GENERALITIES Flashcards
1
Q
Mechanism of Resistance in some Antibiotics
A
2
Q
• Reducing microbial contamination to an acceptable “safe” level (terminology used in food safety)
A
Sanitization
• Heating cutlery
(e.g. at KFC!)
3
Q
the only bacteria WITH sterols.
A
mycoplasma
4
Q
• Rapid cell division occurs
• b-Lactam antibiotics act during this phase
• Constant growth rate
• Continues until either one or more nutrients in the medium become exhausted, or toxic metabolites accumulate and inhibit growth.
A
PHASE 2: LOG OR EXPONENTIAL PHASE
5
Q
Protein A is found in
A
S. aureus
6
Q
Appearance of the vacuolated neurons, as well as their loss of function and the lack of an immune response or inflammation
A
SPONGIFORM ENCEPHALOPATHIES
7
Q
- Most of the cells die because nutrients have been exhausted
- Negative growth rate
A
PHASE 4: DECLINE OR DEATH PHASE
8
Q
o induces the overproduction of cytokines, such as TNF & IL-1
o activates the complement cascade
o activates the coagulation cascade, resulting in disseminated intravascular coagulation
A
Lipid A
9
Q
Which of the following is the OLDEST acid-fast staining method, which requires heating the specimen during the procedure?
A
Ziehl-Neelsen
10
Q
- Noncellular infectious proteins
- Naked proteins that have the same amino acid sequence as certain normal human cell surface proteins but have folded differently
- These are misfolded proteins with the ability to transmit their misfolded shape onto normal variants of the same protein. They characterize several fatal and transmissible neurodegenerative diseases in humans and many other animals
- Pathology: dysfunction due to protein misfolding
A
PRIONS
11
Q
• Physical removal of microorganisms by using such things as soaps or detergents
A
Degerming or Cleaning
- Handwashing with soap and running water
12
Q
Destroys or eliminating ALL forms of microbial life, including spores
A
Sterilization
- Steam sterilization (autoclaving)
- Note that prions require anadapted form ofsterilization because of their high resistanceto any form of sterilization.
13
Q
Xylose-McCullough-Johnson-Harris (EMJH) / Fletcher’s Medium
A
Leptospira Interrogans
14
Q
A–B subunit of Exotoxins
A
o A subunit is the active (toxic) subunit
o B subunit is the binding subunit
15
Q
completely dependent on oxygen for ATP-generation
A
Obligate Aerobes
- • Nocardia, Bacillus cereus, Neisseria, Pseudomonas, Bordetella, Legionella, Brucella, Mycobacterium, Leptospira, Mycoplasma pneumoniae
16
Q
mediate attachment of bacteria
A
pili
17
Q
What are the non-essential components of bacteria?
A
18
Q
DNA is transfered from one bacterium to another
A
Conjugation
19
Q
Spore: formed by gram-positive rods, especially ______
A
Bacillus and Clostridium spp
20
Q
Prokaryotic ribosomes
A
50S + 30S = 70S
21
Q
Bordet-Gengou Agar
A
Bordetella pertussis
22
Q
Eukaryotic Ribososmes
A
60S + 40S = 80S
23
Q
Purified DNA is taken up by a cell
A
Transformation
24
Q
BACTERIA WITH IGA PROTEASE
A
SHiNe My Gong
Streptococcus pneumoniae
Haemophilus influenzae
Neisseria Meningitidis
Neisseria Gonorrhoeae
25
What are the essential components of bacteria
26
utilize oxygen if it is present, but can use fermentation in its absence
**Facultative Anaerobes**
## Footnote
• Staphylococcus, Bacillus anthracis, Corynebacterium, Listeria, Mycoplasmas (in general)
27
Barbour-Stoenner-Kelly (BSK)
Borrelia burgdorferi
28
All bacterial capsules are composed of polysaccharide EXCEPT
**Bacillus anthracis (polypeptide of D-glutamate)**
29
Lowenstein Jensen Agar
M. Tuberculosis
30
Tellurite Agar
Corynebacterium diphtheriae
31
M Protein is found in
S. pyogenes
32
Bile Esculin Media
group D streptococci
33
Bacterial reproduction occurs via
binary fission
34
Which group of infectious agents does not require DNA as genetic material?
Prions
35
allows adherence to mucous membranes
immunoglobulin A (IgA) protease
36
What king of sterols do these organisms have?
Protozoa and animals – \_\_\_\_\_\_
Fungi – \_\_\_\_\_\_\_
Protozoa and animals – cholesterol
Fungi – ergosterol
37
Which component of the susceptibility to lysozymes?
Outer membrane
38
CHOCOLATE AGAR + FACTORS X and V
Haemophilus influenzae
39
mediates **strong adherence** to surface of human cells
glycocalyx
40
41
Endotoxin Shock is caused by presence of \_\_
Lipid A
42
Thiosulfate Citrate Bile Salts (TCBS) Agar
Vibrio cholera
43
exclusively anaerobic but insensitive to the presence of oxygen
**Aerotolerant Anaerobes**
## Footnote
• Propionibacterium (Cutibacterium), Lactobacillus
44
All bacteria have a cell wall composed of peptidoglycan except \_\_\_\_
Mycoplasma – Mycoplasma do not have cells walls!
45
All exotoxins are HEAT-LABILE EXCEPT
Staphylococcal Enterotoxin
46
Gram Staining Steps
47
Colon normal flora
Bacteroides, Escherichia coli
48
Exotoxin vs Endotoxin
49
Dental plaque normal flora
Streptococcus mutans
50
surface proteins called _____ mediate binding to endothelium and to extracellular proteins such as fibronectin
curli
51
Eaton
Mycoplasma pneumoniae
52
accelerates formation of a fibrin clot coating the organisms with a layer of fibrin
coagulase
53
BLOOD-BRAIN BARRIER PENETRABILITY
54
Unique to Gram (-) organisms
Endotoxin/lipopolysaccharide
Periplasmic space
Outer membrane
55
autoclave must reach and maintain a temperature of ______ for around ______ by using saturated steam under at least _____ of pressure.
121° C
15-20 minutes
15 psi
56
Vagina normal flora
* Lactobacillus vaginalis
* Escherichia coli
* Streptococcus agalactia
57
Lipopolysaccharide on the outer membrane of gram-negative bacteria consists of \_\_\_
**Lipid A and O antigen → induction of IL-1 & TNF**
58
spread through subcutaneous tissue
collagenase and hyaluronidase
59
use fermentation but can tolerate low amounts of oxygen because they have SOD
**Microaerophiles**
## Footnote
• Streptococcus, spirochetes (Borreliella, Treponema), Campylobacter, Helicobacter
60
Examples of Bacterial Toxins
61
Bacteria not seen in Gram Stain
62
Eliminates many or all pathogenic microorganisms, **except bacterial spores, on inanimate objects**
Disinfection
* • Application ofrubbing alcohol – to inanimate objects
63
Unique to Gram (+) organisms
Teichoic Acid
64
Charcoal-yeast extract
Legionella pneumophila
65
* Exhaustion of nutrients or the accumulation of toxic products cause growth to cease completely (zero growth rate)
* Spores are formed
PHASE 3: STATIONARY PHASE
66
**PROPHAGE-CODED BACTERIA**
**Lysogenized strains of ABCDE**
* shigA – like toxin: EHEC
* Botulinum
* Cholera
* Diphtheria
* Erythrogenic toxin
\*genetic mechanism responsible for the conversion of a nontoxigenic strain to a toxigenic strain is **Lysogenic phage conversion**
67
toxic component of LPS
Lipid A
68
Bacterial Growth Cycle
## Footnote
* Cells are depleted of metabolites as the result of unfavorable condition
* Adaptation to new environment
* Nutrients are incorporated
* Vigorous metabolic activity occurs but cells do not divide
* Zero growth rate
PHASE 1: LAG PHASE
69
Chocolate Agar
N. meningitidis and N. gonorrhea from STERILE SITES
70
All gram-positive bacteria have NO endotoxin EXCEPT
Listeria monocytogenes
71
destroys both neutrophilic leukocytes and macrophages (e.g. Panton-Valentine leucocidin or PVL)
leucocidin
72
Antibiotics that have activity against **P. aeruginosa** include:
* **Aminoglycosides** (Gentamicin, Amikacin, Tobramycin, but not **Kanamycin**)
* **Quinolones** (Ciprofloxacin, Levofloxacin, but not **Moxifloxacin**)
* **Cephalosporins** (**Ceftazidime**, **Cefepime**, **Cefoperazone**,Cefpirome, Ceftobiprole, but not Cefuroxime, Cefotaxime, or Ceftriaxone)
* **Antipseudomonal Penicillins**: Carboxypenicillins (Carbenicillin and Ticarcillin), and Ureidopenicillins (Mezlocillin, Azlocillin, and Piperacillin). P. aeruginosa is intrinsically resistant to all other Penicillins.
* **Carbapenems** (Meropenem, Imipenem, Doripenem, but not **Ertapenem**)
* **Polymyxins** (Polymyxin B and Colistin)
* **Monobactams** (Aztreonam)
73
cannot grow in the presence of oxygen because they lack SOD, peroxidase and catalase
**Obligate Anaerobes**
## Footnote
• Actinomyces, Bacteroides, Clostridium
74
Skirrows Medium
Campylobacter, helicobacter
75
DNA is transferred by a VIRUS from one cell to another
Transduction
76
Egg Yolk agar
Clostridium perfringens
77
* microorganisms that are the **permanent residents** of the body
* **low-virulence** organisms in their usual anatomic site
* **colonization resistance** occurs when normal flora occupy receptor sites preventing pathogens from binding
NORMAL FLORA
78
Cetrimide Culture medium
Pseudomonas aeruginosa
79
Mannitol Salts
Staphylococci
80
Mouth normal flora
viridans Streptococci
81
Thayer Martin Agar
N. gonorrhea from NONSTERILE sites
82
* a.k.a. “transposable” elements
* Mobile genetic elements
* DNA pieces that move readily from one site to another either within or between the DNA of bacteria, plasmids, and bacteriophages
* “Jumping genes”
* “Cut and paste” or “copy and paste”
* Code for drug-resistant enzymes, toxins, or metabolic enzymes
* Cause mutations in genes into which they insert (via a mutation) or alter the expression of nearby genes (e.g. causing the activation or repression of antibiotic resistance genes).
TRANSPOSONS
83
* Patient related: Disinfection or living tissue or skin
* Healthcare worker related: Reduction or removal of transient microbial flora
**Antisepsis**
## Footnote
* Preoperative skin prep
* Hand rubbing
84
Lysozymes are enzymes that kill bacteria by cleaving which part of the cell wall?
β 1→ 4 glycosidic bond between NAG and NAM
85
a.k.a. Neufeld reaction, a biochemical reaction in which antibodies bind to the bacterial capsule
Quellung reaction
86
ACID FAST staining steps
* Primary Stain - CArbol Fuchsin
* Mordant - Steam Heating
* DEcolorizing Agent - Acid
* Counterstain - Malachite Green / Blue
