Tracy's Material Microbiology Flashcards by Cara Ortega

What does beers law state?

That the concentration of a substance is directly proportional to the amount of light absorbed

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In photometry what do we measure?

The amount of light transmitted through a solution in order to determine the concentration of the light absorbing molecules present within

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Which of the following extensions enable the bacterial cell to attach to host cells

pili

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The bacterial cell contains

contains DNA in the cytoplasm

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The morphology of those bacteria that are round and arranged in pairs is known as:

diplococci

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True or False: prokaryotes contain a nuclear membrane and 80s ribosomes

false

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Those bacteria that can use aerobic respiration or fermentative processes for metabolism are categorized as:
a. microaerophiles
b. oblige aerobes
c. obligate anaerobes
d. facultative anaerobes

d. facultative anaerobes

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Which of the following is a phenotypical characteristic used for classifying bacteria?
a. Staining characteristics
b. Macroscopic morphology
c. Nutritional needs
d. All of these

d. all of these

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The _____ are important for motility of the bacterial cell

flagella

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Exotoxins
a. Are only excreted by gram positive bacteria
b. Consist of LPS
c. Can induce fever upon cell lysis
d. May be extracellular enzymes

d. May be extracellular enzymes

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Microorganisms that are of the same species, but have different physiologic characteristics are known as

biotypes

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T or F? Gram negative bacteria contain an outer LPS layer of endotoxin, core polysaccharide and antigenic O polysaccharide.

True

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The _____ is the bacterial component that is antiphagocytic

capsule

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Those bacteria that are rod shaped are also known as _______.

bacilli

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Gram-positive bacteria contain ______which are not found in gram-negative bacteria.

teichoic acids

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T or F? Most cases of pharyngitis are caused by bacteria.

False

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T or F? If possible, collect the specimen after antibiotics have been initiated.

False

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A selective agar to isolate stool pathogens such as Salmonella and shigalla, which inhibits normal flora coliforms is

Hekton Enteric

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what is an example of enriched media?

blood agar

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The Gram stain of a sputum shows mucus, 30 neutrophils, and 10 squamous epithelial cells per low-power field. The total score using the Bartlett Classification is:
+2
+1
0
-1
None of these is correct

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During the early part of typhoid fever, the specimen that should be cultured is the___

Blood

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In general, cotton swabs are preferred for specimen collection. T or F

false

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_______ wound infections are those that are attributed to an individuals own microbiota.

endogenous from indigenous microbiotia

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T or F. it is generally recommended to collect a single blood culture specimen to diagnose bacteremia.

false

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macConkey agar

differential ; isolation of gram negative bacilli and identification of lactose fermentation

Sheep blood agar

Enriched, nonselective; determination of hemolytic patterns

Thioglycollate broth =

growth at different oxygen levels

Xylose-lysine-deoxycholate agar =

Isolation and differentiation of stool pathogens through inhibition of normal flora coliforms

Modified thayer martin =

isolation of Neisseria gonorrheae

Chocolate agar =

enriched nonselective isolation of fastidious bacteria

Selenite broth =

Enrichment broth used to isolate stool pathogens and suppress normal flora coliforms

colistin nalidixic acid=

Isolation of gram positive bacteria

Anaerobic blood agar =

Isolation of gram negative and gram positive anaerobes

Which of the following is not recommended for the culture of urine because of contamination? a. Clean catch midstream b. Catheterized urine c. Foley catheters d. Suprapubic aspiration

c. foley catheters

what is the purpose of crystal violet

primary stain

what is the purpose of grams iodine

mordant

what is the purpose of acid alcohol

decoloriser

what is the purpose of safranin

secondary or counter stain

While performing the quality control on a gram stain procedure using a control slide of staphylococcus and E. coli, the laboratory professional notices that all of the bacteria are staining pink. This may be due to: a. Inadequate decolorization b. Over decolorization c. Failure to add acid alcohol d. Failure to add safranin

b. over decolorization

Neisseria microscopic arragement appears as

small diplococci that resemble kidney beans

streptococcus pneumonia microscopic arrangement appears

diplococci that resemble lancets

Which of the following is an example of a fluorescent stain used to stain mycobacteria?

Rhodamine-auramine

Gram positive bacteria retain the primary stain because of the: a. High content of peptidoglycan in the cell wall b. Low content of peptidoglycan in the cell wall c. High amount of lipopolysaccharide in the cell wall d. Mycolic acid and waxy compounds in the cell wall

a. High content of peptidoglycan in the cell wall

Purpose of catalase test

differentiate staphylococcus from streptococcus

purpose of coagulase test

differentiates from staphylococcus aureus from other staphylococci

cytochrome oxidase test purpose

produced by neisseria and pseudomonas and other oxidative bacilli

purpose of spot indole

differentiates e coli from other lactose-positive members of enterobacteriacea

purpose of PYR

differentiates group D enterococcus from non enterococcus

Carbohydrate use in the absence of oxygen is known as: Fermentation Oxidation Deamination Reduction

fermentation

Which of the following tests would be most helpful in working up gram-positive cocci isolated from a urine culture? Catalase Spot indole Cytochrome oxidase PYR hydrolysis

catalase

Current versions of the BACTEC measure ________ to detect positive blood cultures.

Fluorometric changes from production of CO2

Colonial characteristics that should be examined include: Size Pigment Elevation All of these are correct

all of these are correct

True or False? A direct smear from a wound specimen with gram-negative bacilli and neutrophils would correlate with growth on blood agar and CNA

false

True or False? Some automated identification systems, such as the microscan walkaway, incorporate antibiotic susceptibility testing along with identification of bacteria.

true

True or False? All automated microbiology analyzers utilize the principle of colorimetry for measurement.

false

The minimal _______ concentration is the minimal concentration of antibiotic that gives 99.9% killing of the inoculum.

bactericidal

True or False? When measuring the zones around sulfonamides in disk diffusion susceptibility testing, measure the outer zone of heavy growth.

true

All of the following antibiotics inhibit cell wall formation, except: Penicillin Cephalosporins Chloramphenicol Vancomycin

chloramphenicol

___________ refers to those antibiotics that inhibit the bacterial growth, but require the host immune system to kill the microorganism.

bacteriostatic

The sulfonamides inhibit bacterial growth by forming folic acid _________. Pg. 119

synthesis

Because of narrow therapeutic index and toxicity concerns, peak and trough levels must be performed when administering: [hint: overview of antibiotic susceptibility testing] Vancomycin and amoxicillin Rifampin and chloramphenicol Tetracycline and gentamycin Tobramycin and gentamycin

Tobramycin and gentamycin pg. 141

True or False? The second generation cephalosporins have primarily a gram-positive spectrum.

false

Which of the following is correct regarding plasmids? a. They are dependent on the bacterial chromosome b. They are also known as transposons (not this one) c. They can only be transferred between organisms in the same genus d. They are extrachromosomal DNA associated with virulence and resistance.

d. They are extrachromosomal DNA associated with virulence and resistance.

In which type of resistance is the antibiotic actively pumped out of the bacterial cell, such that sufficient levels cannot be attained? Restrictive enzyme channels Enzyme inactivation Efflux Modification of target sites

efflux

Which of the following is an example of a narrow-spectrum antibiotic that inhibits cell wall formation? (overview of antibiotics susceptibility testing) Erythromycin Penicillin G Tobramycin Amoxicillin

Penicillin G

Which of the following is correct regarding vancomycin? a. It inhibits protein synthesis b. It has a gram positive spectrum, including MRSA, coagulase-negative staphylococci infections, and Clostridiodes difficile colitis c. It is effective against anaerobes and intracellular pathogens d. It inhibits DNA gyrase activity

b. It has a gram positive spectrum, including MRSA, coagulase-negative staphylococci infections, and Clostridiodes difficile colitis

True or False? An example of intrinsic resistance is the emergence of MRSA.

False

All of the following antibiotics inhibit protein synthesis, except: (overview of antibiotic susceptibility testing) Tetracycline Erythromycin Cefoxitin Chloramphenicol

Cefoxitin

Which of the following is used for systemic antifungal infections? Isoniazid Amphotericin B Nystatin Zidovudine

amphotericin B

True or False? Staphylococcus saprophyticus does not grow on mannitol salt agar

false pg. 161

All of the following virulence factors are associated with staphylococcus aureus EXCEPT: Enterotoxins Cytolytic toxins Cellular components such as protein A Endotoxins

endotoxins

which of the following is an opportunistic staphylococcal pathogen that is the etiologic agent in aggressive infections such as bactermeia and endocarditis; produces smooth glossy colonies that may be pigmented cream to yellow-orange; and may be confused with S. aureus because of its production of bound coagulase. S. saprophyticus S. lugdunensis S. schleiferi subsp. Coagulans S. warneri

s. lugdunensis