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Micro Exam #3
Terms in this set (118)
Organs of the Urinary Tract
urethra, urinary bladder, ureters, and kidneys
What are the 3 modes of UTI
1 = Ascending from fecal matter to urethra
2 = Ascending from catheter
3 = Descending from bloodstream to kidneys
Symptoms of a UTI
Dysuria: burning sensation- Cloudy, bloody, or foul-smelling urine- Fever- Senior mental confusion
What is the test for a UTI
Dip Stick Test
What are the 3 tags for a UTI in a urine sample
1 = Leukocyte Esterase (WBC shouldn't be in urine)
2 = Nitrites
3 = Blood
What is the difference between clean and casual catch?
Clean you have to wipe everything down and sanitize before catching urine because you don't want contamination by normal flora. On both of them you have to do a mid-stream catch though
If there is a delay in urine testing, what are the required conditions for holding?
Held at 4C to prevent multiplication
When testing urine, what are the characteristics of the specimen you are looking for?
Gram - Rods
What are the 2 media used when testing urine?
1 = BAP because most everything grows on it, especially E. coli
2 = MacConkey Agar to determine if it ferments lactose or not
Exercise 28: When testing urine on the 2 media, what should the results be?
Testing E. coli- BAP, there should be a beta hemolytic zone- MacConkey, there should be lactose fermentation
What are the margins in determining the quantitative urine culture specimen?
< 9,999 organisms/mL is normal
10,000 - 99,999 is up to the doctor to decide depending on other symptoms and history
>100,000 microorganisms are actively colonizing
Exercise 29: How would you inoculate a plate when trying to determine the quantity of microorganisms?
Primary line of inoculation, sterilize loop, then criss-cross all the way down
What is the equation for Quantity of microorganisms? What do the acronyms stand for?
CFU/mL = NC * 1000
CFU: colony forming units
NC: number counted
1000: reciprocal of 1:1000 loop used
What are the characteristics of Neisseria?
What are the 2 media used when testing Neisseria?
1 = Chocolate -- round, grey, convex
2 = Modified Thayer Martin
What are the 2 species of Neisseria?
N. meningitidis and N. gonorrhoeae
N. meningitidis - risk group, reservoir, sample
5 - 40 years old
barraks, dorms, and institutions
Why do you gram stain cerebrospinal fluid right away (direct smear)?
Because it is a sample taken when there are life-threatening diseases, so you need to determine what you are dealing with as soon as possible to ensure efficient care
N. gonorrhoeae - risk group, sample, slide
Sexually active adolescents (usually 16-25)
uretheral drainage or vaginal secretions
Gram - diplococcic among many WBC
obligate (only grow in host and cannot be isolated on routine clinical isolation media)
spiral morphology wrapped around a bundle of flagella (Axial filament)
no cell walls = can't gram stain
visualized using dark field microscopy
enter through cuts, bites, and abrasions
What are the 3 common spirochete pathogens? What are their diseases?
1 = Treponema -- syphilis
2 = Borrelia -- Lyme Disease
3 = Leptospira -- Leptospirosis
How is Leptospirosis transmitted?
Through contamination of water, food, or soil with the urine of infected animals
Characteristics of Clostridium
Which species is involved in the disease colitis?
What kind of colitis is Clostridium difficile known for? Risk Group? Clinical Features
After antibiotic treatment
Hospitals and long-term care
Destruction of colonocytes, colonic inflammation, black and watery diarrhea, fever, nausea, headache
What are the 2 toxins released by Clostridium difficile?
A & B -- cause diarrhea and colitis
What is a cytotoxin?
a substance that inhibits or prevents the function of cells or causes destruction of cells
What is present when there is a full-blown infection of Clostridium difficile?,
Pseudomembrane colitis with scattered pseudomembranes across colonic tissue
What species in involved in the neuroparalytic diseases with A, B, & E as the most common neurotoxins?
What are the clinical features of Clostridium botulinum?
Dry mouth and diplopia Dysphagia (difficulty swallowing)
Dysphonia (voice impairment)
Peripheral muscle weakness
What are the 3 types of botulism?
1 = Foodbourne
2 = Wound
3 = Infant
What disease is Clostridium tetani responsible for? How can you get it?
Wounds, Ulcers, Burns, Fractures, Drug Injection
Clinical Features of Clostridium tetani?
Muscles around puncture start to contract, lockjaw, body spasms, and death
What toxin does Clostridium tetani produce?
What are the 2 diseases from Clostridium perfringens?
Gas Gangrene and Food Intoxication
What is a scientific term for Gas Gangrene caused by Claustridium?
What does Gangrene Mean?
destruction of tissue
What is the characteristic of Clostridium on BAP?
Double Beta Hemolysis
What are the 2 ways you can culture anaerobic bacteria?
1 = Anaerobic Jars and Bags
2 = Thioglycollate Broth
How do the Bags and Jars make an anaerobic condition?
Bags have Palladium (catalyst)
Oxygen binds with the H2 gas from the Palladium and is reduced to water
What is Reazurin used for in Bio-Bags?
An Oxygen Reduction Indicator (pink)
What will a Thioglycollate tube of C. perfringens look like? Why?
There will only be growth on the bottom because it is an anaerobic species
What will a Thioglycollate tube of Staphylococcus epidermidis look like? Why?
There will be growth from the top to the bottom because it is facultative, so it can act aerobic or anaerobic depending on what environmental conditions are
What will a Thioglycollate Broth tube with Pseudomonas aeruginosa look like? Why?
Only growth at the top because it is aerobic
What will C. perfringens look like on a Blood Agar Plate?
Double zone of beta hemolysis
What species in responsible for tuberculosis
What are the characteristics of Myocardium tuberculosis?
Cough for 2+ weeks with blood or sputum, pain in the chest, fever, and fatigue
What is unique about Mycobacteria
Cells walls contain Peptidoglycan. Mycolic Acid, and Cord Factor that form a lipid shell and is toxic to mammalian cells
What are the 2 media that can be used for Myocardium tuberculosis?
1 = Middlebrook's Agar Base2 = Lowenstein-Jensen Egg Base
What is the etiological agent of TB in cows? Can humans be infected?
Yes, if they drink unpasteurized milk
What two species is the Myocardium avium complex comprised of?
M. avium and M. intracellulare
What is used to stain Mycobacteria? Why?
Acid-Fast Staining because of the high content of mycolic acid
What is the primary stain for Acid-Fast Staining? What does it do? What color does it stain the cells?
Carbol Fuchsin penetrates the cell wall and combines with the mycolic acid to stain the cells red
What is the counterstain for Acid-Fast Staining?
What is the procedure for Acid-Fast Staining
1 = Collect sample and put a drop in the center of the slide
2 = Air dry and heat-fix
3 = Flood with Carbol Fuchsin, steam, cool, rinse
4 = Decolorize using Acid Alcohol
5 = Counterstain with Methylene Blue
What color should Acid-Fast Bacteria be?
What is an example of an Acid-Fast Bacteria?
What color should those that are not Acid-Fast be?
What is the difference between Food Intoxication and Food Infection?
Food Intoxication = manifests in less than 24 hours
Food Infection = manifests in 1-3 days
What are Staphylococcus aureus and Clostridium perfringens examples of?
What are the characteristics of Enterobacteriaceae?
Glucose Fermenter Nitrate Reducer
What is the main reservoir for Salmonella?
Chickens, uncooked meat, and raw eggs
What is the term for an infection of the intestines with Enteric bacteria?
What disease does Shigella cause?
What is the most common strain of Shigella?
Strain D = S. sonnei
Who is at risk for contracting Shigella?
What is a pathotype?
acronym that describes the disease process they inflict on the host (virulence profile)
What is the most common E. coli pathotype?
EHEC (Shiga-toxin producing)
What is the most widely recognized Serotype of E. coli?
How are serotypes of pathogens created?
O (somatic) antigen
H (flagellar) antigen
What media separates O157:H7 from other E. coli? How can you tell the difference?
Sorbitol-MacConkey Agar because most E. coli are lactose fermenters and Sorbitol +, but O157:H7 is Sorbitol -
O157:H7 is going to have colorless colonies
How do Yersinia bacteria infect the host?
Penetrate the gut lining and enter the lymphatic tissue and blood
What is the main species under the Yersinia genus?
What is the principal reservoir of Yersinia?
What is CIN Agar used for? Why?
Growth and Isolation of Y. enterocolitica
Other pathogens can't grow at 25C and ferment Mannitol Salt
What should Y. enterocolitica look like on its specialized media?
Brick Red Bull's Eye with a white margin
What is XLD used for?
Salmonella and Shigella
What will Salmonella look like on their specialized media? Why
They ferment Xylose, but keep pH neutral with Lysine reaction; then produce H2 = red and orange with black center
What will Shigella look like on XLD Agar? Why?
Don't ferment sugar, so the media is at a constant, neutral pH = pink media with pink colonies
What will E. coli look like on XLD Agar? Why?
Ferment lactose = yellow because of acidic pH
What is MacConkey Agar specifically used for? What's an example?
Gram - enteric bacteria to determine if they can ferment lactose
Example = E. coli
How is colitis caused? What are the clinical features?
Colonization of Enteric bacteria in the large intestines
fever, cramps, blood, and pus in stool
When should Fecal Specimen be collected? Why?
In the early stages because that is when there is the highest number and before they have received any antibiotics
What transport is used for Fecal Specimen? Why? What are 2 examples of pathogens that might be collected in specimen transported?
Carly-Blair Transport because it prevents overgrowth of Enterobacteriaceae and preserves the pathogens
Salmonella and Shigella
What is the Standard Regimen for Enteric Pathogens?
1 = BAP Agar
2 = MacConkey Agar
3 = CIN Agar
4 = XLD Agar
5 = Sorbitol-MacConkey Agar
What is the difference in hyphae and mycelium?
hyphae = filaments
mycelium = interwoven filaments that create a mat
What causes ringworm?
What are the 3 most common genera of mold?
1 = Triptophyton
2 = Microsporum
3 = Epidermophyton
What is Ectothrix? How do you see it?
Infection outside of the hair follicles that can be seen with a UV lamp (Wood's Lamp)
What is Griseofulvin?
an oral antifungal used to treat ringworm
What specific media is used for molds?
Sabourad's Dextrose Agar
What mold is found on bread?
What are the characteristics of Aspergillus niger?
Produces black conidia spores
Grown on Potato Dextrose Agar
What does Penicillium notatum look like? Media?
blue/green conidia spores
Sabourad's Dextrose Agar
golden droplets of Penicillin
What are the collection methods and stain/dye used for mold?
Lactophenol Cotton Blue
What is an antigen?
large protein or carbohydrate on the surface of a cell that provokes an immune response from the host
What is an antibody?
a protein on the surface of B cells that binds to specific antigens
What are the five functions of antibodies responding to antigens?
1 = Agglutinins -- clump antigens together by binding to bacterial or insoluble particles
2 = Precipitins -- bind to antigens and large complexes precipitate out to form visible layer
3 = Complement-Fixing -- bind/"fix" to antigen and create normal human serum agent
4 = Antitoxin -- produced in response to toxins that are seen as precipitin in vitro becauase toxins are soluble
5 = Opsonins -- coat the surface of microorganisms to make them susceptible to phagocytosis by WBC
Where do antibodies come from?
Produced by B-Lymphocytes in response to antigen
B and T cells work together with WBC to seek out antigens
What are the important characteristics of antibodies and how do they know which antigen is which?
They are Homospecific, meaning that they only fit to one antigen and they can tell which is which by the O (somatic) and H (flagellar) antigens
How do we initiate an immune response?
Cells in lymph tissue, connective tissue, and blood are constantly seeking out antigens
How are antibodies produced in the lab? S. pneumoniae
1 = S. pneumoniae is injected into a rabbit and it makes the antibodies
2 = We take those antibodies and use them to determine if someone in infected with S. pneumoniae because there will be agglutination with those antibodies
What is Latex Agglutination?
Adding a larger latex bead/particle to the antibody so that it's easier to see agglutination
What is Enzyme Immunoassay (EIA)
Instead of making a conjugate with latex, you make an antibody-conjugate with an enzyme that reacts with the substance and will change color if there is a reaction
What is known in Direct Serology Testing?
Antibody because it is prepared and used in a test kit
What is an example of Direct Serology Testing?
Latex Agglutination because you put the specific antibody into a serum to determine if there are antigens and it allows you to see agglutination
What is Lateral Flow Immunology?
Performed over a test strip with antibodies conjugated to enzymes, nanoparticles, or fluorescent dye (glows orange with fluorescent)
What is Indirect Serological Testing?
Testing the blood for antobodies (antigen is thought to be known, but have to determine which it is by testing the blood)
What are the 2 places that Indirect Serology can be done?
1 = In Vitro (test tube)
2 = In Vivo (body)
What is an example of Indirect Serology Testing?
Testing for Tuberculosis because you inject the PPD under the skin and the Delayed Hypersensitivity results from the immune response to Myocardium tuberculosis
What are heterophile antibodies?
Antigens that can be found in nature and used to for detection of antibodies in the patient's blood serum
What is an example of Heterophile Antibody Testing?
Testing for Mono because the antigens of horse RBC agglutinate with human antibodies in the blood serum of the Epstein-Barr Virus (mono)
What does an antibody titer measure? What does that tell you?
It is the measure of antibodies in the blood serum that can tell you whether the disease is active or antibodies are present from previous exposure
What is the procedure for antibody titer? Why?
You have to take 2 samples because you need to determine if there is an increase in antibodies to see if it is active. The first is the acute stage and then there is a convalescent stage (10-14 days later)
Is the Antibody Titer direct or indirect?
How do you determine the Antibody Titer number?
You look at the dilution and do the reciprocal of the highest tube dilution
What meningitidis disease does the US have a vaccine for? What serotypes does it cover? What serotype does it not cover?
Covers: A, C, Y, and W-135
Doesn't cover B
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