Microbiology Ultimate

A 5-year-old male patient presents to his local accident and emergency department with his mother. Four days previously, he fell and sustained a graze.  His mother tended to the graze although she is now concerned that the wound is infected.   On examination, the patient is irritable and there is a small area of erythema around the graze.  No pus or lymphadenopathy were present and movement of the elbow was unrestricted.

The F protein is used for bacterial adhesion.  Which of the following receptors does the F protein bind?

a. Transferrin

b. Galactose residues

c. Gangliosides

d. Lactoferrin

e. Fibronectin

e. Fibronectin

A 5-year-old male patient presents to his local accident and emergency department with his mother. Four days previously, he fell and sustained a graze.  His mother tended to the graze although she is now concerned that the wound is infected.   On examination, the patient is irritable and there is a small area of erythema around the graze.  No pus or lymphadenopathy were present and movement of the elbow was unrestricted.

Which of the following virulence factors will be associated with the spread of the bacteria through the skin and soft tissue?

a. Toxin production

b. Coagulase

c. Catalase

d. Streptolysin S

e. Hyaluronidase

e. Hyaluronidase

A 5-year-old male patient presents to his local accident and emergency department with his mother. Four days previously, he fell and sustained a graze.  His mother tended to the graze although she is now concerned that the wound is infected.   On examination, the patient is irritable and there is a small area of erythema around the graze.  No pus or lymphadenopathy were present and movement of the elbow was unrestricted.

Which of the following organisms could be causing this patient’s infection?
a. Coagulase negative Staphylococci

b. Pseudomonas aeruginosa

c. Haemophilus influenza

d. Streptococcus pyogenes

e. Clostridium difficile

d. Streptococcus pyogenes

A 20-year-old patient visits his local GP surgery after experiencing an episode of nausea, vomiting and abdominal cramps.  Upon questioning the patient reveals that his family ate a Chinese takeaway 48 hours previously. No other family member has experienced the same symptoms, although the patient had decided to reheat the leftovers, including the rice, for breakfast the following morning.

The toxins causing this patient’s symptoms are considered to be of which type?
a. Pore-forming toxins

b. Cytotoxins

c. Super-antigen toxins

d. Neurotoxins

e. Enterotoxins

e. Enterotoxins

A 20-year-old patient visits his local GP surgery after experiencing an episode of nausea, vomiting and abdominal cramps.  Upon questioning the patient reveals that his family ate a Chinese takeaway 48 hours previously. No other family member has experienced the same symptoms, although the patient had decided to reheat the leftovers, including the rice, for breakfast the following morning.

Which of the following organisms could be causing this patient’s infection?
a. Bacillus anthracis

b. Clostridium botulinum

c. Bacillus cereus

d. Clostridium tetani

e. Clostridium difficile

c. Bacillus cereus

A 20-year-old patient visits his local GP surgery after experiencing an episode of nausea, vomiting and abdominal cramps.  Upon questioning the patient reveals that his family ate a Chinese takeaway 48 hours previously. No other family member has experienced the same symptoms, although the patient had decided to reheat the leftovers, including the rice, for breakfast the following morning.

 Which of the following virulence factors would be associated with the symptoms this patient experienced?

a. Phospholipase C

b. Emetic toxin

c. Botulinum toxin

d. Diarrhoeal toxin

e. Epsilon toxin

b. Emetic toxin

A 25-year-old female patient presented to the local accident and emergency department with a 12-hour history of abdominal pain, worsening cough and difficulty breathing.  The patient was diagnosed with cystic fibrosis as a young child and has recently been suffering from a range of chest infections, which, until now, have been reasonably easy to treat.

Which of the following actions is associated with Pyocyanin production?

a. Increases iron metabolism in low iron environments

b. Production of exotoxin A

c. Inhibition/block of protein synthesis

d. Production of neuraminidase

e. Catalysis of molecular oxygen to water

Increases iron metabolism in low iron environments

A 25-year-old female patient presented to the local accident and emergency department with a 12-hour history of abdominal pain, worsening cough and difficulty breathing.  The patient was diagnosed with cystic fibrosis as a young child and has recently been suffering from a range of chest infections, which, until now, have been reasonably easy to treat.

Which of the following organisms could be causing this patient’s infection?
a. Streptococcus pneumoniae

b. Klebsiella pneumoniae

c. Pseudomonas aeruginosa

d. Haemophilus influenzae

e. Bordetella pertussis

c. Pseudomonas aeruginosa

A 25-year-old female patient presented to the local accident and emergency department with a 12-hour history of abdominal pain, worsening cough and difficulty breathing.  The patient was diagnosed with cystic fibrosis as a young child and has recently been suffering from a range of chest infections, which, until now, have been reasonably easy to treat.

Which of the following virulence factors are associated with the tissue damage caused during this infection?

a. Catalase

b. Cytochrome oxidase

c. Endotoxin

d. Phospholipase C

e. Hyaluronidase

d. Phospholipase C

Which of the following cells walls has a thicker peptidoglycan layer?

Gram negative

Gram positive

Acid fast

Gram Positive

When observing a Gram positive organisms under the microscope, what colour would you expect the organism to be?

Blue

Pink

Purple

Purple.

The organism appears purple as it retains the primary, crystal violet, stain in its thick peptidoglycan layer.

Do Staphylococci possess the catalase enzyme?

Yes.

Staphylococci are catalase positive.

Which of the following Staphylococci are mostly associated with disease?

Toxin C

Toxin D

Toxin A

Toxin B

Toxin A.

Toxin A is the enterotoxin that is mostly associated with gastrointestinal disease.

What is the role of Protein A?

Bind to Fc receptors of antibodies rendering them inactive.

Bind to fibrinogen and convert to fibrin to form a clot.

Membrane damaging toxin.

Assist in the bacteria gaining entry into the cell.

Protein A binds to the Fc receptors of antibodies enabling the bacteria to evade the immune system.

What percentage of Staphylococci produce enterotoxins?

30-50%

10-30%

40-60%

20-40%

30-50% of Staphylococci produce enterotoxins.

Can Staph aureus produce a capsule?

Yes.  Although only occasionally seen in vitro, this can help the bacteria to adhere to host cells.  It also helps to inhibit chemotaxis and phagocytosis.

Which types of coagulase does the tube coagulase investigation test for?

Both bound and free coagulase.

Bound coagulase.

Free coagulase.

Both bound and free coagulase.

What percentage of Staphylococci strains produce hyaluronidase?

90%

50%

70%

30%

90% of Staphylococci produce hyaluronidase, this is why Staph aureus is associated with skin and soft tissue infections.

Penicillinase enzymes aid the bacteria in resisting which class of antibiotics?

Aminoglycoside antibiotics

Beta-lactam antibiotics

Tetracycline antibiotics

Quinolone antibiotics 

Beta-lactam antibiotics

Penicillin falls in the beta-lactam class of antibiotics and penicillinases break down the structure of these antibiotics rendering them ineffective.

Which of the following conditions is associated with toxin producing Staph aureus?

Toxic Shock Syndrome

Abscesses

Folliculitis

Cellulitis

Toxic shock syndrome is associated with the production of the TSST-1 toxin.

Would antibiotics be prescribed to a patient suffering from Staphylococcal food poisioning?

No

Antibiotics would not be prescribed, as this is the action of the toxin not the bacteria.  Patients would be advised to keep rehydrated.

What percentage of septicaemias are associated with Staph aureus?

5%

10%

15%

20%

15%, it is thought that approximately 15% of septicaemias are caused by Staph aureus.

Which of the following genes are associated with penicillin binding protein 2 production?

TEM gene.

CTX gene.

Mec A gene.

SHV gene

The Mec A gene is responsible for the antibiotic resistance demonstrated by MRSA.

Are coagulase negative staphylococci considered the cause of opportunistic infections? 

Yes. This is because they are associated with infections in immunocompromised patients.

Which of the following laboratory investigations will help to differentiate Staphylococci from Streptococci?

Coagulase

DNase

Catalase

Gram stain

Catalase

Staphylococci are catalase positive and Streptococci are catalase negative.

Why is hyaluronidase important?

Breaks down hyaluronic acids in connective tissue. helps spread of bacteria through tissues. >90% strains produce this enzyme

What are the clinical skin conditions associated with S.Aureus

Impetigo

Scolded Skin

bacteremia caused by - skin infections, post op, catheter related

What are the clinical non-skin conditions associated with S.Aureus

Food poisoning (Intoxication rather than infection)

Pneumonia

Osteomyelitis

Septic arthritis

What is the main clinical condition associated with Streptococcus pyogenes? (Group A Strep)

Pharyngitis

Sore throat, fever, headache malaise

Do Streptococci possess the enzyme catalase?

No

Streptococci which demonstrate no haemolysis at all are classed as exhibiting which type of haemolysis?

Beta

Alpha

Gamma

Gamma

Gamma haemolysis is the term used for those organisms showing no haemolysis on a blood agar plate.

Streptococci which demonstrate complete haemolysis are classed as exhibiting which type of haemolysis?

Gamma

Alpha

Beta

Beta

Red blood cells are broke down by the toxin streptolysin.

Streptococci which demonstrate incomplete haemolysis are classed as exhibiting which type of haemolysis?

Gamma

Beta

Alpha

Alpha

Streptococcus pneumoniae has over how many different strains?

50

100

150

90

90

Which of the following toxins are produced by Streptococcus pneumoniae causing host tissue damage?

Shiga toxin 

Pneumolysin

Toxic shock syndrome toxin

Spe A

Pneumolysin

Pneumolysin is a cytoxin and is responsible for the damage associated with bacterial pneumonia.

Which of the following vaccines are offered to patients over the age of 65, to prevent Streptococcus pneumoniae infections?

Prevenar

Fluzone

Afluria

Pneumovax

Pneumovax

Which of the following Streptococci does NOT produce beta haemolysis?

Group B

Group F

Group A

Group G

Group F

Also known as Streptococcus milleri,

The capsule of Group A streptococcus is composed of which of the following substances?

Hyaluronic acid

Fibronectin

Liproproteins

Fibrin

Hyaluronic acid

The capsule is composed of hyaluronic acid to evade the immune system.

During which stage of the bacterial growth curve is the capsule of Group A Streptococcus lost?

Stationary phase

The lag phase

Log phase

The death phase

Stationary phase

Which of the following conditions are suppurative infections associated with Group A Streptococcus.

You may select more than one answer to this question.

Tonsillitis

Gas gangrene

Food poisoning

Cellulitis

Tonsillitis & Cellulitis

Which of the following exotoxins are associated with necrotising fasciitis?

TSST-1

Cholera toxin

Spe A and B

Shiga toxin

Spe A and B

Which of the following organs are affected by rheumatic fever?

Lungs

Heart

Liver

Skin

Heart

In which of the following areas would Group B streptococci be found as normal flora?

In the respiratory tract 

On the skin

In the vagina

In the vagina

Which of the following clinical conditions are associated with Group F, or Streptococcus milleri?

Abscesses

Cellulitis

Throat infections.

Impetigo

Abscesses

Which of the following enterococci is responsible for 80-90% of human infections?

Enterococcus faecium

Enterococcus termitis

Enterococcus avium

Enterococcus faecalis

Enterococcus faecalis

Patient has come into hospital with a cut on lower leg, limb pain and fever. When looking at the leg it was swollen, warm to the touch and evidence of red colouration moving up the leg.

What is your initial thoughts?

Cellulitis

Erysipelas

Impetigo

Allergic reaction

Cellulitis

Patient has come into hospital with a cut on lower leg, limb pain and fever. When looking at the leg it was swollen, warm to the touch and evidence of red colouration moving up the leg.

Which two of the following organisms could be associated with the patients infection?

Staphylococcus aureus

Clostridium botulinum

Streptococcus pyogenes

Varicella zoster

Staphylococcus aureus

Streptococcus pyogenes

You have isolated a Group A Streptococcus. When observing this organism using a Gram stain which of the following would you expect to see?

Gram positive bacilli

Gram negative bacilli

Gram positive cocci

Gram negative cocci

Gram positive cocci

Patient has come into hospital with a cut on lower leg, limb pain and fever. When looking at the leg it was swollen, warm to the touch and evidence of red colouration moving up the leg.

Which two of the following virulence factors produced by this organism would aid in causing this patients infection?

Catalase

Hyaluronidase

Coagulase

F Protien

Hyaluronidase

F Protein

Patient has come into hospital with a cut on lower leg, limb pain and fever. When looking at the leg it was swollen, warm to the touch and evidence of red colouration moving up the leg.

After 24 hours the skin colour is changing from red to grey-blue, there are open sores and increased exudate.

What would you diagnose?

Cellulitis

Erysipelas

Necrotising fasciitis

Allergic reaction

Necrotising fasciitis

A patient has necrotising fasciitis, with a lot of dying tissue, and in blood cultures Group A Streptococcus has been isolated

Which of the following virulence factors produced by this organism would aid in causing this patients infection?

TSST-1 toxin

Spe A and Spe B toxins

Botulinum toxin

Shiga toxin

Spe A and Spe B toxins

Which of the following is true about the Spe A and B toxins?

They are super antigens

They are non-immunogenic

They help the bacteria to spread through the tissue

They break down DNA in purulent material

They are super antigens

A patient has necrotising fasciitis, with a lot of dying tissue, and in blood cultures Group A Streptococcus has been isolated.

Which two of the following virulence factors may also be contributing to the patients symptoms?

Streptolysin S & O

Urease

Streptokinase

Mucinase

Streptolysin S & O

Streptokinase

A patient has necrotising fasciitis, with a lot of dying tissue, and in blood cultures Group A Streptococcus has been isolated.

Which of the following should be considered as treatment options?

Watch and wait to see if the infection spreads further

Antibiotics alone

Debridement of the infected tissue and high dose antibiotics

Fluids alone

Out of the 51 species of Bacillus, how many are classed as strict pathogens?

1

4

3

2

1

Only Bacillus anthracis is classed as a strict pathogen.

Which route of entry is the most common cause of Bacillus anthracis?

Inoculation

Inhalation

Ingestion

Inoculation

Bacillus species produce the enzyme catalase.  True or false?

True

Bacillus species produce the enzyme catalase.

How many components does the anthrax toxin consist of?

4

2

1

3

3

The 3 components are the protective antigen, lethal factor and oedema factor. 

What are the 3 components of the anthrax toxin?

The 3 components are the protective antigen, lethal factor and oedema factor. 

Which of the following toxins is associated with symptoms after the consumption of rice?

Emetic toxin

Diarrhoeal toxin

Emetic toxin

the emetic toxin causes the patient to vomit after the consumption of contaminated rice.

Eye infections caused by Bacillus cereus are associated with contaminated.....

Soil

Contaminated food

Animal products

Soil

Eye infections are associated with penetration by objects contaminated by soil.

Which of the following are caused by Bacillus cereus?

Gastroenteritis

Skin infections

Urinary tract infections

Bacillus cereus is a cause of gastroenteritis

Which of the following are caused by Clostridium perfringens?

Auto immune disorders

Urinary tract infections

Gas Gangrene

Respiratory tract infection

Gas Gangrene

Which of the following Clostridium species is associated with hospital acquired infections?

Clostridium botulinum

Clostridium perfringens

Clostridium dificille

Clostridium tetani

Clostridium dificille

Clostridium dificille is associated with antibiotic associated diarrhoea

How many toxins are produced by Clostridium perfringens?

3

1

2

5

4

4

The toxins produced are alpha, beta, epsilon and iota.

How many toxins are produced by Clostridium difficile?

5

2

3

4

1

2

The two toxins are toxin A and B.

A patient is suffering from Clostridium difficile and have failed to respond to antibiotics.  Which of the following are potential treatment options?

Chemotherapy

Faecal transplant

Immunoglobulin

Surgery

Faecal transplant

Faecal transplants aim to repopulate the gastrointestinal tract to reduce the Clostridium difficile.

Clostridium botulinum causes a 

Rigid paralysis

Flaccid paralysis

Flaccid paralysis

Clostridium botulinum causes the muscles to relax.

The botulinum toxin blocks neurotransmission at the peripheral cholinergic synapses by preventing the release of.....

Acetylcholine

GABA

Dopamine

Acetylcholine

Acetylcholine activates muscles by blocking this the muscles are permanently relaxed

Clostridium tetani causes

Rigid paralysis

Flaccid paralysis

Rigid paralysis

Clostridium tetani has the opposite affect in comparison to Clostridium botulinum.

Clostridium tetani is prevented through the use of 

Surgery

A vaccine

Immunoglobulins

Antibiotics

A vaccine

TB possesses which type of bacterial cell wall?

Gram negative

Acid fast

Gram positive

Acid fast

Which of the following is thought to have contributed to the increase in reactivation of TB?

Concurrent rise in HIV

Lack of vaccinated individuals

Increase in elderly population

Concurrent rise in HIV

If untreated TB is fatal in what percentage of patients?

20%

50%

40%

30%

50% of untreated cases of TB are fatal

Which two of the following stains will aid in the diagnosis of TB?

Gram stain 

ZN stain

H&E stain 

Auramine stain 

ZN stain

Auramine stain

How is TB transmitted?

Faecal oral route

Person to person contact

Airborne droplets

Airborne droplets

During a TB infection an area of dead tissue develops surrounded by immune cells.  What is this collection of cells referred to?

Tubercle

Pustule

Nodule

Carcinoma

Tubercle

What percentage of TB cases are reactivated in the first five years?

20%

15%

5%

10%

5%

Purified protein derivative (PPD) is injected into a patient to identify past infection using the Mantoux test.  True or false?

True

Roughly how long will it take TB to grown in liquid culture

40-45 days

20-25 days

70-75 days

5-10 days

40-45 days

Which of the following therapeutic options are used in the treatment of TB?

Rifampicin

Penicillin

Erythromycin

Meropenem

Rifampicin

Rifampicin is used in combination with other drugs to treat TB.

Isoniazid is activated by.....

Urease

Coagulase

Citrase

Catalase

Catalse

isoniazid is activated by the presence of catalase.

Patient has laceration from falling off a tractor and into a muddy puddle two weeks ago. They have never had any vaccinations and they now have abdo bloating and jaw pain.

What is your differential diagnosis?

Food poisoning

Cellulitis

Tetanus

Gas gangrene

Tetanus

Patient has laceration from falling off a tractor and into a muddy puddle two weeks ago. They have never had any vaccinations and they now have abdo bloating and jaw pain.

Which of the following organisms could be associated with this patients condition?

Clostridium botulinum

Bacillus cereus

Clostridium tetani

Clostridium difficile

Clostridium tetani

Patient has laceration from falling off a tractor and into a muddy puddle two weeks ago. They have never had any vaccinations and they now have abdo bloating and jaw pain.

You have isolated Clostridium tetani. When observing this organism using a Gram stain, which of the following would you expect to see?

Gram positive bacilli

Gram negative bacilli

Gram positive cocci

Gram negative cocci

Gram positive bacilli

Which of the following virulence factors produced by Clostridium tetani would aid in the bacterial survival in hostile conditions?

Catalase

Alpha toxin

Spore formation

Hyaluronidase

Spore formation

A patient has a clostridium tetani infection but after 4 days their condition appears to be getting worse, muscle spasms, apneic event and cardiac arrest

Which of the following virulence factors may be contributing to this patients symptoms?

Tetanospasmin toxin

Botulinum toxin

Epsilon toxin

Phospholipase C

Tetanospasmin toxin

A second toxin is also associated with the symptoms of Tetanus. Which of the following toxins is produced by Clostridium tetani?

Toxin A

Enterotoxin

Epsilon toxin

Tetanolysin

Tetanolysin

The toxins associated with the clinical condition of Tetanus are considered which type of toxin?

Cytotoxins

Neurotoxins

Gastrotoxins

Pore-forming toxins

Neurotoxins

Motile Enterobacteriaceae express which type of flagella?

Monotrichous

Peritrichous

Amphitrichous

Lophotrichous

Peritrichous

Which component of the bacterial LPS is toxic to the host?

Core polysaccharide

Lipid A

O polysaccharide

Lipid A

Lipid A is bound within the bacterial cell wall, however when released can be very toxic to the host.

E.coli belongs to the bacterial family Escherichieae, which of the following organisms are also found within this group?

Shigella

Klebsiella

Proteus

Salmonella

Shigella

Strains of E.coli causing gastroenteritis can be divided into how many groups? 

4

5

3

2

5

There are 5 groups of E.coli that are associated with gastroenteritis infections.

Which of the following types of E.coli cause actin rearrangement within the host cell, causing a pedestal formation structure under the bacteria?

Enteroaggregative

Enteropathogenic

Enterotoxigenic

Enteroinvasive

Enteropathogenic

EPEC causes actin rearrangement within the host cell.

Which of the following types of E.coli produce a shiga like toxin resulting in Haemolytic uremic syndrome?

Enteropathogenic

Enteroinvasive

Enterotoxigenic

Enterohaemorrhagic

Enterohaemorrhagic

EHEC produces a shiga like toxin, that can result in haemolytic uremic syndrome.

How many Shigella organisms are required to cause an infection within the human host?

<200

<1000

<500

<400

<200

How many species of Shigella as associated with human disease?

5

2

7

4

4

Shigella dysenteriae produces which type of toxin?

Shiga toxin

Toxic shock syndrome toxin

A shiga like toxin

A haemolysin

Shiga toxin

How many different serotypes of Salmonella have been described?

>5000

>1500

>2000

>3000

<2000

What number of Salmonella organisms are required to cause an infection?

100

100,000

1000

1,000,000

1,000,000