Microbio Flashcards
Substrate used in Kovacs Indole Test A. Indole
B. Tryptophan
C. Para-dimethylaminobenzaldehyde
D. Para-dimethylaminocinnamaldehyde
B. Tryptophan
Indole test di erentiates which set of organisms?
A. Morganella and Providencia
B. Salmonella and Shigella
C. P. vulgaris and P. mirabilis
D. E. coli and Klebsiella oxytoca
C. P. vulgaris and P. mirabilis
Inhibitors for gram (+) bacteria on MAC:
A. Crystal violet and vancomycin
B. Colistin and anisomycin
C. Trimethoprim and vancomycin
D. Bile salts and crystal violet
D. Bile salts and crystal violet
Colonies of Salmonella on SSA:
A. Colorless colonies with black center B. Colorless colonies w/o black center
C. Red colonies with black center
D. Red colonies w/o black center
A. Colorless colonies with black center
Which of the following is a correct pair?
A. S. aureus — Pink colonies on MSA
B. K. pneumoniae — Colorless on MAC
C. S. pneumoniae — Non-hemolytic on SBA
D. E.coli — Yellow colonies on XLD
D. E.coli — Yellow colonies on XLD
All members of Enterobacteriaceae are motile at 37C except:
- Klebsiella
- Proteus
- Shigella
- Yersinia
A. 1, 2, and 3
B.1, 3, and 4
C. 1 and 3
D. 1 and 4
B.1, 3, and 4
pH indicator of LIA:
A. Neutral Red
B. Phenol Red
C. Bromthymol blue
D. Bromcresol purple
D. Bromcresol purple
Yellow butt and Red slant in TSI tube indicate fermentation of:
A. Lactose
B. Glucose
C. LActose and Glucose
D. Lactose and/or Glucose
B. Glucose
Heat stable antigen of enterics located on their cell wall:
A. O
B. K
C. H
D. Vi
A. O
ONPG test allows organisms to be classified as lactose fermenters by testing which of the following:
A. B-lactamase
B. B-galactosidase
C. Lactose permease
D. Tryptophanase
B. B-galactosidase
Only oxidase-positive member of Enterobacteriaceae:
A. Shigella
B. Morganella
C. Plesiomonas
D. Edwardsiella
C. Plesiomonas
Vibrio cholerae colonies on TCBS:
A. Blue
B. Green
C. Yellow
D. Red
C. Yellow
Which of the following sets of results represent the most common reactions for Moraxella catarrhalis when tested in CTA sugar tubes?
A. Glucose: Negative; Maltose: Negative; Lactose: Negative; Sucrose: Negative
B. Glucose: Positive; Maltose: Negative; Lactose: Negative; Sucrose: Negative
C. Glucose: Positive; Maltose: Positive; Lactose: Negative; Sucrose: Negative
D. Glucose: Positive; Maltose: Negative; Lactose: Positive; Sucrose: Negative
ALL NEGATIVE !
A. Glucose: Negative; Maltose: Negative; Lactose: Negative; Sucrose: Negative
Neisseria lactamica can be di erentiated from Neisseria meningitidis through which of the following?
A. Colony morphology
B. Use of selective media
C. Glucose and maltose utilization
D. ONPG test
D. ONPG test
Isolates of suspected C. diphtheriae must be tested for in vitro production of exotoxin through:
A. Anton test
B. Elek test
C. Frei test
D. Mantoux test
B. Elek test
Lecithinase production, double zone hemolysis on sheep blood agar, and gram-stained morphology are all useful criteria in the identification of which of the following?
A. Clostridium perfringens
B. Streptococcus agalactiae
C. Escherichia coli
D. Clostridium tetani
A. Clostridium perfringens
Sensitivity test result of Group A streptococci (S. pyogenes) to Bacitracin and SXT respectively:
A. Susceptible and resistant
B. Resistant and susceptible
C. Both susceptible
D. Both resistant
A. Susceptible and resistant
Correct about gram-positive bacteria:
A. Has thinner peptidoglycan compared to gram-negative
B. Cell wall has an outer layer which contains lipopolysaccharide (LPS)
C. Takes up the crystal violet-iodine complex but is easily decolorize
D. Uses selective isolation media like colistin-nalidixic acid (CNA) agar
D. Uses selective isolation media like colistin-nalidixic acid (CNA) agar
Responsible for dark/non-fluorescent background in Auramine Rhodamine stain for acid-fast bacilli:
A. Auramine
B. Rhodamine
C. Potassium permanganate
D. Acid-alcohol
C. Potassium permanganate
Stain for endospore:
A. Wayson
B. Leifson
C. Schaeffer-Fulton
D. Loeffler’s Alkaline Methylene Blue
C. Schaeffer-Fulton
Most common gas for sterilization:
A. Nitrogen dioxide
B. Chlorine dioxide
C. Ethylene oxide
D. Chlorhexidine gluconate
C. Ethylene oxide
HEPA filter size used in laboratory hoods and isolation room:
A. 0.3 um
B. 0.6 um
C. 0.9 um
D. 1.2 um
A. 0.3 um
Incorrect about Autoclaving:
A. Biologic indicator: B. stearothermophilus
B. Can destroy all forms of microbial life including spores
C. Dry heat sterilization
D. 121C/ 15 psi/ 15 mins
C. Dry heat sterilization
Uses a strip with varying concentration of antibiotic along its length and MIC can be obtained:
A. Kirby Bauer
B. Microplate dilution
C. Vitek System
D. E-Test
D. E-Test
0.5 Macfarland standard provides an optical density comparable to density of a bacterial suspension of:
A. 0.5 x 105 CFU/mL
B. 1.5 x 108 CFU/mL
C. 0.5 x 109 CFU/mL
D. 1.5 x 109 CFU/mL
B. 1.5 x 108 CFU/mL
In disk di usion testing, a delay of more than 15 minutes between placing the disks on an inoculated plate and incubation results to:
A. failure of antibiotic to di use in media
B. zones of smaller diameter will result
C. zones of larger diameter will result
D. no e ect of final zone diameter
C. zones of larger diameter will result
The term “palisading”, “picket fence”, and “Chinese letter” describe the common arrangement of cells of:
A. Corynebacterium spp.
B. Mycobacterium tuberculosis but not other mycobacteria
C. Actinomyces but not Nocardia
D. Corynebacterium diphtheriae but not other corynebacteria
A. Corynebacterium spp.
The exchange of cellular DNA between two living bacterial cells that involves an intercellular bridge is which of the following processes?
A. Transformation
B. Transduction
C. Plasmadization
D. Conjugation
D. Conjugation
The slide coagulase test is a rapid screening test for the production of which of the following?
A. Clumping Factor
B. Free Coagulase
C. Extracellular coagulase
D. Catalase
A. Clumping Factor
The bacterial species that can be described as susceptible to bile and optochin, a-hemolytic, a major cause of bacterial meningitis, and often carrying an antiphagocytic capsule is which of the following?
A. Enterococcus faecalis
B. Streptococcus pneumoniae
C. Streptococcus pyogenes
D. Streptococcus agalactiae
B. Streptococcus pneumoniae
Which of the tests provide the best di erentiation of L. monocytogenes & E. rhusopathiae?
A. Gram-stained smear, oxidase, optochin
B. Gram-stained smear, catalase, and motility
C. CAMP test, H2S production, Esculin hydrolysis
D. Reverse CAMP, gram-stained smear, b-hemolysis
C. CAMP test, H2S production, Esculin hydrolysis
Micrococcus and Staphylococcus species are di fferentiated by which test(s)?
- O-F Tube
- Gram Stain
- Catalase Test
- Lysostaphin Susceptibility
A. 1 and 3
B. 2 and 3
C. 1 and 2
D. 1 and 4
D. 1 and 4
In the test for urease production, the presence of the enzyme hydrolyzes urea to which of the following?
A. Ammonia and CO2
B. Putrescine
C. Amines and CO2
D. Amines and water
A. Ammonia and CO2
All of the following are correct regarding methylene blue except:
A. Inhibits gram-positive bacteria in enteric media
B. Can be used as simple bacterial stain
C. Indicator of anaerobiosis
D. pH indicator in TCBS
D. pH indicator in TCBS
LOA reaction of Klebsiella pneumoniae:
A. +–
B. ++-
C. -+-
D. +-+
A. +–
All are correct regarding Staphylococcus saprophyticus EXCEPT: A. Coagulase negative
B. Causes UTI in young women
C. Novobiocin sensitive
D. DNase negative
C. Novobiocin sensitive
Chocolate agar-based medium containing vancomycin, colistin, anisomycin & trimetoprim is known as
A. Thayer-Martin
B. Modified Thayer Martin
C. Martin-Lewis
D. New York City
C. Martin-Lewis
Which of the following is a wrong pair?
A. Brucella abortus - Bang’s bacillus
B. Neisseria meningitides - Meningococcus
C. Haemophilus influenzae - Koch Week’s bacillus
D. Mycobacterium avium intracellulare - Battey bacillus
C. Haemophilus influenzae - Koch Week’s bacillus
Positive result for DNase test:
A. Green
B. Pink
C. Clearing of medium
D. Hemolysis
C. Clearing of medium
Biosafety Cabinet where 30% is recirculated air and 70% is exhausted air outside of facility,
A. Type II-A1
B. Type II-A2
C. Type II-B1
D. Type II-B2
C. Type II-B1
Correct about satellite phenomenon:
1. S.aureus grows around the hemolytic colonies of H.influenzae.
2. H.influenzae grows around the hemolytic colonies of S. aureus
3. Also known as Nagler reaction
4. Uses SBA instead of Chocolate agar
A. 1and2
B. 2and3
C. 1and3
D. 2and4
D. 2and4
Growth requirement of H.influenzae:
1) X factor
2) V factor
3) 5-10% CO2
4) Cysteine
A. 1 only
B. 2 only
C.1,2,3
D. 1, 2, 3, 4
C.1,2,3
Limulus Lysate test detects __________ in body fluids.
A. Endotoxin of gram-negative bacteria
B. Exotoxin of gram-negative bacteria
C. Endotoxin of gram-positive bacteria
D. Exotoxin of gram-positive bacteria
A. Endotoxin of gram-negative bacteria
Which serological test is done for Chlamydia trachomatis on genital smears?
A. ELISA
B. RIA
C. Direct FA using monoclonal antibodies
D. Indirect FA using Chlamydia Antigens
C. Direct FA using monoclonal antibodies
Catalase, oxidase, and coagulase reagents must be tested:
A. Once a week and when the vial is first opened
B. Once each day of use and when the vial is first opened
C. Once a month, running positive control only
D. Once a year, running negative control only
B. Once each day of use and when the vial is first opened
Positive for PYRase hydrolysis:
1) S.pyogenes
2) S.agalactiae
3) S.pneumoniae
4) E.faecalis
A. 1and3
B. 1and4
C. 2and3
D. 2 and 4
B.1and4
All are examples of egg-based media for culture of Mycobacteria except:
A. Lowenstein Jensen
B. Petragnani
C. Middlebrook 7H10 and 7H11
D. none of the choices
C. Middlebrook 7H10 and 7H11
What is the positive result of CAMP test?
A. Satelliting colonies around streaked colonies of S.aureus
B. Arrowhead-shaped growth at the juncture of suspected organism and S.agalactiae colonies
C.Arrowhead-shaped zone of enhance hemolysis at the juncture of suspected organism & beta-lysin producing S.aureus
D. Inhibition of growth of suspected organism when is S.aureus is present
C.Arrowhead-shaped zone of enhance hemolysis at the juncture of suspected organism & beta-lysin producing S.aureus
Selective media for P. aeruginosa:
A. CCFA
B. CIN agar
C. Cetrimide agar
D. MAC with sorbitol
C. Cetrimide agar
Which group of tests best di erentiates Helicobacter pylori from C. jenuni?
A. Catalase, oxidase, and Gram stain
B. Catalase, oxidase, and nalidixic acid sensitivity
C. Catalase, oxidase, and cephalothin sensitivity
D. Urease, nitrate, and hippurate hydrolysis
D. Urease, nitrate, and hippurate hydrolysis
Which Haemophilus is di fficult to isolate and recover from genital ulcers & swollen lymph nodes?
A. H. aphrophilus
B. H. haemolyticus
C. H. ducreyi
D. H. parahaemolyticus
C. H. ducreyi
An enzyme produced by Streptococcus pyogenes that solubilizes the ground substance of mammalian connective tissues and helps to spread the infection.
A. DNase
B. Erythrogenic Toxin
C. Streptokinase
D. Hyaluronidase
D. Hyaluronidase
Infection caused by Legionella with febrile symptoms with no pulmonary involvement:
A. Legionnaire’s disease
B. Pontiac fever
C. Undulant fever
D. Relapsing fever
B. Pontiac fever
Bacteria that prefers O2 for growth but are able to grow also on anaerobic conditions are termed as:
A. microaerophilic
B. aerotolerant anaerobes
C. obligate aerobes
D. facultative anaerobes
D. facultative anaerobes
TSI agar is composed of 3 carbohydrates in a ratio such as:
A. 1% glucose, 1% lactose, 1% sucrose
B. 0.1% glucose, 1% lactose, 1% sucrose
C. 1% glucose, 1% lactose, 1% maltose
D. 1% glucose, 0.1% lactose, 1% maltose
B. 0.1% glucose, 1% lactose, 1% sucrose
The so-called red milk is the result of abundant multiplication of which chromogenic bacterium:
A. Serratia marcescens
B. Proteus vulgaris
C. Pseudomonas syncyanea
D. Aerobacter aerogenes
A. Serratia marcescens
Catalase test should not be performed on:
A. blood agar, because blood has catalase
B. Nutrient agar, because it is not enriched
C. tryptic soy agar, because the protein interferes
D. glass slides, because agar is required
A. blood agar, because blood has catalase
Resulting color of Auramine-Rhodamine stain for M. tuberculosis: A. green fluorescence in dark background
B. yellow-orange fluorescence in dark background
C. red fluorescence in blue background
D. no fluorescence
B. yellow-orange fluorescence in dark background
Cycloserine-cefoxitin-fructose agar (CCFA) is used for the recovery of:
A. Yersinia enterocolitica
B. Yersinia intermedia
C. Clostridium perfringens
D. Clostridium di fficile
D. Clostridium di fficile
Which of the following amino acids are required for growth of Francisella tularensis?
A. Leucine and ornithine
B. Arginine and lysine
C. Cysteine and cystine
D. Histidine and tryptophan
C. Cysteine and cystine
Edwardsiella tarda biochemically may be confused with Salmonella in that it is:
A. Lactose positive
B. Hydrogen sulfide positive
C. Urea positive
D. Non-motileEdwardsiella
B. Hydrogen sulfide positive
What are the resulting changes in Simmons citrate agar if the organism can utilize sodium acetate as its only carbon source? (Positive reaction)
A. Growth on medium, change of color from green to blue
B. Growth on medium, change of color from blue to green
C. No growth on medium, retaining the original color green of medium
D. No growth on medium, retaining the original color blue of medium
A. Growth on medium, change of color from green to blue
Coagulase test uses what primary reagent for testing?
A. Para-dimethylaminobenzaldehyde
B. 3% H2O2
C Sheep RBCs
D. Rabbit plasma
D. Rabbit plasma
The Moeller test for the detection of decarboxylase activity is dependent upon:
A. An alkaline pH shift in the medium
B. The oxidation of gluconate
C. An acid pH basal medium
D. A deamination of tryptophan
A. An alkaline pH shift in the medium
Urea hydrolysis test is performed on what medium?
A. Simmons medium
B. Christensen medium
C. Moellers medium
D. Krigler’s iron agar
B. Christensen medium
Which is the best rapid, noncultural test to perform when Gardnerella vaginalis is suspected?
A. 3% H2O2
B. 10% KOH
C. 30% KOH
D. 10% H2O2
B. 10% KOH
Specimens that may be cultured anaerobically:
1. Sputum
2. Needle aspirate
3. Swabs of infected wounds
4. Suprapubic-aspiration urine
A.1,2,3,and4
B.1and3
C.2and4
D. 2 and 3
C.2and4
Needle aspirate
Suprapubic-aspiration urine
The recommended medium for the recovery of Chlamydia from clinical specimen is:
A. McCoy cells
B. A549 cells
C. Charcoal yeast extract medium
D. WI-38 cells
A. McCoy cells
When clinical specimens are being processed for the recovery of Mycobacterium tuberculosis, the generally recommended method for digestion and decontamination of the sample is:
A. 6% NaOH
B. 1% HCl
C. NALC-NaOH
D. TSP
C. NALC-NaOH
NALC = digestion
NAOH = decontam
Abiotrophia formerly known as nutritionally variant streptococci (NVS) will not grow on routine blood or chocolate agars because they are deficient in:
A. Vitamin B12
B. Pyridoxal/ Vitamin B6
C. Hemin
D. Thiophene-2-carboxyclic hydrazide
B. Pyridoxal/ Vitamin B6
Exfoliatin produced by Staphylococcus aureus is responsible for causing:
A. Toxic shock syndrome
B. Enterocolitis
C. Staphylococcal pneumonia
D. Scalded skin syndrome/ Ritter’s dse.
D. Scalded skin syndrome/ Ritter’s dse.
If the specimen is not transported within 30 mins, it should be placed in which of the following media?
1. Amie’s
2. Stuart’s
3. Kelly’s Medium
4. Fletcher’s semi-solid medium
A. 1 and 2
B. 1 and 3
C. 2 and 3
D. 3 and 4
A. 1 and 2
- Amie’s
- Stuart’s
LIA reaction: red slant / acid butt,
no H2S
A. Escherichia coli
B. Klebsiella pneumoniae
C. Proteus vulgaris
D. Morganella morganii
D. Morganella morganii
What atmospheric condition is needed to recover Campylobacter spp. At 35-37C and 42C?
A. 10% O2, 10% CO2, and 80% N2
B. 5% O2, 10% CO2, and 85% N2
C. 20% O2, 20% CO2, and 60% N2
D. 15% O2, 5% CO2, and 80% N2
B. 5% O2, 10% CO2, and 85% N2
Which test will di fferentiate Pseudomonas spp. from Enterobacteriaceae?
A. Catalase Test
B. Indole Test
C. Urease Test
D. Oxidase Test
D. Oxidase Test
A urine specimen from a maternity patient with the complaint Of cystitis was received in the laboratory. The culture of this sample grew a lactose-positive (lactose fermenter). gram-negative bacillus that was presumptively identified as Escherichia coli. On di erential and selective medium,, this organism would demonstrate which reaction?
A. MacConkey agar - colorless colonies
B. Hektoen enteric agar - blue to green colonies
C. Xylose lysine deoxycholate agar - yellow colonies
D. All of the above are possible reactions
C. Xylose lysine deoxycholate agar - yellow colonies
Which of the following is not a correct statement regarding blood cultures:
A. Collection of 20 mL per culture for adults is recommended
B. 2 or 3 blood cultures recommended as optimum
C. Volume of blood cultures could be more critical than timing of of culture
D. Blood drawn for culture may be allowed to clot
D. Blood drawn for culture may be allowed to clot
Culture media that contains antibiotic vancomycin will inhibit growth of:
A. Gram-positive bacteria
B. Gram-negative bacteria
C. Yeast and molds
D. Normal flora
A. Gram-positive bacteria
An example of a selective enrichment broth would be:
A. Thioglycollate Broth
B. Trypticase Soy Broth
C. Brain Heart Infusion Broth
D. Selenite broth
D. Selenite broth
All of the following contain resident (normal) flora EXCEPT:
A. Oral cavity
B. Skin
C. Colon
D. Cerebrospinal fluid
D. Cerebrospinal fluid
An optimal wound specimen for culture of anaerobic organisms should be:
A. A swab of lesion obtained before administration of antibiotics
B. A swab of lesion obtained after administration of
C. A syringe filled with pus obtained before administration of antibiotics
D. A syringe filled with pus obtained after administration of antibiotics
C. A syringe filled with pus obtained before administration of antibiotics
Colistin-Nalidixic agar is used for selective isolation of:
A. Gram-positive bacteria
B. Gram-negative bacteria
C. Aerobic bacteria
D. Anaerobic bacteria
A. Gram-positive bacteria
Bacteria where growth occurs evenly on thioglycollate broth:
A. Aerobes
B. Anaerobes
C. Microaerophiles
D. Aerotolerant anaerobes
D. Aerotolerant anaerobes
Purpose of adding sodium polyanethol sulfonate (SPS) to nutrient broth media for Blood Culture:
A. Enhances growth of anaerobes
B. Functions as as a preservative
C. Inhibits phagocytosis and complement
D. Promotes formation of a blood
C. Inhibits phagocytosis and complement
Slime production is associated with which Staphylococcus species?
A. S. aureus
B. S. epidermidis
C. S. saprophyticus
D. S. intermedius
B. S. epidermidis
Metachromatic/Volutin granules are inclusions of what species of bacteria? A. Mycobacterium tuberculosis
B. Yersinia pestis
C. Listeria monocytogenes
D. Corynebacterium diphtheriae
D. Corynebacterium diphtheriae
This is also known as the capsular swelling test:
A. India ink test
B. Limulus Lysate test
C. Modified ELEK test
D. Neufeld (Quellung) reaction
D. Neufeld (Quellung) reaction
These are hair-like extensions of the cell used for adherence/ attachment of bacteria to host cell.
A. Flagella
B. Capsule
C. Slime Layer
D. Fimbriae/ Pili
D. Fimbriae/ Pili
All are correct matches for types of flagella except:
A. Monotrichous - flagellum on one pole
B. Lophotrichous - single flagellum at both poles
C. Peritrichous - flagella all over the organism
D. None of the above
B. Lophotrichous - single flagellum at both poles
Mordant used in Kinyoun method of acid-fast staining:
A. Steam
B. Thiosulfate
C. Thermal heat
D. Tergitol
D. Tergitol
Which of the following techniques is performed first before doing smears for gram stain on CSF?
A. Incubate at 37 C for one hour
B. Refrigerate CSF for 12-24 hours and observe for pellicle formation
C. Centrifuge CSF specimen to concentrate cells and microorganisms if present
D. Evaluate using Barlett’s classification
C. Centrifuge CSF specimen to concentrate cells and microorganisms if present
This staining method is specifically designed for bacteria whose cell walls contain long chain fatty acids (Mycolic acid)
A. Gram stain
B. India ink
C. Leifson stain
D. Acid-fast stain
D. Acid-fast stain
Culture media that contains antibiotic vancomycin will inhibit growth of:
A. Gram-positive bacteria
B. Gram-negative bacteria
C. Yeast and molds
D. Normal flora
A. Gram-positive bacteria
Indicator used in MSA used for selective isolation of staphylococcus spp.
A. Neutral red
B. Bromthymol blue
C. Phenol red
D. Bromcresol green
C. Phenol red
Motility medium such as SIM is classified as:
A. Liquid type medium
B. Semi-solid medium
C. Solid-liquefiable medium
D. Solid-non liquefiable medium
B. Semi-solid medium
Reagent used in oxidase test of bacteria:
A. 1% dimethylaminocinnamaldehyde
B. 1% tetramethyl-p-phenylenediamine dihydrochloride
C. L-pyropollidonyl-b-naphthylamide
D. Hydrogen peroxide
B. 1% tetramethyl-p-phenylenediamine dihydrochloride
Negative reaction in Decarboxylase tests (Moeller’s Method) is indicated by which color?
A. Purple
B. Yellow
C. Magenta
D. Blue
B. Yellow
Positive result in Acetamide Utilization test
A. Purple
B. Yellow
C. Magenta
D. Blue
D. Blue
Positive result in Bacitracin Susceptibility test (0.04 units) is a zone of inhibition greater than ___ mm
A. 5
B. 10
C. 15
D. 20
B. 10
Which of the following Streptococcal species has the enzyme hippuricase? A. S. pyogenes
B. S. pneumoniae
C. S. agalactiae
D. S. bovis
C. S. agalactiae
Which of the following Streptococcal species has the enzyme hippuricase? A. S. pyogenes
B. S. pneumoniae
C. S. agalactiae
D. S. bovis
C. S. agalactiae
