Micro Finial Flashcards by Mr. Z

Kohler’s Illumination is:

Series of adjustments that provide maximum resolution.

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True or false: Techoic acid present in cell walls of Gram-negative bacilli contributes towards their Gram-negative nature.

False

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True or false: Anaerobes can be preserved if the specimens are stored in a CO2 incubator.

False

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True or false: If the specimen for G.C. culture cannot be planted immediately on the media, refrigerate the specimen to preserve the organism(s).

False

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True or false: Urines are stable if stored at room temperature for up to 3 hours.

False

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True or false: CSFs are not supposed to be refrigerated prior to set up for culture.

True

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True or false: If sachet for GasPak Pouch is found opened, it is ok for use.

False

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True or false: The anaerobic pouch produces anaerobic condition within 1 hour with 5% CO2 within 24 hours.

False

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True or false: Many microorganisms are susceptible to environmental condition such as the presence of oxygen, change in temperature or changes in pH.

True

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Accepted or rejected: Bone marrow for routine C & S collected in Heparin tube 5 hours old.

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Accepted or rejected: Anaerobic swab for aerobic culture.

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Accepted or rejected: Foley urine aspirate for anaerobic culture.

Rejected

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Accepted or rejected: Foley catheter tip for culture.

Rejected

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Accepted or rejected: Refrigerated urine that is 21 hours old.

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Accepted or rejected: Stool for culture that has been refrigerated for 3 hours.

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Accepted or rejected: Cervical culture for anaerobes.

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Accepted or rejected: Sputum sent through the tube system, specimen overflowed to outer cylinder of the collection unit.

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Accepted or rejected: Stat surgery specimen hand carried from O.R. with no identifying labels.

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T or F: Staph aureus is used as a gram stain positive control organism and E. coli is used as a negative gram stain control at EMc

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The Gram stain differentiates between bacteria based on the composition of their:

Cell wall

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Gram positive bacteria Have ____ techoic acid in cell walls.

higher

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true or false: Gram negative bacteria Cell wall lipid content is very low

false

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In Gram staining, the alcohol acts on:

Membrane lipids

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The differential staining property of Gram staining is primarily due to:

Difference in lipid content in Gram positive and Gram negative bacteria.

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Which of the following may cause Gram positive organisms to appear Gram negative? (2)

- Organisms taken from an old culture. - Iodine was omitted from the stain

Proper identification of each specimen includes a label firmly attached to the container with all the following information EXCEPT:

Diagnosis

Which organism will NOT be encountered when setting up a CSF specimen?

Group A Streptococcus

T or f: A patient's initials and/or patient's last name and first initial, accession number, and date are all used as identifiers on the frosted slide of a glass slide for staining in our lab.

AFB smears are stained with which of the following:

Carbolfuchsin and brilliant green

What organism is the most common cause of meningitis in adults

Streptococcus pneumoniae

What organism is a common cause of meningitis in neonates up to 3-4 weeks of age? This organism is often isolated from vaginal cultures of asymptomatic pregnant women and can be contracted by passing through the birth canal.

Streptococcus agalactiae

T or F: It is okay to use the swab to make a smear after it has been used to inoculate culture media.

Which of the following stains is best used to detect mycobacterial organisms in clinical samples?

Acid fast stain

How is culture media selected for specimen plating?

type of specimen submitted and the organisms likely to be involved

What method is used to concentrate specimens to increase recovery of pathogens in the microbiology lab?

Centrifugation

t or f:GasPak EZ Gas generating pouch systems are a multi-use system that can generate anaerobic, microaerophilic or a capnophilic environment.

t or f: GasPak EZ Campy Pouch is used for cultivation of microaerophilic bacteria.

regarding GasPak EZ Anaerobe Pouch & GasPak EZ Campy Pouch: Which of the following components is not part of the sachet contents?

Desiccant

t or f: The Anaerobic Pouch produces an anaerobic condition within 2.5 hours with 10% CO2 within 48 hours.

t or f: Campy Pouch produces a microaerophilic atmosphere within 5-15% oxygen.

media: Differential, selective medium for isolation of Salmonella and Shigella species from other Gram negative enteric bacilli

media: selective for Yersinia spp; may be useful for isolation of Aeromonas spp

CIN

media: Cultivation of fastidious microorganisms, determination of hemolytic reactions

BAP

media: selective for strep pyogenes and strep agalactiae

SSA Agar

media: Isolation and differentiation of lactose fermenting and non-lactose fermenting enteric bacilli

MAC

media: Cultivation of Haemophilus spp. and pathogenic Neisseria species

CHOC

Plates inoculated for quantitation for a Urine Culture Nephrostomy are usually streaked with a ___________ calibrated loop.

1:100 (0.01)

def? an organism that requires incubation in a carbon dioxide-rich environment for its growth

Capnophiles

Plates inoculated for quantitation for a urine cath culture is streaked with a ________ calibrated loop.

1:1000 (0.0001)

t or f: Fecal pathogens are generally non-lactose fermenters.

t or f: The single biochemical test which best differentiates Proteus from Salmonella and Shigella is Urease.

t or f: Somatic antigens are called O-antigens. Flagellar antigens are called H-antigens. Capsular antigens are called Vi-antigens.

t or f: Shigella species are genetically related to E. coli and serological cross reactions are common. To avoid cross reactions, the suspensions should be boiled before testing.

t or f: For the Salmonella (Polyvalent typing), microorganisms having the Vi-antigen will not agglutinate in O antisera.

Citrobacter freundii may be difficult to differentiate from the following because it produces H2S:

Salmonella, Arizona and Edwardsiella

For identification of Salmonella and Shigella, the following tests are necessary:

Biochemical & Serological identification

A gram-negative bacillus has been isolated from feces and the confirmed biochemical reactions fit those of Shigella. The organism does not agglutinate in Shigella antisera. What should be done next?

Boil the organism and retest with the antisera.

t or f : the purpose of the Cefsulodin-Irgasan-Novobiocin Agar from Hardy Diagnostic is to be selective and differential for Yersenia and Aeromonas.

Plesiomonas shigelloides is a relatively new member of the family Enterobacteriaceae. What characteristic separates it from other members of the Enterobacteriaceae?

It is oxidase positive.

Optimum growth of Campylobacter jejuni is obtained on suitable media incubated at 42C in an atomosphere containing:

6% O2, 10%-15% CO2, 85%-90% nitrogen

MacConkey media for screening suspected cases of hemorrhagic E. Coli O157:H7 must contain:

Sorbitol

An oxidase-positive, motile, gram-negative rod showing a S-shaped or "seagull-wing" appearance, requiring enriched blood agar, and a microaerophilic environment for growth is most likely which organism?

Campylobacter jejuni

A gram-negative curved rod, motile by single polar flagellum, capable of using inorganic nitrogen, gelatin liquified, nitrates reduced, indole produced, oxidase positive, glucose fermentation positive would be:

Vibrio cholera

When performing the oxidase screen on blood agar plate at 24 hours, which organisms can be oxidase positive? Choose the best answer.

Aeromonas, Plesiomonas, Pseudomonas, and Vibrio

t or f: On Hektoen agar, the presence of these 2 ferric salts, sodium thiosulfate & ferric ammonium citrate, in the medium produces a black precipitate in the presence of H2S. This allows Salmonella, which does not produce H2S and appears as green colonies, to be distinguished from Shigella which does produce hydrogen sulfide and appears as black colonies.

Yellow colonies growing on Thiosulfate-citrate-bile salts-sucrose (TCBS) agar from a fecal culture are most likely:

Vibrio cholerae

A gram-negative bacillus recovered from a stool culture was beta hemolytic on blood agar. Aeromonas hydrophilia was suspected. Which test will help differentiate this organism from normal fecal flora of the Enterbacteriaceae family?

oxidase

Shigella serogroup A

Shigella dysenteriae

Shigella serogroup B

Shigella flexneri

Shigella serogroup C

Shigella boydii

Shigella serogroup D

Shigella sonnei

T or F: Below the larynx, the trachea is usually unsterile.

t or f: Respiratory specimens uncontaminated by normal flora can be cultured by anaerobes. These include trans-tracheal aspirates, empyema fluid, lung aspirates, and lung tissue.

t or f: Unrefrigerated sputum specimens received after 3 hours of collection are unacceptable for bacteriological examination.

t or f: Gram stains should be routinely performed on sputum and bronchial washings.

t or f: Sputum specimens containing greater than 25 epithelial cells per low powered field are considered inadequate for bacteriological culture.

t or f: A mouth culture was sent for a diagnosis of possible "Thrush." Therefore, it was set up as a fungus culture.

true

t or f: All Haemophilus require chocolate agar plate in order to grow.

t or f: Staphylococci are facultative organisms while Micrococci are oxidative organisms.

t or f: Staphylococci are Microdase positive while Micrococci are Microdase negative.

t or f: Strep. pneumoniae is Bacitracin sensitive. This test is used for identification of Streptococcus pneumoniae.

false

The satellite phenomenon works on the following basis:

Staphylococcus supplies the NAD, blood agar plate supplies the hemin.

Viridans streptococci can be differentiated from Streptococcus pneumoniae by:

bile solubility

A beta-hemolytic Streptococci that is bacitracin-sensitive, PYR positive and CAMP-negative is:

group a

Establishing the pathogenicity of a microorganism isolated from a child's throat and identified as Corynebacterium diphtheria would depend upon:

A positive toxigenicity test.

Which media is best suitable for the isolation of diphtheria?

Loeffler, Tinsdale, and Cysteine-Tellurite Blood Agar

Upon review of a sputum gram stain, the technician notes that the nuclei of all the neutrophils present in the smear are staining dark blue. The best explanation for this finding is:

The slide was inadequately decolorized with acetone/alcohol.

Media used to support growth of Legionella pneumophila should contain which of the following additives?

Charcoal and yeast extract

The best medium for culture of Bordetella pertussis is:

Regan-Lowe agar.

An 11-year-old patient presents with pharyngitis. A throat swab is collected and submitted only for an aerobic culture. This specimen should be:

Set up immediately.

Haemophilus influenzae becomes resistant to ampicillin when the organism produces a(n):

Beta-lactamase enzyme.

If present, a characteristic that is helpful in separating Pseudomonas aeruginosa from other members of the Pseudomonas family is:

Growth at 42°C.

The porphyrin test was devised to detect strains of Haemophilus capable of:

Synthesis of hemin

Characteristics of the genus Capnocytophaga include:

Colonies are large and spreading after 2–4 days.

A sputum culture was collected from an 83-year-old male. The sputum grew out lancet-shaped, gram-positive diplococcus. On blood agar plate, the colonies were alpha hemolytic. The organism was catalase-negative, bile soluble, and optichin sensitive.

Streptococcus pneumoniae.

The test to differentiate Burkholderia from Stenotrophomonas includes:

oxidase

Select the proper test(s) for identification of the following organism: Streptococcus pyogenes (Group A)

Bacitracin

Select the proper test(s) for identification of the following organism: Streptococcus pneumonia

Optochin Susceptibility Test Bile Solubility Test Quellung Reaction

Select the proper test(s) for identification of the following organism: Haemophilus influenzae

X, V disks ALA Quellung Reaction

Select the proper test(s) for identification of the following organism: Moraxella catarrhalis

DNAse

Select the proper test(s) for identification of the following organism: Staph. aureus

Coagulase DNAse

Staphylococcus aureus can be differentiated from Staphylococcus epidermidis by:

Ferment mannitol, produce clumping factor, and is DNase positive.

An antibiotic that inhibits cell wall synthesis is:

penicillin

Fluid from a cutaneous black lesion was submitted for routine bacteriological culture. After 18 hours of incubation at 35C, there was no growth on MacConkey agar, but moderate growth on Sheep blood agar. The colonies were nonhemolytic, 4-5 mm in diameter, and off-white with a ground glass appearance. Each colony had an irregular edge with comma-shaped outgrowth that stood up like "beaten egg whites" when gently lifted with an inoculating needle. A gram-stained smear of a typical colony showed large, gram-positive, rectangular rods. The organism is most likely:

Bacillus anthracis

Strains of S.aureus may produce an exfoliation toxin causing:

Scalded-skin syndrome

An aspirate of a deep wound was plated on blood agar plates and incubated aerobically and anaerobically. At 24 hours, there was growth on both plates. This indicates that the organism is a(n):

Facultative anaerobe

Haemophilus ducrei has the following characteristics:

A. It is the cause of venereal disease It requires freshly drawn rabbit blood in the culture media

When Staphylocci are resistant to Methicillin:

Susceptibility against penicillinase-resistant penicillins and cephalosporins is reported as resistant.

Chocolate agar base containing vancomycin, colistin, nystatin, and trimethoprim is also known as:

MTM

In a synovial fluid, Enterococcus faecalis was isolated. Which of the 2 different antimicrobial agents listed below are commonly used and may result in synergistic action in the treatment?

A penicillin derivative and an aminoglycoside

An organism isolated from the surface of a skin burn is found to produce a diffusible green pigment on a blood agar plate. Further studies of the organism would most likely show the organism to be:

Pseudomonas aeruginosa

Colonies odor: Bleach-like

Eikenella corrodens

The primary isolation of Neisseria gonorrhoeae requires:

CO2

An aspirate of a deep wound was plated on blood agar plates aerobically and anaerobically. At 48 hours, there was growth on the anaerobic plate only. The next step in the evaluation of this culture is to:

Begin organism identification.

A gram-negative diplococcus that grows on modified Thayer-Martin medium can be further confirmed as Neisseria gonorrhoeae if it is:

Oxidase positive, glucose positive, and maltose negative.

Some Prevotella spp. are normal flora of the urogenital tract. This group may be:

Anaerobic gram-negative rods, some produce black pigment and are bile sensitive.

Features which may help identify Porphyromonas species include:

Anaerobic gram-negative rod, red fluorescence, bile sensitive

An organism from a peritoneal abscess is isolated on Kanamycin-Vancomycin Laked blood agar and grows black colonies on BBE agar. It is non pigmented, catalase positive, and indole negative. The genus of this organism is:

Bacteroides

t or f: Specimens for anaerobes cannot be refrigerated, but specimens for urinary tract pathogens can be refrigerated.

t or f: In neonates, E. coli, Group B Strep, and Listeria monocytogenes are the most common CSF isolate

t or f: A minimum volume of 2.5 ml of CSF is required to perform routine chemistry, hematology, and microbiology.

t or f: Eye culture specimens should be refrigerated since Haemophilus like organisms may be lost at room temperature.

t or f: Neisseria gonorrhoeae is a gram-negative diplococci that is oxidase positive and grows on Thayer Martin agar.

t or f: Brucella requires 5-10% CO2 at 37C and must be kept for 21 days before signed out as negative

t or f: Staph. aureus is DNAse negative and Staph. epidermidis is DNAse positive.

t or f: Anaerobic degradation of mannitol with production of acid is an important characteristic of Staph. aureus.

t or f: Hippurate hydrolysis test can be used for the identification of Group B Strept. and G. vaginalis.

t or f: Borrelia species and Fusobacterium species cause Vincent's disease (also known as trench mouth).

A nonfermenting gram-negative bacillus is isolated from a wound. The growth on sheep blood agar has a grape-like odor. It is oxidase positive. The organism is:

Pseudomonas aeruginosa

Slide coagulase test is bound or free coagulase

bound

Tube coagulase test is bound or free coagulase

free

Select the proper test(s) for identification of the organism Gardnerella vaginalis.

Diffuse hemolysis on V agar Hippurate urease

Select the proper test(s) for identification of the organism Serratia marcescens

DNase

Select the proper test(s) for identification of the organism Peptostreptococcus anaerobius.

SPS

Select the proper test(s) for identification of the organism Staph. Aureus.

DNase coagulase

Select the proper test(s) for identification of the organism Enterococci.

bile esculin 6.5% salt

Select the proper test(s) for identification of the organism Group D Strep, Non Enterococcus.

bile esculin 6.5% salt

Select the proper test(s) for identification of the organism Streptococcus agalactiae (Group B).

CAMP

GP Cell wall has a ____ peptidoglycan layer.

thick

in GP Lipopolysaccharide layer is _____

absent

Culture hold time for urine cultures?

48 hours

0.001 mL loop used for?

Foley, voided, catheter urine

0.01 mL loop used for?

Suprapubic aspirate, nephrostomy

1 colony with 0.001 loop equals?

1,000 CFU/mL

C1 urine code?

<10,000 CFU/mL

C4 urine code?

>100,000 CFU/mL

Most common urinary pathogen?

e. coli

Most common UTI in young females?

Staph saprophyticus

Staph saprophyticus novobiocin result?

Resistant

Enterobacteriaceae characteristics?

Glucose fermenters • Oxidase negative • Reduce nitrate

Rapid tests for GNRs in urine?

Oxidase, Indole

Rapid tests for GPC?

Catalase, PYR, StrepTex, Staphaurex

MIC definition?

Lowest antibiotic concentration inhibiting growth

MBC definition?

Lowest antibiotic concentration killing bacteria

Enterococcus PYR?

pos

Strep bovis PYR?

neg

Enterococcus growth in 6.5% NaCl?

pos

Klebsiella oxytoca indole?

pos

Klebsiella pneumoniae indole?

Negative

Proteus mirabilis indole?

neg

Proteus vulgaris indole?

pos

Proteus urease?

pos

Pseudomonas oxidase?

pos

IMViC for E. coli?

+ + – –

IMViC for Klebsiella?

– – + +

IMViC for Enterobacter?

– – + +

Stool cultures held how long?

48 hours

Salmonella on HEK?

black colonies

Shigella on HEK?

Blue-green colonies

Normal flora HEK color

yellow orange

Salmonella SS?

Colorless with black center

Shigella SS?

colorless

Lactose fermenter SS?

pink/red

Organism targeted? CIN agar

Yersinia

Yersinia colony? CIN agar

Red bull’s-eye

CIN agar Incubation temperature?

Room temperature

Campylobacter atmosphere?

Microaerophilic

Incubation temperature?

42°C

Campylobacter morphology?

Gull-wing GNR

campy Motility?

Darting

E. coli O157:H7 colony? MAC sorbitol

colorless

Normal E. coli colony? MAC

PINK

Vibrio cholerae colony? TCBS

yellow

Vibrio parahaemolyticus colony?

Green/colorless

Shigella oxidase?

neg

Salmonella H2S?

pos

Yersinia urease?

pos

Vibrio oxidase?

pos

Respiratory cultures held?

48 hours

Alpha hemolysis?

Partial RBC lysis

Optochin identifies?

Strep pneumoniae

Optochin positive zone?

>14 mm

Bacitracin identifies?

Group A Strep

Haemophilus influenzae growth?

CHOC only

Strep pneumoniae morphology?

Lancet GPC

Moraxella oxidase?

pos

BBE agar detects?

Bacteroides fragilis group

BBE positive colony?

black

LKV agar selects for?

Bacteroides & Prevotella

PEA agar inhibits?

Gram-negative rods

Boxcar GPR? anarobe

Clostridium

Thin branching GPR? anarobe

Actinomyces

Tapered GNR? anarobe

Fusobacterium

Mycobacteria oxygen requirement

Strict aerobe

Growth rate of mycobacteria

slow

mycobacteria Cell wall contains?

Mycolic acids

Preferred specimen for pulmonary TB?

Sputum

Gastric lavage used for?

Children / patients who can’t produce sputum

Most sensitive stain for AFB

Fluorochrome

AFB Hot stain?

Ziehl-Neelsen

AFB Cold stain?

Kinyoun

MYCOBACTERIAL CULTURE Most isolates appear in?

3–6 weeks

MYCOBACTERIAL CULTURE Cultures discarded after?

8 weeks

Egg-based medium example?

Lowenstein-Jensen

mycobacterium culture Agar-based medium?

Middlebrook 7H10/7H11

Fungi cell type?

eukaryotic

Fungi cell type?

Eukaryotic

Yeast structure?

Single budding cells

Mold structure?

hyphae

Septate example?

aspergillus

Aseptate example?

mucor

Mold temperature?

25°C

Yeast temperature?

Classic dimorphic fungi?

Histoplasma Blastomyces Coccidioides Sporothrix

Blastoconidia formation?

budding

Arthroconidia formation?

hyphae fragmentation

Chlamydoconidia function?

Survival spores

Sporangiospores location?

Inside sporangium

Micro Finial Flashcards

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