Micro

Question 0

First line of defense in body:

Answer 0

Skin
Mucous membranes
Normal microbiota

Question 1

Biofilms differ from planktonic cells in that biofilms:

1. Are more drug resistant
2. Have a slower growth rate
3. Synthesize matrix material
4. All of the above
5. None of the above

Answer 1

All of the above

Question 2

Second line of defense in body:

Answer 2

Phagocytes
Inflammation
Fever
Antimicrobial substances

Question 3

Third line of defense in the body:

Answer 3

Specific response
B cells
T cells
Antibodies

Question 4

Virulence

Answer 4

Extent of pathogenicity

Ex number of virulence factors

Question 5

Outcome of infection

Answer 5

Integrity of host defenses+ # microorganisms + virulence of microorganism

Question 6

Where are virulence genes?

Answer 6

Chromosome
Plasmids
Bacteriophages

Question 7

What are pathogenicity islands?

Answer 7

Unique region exclusively for virulence
On chromosomes and plasmids
Complete package required for delivery of pathogenic traits

Question 8

What are hydrolytic enzymes?

Answer 8

Proteases
Hemolysins
Neuraminidase
Collagenase
Hyaluronidase
Elastase
DNase 
Delete coagulase

Question 9

An envelope Constituent found in gram-negative bacteria but not in gram-positive bacteria is:
Peptidoglycan
Lipids
Cytoplasmic membrane
Periplasmic space
Proteins

Answer 9

Periplasmic space

Question 10

What type of bacteria is innately resistant to cell wall attacking antibiotics?

Answer 10

Micro plasma

Lacks a cell wall

Question 11

In order to deal with secretory immunoglobulins, mucosal pathogens often have a virulence factor called?

Answer 11

IgA1 protease

Question 12

A Species of bacteria well known for its capsule is

Answer 12

Pneumoniae

Question 13

A 37-year-old male is seen at an STI clinic for treatment of gonorrhea. prior treatments for this disease have successfully eradicated organism. however the man has not changed his behavior and has been repeatedly reinfected. what is the most likely strategy enabling the etiologic agent of this patient’s condition to cause repeated infection:

1) antigenic variation
2) siderophorenproduction
3) endospore formation
4) mutation in ribosomal protein gene
5) motility

Answer 13

Antigenic variation

Question 14

Define colony

Answer 14

Population of cells arising from a single cell or endospore or from a group of attached cells

Question 15

Define pure culture

Answer 15

Contains only one species or strain

Question 16

Define mixed culture

Answer 16

contains multiple strains or species

Question 17

What is an example of intracellular species

Answer 17

Chlamydia

Needs to have tissue to grow

Question 19

Which growth phase do bacteria sporulate?

Answer 19

Stationary phase

Question 20

The bacterial growth period during which cells are synthesizing proteins and lipids in preparation for binary fission is known as the blank phase?

Answer 20

Lag phase

Question 21

When do penicillin and lysozyme work?

Answer 21

Log phase

Lag or log phase

Question 22

Each of the following is a typical property of obligate anaerobes except:
Generate 38 ATP
Lack catalase
Lack SOD
Grow best in the absence of air

Answer 22

Generates 38 ATP

Question 23

Clinically important atypical bacteria: no CW

Answer 23

Mycoplasma

Ureaplasma

Question 24

Clinically important atypical bacteria: spirochetes

Answer 24

Treponema
Borrelia
Leptospira

Question 25

Clinically important atypical bacteria: obligate intracellular

Answer 25

Chlamydia Chlamydophila Rickettsia

Question 26

Clinically important atypical bacteria: filamentous, non acid fast

Answer 26

Actinomyces | Streptomyces

Question 27

Clinically important atypical bacteria: filamentous, acid fast

Answer 27

Mycobacterium | Nocardia (weakly)

Question 28

What requirements need to be met for bacterial growth?

Answer 28

Temperature, optimum is 37 C, physiologic pH, optimum is 6.5-7.5, physiologic O2 nutritional factors

Question 29

A bacterium is cultured from a wound. When hydrogen peroxide is added to coloinize of the organism, effervescence is produced. The enzyme responsible for this bubbling is: 1) Catalase 2) Coagulase 3) Hyaluronidase 4) Superoxide dismutase 5) transpeptidase

Answer 29

Catalase`

Question 30

A 17 year old male suffered a foot laceration while swimming in a polluted water area in a river. He did not seek medical treatment, and the wound developed an abscess w/ a foul smelling exudate. One of the bacteria isolated from the exudate lacked superoxide dismutase and catalase. Which of the following best describe the organism? 1) Aerobe 2) Anaerobe 3) Facultative anaerobe 4) More virulent than one that has the 2 enzymes

Answer 30

anaerobe

Question 31

A pharmaceutical company has developed a new compound that is well tolerated by the body and inhibits ergosterol synthesis. Screening of infectious agent activity should be directed toward?

Answer 31

Fungi

Question 32

Each of the following statements concerning fungi is correct except: 1) Have chitin in their cell walls and ergosterol in their cell membranes 2) Have eukaryotic nuclei and contain mitochondria in their cytoplasm 3) Produce endotoxins and exotoxins

Answer 32

Produce endotoxins and exotoxins | endo in Gram - lipid A

Question 33

``` Approximately what % of human infections are due to fungi? 0.1 1 10 20 40 60 ```

Answer 33

20%

Question 34

``` A 71 year old woman was admitted w/ recurrence of poorly differentiated squamous cell carcinoma of the cervix. She underwent extensive gynecologic surery and was maintained postop on broad spectrum intravenous antibiotics. The woman had a central venous catheter placed on the day of the surgery. Beginning 3 days postop, she had temps o f38-38.5 C, which persisted w/o clear source. On day 8 postop, she had temps of 39.2C. Cultures of blood and of the tip of the central line both grew an agent with large ovoid cells, some of which had constricted bud at their ends. The agent, identified as a normal microbiota organism, is most likely: Candida albicans Escherichia coli Staphylococus aureus Aspergillus nidulans None of the above ```

Answer 34

Candida albicans

Question 35

Each of the following statements concerning fungi is correct except: Yeasts are fungi that reproduce by budding Molds are fungi that have elongated filaments called hyphae Thermally dimorphic fungi exist as yeasts or spherules at 37 C and as molds at 25C Both yeasts and molds have a cell wall made of peptidoglycan

Answer 35

Both yeasts and molds have a cell wall made of peptidoglycan

Question 36

64 yo male is admitted w/ mild nuchal rigidity, disorientation to time and place, and marked confusion. A CSF sampled is obrained, stained w/ india ink and examined microscopically. Stained cells average app 6 micrometers in diameter, and contained 80s ribosomes. The likely etiologic agent of this patient’s condition is: Cryptococcus neoformans Mycoplasma pneumoniae Streptococcus pneumoniae

Answer 36

Cryptococcus neoformans

Question 37

Spores and endospores are similar in that they: Are reproductive structures Are resistant to acids, bases, and radiation Often infect the lungs Are produced by bacteria None of the above All of the above

Answer 37

none of the above

Question 38

``` If positive cultures were grown on appropriate media, would this mean a disease state? Urine directly from bladder lung biopsy throat swab fecal sample cardiac valve biopsy joint aspirate ```

Answer 38

``` yes maybe, location no no yes yes ```

Question 39

Leading cause of healthcare associated infection and spread of multiresistant microbes? Length of stay Increasing immunosuppressed population Failure to perform appropriate hand hygiene Failure to clean rooms adequately between patients Increasing number of prescription drugs

Answer 39

failure to perform proper hand washing

Question 40

Distilled water containing Pseudomonas (gram-negative rod) was sterilized and used to wash sterile cardiac catheters. Three patients undergoing cardiac catheterization developed fever and shock. If the water and catheters were sterile, why did the patients exhibit these symptoms?

Answer 40

lipid A portion survived

Question 41

``` If antisepsis is not performed on a venipuncture site, blood cultures would most likely be contaminated with: E coli Clostridium difficile Staphylococcus epidermidis Lactobacillus spp. ```

Answer 41

staph epidermidis

Question 42

``` The minumum concentation of alchohol necessary to kill bacteria and envelop viruses is: 30 40 50 60 70 ```

Answer 42

60%

Question 43

For each item below, give a reasonable method of sterilization [choices are A)autoclave, B)filtration, C)UV radiation, D)γ-radiation, E)bleach, F)oven, regular]. The method must not destroy the item nor render it useless. Method may only be used once. - room air - plastic syringe - heat-sensitive liquid drug - biohazardous waste - surgical blade - hospital bathroom contaminated with Clostridium difficile

Answer 43

- (C) - (D) - (B) - (A) - (F) - (E)

Question 44

``` Which of the following would be most resistant to disinfection? (based on her ranking) Clostridium endospores Enveloped virus Mycobacterium Prions Staphylococcus aureus ```

Answer 44

prions

Question 45

You have just touched a bedpan from a patient with c diff associated diarrhea. The most appropriate procedure to clean your hands is: Alcohol based handrub Flaming over a bunsen burner Soap and water

Answer 45

soap and water