8.5 Gram Pos and Gram Neg Cocci Flashcards
Toxic shock syndrome is attributed to infection with:
A. Staphylocoocus epidermidis
B. Staphylococcus hominis
C. Staphylococcus aureus
D. Staphylococcus saprophyticus
C. Staphylococcus aureus
Which Staphylococcus species, in addition to S. aureus, also produces coagulase?
A. S. intermedius
B. S. saprophyticus
C. S. hominis
D. All of these options
A. S. intermedius
Staphylococcus epidermidis (coagulase negative) is recovered form which of the following sources?
A. Prosthetic heart valves
B. Intravenous catheters
C. Urinary tract
D. All of these options
D. All of these options
Slime production is associated with which Staphylococcus species?
A. S. aureus
B. S. epidermidis
C. S. intermedius
D. S. saprophyticus
B. S. epidermidis
Strains of Staphylococcus species resistant to the B-lactam antibiotics by standardized disk diffusion and broth microdilution susceptibility methods are called:
A. Heteroresistant
B. Bacteriophage group 52S
C. Cross resistant
D. Plasmid altered
A. Heteroresistant
Staphylococcus saprophyticus is best differentiated form Staphylococcus epidermidis by resistance to:
A. 5 ug of lysostaphin
B. 5 ug of novobiocin
C. 10 units of penicillin
D. 0.04 unit bacitracin
B. 5 ug of novobiocin
The following results were observed by using a tube coagulase test:
-Coagulase at 4 hours=+
-DNase=+
-Hemolysis on blood agar=B
-Coagulase at 18 hours=Neg
-Novobiocin=Sensitive (16-mm zone)
-Mannitol salt plate=+ (acid production)
What is the most probable identification?
A. Staphylococcus saprophyticus
B. Staphylococcus epidermidis
C. Staphylococcus aureus
D. Staphylococcus hominis
C. Staphylococcus aureus
Staphylococcus aureus recovered from a wound culture gave teh following antibiotic sensitivity pattern by the standardized Kirby-Bauer method (S=sensitive; R=resistant):
-Pencillin=R
-Cephalothin=R
-Vancomycin=S
-Ampicillin=R
-Cefoxitin=R
-Methicillin=R
Which is the drug of choice for treating this infection?
A. Penicillin
B. Ampicillin
C. Cephalothin
D. Vancomycin
D. Vancomycin
Which of the following test should be used to differentiate Staphylococcus aureus form Staphylococcus intermedius?
A. Acetoin
B. Catalase
C. Slide coagulase test
D. Urease
A. Acetoin
A gram-positive coccus recovered form a wound ulcer form a 31-year-old diabetic patient showed pale yellow, creamy, B-hemolytic colonies on blood agar. Given the following test results, what is the most likely identification?
-Catalase=+
-Glucose OF: positive open tube, negative sealed tube
-Mannitol salt=Neg
-Slide coagulase=Neg
A. Staphylococcus aureus
B. Staphylococcus epidermidis
C. Micrococcus spp.
D. Streptococcus spp.
C. Micrococcus spp.
Urine cultured from the catheter of an 18-year-old female patient produced more than 100,00 col/mL on a CNA plate. Colonies were catalase positive, coagulase negative by the late agglutination slide method as well as the tube coagulase test. The best single test for identification is:
A. Lactose fermentation
B. Urease
C. Catalase
D. Novobiocin susceptibility
D. Novobiocin susceptibility
A staphylococcus spp. recovered from a wound (cellulitis) was negative for the slide coagulase test (clumping factor) and negative for novobiocin resistance. The next test(s) needed for identification is (are):
A. Tube coagulase test
B. B-Hemolysis on blood agar
C. Mannitol salt agar plate
D. All of these options
D. All of these options
Furazolidone (Furoxone) susceptibility is a test used to differentiate:
A. Staphyloccus spp. from Micrococcus spp.
B. Streptococcus spp. from Staphylococcus spp.
C. Staphylococcus spp. from Pseudomonas spp.
D. Streptococcus spp. from Micrococcus spp.
A. Staphyloccus spp. from Micrococcus spp.
Bacitracin resistance (0.04 unit) is used to differentiate:
A. Micrococcus spp. from Staphylococcus spp.
B. Staphylococcus spp. for Neisseria spp.
C. Planococcus spp. from Micrococcus spp.
D. Staphylococcus spp. from Streptococcus spp.
A. Micrococcus spp. from Staphylococcus spp.
Which of the following tests will rapidly differentiate micrococci form staphylococci?
A. Catalase
B. Coagulase
C. Modified oxidase
D. Novobiocin susceptibility
C. Modified oxidase
Streptococcus species exhibit which of the following properties?
A. Aerobic, oxidase positive, and catalase positive
B. Facultative anaerobe, oxidase negative, catalase negative
C. Facultative anaerobe, B-hemolytic, catalase positive
D. May be a-, B-, or y-hemolytic, catalase positive
B. Facultative anaerobe, oxidase negative, catalase negative
Which group of streptococci is associated with erythrogenic toxin production?
A. Group A
B. Group B
C. Group C
D. Group G
A. Group A
A fourfold rise in titer of which antibody is the best indicator of a recent infection with group A B-hemolytic streptococci?
A. Anti-streptolysin O
B. Anti-streptolysin S
C. Anti-A
D. Anti-B
A. Anti-streptolysin O
Bacitracin A disk (0.04 unit) are used for the presumptive identification of which group of B-hemolytic streptococci?
A. Group A
B. Group B
C. Group C
D. Group F
A. Group A
Trimethoprim-sulfamethoxazole (SXT) disks are used along with bacitracin disks to differentiate which streptococci?
A. a-Hemolytic streptococci
B. B-Hemolytic streptococci
C. Streptococcus pneumoniae
D. Enterococcus faecalis
B. B-Hemolytic streptococci
B-Hemolytic streptococci, not of group A or B, usually exhibit which of the following reactions?
Bacitracin: Trimethoprim-sulfamethoxazole
A. Susceptible; Resistant
B. Resistant; Resistant
C. Resistant, Susceptible
D. Susceptible or resistant; Susceptible
D. Susceptible or resistant; Susceptible
A false-positive CAMP test for the presumptive identification of group B streptococci may occur if the plate is incubated in a(n):
A. Candle jar or CO2 incubator
B. Ambient air incubator
C. 35C incubator
D. 37C incubator
A. Candle jar or CO2 incubator
Which test is used to differentiate the viridans streptococci form the group D streptococci and enterococci?
A. Bacitracin disk test
B. CAMP test
C. Hippurate hydrolysis test
D. Bile esculin test
D. Bile esculin test
The bile solubility test causes the lysis of:
A. Streptococcus bovis colonies on a blood agar plat
B. Streptococcus pneumoniae colonies on a blood agar plate
C. Group A streptococci in broth culture
D. Group B streptococci in broth culture
B. Streptococcus pneumoniae colonies on a blood agar plate
S. pneumoniae and the viridans streptococci can be differentiated by which test?
A. Optochin disk test, 5 ug/mL or less
B. Bacitracin disk test, 0.04 unit
C. CAMP test
D. Bile esculin test
A. Optochin disk test, 5 ug/mL or less
The salt tolerance test (6.5% salt broth) is used to presumptively identify:
A. Streptococcus pneumoniae
B. Streptococcus bovis
C. Streptococcus equinus
D. Enterococcus faecalis
D. Enterococcus faecalis
In addition to Enterococcus faecalis, which other streptococci will grow in 6.5% slat broth?
A. Group A streptococci
B. Group B streptococci
C. Streptococcus pneumoniae
D. Group D streptococci (nonenterococci)
B. Group B streptococci
The quellung test is used to identify which Streptococcus species?
A. S. pyogenes
B. S. agalactiae
C. S. sanguis
D. S. pneumoniae
D. S. pneumoniae
The L-pyrrolidonyl-B-napthylamide (PYR) hydrolysis test is a presumptive test for which streptococci?
A. Group A and D (enterococcus) streptococci
B. Group A and B B-hemolytic streptococci
C. Nongroup A or B B-hemolytic streptococci
D. Streptococcus penumoniae and group D streptococci (nonenterococcus)
A. Group A and D (enterococcus) streptococci
A pure culture of B-hemolytic streptococci recovered from a leg wound ulcer gave the following reactions:
-CAMP test=Neg
-Bile esculin=Neg
-PYR=Neg
-Optochin= Resistant
-Hippurate hydrolysis=Neg
-6.5% salt=Neg
-Bacitracin=Resistant
-SXT=Sensitive
The most likely identification is:
A. Group A streptococci
B. Group B streptococci
C. Enterococcus faecalis
D. Nongroup A, nongroup B, nongroup D streptococci
D. Nongroup A, nongroup B, nongroup D streptococci
B-hemolytic streptococci, more than 50,000 col/mL, were isolated from a urinary tract catheter urine specimen. Given the following reactions, what is the most likely identification?
-CAMP test=Neg
-Bile solubility=Neg
-PYR=+
-SXT=Resistant
-Optochin=Resistant
-Hippurate hydrolysis=+/-
-6.5% salt=+
-Bile esculin=+
-Bacitracin= Resistant
A. Group A streptococci
B. Group B streptococci
C. Enterococcus faecalis
D. Nongroup A, nongroup B, nongroup D streptococci
C. Enterococcus faecalis
Nutritionally variant streptococci (NVS) require specific thiol compounds, cysteine, or the active form of vitamin B6. Which of the following test supplies these requirements?
A. CAMP test
B. Bacitracin susceptibility test
C. Bile solubility test
D. Staphylococcal cross-streak test
D. Staphylococcal cross-streak test
Many a-hemolytic streptococci recovered form a wound were found to be penicillin resistant. Given the following results, what is the most likely identification?
-Bile esculin=+
-Hippurate hydrolysis=+
-SXT=Resistant
-PYR=+
-Bile solubility=Neg
-6.5% salt=+
A. Enterococcus faecalis
B. Streptococcus pneumoniae
C. Streptococcus bovis
D. Group B streptococci
A. Enterococcus faecalis
Which two tests best differentiate S. bovis (group D, nonenterococcus) from Streptococcus salivarius?
A. Bile esculin and 6.5% salt broth
B. Starch hydrolysis and acid production form mannitol
C. Bacitracin and PYR
D. Trimethoprim-sulfamethoxazole susceptibility and PYR
B. Starch hydrolysis and acid production form mannitol
Two blood cultures on a newborn grew B-hemolytic streptococci with the following reactions:
-CAMP test=+
-Bile solubility=Neg
-Bacitracin=Resistant
-PYR=Neg
-Trimethoprim-sulfamethoxazole: Resistant
-Hippurate hydrolysis=+
-6.5% salt=+
-Bile esculin=Neg
Which is the most likely identification?
A. Group A streptococci
B. Group B streptococci
C. Group D streptococci
D. Nongroup A, nongroup B, nongroup D streptococci
B. Group B streptococci
MTM medium is used primarily for the selective recovery of which organism form genital specimens?
A. Neisseria gonorrhoeae
B. Neisseria lactamica
C. Neisseria sicca
D. Neisseria flavescens
A. Neisseria gonorrhoeae
Variation in colony types seen with fresh isolates of Neisseria gonorrhoeae and sometimes with Neisseria meningitidis are the result of:
A. Multiple nutritional requirements
B. Pili on the cell surface
C. Use of a transparent medium
D. All of these options
D. All of these options
Gram-negative diplococci recovered form an MTM plate and giving a positive oxidase test can be presumptively identified as:
A. Neisseria gonorrhoeae
B. Neisseria meningitidis
C. Neisseria lactamica
D. All of these options
D. All of these options
The Superoxol test is used as a rapid presumptive test for:
A. Neisseria gonorrhoeae
B. Neisseria meningitidis
C. Neisseria lactamica
D. Moraxella (Branhamella) catarrhalis
A. Neisseria gonorrhoeae
Nonpathogenic Moraxella spp. capable of growing on selective media for Neisseria can be differentiated from Neisseria spp. by which test?
A. Catalase test
B. 10-unit penicillin disk
C. Oxidase test
D. Superoxol test
B. 10-unit penicillin disk
A Gram stain of a urethral discharge form a man showing extracellular and intracellular gram-negative diplococci within segmented neutrophils is a presumptive identification for:
A. Neisseria gonorrhoeae
B. Neisseria meningitidis
C. Moraxella (Branhamella) catarrhalis
D. Neisseria lactamica
A. Neisseria gonorrhoeae
The B-galactosidase test aids in the identification of which Neisseria species?
A. N. lactamica
B. N. meningitidis
C. N. gonorrhoeae
D. N. flavescens
A. N. lactamica
Cystine tryptic digest (CTA) media used for identification of Neisseria spp. should be inoculated and cultured in:
A. A CO2 incubator at 35C for 24 hours
B. A CO2 incubator at 42C for up to 72 hours
C. A nonCO2 incubator at 35C for up to 72 hours
D. An anaerobic incubator at 35C for up to 72 hours
C. A nonCO2 incubator at 35C for up to 72 hours
Culture on MTM media of a vaginal swab produced several colonies of gram-negative diplococci that were catalase and oxidase positive and Superoxol negative. Given the following carbohydrate reactions, select the most likely identification.
-Glucose=+
-Maltose=+
-Sucrose=Neg
-Fructose=Neg
-Lactose=+
A. Neisseria gonorrhoeae
B. Neisseria sicca
C. Neisseria flavescens
D. Neisseria lactamica
D. Neisseria lactamica
Sputum from a patient with pneumonia produced many colonies of gram-negative diplococci on a chocolate plate that were also present in fewer numbers on MTM after 48 hours. Given the following results, what is the most likely identification?
-Catalase=+
-DNase=+
-Glucose=Neg
-Lactose=Neg
-Fructose=Neg
-Oxidase=+
-Tributyrin hydrolysis=+
-Sucrose=Neg
-Maltose=Neg
A. Moraxella catarrhalis
B. Neisseria flavescens
C. Neisseria sicca
D. Neisseria elongata
A. Moraxella catarrhalis
Resistance to which drug categorizes a strain of Staphylococcus aureus as methicillin-resistant Staphylococcus aureus (MRSA)?
A. Oxacillin
B. Colistin
C. Trimethoprim-sulfamethoxazole
D. Tetracycline
A. Oxacillin
An oxacillin-disk screen test is used to detect Streptococcus pneumonia resistance to penicillin. Using Mueller-Hinton agar with 5% sheep blood and aa 1 ug oxacillin disk, what is the recommended inhibition zone size for penicillin susceptibility?
A.>/= 5mm
B. >/= 10mm
C.>/= 15mm
D.>/= 20mm
D.>/= 20mm
Which one of the following organisms is a known producer of B-lactamase-producing strains, and should be tested (screened) by a commercial B-lactamase assay prior to susceptibility testing?
A. Streptococcus pneumoniae
B. Group B streptococci
C. Enterococcus spp.
D. Planococcus spp.
C. Enterococcus spp.
Which test is used for the determination of inducible clindamycin resistance in staphylococci and streptococci?
A. E-test
B. D-zone test
C. A-test
D. Camp test
B. D-zone test
Large gram-positive spore-forming rods growing on blood agar as large, raised, B-hemolytic colonies that spread and appear as frosted green-gray glass are most likely
A. Pseudomonas spp.
B. Bacillus spp.
C. Corynebacterium spp.
D. Listeria spp.
B. Bacillus spp.
Bacillus anthracis and Bacillus cereus can best be differentiate by which test?
B-hemo; motility; oxidase; catalase; lecithinase; glucose
B.cereus: +; +; Neg: +; +; +
B.anthracis: Neg; Neg; Neg: +; +; +
A. Motility and B-hemolysis on a blood agar plate
B. Oxidase and B-hemolysis on a blood agar plate
C. Lecithinase and glucose
D. Lecithinase and catalase
A. Motility and B-hemolysis on a blood agar plate
