MICRO: LAB PRACTICAL #1

1. coagulase testing 2. hemolysis 3. mannitol salt agar (MSA- done in lab)

1. no 2. yes

1. Methicillin Resistant S. aureus 2. person-to-person contact

to reduce the spread of staph related infections- if they're carriers they're given a topical antibiotic

20%, 60% intermittent

1. eradicating S aureus from nasal carriers has been proven to prevent infections in surgery patients.
2. prevents nosocomial infection (esp MRSA) spread in nurseries etc.

1. Salt= selective for salt tolerant bacteria
2. mannitol= differential for ability to ferment (or not) mannitol: pH indicator, fermentation acid released= yellow color
3. good screening tool for S. aureus carriers (it ferments mannitol)

salt tolerant

1. When MRSA bacteria cause infection in people who have not been hospitalized nor had a medical procedure within the last year, it is called CA-MRSA
2. community acquired MRSA

because further testing must be done to determine if it is actually S. aureus and to detect MRSA

likely to be true based on available facts

proved true, or made certain

allows growth of several types of microbes and displays visible differences among those microbes

no, it grows many different types of microbes

no, its exact chemical composition is not known

1. yes 2. metabolizes diff microbes differently, resulting in unique colony colors

the study of microbial causes of disease

it is a faster and cheaper way to identify bacteria

yeast growth

because that's the max incubation time and anything read after that would be invalid

presence of bacteria in the blood

blood poisoning caused by bacteria

life-threatening organ dysfunction caused by host response to infection

yes

fever, difficulty breathing, low blood pressure, fast heart rate, and mental confusion

yeast, bacteria, fungi

low probability of infection

high probability of infection

Coagulase is a protein enzyme that converts fibrinogen to just fibrin; the fibrin clot protects the bacterium from phagocytosis and isolates it from other defenses of the host. so a staphyloccocus sp that's coagulase positive is going to be more isolated from the hosts defenses mechanisms than a coagulase negative strain

MSA plate technique; yellow is positive for acid so its staphylococcus aureus and if its red then its staphylococcus epidermidis!

no, yes

staphylococci, bacillus, corynebacteria

1. apply sterilizing solution to skin
2. 2 draws- one for anaerobic one for aerobic
3. needle/syringe: first draw= anaerobic
4. second draw= aerobic

blood tests positive for infection but is not infected- could occur from not using aseptic technique/skin contaminants

bloodstream is not infected

enzyme that breaks down hydrogen peroxide into water and oxygen

ALL staphylococcus are catalase positive

ALL streptococcus are catalase negative

1. substrate: glucose
2. products: acid and/or gas

pH indicator, fermentation releases acid, lowering pH and changing color

yes, they are both sugars

pink stained acid fast bacillus

blue stained non acid fast bacillus

because they must be to be valid

the unknown would be invalid

AF bacteria grow very slowly, staining a sputum sample is much faster

has mucous from URT, would have infectious bacterial cells present but saliva wouldnt

mycolic acid in cell walls of AFB

gram staining

cell wall less bacteria

acid fast bacteria

yes

sensory/motor function in gut, good bacteria likely to be normal flora

so that it is near an oxygen source and having nutrients provided

if it is a facultative anaerobe

because they're more resistant to antibiotic treatment than free floating bacteria

can cause ongoing infection in prosthetics, really difficult to remove