Staphylococcus & Streptococus

What test allows for the differentiation of Group A streptococci from other -hemolytic streptococci? A) CAMP test B) Hippurate hydrolysis C) Esculin hydrolysis D) Bacitracin sensitivity E) Growth in 6.5% salt

Bacitracin sensitivity

Osteomyelitis

Bone and bone marrow S. aureus

6) Allergens bind to sensitized mast cells carrying surface ____ molecules, causing degranulation. a) IgG b) IgB c) IgM d) IgE

IgE

Scarlet fever can lead to serious complications including: a) glomerulonephritis b) meningitis c) rheumatic fever d) two of the above

two of the above

Scarlet fever can lead to serious complications including: a) glomerulonephritis b) meningitis c) rheumatic fever d) two of the above

two of the above Meningitis - inflammation of the membranes that surround the brain and spinal cord. rheumatic fever - A disorder that usually follows infection by certain bacteria and has as symptoms inflammation of the joints, skin, and heart. It occurs mainly in children and can cause permanent damage to the heart valves.

Tonsillitis

upper respiratory Streptococcus pyogenes

Cystitis is inflammation of the _____. a) urinary bladder b) urethra c) nephron d) kidney

urinary bladder UTI S. aureus

What role do antibiotics play in septic shock? a) reduce the fever and lymphangitis symptoms b) kills gram positive bacteria but are ineffective with gram negative bacteria c) worsen the situation by releasing large quantities of endotoxin d) none of these choices

worsen the situation by releasing large quantities of endotoxin

streptococci are classified

(1) their hemolytic activity (2) the serologic classification of Lancefield. Lancefield classified the streptococci into 20 serogroups, designated A through V, omitting I and J, based on the presence of an antigenic group-specific hapten called the C-substance. This method of classification generally implicates the members of Groups A, B, C, and D in human infectious processes.

Rheumatic fever

(inflammation in the heart or joints) Streptococcus pyrogenes

The majority of organisms normal to the skin are: a) Gram-negative b) Gram-positive c) fungi d) viruses

Gram-positive

(α) Alpha hemolysis

1.produces a green zone around the colony. 2.α-Hemolytic streptococci, the Streptococcus viridans species, are usually nonpathogenic opportunists. 3.they are capable of inducing human infections such as subacute endocarditis, which may precipitate valular damage and heart failure if untreated. 4.Streptococcus pneumoniae,the causative agent of lobar pneumonia,

Deoxyribonuclease (DNase) test:

1.thus this test can be used to reconfirm the identification of S. aureus. 2.The presence of deoxyribonuclease, the enzyme that breaks down DNA. 3.Methyl green dye (indicator)

How is mannitol salt agar differential to mannitol-fermenting organisms? A) Organism will produce acid B) Indicator will turn medium yellow. C) Indicator will turn purple. D) A and B E) A and C F) None of the above

A and B

Mueller-Hinton Agar (MH)

AB sensitivity •Novobiocin Disc -Sensitive > 18 mm -Resistant < 18 mm •Staph chart for ID

Of what type are most bacteria found on the skin? a. Gram negative b. Gram positive c. Salt tolerant d. B and C

B and C

The genus/genera that belongs to the family Micrococcaceae is A. Micrococcus B. Staphylococcus C. Planococcus D. All of these

All of these

Over 90% of streptococcal infections are caused by _________________. A. Streptococcus B. Neisseria C. Beta-hemolytic group A streptococci​ D. Haemophilus

Beta-hemolytic group A streptococci

The bacteria involved in the production of dental caries is/are A. Streptococcus mutans B. S sanguis C. Both (a) and (b) D. Streptococcus pyogenes

Both (a) and (b)

What is the major virulence factor of Streptococcus pneumoniae? A) M protein B) Pyogenic exotoxins C) Capsule D) DNase E) Hyaluronidase

Capsule

What is an indicator of a coagulase-positive? A) Clumping B) No clumping

Clumping

is the purpose of testing for the presence of coagulase? A) Distinguish S. aureus from other species of Staphylococcus. B) Distinguish S. aureus from propionibacterium. C) Distinguish Gram positive from Gram negative organisms. D) None of the above.

Distinguish S. aureus from other species of Staphylococcus.

Which of the following is not considered resident microflora of the skin? a) Staphylococcus b) Corynebacterium c) E. coli d) Streptococcus

E. coli

Exotoxins (staphylococcus)

Enterotoxin --emesis food poisoning TSST1-toxic syndrome Exfoliating toxin--scolded skin syndrome

Pyrogenic Exotoxins

Erythrogenic-Scarlet fever is systemic inflammation to circulating toxins. Streptococcus pyogenes

Catalase breaks down H2O2 into oxygen, so it is an oxidase test. True False

False

What is the most common infection caused by Staphylococcus aureus? A) Staphylococcal enterotoxicosis B) Folliculitis C) Toxic shock syndrome D) Osteomyelitis E) Staphylococcal Bacteremia

Folliculitis It develops when bacteria, such as Staphylococcus, or a fungus enters the body through a cut, scrape, surgical incision, or other break in the skin near a hair follicle. Scratching the affected area can trap fungus or bacteria under the fingernails and spread the infection to hair follicles on other parts of the body.

3 enzymes for superoxide breakdown. Where are they found?

Found in aerobes - Superoxide dismutase -Catalase -Peroxidase

Which is an immune complex disease? a) Cystitis b) Glomerulonephritis c) Prostatitis d) Pyelonephritis

Glomerulonephritis Acute glomerulonephritis most often follows a streptococcal infection of the throat or skin. In children, it is most often associated with an upper respiratory infection, tonsillitis, or scarlet fever.

Alpha-hemolysis is ____________________________________________. A. No hemolysis, and no change in the blood agar around the colony B. Green, cloudy zone around the colony. Partial destruction of rbc's. C. Complete hemolysis, giving a clear zone with a clean edge around the colony D. All of the above

Green, cloudy zone around the colony. Partial destruction of rbc's.

Staphylokinase

It activates plasminogen to form plasmin, which digest fibrin clots. This disrupts the fibrin meshwork which can often form to keep an infection localized. Staphylokinase also cleaves IgG and complement component C3b, inhibiting phagocytosis.

What are the means by which asymptomatic Staphylococcus carriers (like hospital personnel) spread this bacterium a) via the skin b) by nasal dropets c) fomites d) all of the above

K

Some strains of _______ can inhibit the growth of other organisms by decreasing the pH and making hydrogen peroxide. a) Lactobacillus b) Staphylococcus c) Vibrio d) Clostridium

Lactobacillus

3) The acid pH in the vagina is predominantly due to ______ fermenting the _____ present in vaginal cells. a) Staphylococcus, glycogen b) Escherichia, glucose c) Staphylococcus, starch d) Lactobacillus, glycogen

Lactobacillus, glycogen

Latex Test for cell-bound coagulase (clumping factor) and/or Protein A

Latex Test is an agglutination test that detects cell-bound coagulase (clumping factor) and/or Protein A. Approximately 97% of human strains of S. aureus possess both bound coagulase and extracellular coagulase. Approximately 95% of human strains of S. aureus possess Protein A on their cell surface. This test uses blue latex particles coated with human FIBRINOGEN and the HUMAN ANTIBODY IGG. Mixing of the latex reagent with colonies of the suspected S. aureus having coagulase and/or Protein A bound to their surface causes agglutination of the latex particles. Staphylococcus saprophyticus- Staphylococcus aureus+ Staphylococcus epidermidis-

Enzymes and Toxins (shared)

Leukocidin • Hemolysins • DNase

Protein A

Protein A is a surface protein of S. aureus which binds IgG molecules by their Fc region. In serum, the bacteria will bind IgG molecules in the wrong orientation on their surface, which disrupts opsonization and phagocytosis. S. aureus

The most common bacteria to cause infections from soaking in a hot tub is__________. a) Escherichia coli b) Pseudomonas aeruginosa c) Staphylococcus epidermidis d) Staphylococcus aureus

Pseudomonas aeruginosa

Septicemia

S. aureus

Otitis externa is caused most often by _____. a) Streptococcus pyogenes b) Staphylococcus aureus c) Haemophilus influenzae d) two of these choices

Staphylococcus aureus

β-lactamase production is an example of which of the following types of resistance? A) alteration of the target of the drug B) inactivation of the drug C) change in the permeability of the drug D) overproduction of an enzyme in a key metabolic pathway E) removal of the drug via a pump

inactivation of the drug

The most common flesh-eating bacterial species is: a) Staphylococcus b) Streptococcus c) Pseudomonas d) Propionibacterium

Streptococcus

What are hemolysins produced by? ​A. Staphylococcus ​B. Streptococcus ​C. Both A and B​

Streptococcus

Which of the following bacteria are responsible for more infections and more different kinds of infections? A) Streptococcus B) Staphylococcus C) Salmonella D) Pseudomonas E) Neisseria

Streptococcus

The most common cause of meningitis in adults is: a) Neisseria meningitidis b) Haemophilus influenzae type B c) Streptococcus pneumoniae d) Listeria monocytogenes

Streptococcus pneumoniae

Glomerulonephritis is caused by cross-reacting antibodies produced in response to the bacterial pathogen _____. a) Escherichia coli b) Staphylococcus aureus c) Streptococcus mutans d) Streptococcus pyogenes

Streptococcus pyogenes

Puerperal fever is caused by: a) Streptococcus pyogenes b) Staphylococcus aureus c) Pseudomonas aeruginosa d) Streptococcus agalactiae

Streptococcus pyogenes

Invasins

Streptolysin-hemolytic to RBCs streptokinase-digest blood clots Streptococcus pyogenes

3 toxic Oxygen forms (superoxides)

Superoxide Peroxide Hydroxyl

Which of the following statements about the zone of inhibition is FALSE? A) It is measured as a diameter. B) The larger the zone, the more resistant the organism is. C) It is a clearing zone with no growth. D) It is a result of diffusion of the drug out of the paper disk. E) It is measured after incubation.

The larger the zone, the more resistant the organism is.

Novobiocin sensitivity:

This test is used to distinguish S. epidermidis from S. saprophyticus.

Beta-lactam antibiotics have an effect on which of the following types of cells? A) animal cells B) bacterial cells C) fungal cells D) virus-infected cells E) both animal and fungal cells

bacterial cells

Group B

Vaginal mucosa: puerperal fever (childbirth fever), a sometimes-fatal neonatal meningitis, and endocarditis.

Catalase-positive bacteria

include strict aerobes as well as facultative anaerobes. They all have the ability to respire using oxygen as a terminal electron acceptor (ie. Staphylococcus).

Pneumonia

lungs S. aureus

Bronchopneumonia

lungs Streptococcus pyogenes

Leukocidin

a substance toxic to leukocytes, killing the cells with or without lysis. S. aureus

What are the means by which asymptomatic Staphylococcus carriers (like hospital personnel) spread this bacterium a) via the skin b) by nasal dropets c) fomites d) all of the above

all of the above

Group B Streptococcal disease is characterized by: a) early onset neonatal sepsis and meningitis b) late onset neonatal meningitis c) etiology is Streptococcus agalactiae d) all of these choices

all of these choices

Sinusitis can be caused by: a) Staphylococcus aureus b) Streptococcus pneumoniae c) Haemophilus influenzae d) all of these choices

all of these choices

Staphylococcus food poisoning is caused by: a) enterotoxins b) exotoxins c) toxins that cause neural stimulation of the vomiting center of the brain d) all of these choices

all of these choices

Which of the following Staphylococcal infections are matched correctly with infection sites? a) folliculitis - deep internal pus-filled infection b) furuncle - massive lesion on neck and upper back c) boil - an exterior pus-filled infection d) abscess - base of an eyelash

boil - an exterior pus-filled infection

Streptococcus pyogenes (Lancefield group A)

causes necrotizing fasciitis, a rare but devastating infection that destroys skin, muscle, and underlying tissue.

Scarlet fever

childhood disease with red rash Streptococcus pyogenes

Lancefield

classified the streptococci into 20 serogroups, designated A through V, omitting I and J, based on the presence of an antigenic group-specific hapten called the C-substance. This method of classification generally implicates the members of Groups A, B, C, and D in human infectious processes.

Which of the following correctly matches the oral cavity disease with the organism responsible? a) gingivitis -- Porphyromonas b) periodontal disease -- Helicobacter pylori c) orchitis -- paramyxovirus d) dental caries -- Streptococcus mutans

dental caries -- Streptococcus mutans

Streptococcus form ________ , polysaccharides that enable bacteria to adhere to the tooth surface. a) glucose b) fructose c) maltose d) dextrans

dextrans

Another term for the Kirby-Bauer test is the A) minimum inhibitory concentration test. B) E test. C) diffusion susceptibility test. D) minimum bactericidal concentration test. E) broth dilution test.

diffusion susceptibility test.

Toxic shock syndrome is associated with all of the following except: a) Staphylococcus aureus b) super-absorbent tampons c) exotoxin C d) elderly men

elderly men

Which infection refers to inflammation of the lining and valves of the heart? a) septicemia b) rheumatic fever c) endocardiatis d) puerperal fever

endocardiatis Staphylococcus aureus

Group D

enterococci formerly classified as Group D streptococci have been reclassified and are now considered a sepa-rate genus. The enterococci differ significantly from other members of Group D, such as S. bovis, which may be the etiological agent of urinary tract infections. Enterococci such as Enterococcus faecalis may cause infections to the lungs, urinary tract infections, or bloodstream through an intestinal laceration or poor personal hygiene. The enterococci tend to be antibiotic-resistant, particularly to penicillin and more recently to vancomycin.

Staphylococcus aureus causes all of the following except: a) scalded skin syndrome b) carbuncles c) impetigo d) erysipelas

erysipelas

Group C

erysipelas, puerperal fever, and throat infections.

Group A

etiological agents of human respiratory infections such as tonsillitis, bronchopneumonia, and scarlet fever, as well as skin disorders such as erysipelas and cellulitis. glomerulonephritis rheumatic fever

Which of the following are found primarily in the intestines of humans? A) gram-negative aerobic rods and cocci B) aerobic, helical bacteria C) facultatively anaerobic gram-negative rods D) gram-positive cocci E) endospore-forming rods

facultatively anaerobic gram-negative rods

Staphylococcus and Streptococcus can be easily differentiated in a laboratory by which one of the following? A) cell shape B) Gram stain reaction C) growth in high salt concentrations D) ability to cause disease E) glucose fermentation

growth in high salt concentrations

Streptococcus extracellular metabolites

hemolysins leukocidins erythrogenic toxin Secondary hyaluronidase (the spreading factor), which hydrolyzes the tissue cement hyaluronic acid; streptokinase, a fibrinolysin; and the nucleases, ribonuclease and deoxyribonuclease, which destroy viscous tissue debris.

Endocarditis

inflammation of endocardium S. aureus

Pyelonephritis

inflammation of kidneys S. aureus

Glomerulonephritis

inflammation of kidneys Streptococcus pyogenes

staphyloxanthin

is a carotenoid pigment that is produced by some strains of Staphylococcus aureus, and is responsible for the characteristic golden color that gives S. aureus its species name. Staphyloxanthin also acts as a virulence factor. It has an antioxidant action that helps the microbe evade death by reactive oxygen species produced by the host immune system.

The CAMP test

is used to identify Group A Streptococcus pyogenes from Group B Streptococcus agalatiae.

Pyelonephritis is inflammation of the _____. a) bladder b) rectum c) kidney d) urethra

kidney

Pyelonephritis is inflammation of the _____. a) bladder b) rectum c) kidney d) urethra

kidney Inflammation of the kidney and its pelvis, caused by Staphylococcus aureus.

Streptococcus agalactiae (Lancefield group B)

may colonize the vagina as well as the upper respiratory tract of humans, and is the most frequent cause of neonatal pneumonia in the United States.

Which statement about skin is incorrect? a) largest single organ of the body b) dead epithelial cells function as a barrier for infections c) normal microflora are very sensitive to the skin's antimicrobial substance d) consists of a thin epidermis and a thicker underlying dermis layer

normal microflora are very sensitive to the skin's antimicrobial substance

Which of the following statements about scalded skin syndrome is incorrect? a) caused by Staphylococcus aureus b) rarely leads to bacteremia c) most commonly occurs in infants d) exotoxins cause the upper skin layers to separate and peel off

rarely leads to bacteremia

Which of the following conditions is associated with the erythrogenic toxin of Streptococcus pyogenes? a) rheumatic fever b) toxic shock syndrome c) scarlet fever d) roseola

scarlet fever

Which of the following conditions is associated with the erythrogenic toxin of Streptococcus pyogenes? a) rheumatic fever b) toxic shock syndrome c) scarlet fever d) roseola

scarlet fever erythrogenic toxin - a bacterial toxin from certain strains of Streptococcus pyogenes that produces an erythematous reaction when injected intradermally and is responsible for the rash in scarlet fever.

Erysipelas

skin Streptococcus pyogenes Impetigo if it gets on the skin. Necrotizing if it gets deep in the skin. Scarlet Fever 2 weeks Rheumatic Fever Glomerulonephritis

Cellulitis

skin and deeper underlying tissues Streptococcus pyogenes

Streptococcus pyogenes can be differentiated from other haemolytic Streptococci on the basis of A. Bacitracin sensitivity B. Erythromycin sensitivity C. Aminoglycosides sensitivity D. Penicillin sensitivity

Bacitracin sensitivity

Why is Staphylococcus aureus considered a troublesome hospital pathogen? A) Because its optimum growth temperature is 37°C. B) Because it resists the effects of many disinfectants and antibiotics. C) Because it is a facultative anaerobe. D) Because it grows in large, round opaque colonies. E) Because it can digest proteins and lipids, and ferment a variety of sugars.

Because it resists the effects of many disinfectants and antibiotics.

Which of the following cross-reacts with cell wall carbohydrate of Streptococcus pyogenes? A. Cardiac valves B. Synovial fluid C. Myocardium D. Vascular intima

Cardiac valves

Illustrate the chemical reaction involved in the degradation of hydrogen peroxide in the presence of catalase.

Catalase catabolizes hydrogen peroxide to water and molecular oxygen.

Would catalase be classified as an exoenzyme?

Catalase is an endoenzyme, as cellular respiration is an intracellular process.

What is the key test that separates Staphylococcus aureus from other staphylococci? A) Susceptibility to novobiocin B) Mannose fermentation C) Growth on blood agar D) Coagulase test E) Urease test

Coagulase test

Individuals suffering from primary atypical pneumonia have agglutinins to A. Streptococcus MG B. S avium C. S mutans D. Enterococcus faecalis

Streptococcus MG

The bacterial sore throat is caused by A. Staphylococcus aureus B. Haemophilus spp C. Streptococcus pyogenes D. Mycoplasma pneumoniae

Staphylococcus aureus

Staphylococcus aureus is most frequently isolated from what body site? A) Gastrointestinal tract B) Genitourinary tract C) Vagina D) Nostrils E) Stomach

Stomach

Most cases of gonorrhea occur within what age range? A) 14-18 years B) 18-24 years C) 24-26 years D) 26-30 years E) 30-35 years

18-24 years

Staphylococcal food poisoning usually manifests itself following ingestion of contaminated food after A. 2-6 hours B. 8-12 hours C. 12-18 hours D. 18-36 hours

2-6 hours

Staphylococcus saprophyticus

A bacterial species that has been associated with community-acquired urinary tract infections in young women who are sexually active; characterized in the laboratory as gram-positive cocci, but negative for catalase and coagulase.

Which of the following condition is non-suppurative sequelae of Streptococcus pyogenes infections? A. Acute rheumatic fever B. Acute glomerulonephritis C. Erythema nodosum D. All of these

All of these

Which of the following test(s) may establish retrospective diagnosis of streptococcal infection? A. Anti-DNase B test B. ASO test C. Streptozyme test D. All of these

All of these

Gram stain of Staphylococcus aureus

All staphylococci appear as Gram-positive cocci, usually in irregular, often grape-like clusters

Methicillin-Resistant Staphylococcus Aureus (MRSA)

Any of various strains of the bacterium Staphylococcus aureus that are resistant to methicillin and other beta-lactam antibiotics and can cause life-threatening infections.

Production of deoxyribonuclease (DNase) on DNase agar

DNase agar contains 0.2% DNA. To detect DNase production, the plate is inoculated and incubated. After growth, the plate is flooded with 1N hydrochloric acid (HCl). DNase positive cultures show a distinct clear zone around the streak (see Fig. 1) where the DNA in the agar was broken down by the bacterial DNase. DNase negative cultures appear cloudy around the growth where the acid caused the DNA in the agar to precipitate out of solution. Staphylococcus aureus(+) Staphylococcus epidermidis (-) Staphylococcus saprophyticus(-)

Which of the following test indicates the susceptibility to streptococcal pyrogenic exotoxin? A. Schick test B. Disk test C. ASO test D. Precipitation test

Disk test

Meningitis associated with Neisseria meningitidis usually occurs as what type of disease? A) Endemic B) Epidemic C) Pandemic D) Isolated E) Common-source

Epidemic

The toxin of Staphylococcus aureus that may result into scalded skin syndrome is A. Enterotoxin B. Leucocidin C. Epidermolytic toxin D. Haemolysin

Epidermolytic toxin

How do Neisseria gonorrhoeae appear when stained with the Gram stain and viewed microscopically? A) Gram positive cocci in grape-like clusters B) Gram negative rods C) Gram positive diplococci D) Gram negative cocci in grape-like clusters E) Gram negative diplococci

Gram negative diplococci

Staphylococcal enterotoxicosis is associated with eating all but which of the following foods? A) Custards B) Chicken salad C) Ham and processed meats D) Hamburger E) Cream pastries

Hamburger

Virulence factors of Neisseria gonorrhoeae include all except which of the following? A) Pili that promote attachment B) Surface molecules that promote attachment C) IgA protease D) Hemolysis E) Pili that slow phagocytosis

Hemolysis

What is the reservoir of Neisseria meningitidis? A) Soil B) Saltwater C) Human carriers D) Domesticated animals E) Reptiles

Human carriers

What is the principal reservoir for the pathogenic staphylococci? A) Humans B) Large primates C) Soil D) Fresh and salt water E) Herbivores

Humans

What is the function of catalase breaking down hydrogen peroxide? where does this hydrogen peroxide come from?

Hydrogen peroxide is a byproduct of superoxide dismutase breaking down toxic superoxides

Explain the toxic effect of 02 on strict anaerobes.

Hydrogen peroxide is formed as a result of aerobic respiration. This is a cytotoxic compound that requires the presence of specific enzymes for its degradation. Strict anaerobes lack these essential enzymes.

Which is not an effect of the Staphylococcus aureus -toxin? A) It acts upon the human gastrointestinal tract. B) It lyses red blood cells of various mammals. C) It causes leukocyte damage. D) It damages skeletal and heart muscle. E) It damages kidney tissues.

It acts upon the human gastrointestinal tract.

Enterococcus durans

NaCI G

Staphylococcus aureus Growing on Blood Agar; Pigmented Strain

Note beta hemolysis on the blood agar and the organism is sensitive to the antibiotic novobiocin in the Taxo NB® disc. Note the gold, water-insoluble pigment. Beta/gold Novobiocin test/sensitive

Staphylococcus saprophyticus Growing on Blood Agar

Note there is no hemolysis (gamma reaction) on the blood agar and the organism is resistant to the antibiotic novobiocin in the Taxo NB® disc. Gamma/white Novobiocin test/resistant

Staphylococcus epidermidis Growing on Blood Agar

Note there is no hemolysis (gamma reaction) on the blood agar and the organism is sensitive to the antibiotic novobiocin as shown by the zone of inhibition around the Taxo NB® disc. There is no pigmentation. Gamma/white Novobiocin test/sensitive

Staphylococcus aureus coagulation causes

Pimples, boils, and impetigo.

What is the most serious pathogen within the genus Staphylococcus? A) Staphylococcus epidermidis B) Staphylococcus saprophyticus C) Staphylococcus hominis D) Staphylococcus aureus E) Staphylococcus capitis

Staphylococcus aureus Abscesses, boils, carbuncles, acne, and impetigo (skin) •Pneumonia (lungs) •Osteomyelitis (Bone and bone marrow) •Endocarditis (inflammation of endocardium) •Cystitis (inflammation of urinary bladder) •Pyelonephritis (inflammation of kidneys) •Staphylococcal enteritis due to enterotoxin contamination of foods •Septicemia Protein A binds to Fe-IgA TSST - minds to MHC II and T-cell

The most common cause of cystitis (after Escherichia coli) in healthy sexually active women is A. Staphylococcus saprophyticus B. Proteus mirabilis C. Pseudomonas aeruginosa D. Klebsiella pneumoniae

Staphylococcus saprophyticus

Bacteria which produces coagulase is A. S epidermidis B. S saprophyticus C. S aureus D. S hominis

S aureus

The bacteria which is novobiocin resistant is A. Staphylococcus aureus B. S epidermidis C. S saprophyticus D. None of these

S saprophyticus

Bile esculin test

S. bovis, S. mitis , and E. faecalis In the presence of bile, Group D streptococci hydrolyze the glycoside esculin to 6,7-dihydroxy coumarin that reacts with the iron salts in the medium to produce a brown-to-black coloration of the medium fol-lowing incubation

Directigen test

S. pyogenes BSL -2 and S. agalactiae

Primary infections caused by Streptococcus pyogenes are due to the organisms invading what two body sites? A) Nose and vagina B) Skin and eyes C) Eyes and gastrointestinal tract D) Mouth and urethra E) Skin and throat

Skin and throat

The bacteria which are inhibited on crystal violet (1:500,000) blood agar, is/are A. Streptococci B. Staphylococci C. Both (a) and (b) D. None of these

Staphylococci

How are the streptococci differentiated from the staphylococci when viewed microscopically following the Gram stain procedure? A) Staphylococci are Gram positive, while streptococci are Gram negative. B) Staphylococci are Gram positive and grow in grape-like clusters, while streptococci are also Gram positive, but grow in chains. C) Staphylococci are Gram positive cocci, while streptococci are Gram positive bacilli. D) Staphylococci are Gram negative bacilli, while streptococci are Gram negative cocci. E) They cannot be differentiated microscopically.

Staphylococci are Gram positive and grow in grape-like clusters, while streptococci are also Gram positive, but grow in chains.

Mannitol Salt agar (MSA)

Staphylococci are able to tolerate the high salt concentration found in Mannitol Salt agar and thus grow readily. If mannitol is fermented, the acid produced turns the phenol red pH indicator from red (alkaline) to yellow (acid). Staphylaureus G+F+Coag+DNase+ Staphylepidermidis G+F- StaphylsaprophyticusG+F-Novobiocin sensitivity=resistant

Identify the bacteria which is oxidase-negative and catalase-positive? A. Staphylococcus B. Streptococcus C. Neisseria D. Pseudomonas

Staphylococcus

Protein A is found in cell wall of A. coagulase-negative staphylococci B. Staphylococcus aureus C. Micrococci D. none of these

Staphylococcus aureus

The bacteria which can ferment mannitol anaerobically is A. Staphylococcus aureus B. S epidermidis C. S saprophyticus D. None of these

Staphylococcus aureus

What species of the streptococci can be transferred to an infant during delivery? A) Streptococcus pyogenes B) Enterococcus faecalis C) Enterococcus faecium D) Streptococcus bovis E) Streptococcus agalactiae

Streptococcus agalactiae Bacitracin resistant Group B Beta are indigenous to the vaginal mucosa and have been shown to be responsible for puerperal fever (childbirth fever), a sometimes-fatal neonatal meningitis, and endocarditis.

Which streptococcal species is involved in the production of cavities? A) Streptococcus pneumoniae B) Streptococcus agalactiae C) Streptococcus pyogenes D) Enterococcus faecalis E) Streptococcus mutans

Streptococcus mutans

What organism is responsible for the majority of cases of otitis media in children? A) Streptococcus pneumoniae B) Staphylococcus aureus C) Streptococcus pyogenes D) Streptococcus mutans E) Staphylococcus epidermidis

Streptococcus pneumoniae Alpha optochin sensitive Green Ottis media Sinusitis

The major etiology of lobar pneumonia is: a) Staphylococcus aureus b) Streptococcus pneumoniae c) Klebsiella pneumoniae d) two of these choices

Streptococcus pneumoniae Bile soluble

What is the most serious streptococcal pathogen of humans? A) Streptococcus agalactiae B) Streptococcus mutans C) Streptococcus pyogenes D) Enterococcus faecalis E) Streptococcus sanguis

Streptococcus pyogenes Bacitracin sensitive Group A Beta Members of this group are the main etiological agents of human respiratory infections such as tonsillitis, bronchopneumonia, and scarlet fever, as well as skin disorders such as erysipelas and cellulitis. In addition, these organisms are responsible for the development of complicating infections, namely glomeru-lonephritis and rheumatic fever, which may surface when primary streptococcal infections either go untreated or are not completely eradicated by antibiotics.

Which of the following combinations of pathogen and virulence factor is CORRECT? A) Neisseria gonorrhoeae and endotoxin B) Streptococcus pyogenes and protein M C) Staphylococcus aureus and neurotoxin D) Gram-positive bacteria and lipid A E) Escherichia coli and cytotoxin

Streptococcus pyogenes and protein M protein M:the somatic antigen associated with virulence and type specificity of group A streptococci. It is antiphagocytic.

6.5% NaCl broth test

The enterococci can be separated from the non-enterococci by the ability of the former to grow in this medium.

What is the most diagnostic species characteristic of Staphylococcus aureus? A) The production of hyaluronidase B) The production of penicillinase C) The production of coagulase D) The production of leukocidin E) The production of -toxin

The production of coagulase

Production of coagulase

The staphylococcal enzyme coagulase will cause inoculated citrated rabbit plasma to gel or coagulate. The coagulase converts soluble fibrinogen in the plasma into insoluble fibrin. Staphylococcus aureus+ Staphylococcus epidermidis- Staphylococcus saprophyticus-

Why do toxic shock syndrome and necrotizing fasciitis cause such severe pathology to host tissues? A) The streptococcal toxins act as superantigens. B) The organisms have been infected by a temperate bacteriophage. C) The organisms possess M protein. D) The organisms produce streptokinase and hyaluronidase. E) The organisms are extremely resistant to antimicrobial drugs.

The streptococcal toxins act as superantigens.

Account for the ability of streptococci to tolerate 02 in the absence of catalase activity.

The streptococci, which are catalase negative, can grow aerobically on blood agar, as the RBCs in the medium serve as a source of catalase to degrade the H2O2.

Staphylococcus aureus scalded skin syndrome

a disease affecting infants in whom large areas of skin peel off, as in a second-degree burn, as a result of upper respiratory staphylococcal infection even though the skin lesions are sterile; the level of skin separation is subcorneal, unlike a burn or the clinically similar toxic epidermal necrolysis that occurs in Infants and adults and which involves subepidermal cleavage.

How is Neisseria meningitidis spread? A) Through respiratory secretions or droplets B) Through contaminated fomites C) Through consumption of contaminated food or water D) By insect vectors E) Through sexual contact

Through respiratory secretions or droplets

Blood agar with a novobiocin (NB) disc

To isolate staphylococci, clinical specimens are usually grown on Blood agar (described in Lab 14). Staphylococci produce round, raised, opaque colonies 1-2mm in diameter. The novobiocin disc is used to detect sensitivity or resistance to the antibiotic novobiocin.

coagulase

a bacterial enzyme that reacts with a cofactor found in blood plasma to catalyze the formation of fibrin from fibrinogen. It is produced by most of the virulent strains of staphylococci.

Staphylococcus

a genus of gram-positive bacteria made up of spherical microorganisms, tending to occur in grapelike clusters; they are constantly present on the skin and in the upper respiratory tract and are the most common cause of localized suppurating infections. Pathogenic species include S. aureus, S. epidermidis, and S. saprophyticus. S. aureus is also a cause of food poisoning.

Staphylococcus aureus enterotoxin (super-antigen) causes

affecting cells of the intestinal mucosa, causing vomiting and diarrhea. If it goes untreated, it could create a cytokine storm which can lead to toxic shock (T.S.S.).

Most strains of Staphylococcus aureus indicate A. phosphatase production B. a golden-yellow pigment C. β-haemolysis on sheep blood agar D. all of the above

all of the above

Streptolysin O is A. antigenic B. oxygen-labile C. heat-labile D. all of these

all of these

Which of the following are pyogenic cocci: A) Streptococcus B) Staphylococcus C) Neisseria D) all of these

all of these

Hyaluronidase

an enzyme that catalyzes the hydrolysis of hyaluronic acid, the "cement material" of connective tissues; it is found in human testes, as well as in leeches, snake venom, and spider venom, and is produced by various pathogenic bacteria, enabling them to spread through tissue.

E. faecalis

bacitracin resistant

S. bovis

bacitracin resistant

S. mitis

bacitracin resistant

Streptococcus salivarius

bacitracin resistant Catalase negative NaCI NG

What does a positive catalase test look like?

bubble production when hydrogen peroxide is added to culture (O2 bubbles)

Cell wall protein of Streptococcus pyogenes crossreacts with human A. synovial fluid B. cardiac valves C. myocardium D. vascular intima

cardiac valves

Catalase test

catalase test is used to differentiate staphylococci (catalase-positive) from streptococci (catalase-negative). The enzyme, catalase, is produced by bacteria that respire using oxygen, and protects them from the toxic by-products of oxygen metabolism. Catalase-positive bacteria include strict aerobes as well as facultative anaerobes, although they all have the ability to respire using oxygen as a terminal electron acceptor. Catalase-negative bacteria may be anaerobes, or they may be facultative anaerobes that only ferment and do not respire using oxygen as a terminal electron acceptor (ie. Streptococci).

What factor appears to support colonization and proliferation of both Staphylococcus aureus and the coagulase-negative staphylococci within patients? A) An open wound B) A preexisting condition C) A foreign body D) A primary infection E) The use of antibiotics

foreign body

The most severe streptococcal diseases are caused by A) group B streptococci B) group A streptococci C) pneumococci D) enterococci

group A streptococci Protein M

Rheumatic fever damages the _______, and glomerulonephritis damages the______ A) skin, heart B) joints, bone marrow C) heart valves, kidney D) brain, kidney

heart valves, kidney

Among the virulence factors produced by Staphylococcus aureus are hemolysin, coagulase, hyaluronidase, and enterotoxin. Which of these factors contribute(s) to the ability of S. aureus to invade the body? A) coagulase B) enterotoxin C) hemolysin D) hyaluronidase E) coagulase and hemolysin

hyaluronidase

5) Pyelonephritis is inflammation of the _____. a) bladder b) rectum c) kidney d) urethra

kidney

Catalase-negative bacteria

may be anaerobes, or they may be facultative anaerobes that only ferment and do not respire using oxygen as a terminal electron acceptor (ie. Streptococci).

What does the Catalase test test for?

presence of catalase which breaks down hydrogen peroxide

The symptoms in scarlet fever are due to A) streptolysin B) coagulase C) pyrogenic toxin D) alpha toxin

pyrogenic toxin

Which of the following can be used to detect clumping factor? A. tube coagulase test B. slide coagulase test C. precipitation test D. none of these

slide coagulase test

Coagulase-reacting factor is necessary for A. slide coagulase test B. tube coagulase test C. precipitation test D. none of these

tube coagulase test

Which of the following Staphylococcal haemolysins does not cause lysis of human RBCs? A. β haemolysin B. γ haemolysin C. α haemolysin D. δ haemolysin

α haemolysin

Which of the following Staphylococcal haemolysins does not possess leucocidal activity? A. α haemolysin B. γ haemolysin C. β haemolysin D. δ haemolysin

β haemolysin

Crystal violet blood agar is a selective medium for A. β-haemolytic streptococci B. Staphylococcus aureus C. Corynebacterium diphtheriae D. Mycobacterium tuberculosis

β-haemolytic streptococci

A gram-positive coccus that grows in pairs or short chains and that is alpha-hemolytic and optochin-sensitive is: A. Streptococcus pyogenes B. Streptococcus agalactiae C. Streptococcus faecalis D. Streptococcus pneumoniae E. Staphylococcus aureus

✓ D. Streptococcus pneumoniae