominal cramps
- Typically a viral or bacterial infection
What is the significance of microbiology and foodborne illnesses?
- Biological hazards include: -Bacteria
- Viruses
- Parasites
-Bacteria and viruses are responsible for most foodborne illnesses
What is the incidence and mortality of foodborne illnesses in the US?
- About 48-80 million people a year in U.S. contract food poisoning or food borne disease
- 128,000 hospitalized
- 3,000 deaths
What is the pediatric mortality rate of dysentery worldwide?
Diarrheal illness from contaminated food and water cause 2 million deaths in young children
List the six most common bacteria associated with foodborne illness
- Salmonella
- Campylobacter Jejuni
- Shigella
- Escherichia coli
- Staphylococcus aureus
- Bacillus cereus
Define: bacteriophage
Bacterial viruses that is a specific bacterial species used to propagate the virus
Define: plaque
Infections that spreads into a hole or an empty space in the host-cell lawn
Define: bacterial lawn
The cell layer for a bacteriophage
How are plaques formed and what happens during the plaque assay?
- Viruses are introduce into the cell lawn
- Releases virions that infect host cells
- Infection spreads creating a hole
Understand a plaque represent bacteriophage replication and cell death.
- Absorption
- Penetration
- Replication
- Maturation
- Release
What is the procedure of the plaque assay?
- Phage dilution series
- 1/10–>1/100–>1/1000
What is the purposes of the top agar?
Low percentage agar to immobilize bacteria and assist in plaque integrity
Why was it safe to work with the T4 phage?
It’s a lytic phage and interacts with E. coli that mirror those of human lytic viruses
Define: yeast, mold
Multicellular, filamentous fungi as known as molds
Define the function and structural component of mycelium
- Mass of branched filaments (hyphae)
- Hyphae- threadlike filaments that form mycelium
Define the function and structural component of vegetative hyphae
-Secretes digestive enzymes, break down and absorb nutrients from environment
Define the function and structural component of aerial hyphae
- Spore bearing structure
- Tips are asexual spores
- Mycelium is embedded on
Define the function and structural component of Conidiaphore
Speciallized cells/stalks from which spores form
Define the function and structural component of conidia/spores/conidiospores
- Produced by mitosis
- Asexual spores
- Disseminated by wind
- Colored
- Unicellular
Distinguish among Aspergillus niger
- Soil fungus
- Causes pulmonary infection and allergies
Distinguish among Rhizopus
- Soil fungus
- Spoilage of foods, plant pathogens
Distinguish among Penicillium
- Soil fungus
- Important in cheese and antibiotic production (penicillin), agent of food spoilage
Define: dermatophyte
- Trichophyton and Microsporum
- Digest keratin, the material found in outer layer of skin, hair, nails
Define: dermatophytosis
Or ringworm is a clinical condition caused by fungal infection of the skin in humans
Define: onychomycosis
Nails that thicken, discolor, crumble and fall off
What are the types of syndromes associated wih dermatophytes?
- Tinea pedis
- Tinea unguium
- Tinea corporis
- Tinea cruris
- Tinea capitis
How are dermatophytes diagnosed?
Enlarging raised red rings of ring worm, infection on the skin on feet or groin
What makes skin an ideal environment for fungal infections?
- Warm
- Moist
- Outsides of hair shafts or in interiors
Visually identify the clinical syndromes associated with dermatophytes
- Tinea pedis (Feet)
- Tinea unguium (Fingernails and Toenails)
- Tinea corporis (arms, legs, and trunk)
- Tinea cruris (Groin area)
- Tinea capitis (Scalp)
Define: yeast and pseudohyphae
String connected budding cells
What is the clinical significance of the yeast Candida albicans?
- Urogenital yeast infection
- Thrush (oral yeast infection)
- Skin infection
Under what circumstances would Candida become pathogenic?
When there is a decline in normal bacterial populations due to antibiotic use or immunocompromised status
Visually identify the clinical syndromes associated with yeast
- Thrush (oral)
- Skin lesion
What distinguishes molds from yeast?
- Mold is a type of fungus that grows in multicellular filaments called hyphae
- Yeast is a type of fungus that grows as a single cell
What is the selective toxicity and mechanism of action of polyenes and azoles?
- Polyenes target cell membrane
- Amphoteracin B, kidney toxicity
- Arzoles targets cell membrane
- Imidazole, clotrimazole, miconazole topical; ketoconazole-systemic, broad spectrum (taken orally)
Define: protozoan and helminth
-Protozoa are identified on the basis of cellular morphology
Define: trophozoite (trophs)
-Trophs are vegetative form, metabolically active, feeding, growing
Define: Cyst
metabolically inactive, protective when environment lacks food, moisture, oxygen
What are the morphologies, clinical significance, presentation and transmission of Giardia lamblia
- Fecal smears
- Parasite of small intestine
- Abdominal cramping and diarrhea
- Contaminated water
- Block lipid absorption
- Yellow, foamy diarrhea known as streatorrhea
- Troph symmetrical nuclei, cysts with 4 nuclei (face)
What are the morphologies, clinical significance, presentation and transmission of Plasmodium vivax
- Cause- Malaria
- Transmit by mosquito
- Progeny lyse RBC
- Aquired by Anopheles
- Ring forms within RBC
What are the morphologies, clinical significance, presentation and transmission of Trichomonas vaginalis
- Cause- Trichomoniasis
- Most common pathogenic protozoan infection of human
- 180 million cases annually
- Sexually transmitted (mainly females)
- Live up to 24 hours in urine, semen
- No cyst
- Face one eye
What is the definitive host for Plasmodium?
Anopheles Mosquito
What are the 3 major groups of parasitic worms?
- Trematodes (flatworms)
- Cestodes (tapeworms)
- Nematodes (round worms)
Flatworm (Trematode): Schistosomes
a) Cite the numbers of cases worldwide
> 200 million persons infected worldwide
Flatworm (Trematode): Schistosomes
a) What clinical presentation is associated with schistosome infestation
Live in the blood stream of humans and animals
Tapeworm intestinal and neural cysticercosis (Cestodes): Taenia solium
a)Explain the clinical presentation of each
Grow in the intestinal tract 12-60 feet
Roundworm (Nematode): Ascaris lumbercoides.
a) Cite the numbers of cases worldwide
1-2 billion people worldwide
Roundworm (Nematode): Ascaris lumbercoides.
b) Explain the clinical presentation
- Duodenum
- Bloodstream
- Heart
- Pulmonary Circulation
- Alveoli
- Respiratory system
- Cough up and recycle
Define agglutination
Visible clumping of cell bound (or particle bound) antigen with specific antibody
Define antigen
- Any cell, particle, or chemical that includes a specific immune response by B cells or T cells and can stimulate resistance to an infection or a toxin
- Non-self
Define antibody
-A large protein molecule evoked in response to an antigen that interacts specifically with that antigen
Define antibodies
- Antibodies of a particular type collectively.
- Also called immunoglobulin.
What are the blood cells?
It has four main components: plasma, red blood cells, white blood cells, and platelets.
What are the significance of agglutination in blood typing?
Identification of blood group antigens and red blood cell disorders
Know the differences between blood types A, B and O?
- Type B blood, you could get a transfusion from someone with B or O blood, but not A or AB.
- Type A blood, you could get a transfusion from someone with A or O blood, but not B or AB.
- Type AB or -Type O blood. If you have both A and B markers on the surface of your cells (Type AB blood) universal receiver
- Type O blood universal donor
What is the D (Rh) antigen?
The commonly used terms Rh factor, Rh positive and Rh negative refer to the D antigen only.
How is that these antigens are expressed on the surface of the RBC cell membrane?
Extended out from the surface of the cell into the environment so they are available for antibody recognition and binding
How is the blood typing procedure performed and what constitutes a positive result?
- Add a drop anti-A antibody to RBC
- Add a drop anti-B antibody to RBC
- Add a drop anti-D antibody to RBC
- Gently rock slide to mix and wait 30-60 sec
- Check for visible agglutination for positive results
How is the anti-A, B, and D antibodies can be used to determine the blood type?
Using the agglutination reactions to determine the ABO, Rh(D) type
Know the purpose of Elisa and how is done
- Test that detects and measures antibodies in your blood
- 4 columns; 1 Negative, 2 Positive, 3 Donor 1, 4 Donor 2
- Drop antigen into each circle (let stand for 5 min)
- Drop (-) sample on (-) column and same for the rest
- Let sit for 5 min
- Drop secondary antibody onto each circle
- Let sit for 5 min
- Drop substrate onto each circle
- Observe for color change (bright pink)
