Micro Exam #2
Which selective medium is used for the isolation of Gram-positive microorganisms? Columbia CNA with 5% sheep blood trypticase soy agar with 5% sheep blood eosin methylene blue modified Thayer-Martin
Columbia CNA with 5% sheep blood
Streptococcus species exhibit which of the following properties? Aerobic, oxidase positive, and catalase positive Facultative anaerobe, oxidase negative, catalase negative Facultative anaerobe, β-hemolytic, catalase positive May be α-, β-, or γ-hemolytic, catalase positive
Facultative anaerobe, oxidase negative, catalase negative
Micrococcus and Staphylococcus species are differentiated by which test(s)? Fermentation of glucose (OF tube) Catalase test Gram stain All of these option
Fermentation of glucose (OF tube)
The β-galactosidase test (ONPG) aids in the identification of which Neisseria species? N. lactamica N. meningitidis N. gonorrhoeae N. flavescens
N. lactamica
Which nonculture method is best for the diagnosis of Neisseria gonorrhoeae in an adult female? Clinical history Gram stain of cervical secretions MALDI-TOF MS NAAT
NAAT
Which of the following products is responsible for satellite growth of Haemophilus spp. around colonies of Staphylococcus and Neisseria spp. on sheep blood agar? NAD Hemin Indole Oxidase
NAD
A Gram stain of a urethral discharge from a man showing extracellular and intracellular gram-negative diplococci within segmented neutrophils is a presumptive identification for: Neisseria gonorrhoeae Neisseria meningitidis Moraxella (Branhamella) catarrhalis Neisseria lactamica
Neisseria gonorrhoeae
Clinical resistance to penicillin correlates most frequently with beta-lactamase production in: Chlamydia trachomatis Neisseria gonorrhoeae Neisseria meningitidis Treponema pallidum
Neisseria gonorrhoeae
Erythromycin eye drops are routinely administrated to infant to prevent infections by E. Coli Haemophilus influenzae Pseudomonas aeruginosa Neisseria gonorrhoeae
Neisseria gonorrhoeae
MTM medium is used primarily for the selective recovery of which organism from genital specimens? Neisseria gonorrhoeae Neisseria meningitidis Neisseria sicca Neisseria flavescens
Neisseria gonorrhoeae
The Superoxol test is used as a rapid presumptive test for: Neisseria gonorrhoeae Neisseria meningitidis Neisseria lactamica Moraxella (Branhamella) catarrhalis
Neisseria gonorrhoeae
All species of the genus Neisseria have the enzyme to oxidize: Naphthylamine Dimethylaminobenzaldehyde Glucopyranoside Tetramethyl-phenylenediamine
Tetramethyl-phenylenediamine
A method for the definitive identification of Neisseria gonorrhoeae is: Degradation of amino acids EIA Utilization of carbohydrates Resistance to penicillins and cephalosporins
Utilization of carbohydrates
Which of the following is a characteristic of strains of Haemophilus influenzae that are resistant to ampicillin? beta lactamase Hydrolysis of chloramphenicol Hydrolysis of urea All of these options
beta lactamase
Streptococcus pneumoniae can be differentiated best from the viridans group of streptococci by: Gram stain the type of hemolysis colonial morphology bile solubility
bile solubility
Viridans streptococci can be differentiated from Streptococcus pneumoniae by: alpha hemolysis colony morphology Catalase reaction result bile solubility
bile solubility
A nonhemolytic streptococcus that has been isolated from an ear culture grows up to the edge of a 0.04 unit bacitracin disk. Which of the following tests would help to determine if the organism is Enterococcus? hydrolysis of PYR growth in the presence of penicillin optochin susceptibility fermentation of mannitol
hydrolysis of PYR
Which of the following would best differentiate Streptococcus agalactiae from Streptococcus pyogenes? ability to grow in sodium azide broth positive bile-esculin reaction hydrolysis of sodium hippurate beta-hemolysis on sheep blood agar
hydrolysis of sodium hippurate
"Nutritionally variant" streptococci are: enterococci group D enterococci beta hemolytic streptococci in the genera Granulicatella and Abiotrophia
in the genera Granulicatella and Abiotrophia
A beta-hemolytic Gram-positive coccus was isolated from the cerebrospinal fluid of a 2-day-old infant with signs of meningitis. The isolate grew on sheep blood agar under aerobic conditions and was resistant to a bacitracin disc. Which of the following should be performed for the identification of the organism? oxidase production catalase formation latex antigen grouping esculin hydrolysis
latex antigen grouping
Which of the following tests is used routinely to identify Staphylococcus aureus? Slide coagulase test Tube coagulase test Latex agglutination All of these options
All of these options
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): Tube coagulase test β-Hemolysis on blood agar Mannitol salt agar plate All of these options
All of these options
Gram-negative diplococci recovered from an MTM plate and giving a positive oxidase test can be presumptively identified as: Neisseria gonorrhoeae Neisseria meningitidis Neisseria lactamica All of these options
All of these options
Staphylococcus epidermidis (coagulase negative) is recovered from which of the following sources? Prosthetic heart valves Intravenous catheters Urinary tract All of these options
All of these options
Staphylococcus saprophyticus is best differentiated from Staphylococcus epidermidis by resistance to: 5 μg of lysostaphin 5 μg of novobiocin 10 units of penicillin 0.04 unit of bacitracin
5 μg of novobiocin
Variation in colony types seen with fresh isolates of Neisseria gonorrhoeae and sometimes with Neisseria meningitidis are the result of: Multiple nutritional requirements Pili on the cell surface Use of a transparent medium All of these options
All of these options
A fourfold rise in titer of which antibody is the best indicator of a recent infection with group A β-hemolytic streptococci? Anti-streptolysin O Anti-streptolysin S Anti-A Anti-B
Anti-streptolysin O
An important characteristic of Neisseria gonorrhoeae or the infection it produces is A Gram stain of the organism reveals gram-negative bacilli. Asymptomatic infections are common in females. Produces disease in humans and domestic animals. The bacteria survive long periods outside the host's body.
Asymptomatic infections are common in females.
Group B, beta-hemolytic streptococci may be distinguished from other hemolytic streptococci by which of the following procedures? latex antigen grouping growth in 6.5% NaCI broth growth on bile esculin medium bacitracin susceptibility
latex antigen grouping
Bacitracin A disks (0.04 unit) are used for the presumptive identification of which group of β-hemolytic streptococci? Group A Group B Group C Group F
Group A
Which group of streptococci is associated with erythrogenic toxin production? Group A Group B Group c Group G
Group A
Strains of Staphylococcus species resistant to the β-lactam antibiotics by standardized disk diffusion and broth microdilution susceptibility methods are called: Heteroresistant Bacteriophage group 52A Cross resistant Plasmid altered
Heteroresistant
A suspension of the test organism for use in broth dilution and disk diffusion testing is adjusted to match the turbidity of a #0.5 McFarland Standard #1.0 McFarland Standard #2.0 McFarland Standard #3.0 McFarland Standard
#0.5 McFarland Standard
Characteristically, enterococci are: unable to grow in 6.5% NaCI relatively resistant to penicillin sodium hippurate positive bile esculin negativ
relatively resistant to penicillin
Nonpathogenic Moraxella spp. capable of growing on selective media for Neisseria can be differentiated from Neisseria spp. by which test? Catalase test 10-unit penicillin disk Oxidase test Superoxol test
10-unit penicillin disk
The colony count from a suprapubic urine culture growing 10 colonies of Staphylococcus saprophyticus (used 10ul loop) is: 0 CFU/mL 100 CFU/mL 1,000 CFU/mL 100,000 CFU/mL
100,000 CFU/mL
Cystine tryptic digest (CTA) media used for identification of Neisseria spp. should be inoculated and cultured in: A CO2 incubator at 35°C for 24 hours A CO2 incubator at 42°C for up to 72 hours A nonCO2 incubator at 35°C for up to 72 hours An anaerobic incubator at 35°C for up to 72 hours
A nonCO2 incubator at 35°C for up to 72 hours
The Gram stain from a blood culture shows Gram-positive cocci in chains. The subcultured plates from the blood culture bottle show no growth Additional testing should be done to detect the presence of: Staphylococcus saprophyticus Aerococcus urinae Abiotrophia defectiva Streptococcus pneumoniae
Abiotrophia defectiva
β-Hemolytic streptococci, not of group A or B, usually exhibit which of the following reactions? Bacitracin --> Susceptible | Trimethoprim-sulfamethoxazole --> Resistant Bacitracin --> Resistant | Trimethoprim-sulfamethoxazole --> Resistant Bacitracin --> Resistant | Trimethoprim-sulfamethoxazole --> Susceptible Bacitracin --> Susceptible or Resistant | Trimethoprim-sulfamethoxazole --> Susceptible
Bacitracin --> Susceptible or Resistant | Trimethoprim-sulfamethoxazole --> Susceptible
Which test is used to differentiate the viridans streptococci from the group D streptococci and enterococci? Bacitracin disk test CAMP test Hippurate hydrolysis test Bile esculin test
Bile esculin test
An organism previously thought to be nonpathogenic, Moraxella catarrhalis, is now known to be associated with opportunistic respiratory infection and nosocomial transmission. Characteristic identification criteria include: Beta-lactamase negative Butyrate esterase positive Gram-negative bacilli Oxidase negative
Butyrate esterase positive
An isolate of an unknown beta-hemolytic Streptococcus is streaked perpendicular to a streak of beta-lysin-producing Staphylococcus aureus. After incubation a zone of arrowhead hemolysis is noted at the interface of the 2 streaks. What is the name of the test and the presumptive identification of the unknown Streptococcus? hippurate hydrolysis and S agalactiae CAMP test and S pyogenes hippurate hydrolysis and S pyogenes CAMP test and S agalactiae
CAMP test and S agalactiae
A false-positive CAMP test for the presumptive identification of group B streptococci may occur if the plate is incubated in a(n): Candle jar or CO2 incubator Ambient air incubator 35°C incubator 37°C incubator
Candle jar or CO2 incubator
The primary isolation of Neisseria gonorrhoeae requires: Anaerobic conditions Starch media Carbon dioxide Blood agar
Carbon dioxide
The test used most often to separate the Micrococcaceae family from the Streptococcaceae family is: Bacitracin Catalase Hemolysis pattern All of these options
Catalase
Haemophilus species that require the V factor (NAD) are easily recovered on which primary agar plate? Blood agar made with sheep red cells Blood agar made with horse red cells Chocolate agar Xylose agar
Chocolate agar
Colonies of Neisseria sp. turn color when a redox reagent is applied. The color change is indicative of the activity of the bacterial enzyme Beta-galactosidase Urease Cytochrome oxidase Phenylalanine
Cytochrome oxidase
Which test is used for the determination of inducible clindamycin resistance in staphylococci and streptococci? E-test D-zone test A-test Camp test
D-zone test
Streptococcus pneumoniae
Examine the gram stain illustration. The organism labeled "A" is most likely which of the following?
The use of molecular testing to identify the presence of Methicillin-Resistant Staphylococcus aureus (MRSA) is not always the best method because false-positive results can occur. However, the main purpose for performing molecular testing on surveillance cultures for MRSA is all of the following, EXCEPT? Shorter turnaround time High sensitivity Reduction of patient isolation days Does not require culture confirmation
Does not require culture confirmation
Gamma-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 Hippurate hydrolysis = ± Bile solubility = Neg 6.5% salt = + PYR = + Bile esculin = + SXT = Resistant Bacitracin = Resistant Optochin = Resistant Group A streptococci Group B streptococci Enterococcus faecalis Nongroup A, nongroup B, nongroup D streptococci
Enterococcus faecalis
Many gamma-hemolytic streptococci recovered from a wound were found to be penicillin resistant. Given the following results, what is the most likely identification? Bile esculin = + PYR = + 6.5% salt = + Hippurate Bile solubility= Neg hydrolysis = + SXT = Resistant Enterococcus faecalis rect answerStreptococcus pneumoniae Streptococcus bovis Group B streptococci
Enterococcus faecalis
The salt tolerance test (6.5% salt broth) is used to presumptively identify: Streptococcus pneumoniae Streptococcus bovis Streptococcus equinus Enterococcus faecalis
Enterococcus faecalis
Which of the following may be used as a positive quality control organism for the bile esculin test? Staphylococcus epidermidis Staphylococcus aureus Streptococcus pyogenes Enterococcus faecalis
Enterococcus faecalis
Which one of the following organisms is a known producer of β-lactamase-producing strains, and should be tested (screened) by a commercial β-lactamase assay prior to susceptibility testing? Streptococcus pneumoniae Group B streptococci Enterococcus spp. Planococcus spp.
Enterococcus spp.
Some species of Staphylococcus produce an enterotoxin. What does it cause? Food poisoning Septicemia UTI infections Skin infections
Food poisoning
A thick peptidoglycan cell wall is MOST often associated with which of the following? Gram-negative bacteria Gram-positive bacteria Both Gram-negative and Gram-positive bacteria Yeast
Gram-positive bacteria
In the bacitracin susceptibility test, if there is a zone of inhibition surrounding the disk following overnight incubation at 37°C, the colony most likely consists of: Staphylococcus aureus Group A Streptococcus Streptococcus pneumoniae Groun B streptococcus
Group A Streptococcus
The L-pyrrolidonyl-β-napthylamide (PYR) hydrolysis test is a presumptive test for which streptococci? Group A and D (enterococcus) streptococci Group A and B β-hemolytic streptococci Nongroup A or B β-hemolytic streptococci Streptococcus pneumoniae and group D streptococci (nonenterococcus)
Group A and D (enterococcus) streptococci
Two blood cultures on a newborn grew β-hemolytic streptococci with the following reactions: CAMP test = + Hippurate hydrolysis = + Bile solubility = Neg 6.5% salt = + Bacitracin = Resistant Bile esculin = Neg PYR = Neg Trimethoprim-sulfamethoxazole = Resistant Which is the most likely identification? Group A streptococci Group B streptococci Group D streptococci Nongroup A, nongroup B, nongroup D streptococci
Group B streptococci
Which Haemophilus species is generally associated with endocarditis? H. influenzae H. ducreyi H. parainfluenzae H. haemolyticus
H. parainfluenzae
A small, gram-negative coccobacillus recovered from the CSF of a 2-year-old child gave the following results: Indole = + Glucose = + (acid) X requirement = + V requirement = + Urease = + Lactose = Neg Sucrose = Neg Hemolysis = Neg Which is the most likely identification? Haemophilus parainfluenzae Haemophilus influenzae Haemophilus ducreyi Haemophilus aphrophilus
Haemophilus influenzae
Which of the following plates should be used in order to identify Haemophilus haemolyticus and Haemophilus parahaemolyticus? Sheep blood agar and chocolate agar Horse blood agar and Mueller-Hinton agar with X and V strips Brain-heart infusion agar with sheep red cells added Chocolate agar and Mueller-Hinton agar with X factor added
Horse blood agar and Mueller-Hinton agar with X and V strips
Which of the following enzymes contribute to the virulence of S. aureus? Urease and lecithinase Hyaluronidase and β-lactamase Lecithinase and catalase Cytochrome oxidase
Hyaluronidase and β-lactamase
Enterococcus faecalis
Illustrated in the photograph is a bile esculin agar plate inoculated with a bacterial isolate from a urinary tract infection. The most likely identification is:
Haemophilus influenzae causes ocular infections (pinkeye) and requires X and V factors in the primary medium for growth. The subspecies Haemophilus influenza (biogroup) aegyptius can further be identified and differentiated by which two tests? Indole and xylose Glucose and urease Oxidase and catalase ALA test and oxidase
Indole and xylose
A vaginal/rectal swab is collected from a pregnant patient to screen for group B Streptococcus colonization. The best medium to inoculate the specimen to is: CNA agar LIM broth sheep blood agar thioglycollate broth
LIM broth
Neisseria lactamica closely resembles Neisseria meningitidis but can be differentiated from it by its ability to metabolize Maltose Lactose Glucose Sucrose
Lactose
Which of the following media is both selective and differential? Sheep blood agar Chocolate agar Mannitol salt agar Mueller-Hinton agar
Mannitol salt agar
Lysostaphin is used to differentiate Staphylococcus from which other genus? Streptococcus Stomatococcus Micrococcus Planococcus
Micrococcus
A light yellow colony from a skin lesion grew aerobically and tested as catalase positive and coagulase negative. The organism Gram stained as positive cocci in clusters. The organism was modified oxidase positive, bacitracin (0.04U) susceptible and resistant to lysostaphin. What is the identification of this organism? Staphylococcus aureus Micrococcus luteus Staphylococcus epidermidis Peptostreptococcus anaerobius
Micrococcus luteus
A gram-positive coccus recovered from a wound ulcer from a 31-year-old diabetic patient showed pale yellow, creamy, non-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 Staphylococcus aureus Staphylococcus epidermidis Micrococcus spp Streptococcus spp
Micrococcus spp
Which of the following tests will rapidly differentiate micrococci from staphylococci? Catalase Coagulase Modified oxidase Novobiocin susceptibility
Modified oxidase
A Gram stain performed on a sinus aspirate revealed Gram-negative diplococci within PMNs. Oxidase testing is positive and carbohydrate degradation tests are inert. The organism most likely is: Hide answer choices Neisseria lactamica Moraxella catarrhalis Neiseeria meningitidis Treponema pallidum
Moraxella catarrhalis
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 = + Oxidase = + DNase = + Tributyrin hydrolysis (butyrate esterase) = + Glucose = Neg Sucrose = Neg Lactose = Neg Maltose = Neg Fructose = Neg Moraxella catarrhalis Neisseria flavescens Neisseria sicca Neisseria elongata
Moraxella catarrhalis
Which DNA+ organism's colony is not easily broken up and therefore displays the "hockey puck" characteristic where it can be pushed across the plate of medium? Moraxella catarrhalis Neisseria gonorrhoeae Neisseria meningitidis Vibrio cholera
Moraxella catarrhalis
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 = + Sucrose = Neg Lactose = + Maltose = + Fructose = Neg Neisseria gonorrhoeae Neisseria sicca Neisseria flavescens Neisseria lactamica
Neisseria lactamica
A gram-negative, "kidney bean" cellular morphology is distinguishing characteristic of Neisseria meningitidis Yersinia pestis Bartonella spp. Actinobacter spp.
Neisseria meningitidis
An 18-year-old boy is admitted to the hospital with suspected meningitis. He is lethargic and presents with a rigid neck. He has not had most of the recommended vaccines from childhood to now. Gram stain of his spinal fluid shows many PMNS with intra and extra cellular Gram-negative diplococci. The suspected pathogen is: Listeria monocytogenes Haemophilus influenzae Streptococcus agalactiae Neisseria meningitidis
Neisseria meningitidis
A pure culture of β-hemolytic streptococci recovered from a leg wound ulcer gave the following reactions: CAMP test = Neg Hippurate hydrolysis = Neg Bile esculin = Neg 6.5% salt = Neg PYR = Neg Bacitracin = Resistant Optochin = Resistant SXT = Sensitive The most likely identification is: Group A streptococci Group B streptococci Enterococcus faecalis Nongroup A, nongroup B, nongroup D streptococci
Nongroup A, nongroup B, nongroup D streptococci
Urine cultured from the catheter of an 18-year-old female patient produced more than 100,000 col/mL on a BAP plate. Colonies were catalase positive, coagulase negative by the latex agglutination slide method as well as the tube coagulase test. The best single test for identification is: Lactose fermentation Urease Catalase Novobiocin susceptibility
Novobiocin susceptibility
S. pneumoniae and the viridans streptococci can be differentiated by which test? Optochin disk test, 5 μg/mL or les Bacitracin disk test, 0.04 unit CAMP test Bile esculin test
Optochin disk test, 5 μg/mL or les
A urethral swab obtained from a man with a urethral exudate was plated directly on chocolate agar and modified Thayer-Martin agar, and a Gram stain was made. The Gram stain showed Gram-negative diplococci. The culture plates were incubated at 35 C in ambient air, but had no growth at 48 hours. The most likely failure for organism growth is that the: Wrong media were used Anaerobic chocolate agar plate not set up Organism only grows at room temperature Organism requires CO2 for growth
Organism requires CO2 for growth
Resistance to which drug categorizes a strain of Staphylococcus aureus as methicillin-resistant Staphylococcus aureus (MRSA)? Oxacillin Colistin Trimethoprim-sulfamethoxazole Tetracycline
Oxacillin
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 positive Oxidase positive and glucose positive, maltose negative Oxidase positive, maltose positive, and glucose negative Glucose positive, oxidase negative and maltose negative
Oxidase positive and glucose positive, maltose negative
Gram-positive cocci in chains are seen on a Gram stain from a blood culture. The organism grows as a beta-hemolytic colony. Further tests that could be performed include: PYR, bacitracin, and hippurate catalase and agglutination test for Protein A oxidase and mass spectrometry Voges-Proskauer and methyl red
PYR, bacitracin, and hippurate
Which of the following is the most reliable test to differentiate Neisseria lactamica from Neisseria meningitidis? Growth on a modified Thayer-Martin agar Nitrite reduction to nitrogen gas Rapid ONPG Utilization of maltose
Rapid ONPG
A tech receives a request for VRE colonization testing on a patient in the hospital. Which of the following is an appropriate area of the body for culture for screening?
Rectal area
A tech receives a request for VRE colonization testing on a patient in the hospital. Which of the following is an appropriate area of the body for culture for screening? Anterior nares Rectal area Groin Urine
Rectal area
Gram positive cocci isolated from a catheterized urine culture on a 76-year-old male gave the following reactions: Blood agar- creamy, white, opaque colonies with are not hemolytic Catalase- positive Slide coagulase- negative Tube coagulase- negative Novobiocin- susceptible The next action that the medical laboratory professional should take is to: Report the isolate as coagulase negative staphylococcus Report the isolate asStaphylococcus epidermidis Report the isolate asStaphylococcus saprophyticus Perform further testing to speciate the organism
Report the isolate as coagulase negative staphylococcus
Slime production is associated with which Staphylococcus species? S. aureus S. epidermidis S. intermedius S. saprophyticus
S. epidermidis
The quellung test is used to identify which Streptococcus species? S. pyogenes S. agalactiae S. sanguis S. pneumoniae
S. pneumoniae
Nutritionally variant streptococci (NVS) require specific thiol compounds, cysteine, or the active form of vitamin B6. Which of the following tests supplies these requirements? CAMP test Bacitracin susceptibility test Bile solubility test Staphylococcal cross-streak test
Staphylococcal cross-streak test
Colistin-nalidixic acid agar (CNA) is used primarily for the recovery of Neisseria species Enterobacteriaceae Pseudomonas aeruginosa Staphylococcus aureus
Staphylococcus aureus
The following results were observed by using a tube coagulase test: Coagulase at 4 hours = + Coagulase at 18 hours = Neg DNase = + Novobiocin = Sensitive (16-mm zone) Hemolysis on blood Mannitol salt plate = + agar = β (acid production) What is the most probable identification? Staphylococcus saprophyticus Staphylococcus epidermidis Staphylococcus aureus Staphylococcus hominis
Staphylococcus aureus
Toxic shock syndrome is attributed to infection with: Staphylococcus epidermidis Staphylococcus hominis Staphylococcus aureus Staphylococcus saprophyticus
Staphylococcus aureus
A 55-year-old man presents to the emergency room with chest pain and is found to have patient is admitted and scheduled for a triple bypass procedure. During recovery, he becomes septic, developing a high grade fever and pneumonia. Gram-positive cocci in clusters, isolated from both his lungs via an induced sputum specimen and the surgical incision, produce beta-hemolytic, catalase-positive colonies on sheep blood agar. Identity the organism most likely isolated and the biochemical test performed to confirm the identification. Staphylococcus aureus and latex agglutination Streptococcus pyogenes and PYR Streptococcus agalactiae and latex agglutination Enterococcus faecium and PYR
Staphylococcus aureus and latex agglutination
Bacitracin resistance (0.04 unit) is used to differentiate: Staphylococcus spp. form Micrococcus spp Staphylococcus spp. from Neisseria spp. Planococcus spp. from Micrococcus spp Staphylococcus spp. from Streptococcus spp.
Staphylococcus spp. form Micrococcus spp
.Furazolidone (Furoxone) susceptibility is a test used to differentiate: Staphylococcus spp. from Micrococcus spp Streptococcus spp. from Staphylococcus spp Staphylococcus spp. from Pseudomonas spp Streptococcus spp. from Micrococcus spp
Staphylococcus spp. from Micrococcus spp
Which two tests best differentiate S. bovis (group D, nonenterococcus) from Streptococcus salivarius (S.viridans) ?
Starch hydrolysis and acid production from mannitol
Which two tests best differentiate S. bovis (group D, nonenterococcus) from Streptococcus salivarius (S.viridans) ? Bile esculin and 6.5% salt broth Starch hydrolysis and acid production from mannitol Bacitracin and PYR Trimethoprim-sulfamethoxazole susceptibility and PYR
Starch hydrolysis and acid production from mannitol
A Gram-positive coccus isolated from a blood culture has the following characteristics: optochin susceptibility: negative bacitracin (0.04 U) susceptibility: negative bile esculin hydrolysis: negative hippurate hydrolysis: positive catalase: negative This organism is most likely: Staphylococcus aureus Streptococcus pneumoniae Streptococcus pyogenes Streptococcus agalactiae
Streptococcus agalactiae
A gray, nonhemolytic, catalase-negative colony grows on a CNA plate. The following biochemical results are obtained: 65% NaCI negative bile esculin positive PYR negative bacitracin resistant hippurate hydrolysis negative CAMP Test negative The most likely identification is: Enterococcus faecalis Streptococcus bovis Streptococcus viridans Streptococcus pneumonia
Streptococcus bovis
The optochin disk is used for the identification of: Haemophilus infiuenzae group A beta-hemolytic streptococci Streptococcus pneumoniae Enterococcus
Streptococcus pneumoniae
The bile solubility test causes the lysis of: Streptococcus bovis colonies on a blood agar plate Streptococcus pneumoniae colonies on a blood agar plate Group A streptococci in broth culture Group B streptococci in broth culture
Streptococcus pneumoniae colonies on a blood agar plate
A 56-vear-old male has 2 sets of blood cultures that grow Gram-positive cocci after being admitted to the hospital with an oozing leg wound post operation. The infected area is red, swollen, and warm to the touch. A red line has appeared at the sight of the wound and is beginning to travel up the patient's leg. Biochemicals performed from the beta hemolytic colonies on the sheep blood agar plate revealed the following: CAMP test negative hippurate hydrolysis negative PYR positive bacitracin sensitive 65% NaCI no growth bile esculin negative The most likely identification is: Streptococcus pyogenes Streptococcus agalactiae Staphylococcus aureus Enterococcus faecalis
Streptococcus pyogenes
A 56-vear-old male has 2 sets of blood cultures that grow Gram-positive cocci after being admitted to the hospital with an oozing leg wound post operation. The infected area is red, swollen, and warm to the touch. A red line has appeared at the sight of the wound and is beginning to travel up the patient's leg. Biochemicals performed from the beta hemolytic colonies on the sheep blood agar plate revealed the following: CAMP test negative hippurate hydrolysis negative PYR positive bacitracin sensitive 65% NaCI no growth bile esculin negative The most likely identification is: Streptococcus pyogenes Streptococcus agalactiae Staphylococcus aureus Enterococcus faecalis
Streptococcus pyogenes
A common cause of acute exudative pharyngitis is: Staphylococcus aureus (beta-hemolytic] Streptococcus pneumoniae Streptococcus agalactiae Streptococcus pyogenes
Streptococcus pyogenes
Which of the following organisms is, to date, considered universally susceptible to penicillin: Haemophilus influenzae Neisseria gonorrhoeae Streptococcus pyogenes Corynebacterium diphtheriae
Streptococcus pyogenes
A young boy who routinely bites is finger nails develops a wound on his right pointer finger. A culture reveals alpha hemolytic, dry colonies on the blood and CNA plates that are catalase negative, resistant to optochin, and 6.5% NaCI negative. Gram stain of the colony is Gram-positive cocci in chains. The organism most likely isolated is: Enterococcus faecium Enterococcus faecalis Streptococcus viridans Streptococcus agalactiae
Streptococcus viridans
Staphylococcus aureus recovered from a wound culture gave the following antibiotic sensitivity pattern by the standardized Kirby-Bauer method (S = sensitive; R = resistant): Penicillin = R Ampicillin = S Cephalothin = R Cefoxitin = R Vancomycin = S Methicillin = R What is the drug of choice for treatment? Penicillin Ampicillin Cephalothin Vancomycin
Vancomycin
The δ-ALA test (for porphyrins) is a confirmatory procedure for which test used for identification of Haemophilus species? X factor requirement V factor requirement Urease production Indole production
X factor requirement
A pregnant patient is screened at 36 weeks gestation tor group B Streptococcus (GBS). A vaginal swab is collected and cultured in Todd-Hewitt broth with 8 ug gentamicin/mL and 15 ug nalidixic acid/mL. The broth is subcultured onto sheep blood agar after 24 hours of incubation. No GBS are seen on the subculture and the results are reported as negative. The patient later goes on to deliver an infant with early onset GBS disease. What is the most likely reason for the negative GBS culture? the patient was screened too early since screening after 38 weeks is recommended a vaginal swab was collected instead of a vaginal/rectal swab the Todd-Hewitt broth used was inhibitory to the organism the selective broth was incubated only 24 hours before subculture
a vaginal swab was collected instead of a vaginal/rectal swab
Children who have infections with beta-hemolytic streptococci can develop: acute pyelonephritis acute glomerulonephritis chronic glomerulonephritis nephrosis
acute glomerulonephritis
Gram stain examination from a blood culture bottle shows dark blue, spherical organisms in Clusters. Growth on sheep blood agar shows small, round, pale yellow colonies. Further tests should include: catalase production and agglutination test for Protein A bacitracin susceptibility and latex grouping oxidase and indole reactions Voges-Proskauer and methyl red reactions
catalase production and agglutination test for Protein A
The enterotoxin produced by certain strains of hemolytic, coagulase positive Staphylococcus aureus: is the primary cause of subacute endocarditis creates a biofilm on indwelling catheters causes a rapidly occurring (2-6 hours after ingestion) food poisoning is of extremely low virulence
causes a rapidly occurring (2-6 hours after ingestion) food poisoning
The enterotoxin produced by certain strains of hemolytic, coagulase positive Staphylococcus aureus: is the primary cause of subacute endocarditis creates a biofilm on indwelling catheters causes a rapidly occurring (2-6 hours after ingestion) food poisoning is of extremely low virulence
causes a rapidly occurring (2-6 hours after ingestion) food poisoning
A reliable test for distinguishing Staphylococcus aureus from other staphylococci is: oxidase coagulase catalase optochin susceptibility
coagulase
It is important to differentiate between Enterococcus and group D streptococci because: viridans streptococci are often confused with enterococci several enterococci cause severe puerperal sepsis group D streptococci are avirulent enterococci often show more antibiotic resistance than group D streptococci
enterococci often show more antibiotic resistance than group D streptococci
Which 2 diseases are usually preceded by infection with beta-hemolytic streptococci? rheumatic fever, undulant fever glomerulonephritis, rheumatic fever rheumatic fever, tularemia glomerulonephritis, undulant fever
glomerulonephritis, rheumatic fever
A beta-hemolytic streptococci that is bacitracin-sensitive and CAMP-negative is: group B group A beta-hemoyltic, not group A, B, or D group D
group A
A beta-hemolytic Streptococcus that is bacitracin-resistant and CAMP-positive is: group A or B group A group B group D
group B
The organism most commonly associated with neonatal purulent meningitis is: Neisseria meningitidis Streptococcus pneumoniae group B streptococci Haemophilus influenzae
group B streptococci
A gamma-hemolytic Streptococcus that blackens bile esculin agar but dos not grow In 6.5% NaCI broth is most likely: group B Streptococcus Enterococcus group D Streptococcus (Streptococcus bovis group] Streptococcus pneumoniae
group D Streptococcus (Streptococcus bovis group]
A catheterized urine is inoculated onto blood and MacConkey agar using a 0.01 mL loop. After 24 hours, 68 colonies of a small translucent nonhemolytic organism grew on blood agar but not MacConkey. Testing reveals small Gram-positive, catalase-negative cocci. The preliminary report and follow up testing would be: growth of 680 CFU/mL of Gram-positive cocci, optochin and bacitracin susceptibility tests to follow growth of 6,800 CFU/mL of a Staphylococcus species, latex agglutination test to follow growth of 6,800 CFU/mL of a Streptococcus species, PYR, esculin hydrolysis and 6.5% NaCI growth test to follow growth of 6,800 CFU/mL of a Streptococcus species, no further testing
growth of 6,800 CFU/mL of a Streptococcus species, PYR, esculin hydrolysis and 6.5% NaCI growth test to follow
A urine isolate Gram stain shows Gram-positive cocci in clusters. The organism tested catalase positive. To identify this organism from culture, the technician should perform a coagulase test and a/an: polymyxin B susceptibility novobiocin susceptibility oxidase a beta-lactamase
novobiocin susceptibility
Which test is used to differentiate viridans streptococci from Streptococcus pneumoniae? CAMP test bacitracin disk test hippurate hydrolysis test optochin test
optochin test
After 24 hours a blood culture from a newborn grows catalase-negative, Gram-positive Cocci. The bacterial colonies are small, translucent and beta-hemolytic on a blood agar plate. Biochemical test results of a pure culture are: bacitracin: resistant CAMP reaction: positive bile esculin: not hydrolyzed 6.5% NaCI broth: no growth Assuming that all controls react properly and reactions are verified, the next step would be to: perform a Streptococcus group typing report the organism as Streptococcus pneumoniae report the organism as Staphylococcus aureus report the organism as Staphylococcus epidermidis
perform a Streptococcus group typing
The laboratory aid prepared and performed a Gram stain of a vaginal smear for Neisseria gonorrhoeae, as requested by a resident. The findings on the stain were: Many white bloods cells Few epithelial cells Few Gram-negative diplococci Few Gram-positive cocci in chains The technologist should: Report out smear positive for gonorrhea Report out smear negative for gonorrhea Request a new specimen due to number of white blood cells presence of gram negative diplococci in vaginal samples is not diagnostic for N. gonorrhoeae. Women have vaginal commensal flora that resembles gonococci.
presence of gram negative diplococci in vaginal samples is not diagnostic for N. gonorrhoeae. Women have vaginal commensal flora that resembles gonococci.
A technologist is reading a Gram stain from a CSF and observes many intracellular Gram-negative diplococci. Which set of chemistry and hematology CSF results would most likely be seen in someone with this type of infection? CSF results WBC glucose protein A increased increased increased B decreased decreased decreased C increased decreased increased D decreased increased decreased result A result B result C result D
result C
The procedure that assures the most accurate detection of mecA-mediated oxacillin resistance in routine broth microdilution susceptibility testing against S aureus is: addition of 4% NaCI incubation at 30°C incubation for 48 hours testing with cefoxitin
testing with cefoxitin
Three sets of blood cultures were obtained from an adult patient with fever and suspected endocarditis. The aerobic bottle of one set had growth of Staphylococcus epidermidis at 5 days of incubation. This indicates that: there was low-grade bacteremia the organism is most likely a contaminant the patient has a line Infection the blood culture bottles are defective
the organism is most likely a contaminant
During the previous month, Staphylococcus epidermidis has been isolated from blood cultures at 2- 3 times the rate from the previous year. The most logical explanation for the increase in these isolates is that: the blood culture media are contaminated with this organism the hospital ventilation system is contaminated with Staphylococcus epidermidis there has been a break in proper skin preparation before drawing blood for culture a relatively virulent isolate Is being spread trom patient to patient
there has been a break in proper skin preparation before drawing blood for culture
Trimethoprim-sulfamethoxazole (SXT) disks are used along with bacitracin disks to differentiate which streptococci? α-Hemolytic streptococci β-Hemolytic streptococci Streptococcus pneumoniae Enterococcus faecalis
β-Hemolytic streptococci
An oxacillin-disk screen test is used to detect Streptococcus pneumonia resistance to penicillin. Using Mueller-Hinton agar with 5% sheep blood and a 1 μg oxacillin disk, what is the recommended inhibition zone size for penicillin susceptibility? ≥5 mm ≥10 mm ≥15 mm ≥20 mm
≥20 mm