Micro - Clinical Bacteriology Flashcards
(160 cards)
1
Q
What are the two functions of the peptidoglycan layer in bacteria?
A
Rigid support and protection against osmotic damage
2
Q
What is the chemical composition of the bacterial peptidoglycan layer?
A
A sugar backbone with cross-linked peptide side chains
3
Q
What is the major surface antigen in gram-positive bacteria?
A
Cell wall
4
Q
Which two cytokines does teichoic acid induce?
A
Tumor necrosis factor and interleukin-1
5
Q
What structure in gram-negative bacteria induces tumor necrosis factor and interleukin-1?
A
The lipid A component of lipopolysaccharide
6
Q
What is the major surface antigen in gram-negative bacteria?
A
Outer membrane (polysaccharide component of lipopolysaccharide)
7
Q
Where is endotoxin (lipopolysaccharide) located in gram-negative bacteria?
A
In the outer membrane
8
Q
Which bacterium has a nonpolysaccharide capsule?
A
Bacillus anthracis (which has D-glutamate)
9
Q
_____ are bacterial structures that mediate adherence to the host cell surface and are composed of glycoprotein.
A
Fimbriae (pili)
10
Q
What bacterial structure establishes attachment between two bacteria during conjugation?
A
Sex pili
11
Q
_____ are bacterial structures that provide motility and are composed of protein.
A
Flagella
12
Q
What bacterial structure provides resistance to desiccation, heat, and chemicals?
A
Spores
13
Q
What is the chemical composition of a spore?
A
Keratin-like coat and dipicolinic acid
14
Q
What kind of genetic information is stored in the bacterial plasmid?
A
Genes for antibiotic resistance, enzymes, and toxins
15
Q
What structure aids bacteria in adhering to foreign objects, such as indwelling catheters?
A
Glycocalyx
16
Q
What is the chemical composition of glycocalyx?
A
Polysaccharide
17
Q
What structures are common to both gram-positive and gram-negative bacteria?
A
Flagellum, pilus, capsule, peptidoglycan, and cytoplasmic membrane
18
Q
What structure is unique to gram-positive organisms?
A
Teichoic acid
19
Q
What structures are unique to gram-negative organisms?
A
Outer membrane (endotoxin/lipopolysaccharide)-lactamases in periplasmic space
20
Q
What is between the capsule and peptidoglycan layers in gram-negative organisms?
A
The outer membrane (which contains endotoxin/lipopolysaccharide)
21
Q
What is the difference between the peptidoglycan layer of gram-positive organisms and that of gram-negative organisms?
A
The peptidoglycan layer in gram-positive bacteria is much thicker than that of gram-negative bacteria
22
Q
What is between the inner cytoplasmic and outer membranes in gram-negative organisms?
A
Periplasmic space (the location of many enzymes, including -lactamases)
23
Q
Name the two major gram positive cocci.
A
Staphyloccus and Streptococcus
24
Q
What are the major gram negative cocci?
A
Neisseria
25
*Clostridium* is a _____ (gram positive/gram negative) _____ (coccus/bacillus) .
Gram positive bacillus
26
*Corynebacterium* is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram positive bacillus
27
*Listeria* is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram positive bacillus
28
What unique staining characteristic do *Mycobacterium* and *Nocardia* possess?
*Mycobacterium* and *Nocardia* are acid fast
29
*Haemophilus* is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram negative bacillus
30
*Legionella* is a _____ (gram positive/gram negative) _____ (cocci/bacillus).
Gram negative bacillus
31
*Bordatella* is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram negative bacillus
32
*Yersinia* is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram negative bacillus
33
*Francisella* is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram negative bacillus
34
*Brucella* is a _____ (gram positive/gram negative) _____ (cocci/bacillus).
Gram negative bacillus
35
*Pasteurella* is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram negative bacillus
36
*Bartonella* is a _____ (gram positive/gram negative) _____ (cocci/bacillus).
Gram negative bacillus
37
*Gardnerella* is a _____ (gram positive/gram negative) _____ (coccus/bacillus).
Gram negative bacillus (gram staining can be variable)
38
What are the two types of gram positive branching, filamentous bacteria?
*Actinomyces* and *Nocardia*
39
Name three types of spirochetes.
*Leptospira, Borrelia, Treponema*
40
What type of bacteria contains sterols but lacks cell walls?
*Mycoplasma*
41
What type of bacteria contain mycolic acid in their cell walls and have high lipid content?
*Mycobacteria*
42
Name six organisms that do not stain well by Gram stain.
*Treponema, Rickettsia*, Mycobacteria, *Mycoplasma, Legionella pneumophila*, and *Chlamydia* Remember: These rascals may microscopically lack color
43
Name two methods used for visualizing treponemes.
Dark field microscopy and fluorescent antibody staining
44
Name three predominantly intracellular parasites that do not Gram stain well.
*Rickettsia, Legionella*, and *Chlamydia*
45
*Mycobacteria* can be visualized by acid-fast stain as a result of what characteristic?
High lipid content in the cell wall
46
What is the reason that *Mycoplasma* do not Gram stain?
It does not have a cell wall
47
Which primarily intracellular organism does not Gram stain well but can be seen with silver stain?
*Legionella pneumophilia*
48
*Borrelia*, *Plasmodium*, *Trypanosoma*, and *Chlamydia* species can be visualized using what type of stain?
Giemsa stain
49
Periodic acid-Schiff (PAS) staining is used to stain what types of metabolic substances?
Glycogen and mucopolysaccharides (PASs the sugar)
50
True or False: Periodic acid-Schiff staining is used to diagnose Whipples disease.
TRUE
51
Ziehl-Neelsen stain is used to stain what organisms?
Acid-fast bacteria
52
India ink and mucicarmine can be used to visualize what pathogen?
*Cryptococcus neoformans*
53
Silver stain is used to stain what organisms?
*Pneumocystis* and *Legionella*
54
*Haemophilus influenzae* requires what medium to grow?
Chocolate agar with factors V (NAD) and X (hematin)
55
*Neisseria gonorrhoeae* requires what medium to grow?
Thayer-Martin (VPN) media
56
*Bordetella pertussis* requires what medium to grow?
Bordet-Gengou (potato) agar
57
Which media are used to culture *Corynebacterium diphtheriae*?
Tellurite plate, Loefflers medium
58
*Mycobacterium tuberculosis* requires what medium to grow?
L&wenstein-Jensen agar
59
Lactose-fermenting enterics on MacConkeys agar grow colonies that are what color?
Pink
60
*Legionella* requires what medium to grow?
Charcoal yeast extract agar buffered with cysteine
61
Fungi require what medium to grow?
Sabourauds agar
62
In what medium can *Mycoplasma pneumoniae* grow?
Eatons agar
63
*Escherichia coli* can grow on what medium other than MacConkeys agar?
Eosin-methylene blue agar
64
What is the appearance of *Escherichia coli* when it is grown on eosin-methylene blue agar?
Colonies with blue-black color and metallic sheen
65
Which bacteria are obligate aerobes?
They are all obligate aerobes (remember: **N**ocardia, **P**seudomonas aeruginosa, **M**ycobacterium tuberculosis, and **B**acillus = **N**agging **P**ests **M**ust **B**reathe)
66
Why does *Mycobacterium tuberculosis* have a predilection for the apices of the lung?
The apices of the lung have the highest partial pressure of oxygen
67
Which aerobe is commonly associated with burn wound infections, nosocomial pneumonia, and pneumonias in patients with cystic fibrosis?
*Pseudomonas aeruginosa* (remember: Pseudomonas **AER**uginosa is an **AER**obe)
68
What do *Clostridium, Bacteroides*, and *Actinomyces* have in common?
They are obligate anaerobes (remember, they **C**annot **B**reathe **A**ir)
69
The lack of which enzymes makes obligate anaerobes susceptible to oxidative damage?
Catalase and/or superoxide dismutase
70
What are characteristics of anaerobe infections in tissue?
They are generally foul smelling and difficult to culture and produce carbon dioxide and hydrogen gas
71
Why are aminoglycosides ineffective against anaerobes?
Amin**O**glycosides require **O**xygen to enter a bacterial cell
72
Which organisms are obligate intracellular organisms that cannot make their own ATP?
*Rickettsia* and *Chlamydia* (remember: Stay inside (cells) when it is **R**eally **C**old)
73
Which bacteria are facultative, intracellular organisms?
**S**almonella, **N**eisseria, **B**rucella, **M**ycobacterium, **L**isteria, **F**rancisella, **L**egionella, and **Y**ersinia (remember: **S**ome **N**asty **B**ugs **M**ay **L**ive **F**acultative**L**y)
74
Name five encapsulated bacteria.
*Klebsiella pneumoniae, Salmonella, Streptococcus pneumoniae, Haemophilus influenzae* and *Neisseria meningitidis* (remember: **K**apsules **Shield SHiN)**
75
A polysaccharide capsule adds virulence by what mechanism?
Preventing phagocytosis
76
Which test is used to see if an organism is encapsulated?
The Quellung reaction, in which the capsule swells (remember: **Quelling** = capsular **swellung)**
77
What part of the bacteria is used as antigen in vaccines against *Streptococcus pneumoniae, Haemophilus influenzae* type B, and *Neisseria meningitidis*?
The capsule
78
In the synthesis of vaccines against encapsulated bacteria, conjugation of polysaccharides with protein has what effect on the bodys immune response?
Increases immunogenicity and T-cell-dependent response
79
Which four bacteria are urease-positive?
*Helicobacter pylori, Proteus, Klebsiella,* and *Ureaplasma* (remember: **P**articular **K**inds **H**ave **U**rease
80
*Staphylococcus aureus* produces a _____ (yellow, red, or blue-green) pigment.
Yellow
81
*Pseudomonas aeruginosa* produces a _____ (yellow, red, or blue-green) pigment.
Blue-green
82
*Serratia marcescens* produces a _____ (yellow, red, or blue-green) pigment.
Red
83
\_\_\_\_\_ produces yellow "sulfur" granules.
*Actinomyces* **israelii** (remember: **Israel** has **yellow sand**)
84
Protein A in *Staphylococcus aureus* binds to the _____ region of immunoglobulin and disrupts two immune functions, \_\_\_\_\_and \_\_\_\_\_.
Fc; Opsonization and phagocytosis
85
Immunoglobulin A protease is secreted by which bacteria?
*Streptococcus pneumoniae, Haemophilus influenzae*, and *Neisseria*
86
What protein from Group A *Streptococcus* prevents phagocytosis by the bodys immune cells?
M protein
87
Exotoxins are found in which of the following: gram-negative bacteria, gram-positive bacteria, or both?
Both gram-negative and gram-positive bacteria
88
In what structures and in what type of bacteria are endotoxins found?
Endotoxins are found in the outer membrane of most gram-negative bacteria and in *Listeria*
89
Exotoxins _____ (are, are not) secreted; Endotoxins _____ (are, are not) secreted.
Exotoxins are secreted; endotoxins are not secreted
90
What is the difference in the chemical composition of endotoxin vs exotoxin?
Exotoxins are polypeptides whereas endotoxins are lipopolysaccharides
91
Where are the genes for exotoxin located?
In the plasmid or the bacteriophage
92
Where are the genes for endotoxin located?
In the bacterial chromosome
93
What are the major clinical effects of endotoxin and how are they induced?
Fever and shock due to induction of tumor necrosis factor and interleukin-1
94
Which bacterial toxin (endotoxin or exotoxin) can be used as a vaccine?
Exotoxin toxoid is used as a vaccine against exotoxin-producing organisms
95
\_\_\_\_\_ (endotoxin, exotoxin) is heat stable; _____ (endotoxin, exotoxin) is not.
Endotoxins (stable at 100°C for 1 hour), exotoxins (destroyed rapidly at 60°C, except staphylococcal enterotoxin)
96
Which organism produces an exotoxin that is heat stable?
*Staphylococcus aureus*
97
Bacteria that cause tetanus, botulism, and diphtheria involve which kind of toxin?
Exotoxins
98
Gram-negative rods that cause meningococcemia and sepsis involve which kind of toxin?
Endotoxins
99
Superantigens directly bind to which two receptors?
Major histocompatibility complex II and T-lymphocyte receptor
100
The binding of superantigens to MHC II and T-cell receptor results in the widespread release of what factors?
Interferon and IL-2
101
Name two characteristic organisms with superantigen exotoxins.
*Staphylococcus aureus* and *Streptococcus pyogenes*
102
Which two *Staphylococcus aureus* toxins cause disease in humans?
Toxic shock syndrome toxin 1 and enterotoxin
103
What are the symptoms of toxic shock syndrome?
Fever, rash, and shock
104
Which toxin produced by *Staphylococcus aureus* causes food poisoning?
Enterotoxin
105
*Staphylococcus aureus* exfoliatin can cause what illness?
Staphylococcus scalded skin syndrome
106
The superantigen released by *Streptococcus pyogenes* causes what syndrome?
Toxic shock-like syndrome (caused by erythrogenic toxin)
107
What are the functions of the two components of the A-B toxins found in certain bacteria, such as *Corynebacterium diphtheriae*?
B (binding) allows endocytosis and A (active) ADP-ribosylates host cell proteins
108
Name four organisms that have adenosine diphosphate ribosylating A-B toxin.
*Corynebacterium diphtheriae, Vibrio cholerae, Escherichia coli*, and *Bordetella pertussis*
109
Which two organisms adenosine diphosphate ribosylating A-B toxins stimulate adenylate cyclase?
*Vibrio cholerae* and *Escherichia coli*
110
Diphtheria toxin causes pharyngitis and a pseudomembrane in the throat by the adenosine diphosphate ribosylation of what factor?
Elongation factor 2
111
What organism causes pharyngitis with pseudomembrane formation?
*Corynebacterium diphtheriae*
112
What is the effect of increased adenylyl cyclase activity caused by cholera toxin?
Increased chloride pumping into gut and decreased sodium absorption, pulling excess water into the gut
113
The toxin released by what bacterium produces what is commonly referred to as rice-water diarrhea?
*Vibrio cholerae*
114
\_\_\_\_\_ (adenylate, guanylate) cyclase is stimulated by the heat-labile toxin of *Escherichia coli*, whereas _____ (adenylate, guanylate) cyclase is stimulated by the heat-stabile toxin of *Escherichia coli*.
**A**denylate, **g**uanylate (remember: **l**abile like the **a**ir, **s**table like the **g**round)
115
Which organism causes whooping cough?
*Bordetella pertussis*
116
How does *Bordetella pertussis* toxin cause lymphocytosis?
By the inhibition of the chemokine receptor
117
Pertussis toxin causes the _____ (stimulation/inhibition) of Gi, which results in an _____ (increase/decrease) in cAMP
Inhibition; increase
118
Which organism causes gas gangrene and what toxin is responsible?
*Clostridium perfringens* causes gas gangrene by release of its toxin (lecithinase)
119
What is the characteristic finding of *Clostridium perfringens* plated on blood agar?
Double zone of hemolysis
120
*Clostridium tetani* tetanus causes lockjaw by decreasing the level of what neurotransmitters?
Glycine and GABA (both are inhibitory neurotransmitters)
121
What is the mechanism of botulinum toxin-induced paralysis?
Inhibition of the release of acetylcholine
122
What foods are associated with botulism?
Canned food and honey
123
Name two organisms that produce Shiga toxin.
*Shigella* and *Escherichia coli* O157:H7
124
What does Shiga toxin do in the host cell?
Shiga toxin cleaves host cell rRNA inactivating the 60S ribosomal subunit
125
Exaggerated release of cytokines caused by Shiga toxin can lead to what syndrome?
Hemolytic-uremic syndrome
126
Which antibody is used to help diagnose rheumatic fever?
Antistreptolysin O antibody
127
*Vibrio cholerae* toxin causes watery diarrhea by permanently activating which protein?
Gs
128
Pertussis toxin causes whooping cough by permanently disabling which protein?
Gi (Turns the off off)
129
Both cholera and pertussis toxins act by adenosine diphosphate ribosylation that permanently _____ (activates/inactivates) adenyl cyclase, thereby _____ (increasing/decreasing) cAMP.
Activates; increasing
130
What is the mechanism of action of *Bacillus anthracis* edema factor?
Edema factor is a bacterial form of adenylate cyclase, which increases levels of cAMP
131
How does anthrax edema factor differ from pertussis, cholera, and *Escherichia coli* toxin induction of cAMP production?
Anthrax edema factor is itself an adenylate cyclase, whereas pertussis, cholera, and *Escherichia coli* toxins permanently activate endogenous adenylate cyclase
132
What is the chemical composition of endotoxin and where is it found?
It is a lipopolysaccharide found in the cell walls of gram-negative bacteria
133
What type of bacteria has endotoxins, gram-positive or gram-negative?
Gram-negative bacteria (remember: e**N**dotoxin is an integral part of the cell wall of gram-**N**egative bacteria)
134
What is the most active part of an endotoxin?
Lipid A
135
Which cell type is activated by endotoxins?
Macrophages
136
How is complement activated by endotoxins?
Via the alternative pathway
137
Endotoxins activate the coagulation cascade via what factor?
Hageman factor
138
The activation of macrophages by endotoxin results in the release of which substances?
Interleukin-1, tumor necrosis factor, and nitric oxide
139
The release of which cytokines by endotoxin-activated macrophages results in fever?
Interleukin-1 and tumor necrosis factor
140
The release of nitric oxide by endotoxin-activated macrophages results in what condition?
Hypotension (shock)
141
Which component of the alternative complement pathway causes hypotension and edema?
C3a
142
The activation of the coagulation cascade by endotoxins results in what condition?
Disseminated intravascular coagulation
143
What are the four phases of the bacterial growth curve?
Lag phase, log phase, stationary phase, and death phase
144
During which phase of the bacterial growth curve is there metabolic activity without division?
Lag phase
145
During which phase of the bacterial growth curve is there rapid cell division?
Log phase
146
What is the cause of slowed growth during the stationary phase of the bacterial growth curve?
Nutrient depletion
147
During which phase of the bacterial growth curve does spore formation occur in some bacteria?
Stationary phase
148
What causes cell death during the death phase of the bacterial growth curve?
Prolonged nutrient depletion and a buildup of waste products
149
The process of direct DNA transfer from one bacterium to another is called what?
Conjugation
150
What type of bacterial genetic transfer involves the phage-mediated transfer of DNA between prokaryotes?
Transduction
151
What kind of DNA is transferred during transformation: chromosomal, plasmid, or both?
Both
152
What type of bacterial genetic transfer involves the direct uptake of purified DNA by both prokaryotes and eukaryotes?
Transformation
153
Are chromosomal *and* plasmid genes transferred in F+ F- conjugation or in Hfr F- conjugation?
Hfr F- conjugation; ONLY plasmid genes are transferred in F+ F- conjugation
154
What kind of DNA is transferred during transposition: chromosomal, plasmid, or both?
Both
155
When DNA is transferred from one chromosome (or plasmid) to another within the same cell it is called \_\_\_\_\_.
Transposition
156
When an F+ plasmid is incorporated into the chromosomal DNA of a bacterial cell, that cell is then termed an _____ cell.
Hfr
157
What type of transduction is described here: a lytic phage infects a bacterium, cleaves the bacterial DNA, and repackages bacterial DNA in viral capsids to infect other bacteria.
Generalized transduction
158
What type of transduction is described here: a lysogenic phage infects a bacterium, inserts DNA into the chromosomal DNA of the bacterium, and repackages flanking chromosomal DNA into its capsid upon excision to infect other bacteria.
Specialized transduction
159
In which of the following can chromosomal DNA *not* be incorporated into transferred DNA: generalized transduction, specialized transduction, F+ F- conjugation, Hfr F- conjugation and transposition.
F+ F- conjugation
160
Name 5 bacterial toxins coded for in a lysogenic phage.
Shig**A**-like toxin, **B**otulism toxin, **C**holera toxin, **D**iptheria toxin, **E**rythrogenic toxin of *Streptococcus pyogenes* (remember: **ABCDE**)
