3 Review Of Medical Microbiology Flashcards

1
Q

Prokaryotic organisms

Unicellular organisms that lack a true nucleus and nuclear membrane

A

Bacteria

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2
Q

Single, closed circular chromosome of double-stranded DNA

A

Nucleiod

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3
Q

Has nucleiod, plasmid and chromosomal or plasmid exchange via transformation, transduction or conjugation

A

Genome

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4
Q

3 Means of genetic recombination

A

Transformation
Transduction
Conjugation

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5
Q

Energy generation of bacteria?

A

Electron transport chain

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6
Q

Size of bacteria

A

0.2 to 2 um in diameter and 1-6 um in length

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7
Q

3 nutritional needs of bacteria

A

Carbon
Nitrogen
Energy (ATP)

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8
Q

Needed for synthesis of cellular constituents

A

Carbon

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9
Q

Necessary for synthesis of protein

A

Nitrogen

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10
Q

Needed for cellular functions

A

Energy

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11
Q

Optimum pH for growth

A

7.0 to 7.5

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12
Q

Optimum growth temperature

A

35 to 37 degree celsius

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13
Q

Require oxygen for growth

A

Obligate aerobes

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14
Q

Grow in the presence of oxygen but grow best in anaerobic environment

A

Aerotolerant aerobes

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15
Q

Grow in both aerobic and anaerobic environments

A

Facultative anaerobes

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16
Q

Cannot grow in the presence of oxygen

A

Obligate anaerobes

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17
Q

Require concentrations of 5% to 10% CO2 for optimal growth

A

Capnophilic

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18
Q

Grow optimally in a reduced level of oxygen

A

Microaerophilic

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19
Q

Anaerobic process by which bacteria catabolize carbohydrates to produce energy
Carried out by both obligate and facultative anaerobes

A

Fermentation

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20
Q

Final electron acceptor in fermentation

A

Organic compound

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21
Q

Efficient process by which obligate aerobes and facultative anaerobes generate energy

More efficient mechanism for energy generation than fermentation

A

Respiration(oxidation)

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22
Q

Final electron acceptor of respiration

A

Molecular oxygen

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23
Q

Osmotic barrier and may be a site of antibiotic infection

Essential for bacterial viability

A

Cell membrane

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24
Q

Thick, rigid peptidoglycan layer

Site of action of penicillin and cephalosporin

A

Gram positive cell wall

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25
Q

Component of gram positive wall

A

Teichoic and lipoteichoic acids

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26
Q

Thinner peptidoglycan layer, but also an outer LPS layer

A

Gram negative wall

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27
Q

Virulence factor

Causes shock, sepsis, fever, DIC, and leukopenia

A

Endotoxin

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28
Q

Prevent or inhibit phagocytosis

CHIEF DTERMINANT OF VIRULENCE

A

Capsule

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29
Q

Short, hairlike structures that serve to attach bacteria to target cells

A

Pili/Fimbriae

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30
Q

Exchange of DNA between bacteria during conjugation

A

Conjugation pili

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31
Q

Example of bacteria that uses conjugation pili

Interference with attachment prevents infection

A

Neisseria gonorrhoeae

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32
Q

Means of survival that make disease control very difficult

A

Flagella

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33
Q

Spore forming genera

A

Bacillus and clostridium

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34
Q

Examines smears of clinical specimen
Initial treatment, and often presumptive ID can be made

Composition of it and its function

A
Gram’s stain
V primary stain
I   Mordant-binds crystal violet to cell wall
A  wash out any unbound dye
S   Counterstain
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35
Q

Serves as internal control in gram stain that act as cellular debris
Stain pink

A

WBC AND RBC

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36
Q

Orange fluorescent stain that is used to detect bacteria in body fluids
Very sensitive and can detect small numbers of bacteria that are living or dead

A

Acridine orange stain

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37
Q

Detect bacteria in direct smears with excess cellular debris

A

Acridine orange stain

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38
Q

Demonstrates metachromatic granules and characteristic morphology of C. diphtheriae from Loefflercoagulated serum medium

A

Methylene blue

39
Q

Detect organisms that do not stain well woth other conventional stains

A

Acid fast

40
Q

Example of mycobacterium

A

Mycobacterium spp, Nocardia, Actinomyces

41
Q

Primary stain in acid fast

Contains a surface-active detergent to facilitate penetration of the stain without heating

A

Carbolfuchsin

42
Q

Counterstain in acid fast

A

Methylene blue

43
Q

Fluorescent stain that detect mycolic acid and can be used for staining acid fast organisms

Cell appear yellow against a dark background

A

Auramine-rodamine stain

44
Q

Stained with auramine-rhodamine, decolorized with acid alcohol and then flooded with potassium permanganate

A

Process of auramine rodamine stain

45
Q

Binds specifically to chitin which is found in fungal cell walls

Detect yeast cells and hyphae in skin scrapings and other specimens

A

Calcofluor white stain

46
Q

Microorganisms that are frequently found on or in the bodies of healthy personss

Local conditions select for those organisms suited for growth in a particular area

A

Normal flora

47
Q

Colonize an area for months or years

A

Resident flora

48
Q

Present at a site temporarily

A

Transient flora

49
Q

Live at the expense of the host

A

Parasite

50
Q

Benefit of the host

A

Symbionts

51
Q

Neutral effect on the host

A

Commensals

52
Q

Harbors an organism without manifesting symptoms but is capable of transmitting infection

A

Carrier

53
Q

Organisms that do not normally cause infection

A

Opportunists

54
Q

Not eliminated by washing or superficial antisepsis

A

Skin

55
Q

Effective barrier to microbial invasion

A

Intact skin

56
Q

NF of skin in sebaceous glands

A

Propionobacterium acnes

57
Q

NF OF SKIN

A

Micrococcus, Staphylococcus, diphtheroids

58
Q

NF of mouth

A

Strep,
Coag (-) staph
Peptostreptococcus
Other anaerobes

59
Q

NF of nose and nasopharynx

A

S. aureus, S. epidermidis and Strep

60
Q

Present transiently during commjnity outbreaks of infections

A

Strep pneumoniae
H. influenzar
N. meningitidis

61
Q

NF of GI

A
Bacteroides
Eubacterium
Anaerobic strep
Enterococcus
Clostridium
Enterobacteriaceae
62
Q

NF of vagina

A

lactobacillus
Anaerobic gram (-) rod shaped bacteria
Gram pos cocci

63
Q

Nonspecific mechanism of resistance to disease

A

Innate immunity or natural immunity

64
Q

Examples of innate immunity

Give 5

A

Physical barriers- skin mucous membranes, cilia
Cleansing action-of fluids in the eyes, respiratory, digestive, urinary and genital tracts
Antimicrobial substances-secretory IgA, lysozyme, b-lysins and INF
Indigenous microbial flora-compete with invading bacteria and produce inhibitory bacteriocins
Phagocytosis, inflammation and complement activation

65
Q

Response to a specific foreign antigen

A

Acquired or specific immunity

66
Q

Response to immunizatio or disease

A

Active

67
Q

Placental transfer or infusions of serum or plasma

A

Passive

68
Q

Involves antibody production by B cell

A

Humoral response

69
Q

Involves cells, such as macrophages, cytokines and T lymphocytes
Provides immunity against intracellular pathogens, including viruses, fungi and mycobacteria

A

Cell-mediated immunity

70
Q

Criteria for a successful pathogen

A
DASMA
D- egree of pathogenicity
A- ppopriate portal of entry
S- ufficient infective dose
M- ust be able to overcome host resistance mechanisms including immune responses and cause disease in SUSCEPTIBLE HOST
A- ppropriate portal of exit
71
Q

Ditectly related to its virulence

A

Degree of pathogenicity

72
Q

Virulence factors?

A

Adhesion
Capsular polysaccharide
Production of extracdllular toxins and enzymes

73
Q

Bacteria that has low infective dose?

A

Shigella

74
Q

Bacteria that has high infective dose

A

Salmonella

75
Q

Transmission of bacteria?

A
  1. Airborne transmission
  2. Ingestion of contaminated food and water
  3. Sexual transmission
  4. Animal and human bites
  5. Arthropod vectors
  6. Zoonoses
76
Q

General guidelines in collecting and handling of clinical specimens

A
  1. Should be from the infection site and not contaminated by the surrounding area
  2. Should be collected before antimicrobials are administered
  3. Appropriate collection devices and containers should be used and must be sterile. Aseptic techniques is required
  4. Should be labeled with Px ID, date and time of collection and the source of specimen
77
Q

Transport medium for stool

A

Buffered glycerol saline

Cary-blair transport medium

78
Q

Amount of blood to be collected for blood culture

A

20-30 ml for adult

1-5 ml for infants and small children

79
Q

Effect of swabs in abscess aspirates or exudates as well as synovial, pericardial and chest fluid

A

Inhibit growth of anaerobes or increase the likelihood of contamination with indigenous bacterial flora from adjacent tissues

80
Q

Guidelines in collection of specimen in the genital tract of male

A
  1. Exudates may be expressed from the urethral orifice or small-diameter swab may be inserted to 3-4 cm into the urethra
  2. Played immediately on the appropriate media and not allowed to dry or be exposed to cold temp
  3. Direct gram’s stain smear should be prepared
81
Q

Guidelines in collection of spx in the cervix of female

A
  1. Cervical mucus plug is removed
  2. Sterile swab is inserted into the cervix, rotated, and allowed to remain for a few seconds
  3. Plated immediately to appropriate media
  4. Gram’s stain.
82
Q

What is lethal to genital pathogens?

A

Refrigeration

83
Q

Exemption in the transport of specimens in the lab

A
  1. Temp sensitive organisms (neisseria)
  2. Blood culture bottles
  3. CSF
84
Q

Least desirable collection and transport media

Inappropriate for culturing anaerobes, although in some clinical settings, culturettes are often used

A

Swabs

85
Q

Used in all labs

Compositin of it?

A

BAP, 5% sheep RBC

86
Q

For fastidipus isolates?

A

CAP

87
Q

Specialized media that are used when specific organisms are suspected

A

MSA
Bismuth sulfite agat
Campylobacter agar
TCBS agar

88
Q

Can be a substitute to EMB

A

MacConkey agar

89
Q

Recommended for the culture of anaerobes

A

Prereduced anaerobically sterilized (PRAS) cultute media

90
Q

Normal incubation temperature

A

35-37 degree celsius

91
Q

Enhances the growth of fastidious bacterial isolates

A

Capnophilic atmosphere of 5-10% CO2

92
Q

Recommended incubation of stool cultures for isolation of C. jejuni

A

Microaerophilic, capnophilic atmosphere at 42 to 45 degree celsius

93
Q

Specimen rejection criteria

A
  1. 24 hr urine or sputum collections
  2. Specimens received in nonsterile or contaminated containers (leaked out)
  3. Specimens contaminated with barium or other foreign substances
  4. Culturing Foley catheter tips
  5. Saliva instead of sputum
  6. Unrefrigwrated urine specimens 2 hrs or more post collection
  7. Anaerobic culturing of midstream urine, upper respiratory tract, superficial skin or feces specimens
94
Q

Appropriately cultured from feces

A

Clostridium species