final microlab

•Snyder test

+Snyder test is designed to favor oral bacteria and discourage others. This is accomplished by lowering the pH to 4.8. +Bromcresol green is the differential ingredient; It's green at 4.8 and above but turns yellow below it. +A positive yellow test after 24-hours indicates the presence dental decay-causing bacteria. +This was the molten agar that was kept warm. It congealed after inoculation., test bacteria activity, measures acid production by oral lactobacilli that produce dental carries, 2% dextrose in the medium - as a fermentable carbohydrate -makes acid and drops the pH Predicts whether we have decay causing bacteria in our mouth -------------------------------------------------note--------- green indicator of PH4.8, has LACTOSE, Will turn yellow when ph drips, will check oral microflora for its porential to cause toothe decay 1.bactobacilli(젖산균, 입냄새의 주범)-- produce--> lactic acid 2 strep mutans -(Streptococcus mutans is facultatively anaerobic, Gram-positive coccus-shaped bacterium commonly found in the human oral cavity and is a significant contributor to tooth decay) ------------------------------------------------------------------

5.Kirby-Bauer Method (Disk Diffusion)

------------------------------------------------------------------------ antibiotic sensitivity: susceptibility Inhibition zone: (area of no bacterial growth) is compared against a standard Inhibition reflects organism susceptibility, paper disks containing defined amounts of drug are placed on a plate on which a suspension of bacteria has been spread; look for zone of inhibition, look for the clear zone where no bacteria grow (zone of inhibition), a highly standardized disc diffusion method that is approved for and widely used in clinical laboratories, used to determine the effectiveness of certain antimicrobials; sensitivity and resistance determined using tables that relate zone diameter to degree of microbial resistance

6.Specialized media: Understand the reasons for each assay, the principles behind each, and the types of bacteria that they select for.

...

7.Be prepared to answer any relevant questions about the 1918 Influenza movie that were covered on your worksheets.

...

Understand the organisms that each of the following media selects for and against, and the ways to interpret growth patterns:

...

Which component is specific for Group A surface antigens?

...

exam3

...

Note: Any information that is covered in the Assignments and Projects that is not covered in the above-mentioned topics may also be included in a Lab Exam.

... see NOTES..

•Blood Agar

..., Defibrinated sheep's blood. NaCl- 0.5% minimize spontaneous hemolysis., •a nutritious medium to which 5% sterile sheep blood has been added after the sterile medium has been tempered •excellent for growing streptococci, non-selective and differential. Certain bacteria produce hemolysins. When the cells lyse, the area around the colony becomes clear and detectable., 5% sheeps blood; alpha-partial green, beta-complete, gamma-none

•EMB

..., Eosin Methylene Blue Agar, Eosine Methylene Blue selects gram -, also differentiates between lactose +/- organisms, if it's lactose + there's a color change negative no color change, Eosin Methylene Blue - contains two dyes, eosin and methylene blue, that inhibit the growth of Gram positive bacteria., E.coli is an aggressive fermenter- turns metallic green. Klebsiella, for instance, is medium aggressive- turns pink., tests for fecal coloforms, coloform bacillus, black colonies metallic green sheen, (Q)Besides MacConkey Agar, what other medias would be useful for isolating E. Coli (gram -) from a stool sample? This media inhibits gram + , Eosine Methylene Blue selects gram -, also differentiates between lactose +/- organisms, if it's lactose + (purple/green) negative (pink)

Understand the principles behind this antibody-based latex bead assay and its selectivity.

Before- uniformly red after putting bacteria- red clumps- its AGGLUTINATION Reaction

Understand the selective and differential properties of this growth medium.

Deep pink colony - MRSA가있다는 뜻, selective agent will inhibit non MRSA trains , has Metacilin

McConkey

EA- mucoic EC powdery pink Inhibits-gram positive Inhibitor-Crystal violet, bile salts Indicator-neutral red used to differentiate lactose no factro fermentors fish appearance, lactose acid pink

2.HardyCHROM MRSA plates

HardyCHROM™ MRSA is a selective and differential chromogenic medium for the qualitative direct detection of nasal colonization by methicillin-resistant Staphylococcus aureus (MRSA). Not intended to diagnose infection or guide therapy. HardyCHROM™ MRSA simplifies the identification of MRSA infections. MRSA strains grown in the presence of chromogenic substrates produce deep pink to magenta colonies. Selective agents will inhibit non-MRSA strains.

How is a positive result determined?

POSITIVE RESULT:Any pink to purple Test Line along with any shade of a blue procedural Control Line is a positive result for the detection of Group A Streptococcus antigen.

Selective vs differential growth media

Selective- suppress growth of unwanted species and encourage growth of other species, Restrict the type of microorganisms that can grow *Must also be differential*, -Selective: ingredients that favor the growth of targeted bacteria (ex. unusual sugars). also ingredients that can inhibit the growth of competing bacteria (ex. antibiotics, bile salts, etc.) -Differential: ingredients that make the target organism look different and stand out amongst other organisms, Allow for the growth of different microbes but permits ways of telling them apart. Doesn't kill one type., Contains various substrates and pH indicators to indicate presence/absence of certain chemical reactions; organisms not prevented from growing. Commonly used to identify organisms that break down a particular substrate., Result in different growth appearances by different groups of bacteria

•Catalase test.

Tests whethere bacteria produce the enzyme catalase, which breaks down hydrogen peroxide, a toxic byproduct of aerobic respiration. Bubbles are produced when hydrogen peroxide is added to a bacterial culture that produces catalase. ----------------------------------------------------------(note) H2O2 (hydrogen peroxid)-toxic to cellular resp 2H2O2=(catalize)=> 2H2O(water)+ O2(oxy) micrococcus luteus 에peroxide 넣으면 , if bubble, then it means that it produce catalize. ------------------------------------------------------------------------------ , this test is used to differentiate between gram positive cocci. It differentiates Staphyloccocus (positive) and Streptococcus (negative), H2O2 (hydrogen peroxide). Bubbles: positive; NR: negative, Tests whethere bacteria produce the enzyme catalase, which breaks down hydrogen peroxide, a toxic byproduct of aerobic respiration. Bubbles are produced when hydrogen peroxide is added to a bacterial culture that produces catalase., + = staphylococcus, - = streptococcus

1.Understand the principles of the QuickVue Group A strep assay.

The QuickVue In-Line Strep A test allows for the rapid detection of group A streptococcal antigen directly from patient throat swab specimens. (Streptococci are gram-positive, spherical or oval microorganisms that appear in chains or clusters. Streptococci belong to the genus Streptococcus. There are over 30 recognized species within this genus. The streptococci organisms cause an array of diseases in humans to include: pharyngitis, scarlet fever, impetigo, rheumatic fever, pneumonia, meningitis, otitis media, sinusitis, endometritis, septicemia and other conditions.) Group A Strep is a BETA- (complete) hemolysis Cause strep throat, flesh eating bacteria

4.MMWR Exercise-morbidity and mortality weekly report

Understand the meanings of all relevant terms such as incidence, morbidity, and mortality. Know how to calculate these values. Understand the value of K.

Specialized media

Used for detection of specific organisms that have specific requirements or are present in large mixtures of organisms.

3.StaphSlide Assay

antibody based colorimetric assay - (Quick & accurate assay )antibody made to bind specific antigen (monoclonal antibodies) Red dye attached to constant regions

계산하는법

incidence- morbidity- mortality-

p403

incidence-the number of NEW CASES of a disease in a population, morbidity-number of susceptable people who have the disease within a defined population during a specific time period mortality- a number of people who die from specific disease out of total population afflicted withh that disese in a specificed time period K- some power of 10 so the rate can be reported as a whole number of cases

What type of assay is it?

lateral flow immnoassay - diffuse away from well intercepting antibodies of strep A specific antigen

•MSA

mannitol salt agar; differentiates between mannitol fermenters vs. nonfermenters, contains sugar - MANNITOL -Sodium Chloride (NaCl) selectively inhibits the growth of Gram -ve bacteria (due to high NaCl Conc.), Mannitol Salt Agar; Selective & Differential; Isolation and differentiates Staph species; Quadrant Streak

Understand the principles of this method and the ways to interpret growth patterns.

standard tool for measuring the effectiveness of antimicribics against pathogenic microorganisms. antimicribic-impregnated paper disks are placed on plate that has been inoculated to form a bacterial lawn. Plates are incubated , As drug moves through the agr, it establishes a concentration gradient. if organism is susceptible to it, a clear zone will appear around the disk where growht has been inhibited. the sieze of this zone of inhibition depends upon the sensitivity of the bacteria to the specific antimicribial agent and the point at which the chemical's minimum inhibitory concentration is reached. The zone may be produced as a result of killing the bacteria. or may only srop bacterial growth without killing them.