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Microbiology Course Objectives
Exam 1
47
Microbiology
Graduate
10/21/2012

Additional Microbiology Flashcards

 


 

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Term
Components of gram negative cell walls
Definition
Outer membrane, peptidoglycan, periplasmic space, cytoplasmic membrane, cellular appendages
Term
Components of gram positive cell walls
Definition
peptidoglycan, cytoplasmic membrane, cellular appendages
Term
Aerobic
Definition
a organism that can grow in ambient air
Term
facultative anaerobe
Definition
a organism that can grow in ambient air or anaerobic conditions
Term
microaerophilic
Definition
an organism that can grow in environments where the partial pressure of oxygen is less than atmospheric partial pressure of oxygen
Term
capnophilic
Definition
an organism that prefers to grow in an atmosphere of concentrated carbon dioxide
Term
Blood Agar
Definition
infused with 5% sheep’s blood, used for cultivation of fastidious microorganisms, and determination of hemolytic reactions
Term
Chocolate Agar
Definition
enriched with 2% hemoglobin or IsoVitaleX, used for cultivation of Haemophilus spp. and pathogenic Neisseria spp.
Term
MacConkey Agar
Definition
infused with lactose, gram positive organisms inhibited by crystal violet and bile salts, neutral red as indicator, used for isolation and determination of lactose fermenting and non-lactose-fermenting enteric bacilli
Term
MacConkey Sorbitol Agar
Definition
modification of MacConkey agar in which lactose has been replaced by d-sorbitol, used for selection and differentiation of E.coli in stool specimens
Term
XLD (xylose lysine desoxycholate) Agar
Definition
Sodium desoxycholate inhbitis gram-positive organisms, used for isolation and differentiation of Salmonella and Shigella spp. from other gram-negative enteric bacilli
Term
Thayer- Martin Agar
Definition
Blood agar base enriched with hemoglobin and supplement B, used to select for N.gonorrhoea and N.meningitidis
Term
Bordet-Gengou Agar
Definition
contains blood, potato extract, and glycerol with antibiotics, used to isolate for Bordetella pertussis
Term
Buffered charcoal yeast extract (BCYE) Agar
Definition
yeast extract, agar, charcoal and salts, enrichment for Legionella spp.
Term
Campy blood Agar
Definition
Brucella agar base with sheeps blood and antibiotics (vancomycin), selective for Campylobacter spp.
Term
Cefsulodin-irgasan-novobiocin (CIN) Agar
Definition
yeast extract, mannitol and bile salt, selective for Yersinia spp.; may be useful for isolation of Aeromonas spp.
Term
Columbia colistin malidixic (CNA) Agar
Definition
derivative of sheep’s blood agar, selective isolation of gram-positive cocci
Term
Cysteine-tellurite blood Agar
Definition
infusion agar base with sheeps blood, isolation of C.diphtheriae due to reduction of potassium tellurite which shows as black colonies
Term
Mannitol salts Agar
Definition
High salt concentration, selective isolation of staphylococci
Term
Regan Lowe Agar
Definition
charcoal agar supplemented with horse blood, enrichment and selective medium for isolation of Bordetalla pertussis
Term
Thiosulfate citrate bile salts (TCBS) Agar
Definition
peptone base with yeast extract, selective and differential for vibrios
Term
Chromagar MRSA
Definition
isolation and differentiation of methicillin resistant Staphylococcus aureus
Term
Chromagar O157
Definition
detection of E.coli O157
Term
LIM Broth
Definition
selective enrichment broth for determination of group B streptococci
Term
Mueller-Hinton Agar
Definition
used for antibiotic susceptibility testing, isolates Neisseria spp. and Moraxella spp.
Term
four important criteria for collection of specimens for bacterial culture
Definition
(1) Timing
(2) Appropriate collection techniques
(3) specimen transport
(4) specimen labeling
Term
Characteristics that differentiate Staphylococi from Streptococci
Definition
Catalse test (staph is positive, strep is negative) and gram stain (staph has grape like clusters, strep in chains)
Term
Beta Hemolytic Strep
Definition
S.agalactiae and S.pyogenes
Term
Alpha hemolytic strep
Definition
s. pneumoniae, Viridans, S.bovis, S.milleri
Term
Catalase Test
Definition
hydrogen peroxide allows direct analysis of bacterial colony for presence of catalase enzyme. Positive = bubbles ( Staphylococci, Corynebacteria, some GNRS). Negative = no bubbles (streptococci, clostridia)
Term
Coagulase Test
Definition
EDTA plasma mixed with organism clumps on slide because of alteration of fibrinogen or in a tube due to activation of coagulase reacting facto.r. Positive = clumping (S.aureus), negative = no clumping (all other staph)
Term
Novobiocin Test
Definition
antibiotic disk on miller-hinton plate, lawn growth. Positive = resistant zone < 22mm (s.saprophyticus), negative = sensitive zone > 22mm (other staph)
Term
PYR
Definition
identify S. pyogenes and entercocci from other strep due to red color change on disk
Term
Bile Solubility
Definition
differentiates S. pneumonia from Viridins strep. Strep pneumonia disintegrates on the agar, and viridins strep does not
Term
P disk
Definition
test use to determine the effect of Optochin on an organism. Optochin lyses pneumococci, but alpha-streptococci are resistant. Positive = zone of inhibition > 14mm (Streptococcus pneumoniae), negative- no zone of inhibition ( other alpha hemolytic streptococci)
Term
Bacitracin (A disk)
Definition
used to determine the effect of bacitracin on an organism, streptococcus pyogenes is inhibited by bacitracin, other beta hemolytic streoptococci are not. Positive = any zone of inhibition (group A), negative= no zone
Term
Esculin hydrolysis
Definition
most gram-positive bacteria are inhibited by bile in an agar slant. If streptococci and enterococci can grow in the presence of 40% bile and hydrolyze esculin, they turn the indicator a dark brown color. This is a result of esculetin and ferric ions to form phenolic iron complex. Positive = blackening of the agar, (streptococci and entercocci), negative = no blackening
Term
NaCl Broth
Definition
used to determine the ability of an organism to grow in high concentrations of salt. Used to differentiate enterococci from nonenterococci. Positive = visible turbidity in broth with/without color change ( enterococcus faecalis), negative = no turbidity, no color change (streptococcus)
Term
Staph Latex Test
Definition
alternative test to coagulase testing. Latex beads are coated with clumping factor and protein A. S. aureus will clump = positive. More sensitive than coagulase test
Term
Strep Latex Test
Definition
Lancefield grouping: antisera agglutination reactions. Antisera + carbohydrate from unknown beta hemolytic strep allows you to determine it's group. The latex beads contain the antisera and you extract the carbohydrate antigen from the organism by acid or enzyme. Mix the latex beads with the carbohydrate antigen and clumping determines group.
Term
Bacillus spp.
Definition
found in the soil, can cause cutaneous, pulmonary infections along with food poisoning. Spores can be seen via special spore stain, They are gram positive rods in singles or chains, and on the blood plate they are large, spreading, flat colonies. They can be identified on the basis of motility, hemolysis, penicillin resistance and lecithinase.
Term
Listeria spp.
Definition
found everywhere, transmitted to humans via food or through the placenta. Can cause septicemia or meningitis. On the gram stain it’s a gram-positive coccobacilli, and on the blood plate its hemolytic. It can be IDed by a positive catalase test, positive motility test, positive CAMP test, positive Esculin hydrolysis test and positive hippurate hydrolysis test.
Term
Corynebacterium spp.
Definition
obligate human parasite transmitted via drop nuclei. It can cause throat inflammation, pseudomembrane; toxin and cutaneous infections. Treated by antitoxin, penicillin, erythromycin, or vaccination. On a gram stain it is pleomorphic, but some spp. needs selective media to be cultured.
Term
Erysiplothrix spp.
Definition
found in animals and causes wound infections. On the gram stain it shows short rods and long filaments. On the blood plate it can be either large and rough or small and smooth. Identified by a negative motility test and H2S produced on TSI
Term
Lactobacillus spp.
Definition
fond in food and nature, normal flora of the oral, GI and vaginal tracts. It is a rare pathogen and presents on the gram stain as pleomorphic, long chains, coccobacilli or spiral forms. On the plate it has multiple morphologies and is often alpha hemolytic. It can be IDed by colony and microscopic morphologies and a negative catalase test
Term
How to differentiate C. diphtheria from other Corynebacterium spp.?
Definition
Elek Test and Urease Test
Term
How to differentiate pathogen Neisseria from nonpathogen Neisseria and Moraxella?
Definition
N. gonorrhoeae ferments glucose only
N. meningitis and M. catarrhalis ferment glucose AND maltose
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