3 Review Of Medical Microbiology Flashcards
(94 cards)
1
Q
Prokaryotic organisms
Unicellular organisms that lack a true nucleus and nuclear membrane
A
Bacteria
2
Q
Single, closed circular chromosome of double-stranded DNA
A
Nucleiod
3
Q
Has nucleiod, plasmid and chromosomal or plasmid exchange via transformation, transduction or conjugation
A
Genome
4
Q
3 Means of genetic recombination
A
Transformation
Transduction
Conjugation
5
Q
Energy generation of bacteria?
A
Electron transport chain
6
Q
Size of bacteria
A
0.2 to 2 um in diameter and 1-6 um in length
7
Q
3 nutritional needs of bacteria
A
Carbon
Nitrogen
Energy (ATP)
8
Q
Needed for synthesis of cellular constituents
A
Carbon
9
Q
Necessary for synthesis of protein
A
Nitrogen
10
Q
Needed for cellular functions
A
Energy
11
Q
Optimum pH for growth
A
7.0 to 7.5
12
Q
Optimum growth temperature
A
35 to 37 degree celsius
13
Q
Require oxygen for growth
A
Obligate aerobes
14
Q
Grow in the presence of oxygen but grow best in anaerobic environment
A
Aerotolerant aerobes
15
Q
Grow in both aerobic and anaerobic environments
A
Facultative anaerobes
16
Q
Cannot grow in the presence of oxygen
A
Obligate anaerobes
17
Q
Require concentrations of 5% to 10% CO2 for optimal growth
A
Capnophilic
18
Q
Grow optimally in a reduced level of oxygen
A
Microaerophilic
19
Q
Anaerobic process by which bacteria catabolize carbohydrates to produce energy
Carried out by both obligate and facultative anaerobes
A
Fermentation
20
Q
Final electron acceptor in fermentation
A
Organic compound
21
Q
Efficient process by which obligate aerobes and facultative anaerobes generate energy
More efficient mechanism for energy generation than fermentation
A
Respiration(oxidation)
22
Q
Final electron acceptor of respiration
A
Molecular oxygen
23
Q
Osmotic barrier and may be a site of antibiotic infection
Essential for bacterial viability
A
Cell membrane
24
Q
Thick, rigid peptidoglycan layer
Site of action of penicillin and cephalosporin
A
Gram positive cell wall
25
Component of gram positive wall
Teichoic and lipoteichoic acids
26
Thinner peptidoglycan layer, but also an outer LPS layer
Gram negative wall
27
Virulence factor
| Causes shock, sepsis, fever, DIC, and leukopenia
Endotoxin
28
Prevent or inhibit phagocytosis
| CHIEF DTERMINANT OF VIRULENCE
Capsule
29
Short, hairlike structures that serve to attach bacteria to target cells
Pili/Fimbriae
30
Exchange of DNA between bacteria during conjugation
Conjugation pili
31
Example of bacteria that uses conjugation pili
| Interference with attachment prevents infection
Neisseria gonorrhoeae
32
Means of survival that make disease control very difficult
Flagella
33
Spore forming genera
Bacillus and clostridium
34
Examines smears of clinical specimen
Initial treatment, and often presumptive ID can be made
Composition of it and its function
```
Gram’s stain
V primary stain
I Mordant-binds crystal violet to cell wall
A wash out any unbound dye
S Counterstain
```
35
Serves as internal control in gram stain that act as cellular debris
Stain pink
WBC AND RBC
36
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
Acridine orange stain
37
Detect bacteria in direct smears with excess cellular debris
Acridine orange stain
38
Demonstrates metachromatic granules and characteristic morphology of C. diphtheriae from Loefflercoagulated serum medium
Methylene blue
39
Detect organisms that do not stain well woth other conventional stains
Acid fast
40
Example of mycobacterium
Mycobacterium spp, Nocardia, Actinomyces
41
Primary stain in acid fast
| Contains a surface-active detergent to facilitate penetration of the stain without heating
Carbolfuchsin
42
Counterstain in acid fast
Methylene blue
43
Fluorescent stain that detect mycolic acid and can be used for staining acid fast organisms
Cell appear yellow against a dark background
Auramine-rodamine stain
44
Stained with auramine-rhodamine, decolorized with acid alcohol and then flooded with potassium permanganate
Process of auramine rodamine stain
45
Binds specifically to chitin which is found in fungal cell walls
Detect yeast cells and hyphae in skin scrapings and other specimens
Calcofluor white stain
46
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
Normal flora
47
Colonize an area for months or years
Resident flora
48
Present at a site temporarily
Transient flora
49
Live at the expense of the host
Parasite
50
Benefit of the host
Symbionts
51
Neutral effect on the host
Commensals
52
Harbors an organism without manifesting symptoms but is capable of transmitting infection
Carrier
53
Organisms that do not normally cause infection
Opportunists
54
Not eliminated by washing or superficial antisepsis
Skin
55
Effective barrier to microbial invasion
Intact skin
56
NF of skin in sebaceous glands
Propionobacterium acnes
57
NF OF SKIN
Micrococcus, Staphylococcus, diphtheroids
58
NF of mouth
Strep,
Coag (-) staph
Peptostreptococcus
Other anaerobes
59
NF of nose and nasopharynx
S. aureus, S. epidermidis and Strep
60
Present transiently during commjnity outbreaks of infections
Strep pneumoniae
H. influenzar
N. meningitidis
61
NF of GI
```
Bacteroides
Eubacterium
Anaerobic strep
Enterococcus
Clostridium
Enterobacteriaceae
```
62
NF of vagina
lactobacillus
Anaerobic gram (-) rod shaped bacteria
Gram pos cocci
63
Nonspecific mechanism of resistance to disease
Innate immunity or natural immunity
64
Examples of innate immunity
| Give 5
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
Response to a specific foreign antigen
Acquired or specific immunity
66
Response to immunizatio or disease
Active
67
Placental transfer or infusions of serum or plasma
Passive
68
Involves antibody production by B cell
Humoral response
69
Involves cells, such as macrophages, cytokines and T lymphocytes
Provides immunity against intracellular pathogens, including viruses, fungi and mycobacteria
Cell-mediated immunity
70
Criteria for a successful pathogen
```
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
Ditectly related to its virulence
Degree of pathogenicity
72
Virulence factors?
Adhesion
Capsular polysaccharide
Production of extracdllular toxins and enzymes
73
Bacteria that has low infective dose?
Shigella
74
Bacteria that has high infective dose
Salmonella
75
Transmission of bacteria?
1. Airborne transmission
2. Ingestion of contaminated food and water
3. Sexual transmission
4. Animal and human bites
5. Arthropod vectors
6. Zoonoses
76
General guidelines in collecting and handling of clinical specimens
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
Transport medium for stool
Buffered glycerol saline
| Cary-blair transport medium
78
Amount of blood to be collected for blood culture
20-30 ml for adult
| 1-5 ml for infants and small children
79
Effect of swabs in abscess aspirates or exudates as well as synovial, pericardial and chest fluid
Inhibit growth of anaerobes or increase the likelihood of contamination with indigenous bacterial flora from adjacent tissues
80
Guidelines in collection of specimen in the genital tract of male
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
Guidelines in collection of spx in the cervix of female
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
What is lethal to genital pathogens?
Refrigeration
83
Exemption in the transport of specimens in the lab
1. Temp sensitive organisms (neisseria)
2. Blood culture bottles
3. CSF
84
Least desirable collection and transport media
| Inappropriate for culturing anaerobes, although in some clinical settings, culturettes are often used
Swabs
85
Used in all labs
| Compositin of it?
BAP, 5% sheep RBC
86
For fastidipus isolates?
CAP
87
Specialized media that are used when specific organisms are suspected
MSA
Bismuth sulfite agat
Campylobacter agar
TCBS agar
88
Can be a substitute to EMB
MacConkey agar
89
Recommended for the culture of anaerobes
Prereduced anaerobically sterilized (PRAS) cultute media
90
Normal incubation temperature
35-37 degree celsius
91
Enhances the growth of fastidious bacterial isolates
Capnophilic atmosphere of 5-10% CO2
92
Recommended incubation of stool cultures for isolation of C. jejuni
Microaerophilic, capnophilic atmosphere at 42 to 45 degree celsius
93
Specimen rejection criteria
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
Appropriately cultured from feces
Clostridium species
