Microbiology Superset RidEZ - Part 1 Flashcards
1
Q
Function and chemical composition of bacterial structure: Peptidoglycan
A
Function:
- Rigid support
- Protects against osmotic pressure
Chemical composition:
Sugar backbone with cross-linked peptide side chains
2
Q
Function and chemical composition of bacterial structure: Cell wall/cell membrane
A
Gram positives only
Function: Major surface antigen
Chemical composition: Teichoic acid, which induces TNF and IL-1
3
Q
Function and chemical composition of bacterial structure: Outer membrane
A
Gram negatives only
Function: Site of endotoxin (lipopolysaccharide) and major surface antigen
Chemical composition: Lipid A induces TNF and IL-1, and polysaccharide is the antigen
4
Q
Function and chemical composition of bacterial structure: Plasma membrane
A
Function: Site of oxidative and transport enzymes
Chemical composition: Lipoprotein bilayer
5
Q
Function and chemical composition of bacterial structure: Ribosome
A
Function: Protein synthesis
Chemical composition: 50S and 30S subunits
6
Q
Function and chemical composition of bacterial structure: Periplasm
A
Function: Space between the cytoplasmic membrane and outer membrane in gram-negative bacteria
Chemical composition: Contains many hydrolytic enzymes, including beta-lactamases
7
Q
Function and chemical composition of bacterial structure: Capsule
A
Function: Protects against phagocytosis
Chemical composition: Polysaccharide (except Bacillus anthracis which contains D-glutamate)
8
Q
Function and chemical composition of bacterial structure: Pilus/fimbria
A
Function: Mediates adherence of bacteria to cell surface; sex pilus forms attachment between 2 bacteria during conjugation
Chemical composition: Glycoprotein
9
Q
Function and chemical composition of bacterial structure: Flagellum
A
Function: Motility
Chemical composition: Protein
10
Q
Function and chemical composition of bacterial structure: Spore
A
Function: Provides resistance to dehydration, heat, and chemicals
Chemical composition: Keratin-like coat and dipicolinic acid
11
Q
Function and chemical composition of bacterial structure: Plasmid
A
Function: Contains a variety of genes for antibiotic resistance, enzymes, and toxins
Chemical composition: DNA
12
Q
Function and chemical composition of bacterial structure: Glycocalyx
A
Function: Mediates adherence to surfaces, especially foreign surfaces (eg indwelling catheters)
Chemical composition: Polysaccharide
13
Q
Function of this structure: IgA proteases
A
Function: Allow some organisms to colonize mucosal surfaces
14
Q
Which bacteria have IgA proteases?
A
- Streptococcus pneumoniae
- Neisseria meningitidis
- Neisseria gonorrheae
- Hemophilus influenzae
15
Q
Which bacterial substances induce cytokines, and which are they?
A
Cytokines induced:
- IL-1
- TNF
Gram positive inducer: Teichoic acid
Gram negative inducer: Lipopolysaccharide (Endoxtoxin)
16
Q
What does the capsule of Bacillus anthracis consist of?
A
D-glutamate
17
Q
What bacterial structure contains D-glutamate?
A
Capsule of Bacillus anthracis
18
Q
What are the main differences between gram negative and gram positive organisms?
A
Peptidoglycan cell wall: Gram positive has thick. Gram negative has thin.
Flagellar basal body rings: Gram positive has two. Gram negative has four.
Outer antigen: Gram positive: Teichoic acid. Gram negative: Lipidpolysaccharide
Periplasmic space: Gram positive does not have. Gram negative has.
Porin channel: Gram positive does not have. Gram negative has.
Lysozyme and penicillin attack: Gram positive are sensitive. Gram negative are resistant.
19
Q
What bacteria do not gram stain well?
A
Mnemonic: These Rascals May Microscopically Lack Color
- Treponema
- Rickettsia
- Mycobacteria
- Mycoplasma
- Legionella pneumophila
- Chlamydia
20
Q
Why does the following bug not gram stain well?: Treponema
A
Too thin to be visualized
21
Q
Why does the following bug not gram stain well?: Rickettsia
A
Intracellular parasite
22
Q
Why does the following bug not gram stain well?: Mycobacteria
A
high-lipid-content cell wall
23
Q
Why does the following bug not gram stain well?: Mycoplasma
A
No cell wall
24
Q
Why does the following bug not gram stain well?: Legionella pneumophila
A
Primarily intracellular
25
Why does the following bug not gram stain well?: Chlamydia
Intracellular parasite which lacks muramic acid in cell wall
26
How is the following bug visualized?: Treponema
1. Darkfield microscopy
2. Fluorescent antibody staining
3. silver stain
27
Why does the following bug not gram stain well?: Mycobacteria
Acid fast for high lipid content cell wall
28
What are the stages of bacterial growth and what are their relative lengths?
1. Lag phase: x
2. Log phase: 1.5x
3. Stationary phase: 2.5x
4. Death phase: 4x
29
What happens in the following phase of bacterial growth, and where does it fall in the order?: Lag
1st phase: Metabolic activity without division
30
What happens in the following phase of bacterial growth, and where does it fall in the order?: Log
2nd phase: Rapid cell division
31
What happens in the following phase of bacterial growth, and where does it fall in the order?: Stationary
3rd phase: Nutrient depletion slows growth
32
What happens in the following phase of bacterial growth, and where does it fall in the order?: Death
4th phase: Prolonged nutrient depletion and buildup of waste products leads to death
33
Bacterial endotoxins and exotoxins: Source?
Exotoxin: Certain species of gram positive and gram negative bacteria
Endotoxin: Cell wall of most gram-negative bacteria
34
Bacterial endotoxins and exotoxins: Secreted from cell?
Exotoxin: Yes
Endotoxin: No
35
Bacterial endotoxins and exotoxins: Chemistry
Exotoxin: Polypeptide
Endotoxin: Lipopolysaccharide
36
Bacterial endotoxins and exotoxins: Location of genes
Exotoxin: Plasmid or bacteriophage
Endotoxin: Bacterial chromosome
37
Bacterial endotoxins and exotoxins: Toxicity (fatal dosage)
Exotoxin: High (fatal dose on the order of 1 microgram)
Endotoxin: Low (fatal dose on the order of hundreds of micrograms)
38
Bacterial endotoxins and exotoxins: Clinical effects
Exotoxin: Toxin specific
Endotoxin: Fever and shock
39
Bacterial endotoxins and exotoxins: Mode of action
Exotoxin: Toxin specific
Endotoxin: Includes TNF and IL-1
40
Bacterial endotoxins and exotoxins: Antigenicity
Exotoxin: Induces high-titer antibodies called antitoxins
Endotoxin: Poorly antigenic
41
Bacterial endotoxins and exotoxins: Vaccines
Exotoxin: Toxoids used as vaccines
Endotoxin: No toxoids formed and no vaccine available
42
Bacterial endotoxins and exotoxins: Heat stability
Exotoxin: Destroyed rapidly at 60 degrees celsius (except Staphylococcal enterotoxin)
Endotoxin: Stable at 100 degrees celsius for 1 hour
43
Bacterial endotoxins and exotoxins: Typical diseases
Exotoxin: Tetanus, botulism, diphtheria
Endotoxin: Meningococcemia, sepsis by gram negative rods
44
Mechanism of superantigens
1. Bind directly to MHC II and T cell receptor
2. Large numbers of T cells are activated.
3. Stimulates release of IFN-gamma and IL-2
45
Mechanism of ADP ribosylating A-B toxins
Interfere with host cell function
1. B (binding) component binds to a receptor on surface of host cell.
2. The toxin is endocytosed.
3. A (active) component attaches an ADP-ribosyl to a host cell protein.
4. That protein's function is altered.
46
List of bugs that release superantigens
1. Staphylococcus aureus
| 2. Streptococcus pyogenes
47
List of bugs that release ADP ribosylating A-B toxins
1. Corynebacterium diphtheriae
2. Vibrio cholerae
3. E. coli
4. Bordetella pertussis
48
What to know about exotoxins released by Staphylococcus aureus
Superantigens
1. TSST-1 causes toxic shock syndrome (fever, rash, shock).
2. Enterotoxins cause food poisoning.
49
What to know about exotoxins released by Streptococcus pyogenes
Scarlet fever (superantigen)
1. Erythrogenic
2. Causes toxic shock-like syndrome
Streptolysin O (hemolysin). The antigen for ASO antibody is found in rheumatic fever
50
What to know about exotoxins released by Corynebacterium diphtheriae
ADP ribosylating A-B toxin (similar to Pseudomonas exotoxin A)
Encoded by beta-prophage
Disease: Pseudomembranous pharyngitis (grayish-white membrane) with lymphadenopathy
```
Mechanism:
Inactivates elongation
factor 2 (EF-2)
```
```
Mnemonic: ABCDEFG
ADP ribosylation
Beta-prophage
Corynebacterium
Diphtheriae
Elongation Factor 2
Granules (metachromatic)
```
51
What to know about exotoxins released by Vibrio cholerae
1. A-B toxin ADP ribosylates Gs protein thus:
2. Permanently activates Gs protein
3. Constant stimulation of adenylyl cyclase which:
4. Increases pumping of Cl into gut
5. H2O follows it
6. Leads to rice water diarrhea
52
What to know about exotoxins released by E. coli
E.coli 0157:H7 produces Shiga toxin.
ADP ribosylating A-B toxins
Heat-labile: Permanent activation of adenylyl cyclase (cholera-like mechanism) leading to watery diarrhea
Heat-stabile: Stimulates guanylate cyclase
Mnemonic: Labile like the Air, Stabile like the Ground.
53
What to know about exotoxins released by Bordetella pertussis
1. ADP ribosylating A-B toxin
2. Permanently disables Gi
3. Constant stimulation of adenylate cyclase
4. Causes whooping cough
5. Also inhibits chemokine receptor causing lymphocytosis
54
What to know about exotoxins released by Clostridium perfringens
alpha toxin (aka lecithinase) causes:
1. gas gangrene
2. myonecrosis
3. hemolysis (See double zone of hemolysis on blood agar.)
PERFringens PERForates a gangrenous leg.
55
What to know about exotoxin released by Clostridium botulinum
Properties:
1. Preformed
2. Heat-labile
Mechanism:
Blocks the release of acetylcholine causing:
1. anticholinergic symptoms
2. CNS paralysis (especially cranial nerves)
3. Floppy baby syndrome
BOTulinum is from bad BOTtles of food and honey and sausage (causes flaccid paralysis)
56
What to know about exotoxins released by Clostridium tetani
Blocks the release of inhibitory neurotransmitter glycine from Renshaw cells in the spinal cord. Causes "lockjaw"
57
What to know about exotoxins released by Bacillus anthracis
1 toxin in the toxin complex is edema factor, an adenylate cyclase
58
What to know about exotoxins released by Shigella
Shiga toxin (also produced by E.coli 0157:H7).
Cleaves host cell rRNA. Also enhances cytokine release causing hemolytic uremic syndrome.
59
Endotoxin: What is it and where is it found?
Lipopolysaccharide found in the outer membrane of gram-negative bacteria. Heat stable.
60
Endotoxin: What does it activate and what do they release?
1. Macrophages (IL-1, TNF, Nitric oxide)
2. Alternative complement pathway (C3a, C5a)
3. Hageman factor (Coagulation cascade)
61
What mediators are released when endotoxin activates macrophages, and what do they do?
1. IL-1: Fever
2. TNF: Fever and Hemorrhagic tissue necrosis
3. Nitric Oxide: Hypotension (shock)
62
What mediators are released when endotoxin activates the alternative complement cascade, and what do they do?
1. C3a: Hypotension and edema
| 2. C5a: Neutrophil chemotaxis
63
What mediators are released when endotoxin activates Hageman factor, and what do they do?
Coagulation cascade: Disseminated intravascular coagulopathy
64
What method is used to differentiate Neisseria?
Sugar fermentation
65
What do meningococci ferment?
MeninGococci ferment Maltose and Glucose
66
What do gonococci ferment?
Gonococci ferments Glucose
67
What are the pigment producing bacteria and what pigments do they produce?
Staphylococcus aureus: Yellow pigment (Aureus means gold in Latin)
Pseudomonas aeruginosa: blue-green pigment
Serratia marcescens: red pigment (think red maraschino cherries)
68
Special culture requirements for: Hemophilus influenzae
Chocolate agar with factors V (NAD) and X (hematin)
Mnemonic: When a child has "flu" mom goes to five (V) and dime (X) to buy some chocolate.
69
Special culture requirements for: Neisseria gonorrhoeae
Thayer-Martin media
70
Special culture requirements for: Bordetella pertussis
Bordet-Gengou (potato) agar
71
Special culture requirements for: M. tuberculosis
Lowenstein-Jensen agar
72
Special culture requirements for: Lactose-fermenting enteric bacteria
Pink colonies on MacConkey's agar
73
Special culture requirements for: Legionella
Charcoal yeast extract agar buffered with increased iron and cysteine
74
Special culture requirements for: Fungi
Sabouraud's agar
75
What microbes can be stained with: Congo red
Amyloid. Apple-green birefringence in polarized light (because of beta-pleated sheets)
76
What microbes can be stained with: Giemsa's
1. Borrelia
2. Plasmodium
3. Trypanosomes
4. Chlamydia
77
What microbes can be stained with: periodic acid-Schiff (PAS)
Glycogen and mucopolysaccharides. Used to diagnose Whipple's disease
78
What microbes can be stained with: Ziehl-Neelsen
Acid-fast bacteria.
79
What microbes can be stained with: India ink
Cryptococcus neoformans
80
What microbes can be stained with: Silver stain
1. Fungi
2. PCP (Pneumocystis Pneumonia)
3. Legionella
4. Treponema
81
For the following genetic transfer procedure, explain the process: Conjugation
Direct cell to cell DNA transfer
82
For the following genetic transfer procedure, explain the process: Transduction
Phage-mediated cell to cell DNA transfer
83
For the following genetic transfer procedure, explain the process: Transformation
Purified DNA taken up by a cell
84
For the following genetic transfer procedure, explain the processd: Transposition
DNA transfer to same or another chromosome or plasmid WITHIN a cell
85
For the following genetic transfer procedure, give the types of cells involved: Conjugation
Prokaryotic
86
For the following genetic transfer procedure, give the types of cells involved: Transduction
Prokaryotic
87
For the following genetic transfer procedure, give the types of cells involved: Transformation
Prokaryotic or eukaryotic
88
For the following genetic transfer procedure, give the types of cells involved: Transposition
Prokaryotic or eukaryotic
89
For the following genetic transfer procedure, give the nature of DNA transferred: Conjugation
Chromosomal or plasmid
90
For the following genetic transfer procedure, give the nature of DNA transferred: Transduction
Generalized transduction: Any gene
Specialized transduction: Only certain genes
91
For the following genetic transfer procedure, give the nature of DNA transferred: Transformation
Any DNA
92
For the following genetic transfer procedure, give the nature of DNA transferred: Transposition
DNA sequences "jumping genes"
93
What is lysogeny?
When the genetic code for a bacterial toxin is encoded in a lysogenic phage.
94
Name 4 lysogenic toxins.
BCDE
1. Botulinum
2. Cholera
3. Diphtheria
4. Erythrogenic toxin of Streptococcus Pyogenes
95
List four obligate aerobes.
Nocardia, Pseudomonas aeruginosa, Mycobacterium tuberculosis, Bacillus
Mnemonic: Nagging Pests Must Breathe
96
Where in the lung does M. tuberculosis prefer, and why?
Apices of the lung, as they have the highest PO2.
97
What conditions occur concurrently with P. Aeruginosa infection?
1. Burn wounds
2. Nosocomial pneumonia
3. Pneumonias in Cystic Fibrosis patients
98
List 3 obligate anaerobes
Clostridium, Bacteroides, and Actinomyces
99
What enzymes do obligate anaerobes lack?
Catalase (aka glutathione peroxidase)
AND/OR
Superoxide dismutase (converts O2-radical[ie superoxide] to H2O2)
100
Why are anaerobes foul-smelling?
They produce short-chain fatty acids.
101
What do anaerobes produce in tissue?
CO2 and H2 gases
102
Where are anaerobes normal flora?
1. GI tract
| 2. Between teeth and gums
103
What antibiotics are particularly ineffective against anaerobes?
AminO2glycosides, as they require O2 to enter the bacterial cell.
104
List the obligate intracellular bacteria.
Rickettsia and Chlamydia.
Mnemonic: Stay inside (cells) when it is Really Cold
105
What is the defining characteristic of obligate intracellular bacteria.
Can't make their own ATP.
106
List the facultative intracellular bacteria.
Mnemonic: Some Nasty Bugs May Live FacultativeLY
Salmonella, Neisseria, Brucella, Mycobacterium, Listeria, Francisella, Legionella, Yersinia
OR
Mnemonic: My Liege, Your Niece Lists Frank, Bruce and Sam.
Mycobacterium, Leigonella, Yersinia, Neisseria, Listeria, Francisella, Brucella, Salmonella.
107
List four major examples of encapsulated bacteria
1. Streptococcus pneumoniae
2. Hemophilus influenzae (especially B serotype)
3. Neisseria meningitidis
4. Klebsiella pneumoniae
108
What does a positive quellung reaction indicate?
Positive quellung: If encapsulated bug is present, capsule swells when specific anticapsular antisera are added.
Mnemonic: Quellung = capsular "swellung"
109
In which vaccines does the capsule serve as an antigen?
Pneumovax, H influenzae B, Meningococcal vaccines
110
What does conjugation with protein do to vaccines that have a capsular antigen?
Increases the immunogenicity and T-cell dependent responce.
111
Which bacteria form spores?
Gram positive soil bugs (eg Bacillus anthracis, Clostridium perfringens, Clostridium tetani)
112
How can one destroy spores?
Autoclave (as is done to surgical equipment)
113
Which bacteria are alpha hemolytic?
Streptococcus (all catalase-negative)
If optochin sensitive, bile soluble, or quellung positive: Streptococcus Pneumoniae
If optochin resistant, bile insoluble, or quellung negative: Streptococcus Viridans (eg S. Mutans)
114
Which bacteria are beta-hemolytic?
Rods:
Listeria monocytogenes
Cocci:
If catalase positive and coagulase positive: Staphylococcus Aureus
If catalase negative, Streptococcus.
Then, if bacitracin sensitive, S. pyogenes. If bacitracin resistant, S. agalactiae.
115
What are the important points about Listeria monocytogenes?
1. Tumbling motility
2. Meningitis in newborns
3. Unpasteurized milk
116
Gram positive: Which are catalase positive and which are catalase negative?
Positive: Staph
Negative: Strep
117
Gram positive: Which are catalase positive bacteria make coagulase?
Staph aureus does.
Staph epidermidis and saprophyticus do not.
118
What is Protein A?
Virulence factor of Staphylococcus Aureus. Binds Fc-IgG, inhibiting complement fixation and phagocytosis.
119
What disease states does Staphylococcus Aureus cause?
Inflammatory:
1. Skin infections
2. Organ abscesses (acute bacterial endocarditis, osteomyelitis)
3. Pneumonia
Toxin-mediated:
1. Toxic shock syndrome (TSST-1)
2. Scalded skin syndrome (exfoliative toxin)
3. Rapid-onset food poisoning (ingestion of preformed enterotoxin)
120
What disease states does Streptococcus Pyogenes cause?
Pyogenic
1. Pharyngitis
2. Cellulitis
3. Impetigo
Toxigenic
1. Scarlet fever
2. Toxic shock syndrome
Immunologic
1. Rheumatic fever
2. Acute glomerulonephritis
121
What are two sequelae of Streptococcus Pyogenes pharyngitis?
Rheumatic fever and acute glomerulonephritis
Mnemonoic: PHaryngitis gives you rheumatic PHever and glomerulonePHritis
122
Which antibody enhances host defenses against Streptococcus Pyogenes?
Antibody to M protein
123
Antibody to M protein enhances host defenses against what?
Streptococcus Pyogenes
124
What does ASO titer detect?
Recent S. Pyogenes infection
125
How can one detect recent S. Pyogenes infection?
ASO titer
126
What are the signs and symptoms of rheumatic fever?
1. Subcutaneous nodules
2. Polyarthritis
3. Erythema marginatum
4. Chorea
5. Carditis (bacterial endocarditis)
Mnemonic: No "rheum" for SPECCulation
127
What is streptococcus pneumoniae the most common cause of?
1. Meningitis
2. Otitis media (in children)
3. Pneumonia
4. Sinusitis
S. pneumoniae MOPS are Most OPtochin Sensitive
128
What is the most common cause of meningitis?
Streptococcus pneumoniae
129
What is the most common cause of otitis media?
Streptococcus pneumoniae
130
What is the most common cause of pneumonia?
Streptococcus pneumoniae
131
What is the most common cause of sinusitis?
Streptococcus pneumoniae
132
What is indicated by "rusty" sputum?
Streptococcus pneumoniae infection
133
What are common associations with Pneumococcus?
Streptococcus Pneumoniae
1. "Rusty" sputum
2. Sepsis in sickle cell anemia 3. splenectomy
134
What does sepsin in sickle cell anemia indicate?
Streptococcus pneumoniae
135
What do Group B streptococci cause?
B for Baby
1. Pneumonia
2. Meningitis
3. Sepsis
136
3 most common causes of meningitis in infants younger than 3 months of age
1. E. coli
2. Listeria monocytogenes
3. Group B streptococcus
137
How do infants with meningitis present?
1. Fever
2. Vomiting
3. Poor feeding
4. Irritability
138
Name the Lancefield Group D bacterial categories and examples of each.
Enterococci:
1. Enterococcus faecalis
2. Enterococcus faecium
Non-enterococci
1. Streptococcus bovis
2. Streptococcus equinus
139
What is Streptococcus bovis infection a sign of?
Colonic malignancy
140
What kind of hemolysis do enterococci cause?
Variable
| CMMRS says alpha; FA says variable and gamma
141
What drug resistances do the enterococci show?
1. Penicillin G
2. Ampicillin
3. Vancomycin
142
What is Lancefield grouping determined by?
Differences in the C carbohydrate on the bacterial cell wall
143
Which Group D bacteria are hardier?
Enterococci are hardier than nonenterococci. They can grow in 6.5% NaCl
144
A colony of bacteria grows in 6.5% NaCl. What is it?
Enterococcus
145
What disease states/problems does Staphylococcus epidermidis cause?
Infection of prosthetic devices and catheters. Contaminates blood cultures.
146
How is Streptococcus Viridans characterized?
1. Alpha hemolysis
2. Optochin resistant
3. Normal mouth flora
(Mnemonic: Viridans lives in the mouth because it is not afraid of-the-chin)
147
Where is Strep. Viridans part of the normal flora?
Oropharynx
148
What disease states/problems does Streptococcus Viridans cause?
1. Dental caries (Streptococcus mutans)
| 2. Subacute Bacterial endocarditis (Streptococcus Sanguis)
149
What disease states does Streptococcus mutans cause?
Dental caries
150
What disease states does Streptococcus sanguis cause?
Subacute bacterial endocarditis
Sanguis = blood, lots of blood in the heart.
151
How are clostridia characterized?
1. Gram positive rods
2. Spore forming
3. Obligate anaerobes
152
What disease state does Clostridium difficile cause, and what is its mechanism?
Disease state: pseudomembranous colitis secondary to clindamycin or ampicillin use. (Mnemonic: DIfficile causes DIarrhea)
Mechanism:
1. Antibiotic kills off protective flora
2. C. difficile takes hold and proliferates
3. Produces cytotoxin, an enterotoxin.
4. Cytotoxin kills enterocytes.
153
Treatment for C. difficile infection
Metronidazole
154
Lab diagnosis basis for Cornyebacterium diphtheriae
Gram positive rods with metachromatic granules, grown on tellurite agar (aka Loffler's coagulated serum medium)
155
How is Bacillus anthracis characterized?
1. Gram positive rod
2. Spore forming
3. Protein capsule
156
Which bacteria have a protein capsule?
Bacillus anthracis (the only one)
157
What are the mechanisms of anthrax infection and disease?
1. Non-inhalation contact with bacillus anthracis
2. Formation of malignant pustule (painless ulcer)
3. Progression to bacteremia
4. Death
1. Inhalation of spores
2. Development of flulike symptoms that rapidly progress to fever, pulmonary hemorrhage and shock.
158
What organism: Development of flulike symptoms followed by fever, pulmonary hemorrhage and shock.
Inhalation anthrax: Bacillus anthracis
159
What do skin lesions in anthrax look like?
Vesicular papules covered by black eschar
160
What is Woolsorter's disease
Inhalation of Bacillus anthracis spores from contaminated wool
161
What organism: Gram-positive rods forming long branching filaments resembling fungi
Actinomyces israelii or Nocardia asteroides
162
What organism: Oral or facial abscesses with yellow granules in sinus tracts
Actinomyces israelii
163
What disease state does Actinomyces israelii cause?
Oral or facial abscesses with yellow granules draining out skin through sinus tracts
164
How is Actinomyces israelii characterised?
Gram-positive anaerobic rods forming long branching filaments resembling fungi (Nocardia also has this description)
Causes oral or facial abscesses with yellow granules
165
How is Nocardia asteroides characterized?
Gram-positive (weakly acid fast) rods forming long branching filaments resembling fungi (Actinomyces also has this description)
166
What disease state does Nocardia asteroides cause?
Pulmonary infection in immunocompromised patients
167
What is the treatment for Actinomyces israelii?
Penicillin
Mnemonic: SNAP (Sulfa for Nocardia; Acintomyces use Penicillin)
168
What is the treatment for Nocardia Asteroides?
Sulfonamides
Mnemonic: SNAP (Sulfa for Nocardia; Acintomyces use Penicillin)
169
Penicillin G and Gram negative bugs
Gram-negatives are resistant to benzyl penicillin G. The gram-negative outer membrane layer inhibits entry of penicillin G and vancomycin.
May be susceptible to penicillin derivatives such as ampicillin.
170
What bacteria genus can live in neutrophils?
Neisseria
171
How are neisseria characterized?
Gram-negative cocci that resemble paired coffee beans
172
Gonococcus and meningococcus: Polysaccharide capsule
G: No
M: Yes
173
Gonococcus and meningococcus: Maltose fermentation
G: No (Gonococcus ferments Glucose)
M: Yes (MeninGococcus ferments Maltose and Glucose)
174
Gonococcus and meningococcus: Vaccine availability
G: No
M: Yes
175
What disease states does Gonococcus cause?
1. Gonorrhea
2. septic arthritis
3. neonatal conjunctivitis
4. PID
176
What disease states does Meningococcus cause?
1. Meningococcemia
2. Meningitis
3. Waterhouse-Friderichsen syndrome
177
What is Waterhouse-Friderichsen syndrome?
massive, usually bilateral, hemorrhage into the adrenal glands caused by fulminant meningococcemia.
Characterised by overwhelming bacterial infection, rapidly progressive hypotension leading to shock, disseminated intravascular coagulation (DIC) with widespread purpura, particularly of the skin, and rapidly developing adrenocortical insufficiency associated with massive bilateral adrenal hemorrhage.
178
What disease states does Haemophilus Influenzae cause?
HaEMOPhilus causes
1. Epiglottitis
2. Meningitis
3. Otitis media
4. Pneumonia
Does not cause flu (that's a virus)!
179
How is Haemophilus Influenzae characterized?
Small gram-negative coccoid rod.
180
How is Haemophilus Influenzae transmitted?
Aerosol
181
Which type of Haemophilus Influenzae is most pathogenic?
capsular type B
182
Treatment for Haemophilus Influenzae meningitis
Ceftriaxone
183
Prophylaxis for Hemophilus Influenzae
Vaccine: Type B polysaccharide conjugated to diphtheria toxoid or other protein. Given between 2 and 18 months of age.
Close contacts of infected person: Rifampin
184
How are enterobacteriaceae characterized?
Gram negative diverse group
Mnemonic: COFFEe
3. Capsule (K [kapsular] antigen related to virulence of the bug)
2. O antigen (somatic antigen which is the polysaccharide of endotoxin)
4. Flagella (H antigen found in motile species)
5. Ferment glucose
6. Enterobacteriaceae (woo!)
185
Enterobacteriaceae list
1. Escherichia coli
2. Klebsiella pneumoniae
3. Proteus mirablis
4. Enterobacter sp.
5. Serratia
6. Shigella
7. Salmonella
8. Yersinia enterocolitica
186
What disease states does Klebsiella cause?
1. Pneumonia in alcoholics and diabetics (In the name: Klebsiella pneumoniae)
2. Nosocomial UTIs (large mucoid capsule and viscous colonies)
Mnemonic: AAA (Aspiration pneumonia, Abscess in lungs, Alcoholics)
187
Signs and symptoms of Klebsiella infection
1. Red currant jelly sputum
| 2. Abscess in lungs
188
Orange sputum: What bugs?
1. Pneumococcus
| 2. Klebsiella (or described as "red currant jelly sputum")
189
Red currant jelly sputum: What bug?
Klebsiella
190
Lactose-fermenting enteric bacteria
Mnemonic: Test lactose with MacConKEE’S.
1. Citrobacter
2. Klebsiella
3. E. coli
4. Enterobacter
5. Serratia
191
Salmonella vs. Shigella: Lactose fermenter?
Neither
192
Salmonella vs. Shigella: Motile
Both (Though, the evidence that shigella is motile is recent.)
Can invade and disseminate hematogenously.
193
Salmonella vs. Shigella: Animal reservoir
Salmonella: Yes
Shigella: No
194
Shigella transmission
4 Fs:
1. Food
2. Fingers
3. Feces
4. Flies
195
Salmonella vs. Shigella: Virulence
Salmonella: 100,000 organisms
Shigella: 10 organisms
196
True or False: Salmonellosis symptoms may be prolonged with antibiotic treatments
True
197
What type of inflammatory response is seen in Salmonellosis?
Monocytes
198
Transmission of Yersinia enterocolitica
1. Pet feces (eg puppies)
| 2. Contaminated milk or pork
199
Yersinia enterocolitica infection: Clinical presentation
1. Outbreaks are common in day-care centers
| 2. Can mimic Crohn's or appendicitis
200
What bug causes contamination of this food: Seafood
Vibrio:
1. parahaemolyticus
2. vulnificus
201
What bug causes contamination of this food: Reheated rice
Bacillus cereus
Mnem: "Food poisoning from reheated rice? Be serious!"
202
What bug causes contamination of this food: Meat
1. Staphylococcus Aureus (starts quickly and ends quickly)
2. Salmonella (including poultry)
3. Clostridium perfringens (reheated meat dishes)
4. Vibrio (parahaemolyticus, vulnificus) (in seafood)
5. E. coli O157:H7 (undercooked meat)
6. Clostridium Botulinum (in sausage)
203
What bug causes contamination of this food: Mayonnaise
Staphylococcus Aureus (starts quickly and ends quickly)
204
What bug causes contamination of this food: Custard
Staphylococcus Aureus (starts quickly and ends quickly)
205
What bug causes contamination of this food: Reheated meat
Clostridium perfringens
Mnem: "Food poisoning from reheated meat? Clostridium perfringens!"
206
What bug causes contamination of this food: Bulging cans
Clostridium botulinum
| BOTulinum is from bad BOTtles of food and honey and sausage
207
What bug causes contamination of this food: Sausage
Clostridium botulinum
| BOTulinum is from bad BOTtles of food and honey and sausage
208
What bug causes contamination of this food: Honey
Clostridium botulinum
| BOTulinum is from bad BOTtles of food and honey and sausage
209
What bug causes contamination of this food: Poultry
Salmonella
210
What bug causes contamination of this food: Eggs
Salmonella
211
Bloody or watery diarrhea: Vibrio parahaemolyticus
Either bloody or watery
212
Bloody or watery diarrhea: Campylobacter
Bloody
213
Bloody or watery diarrhea: Salmonella
Bloody
214
Bloody or watery diarrhea: Shigella
Bloody
215
Bloody or watery diarrhea: Enterohemorrhagic E. coli
Bloody
216
Bloody or watery diarrhea: Enteroinvasive E. coli
Bloody
217
Bloody or watery diarrhea: Yersinia enterocolitica
Bloody
218
Bloody or watery diarrhea: C. difficile
Bloody
219
Bloody or watery diarrhea: Entamoeba histolytica
Bloody
220
Bloody or watery diarrhea: Enterotoxigenic E. coli
Watery
221
Bloody or watery diarrhea: Vibrio cholerae
Watery
222
Bloody or watery diarrhea: C. perfringens
Watery
223
Bloody or watery diarrhea: Protozoa
Watery
224
Bloody or watery diarrhea: Viruses
Watery
225
Diagnosis: Bloody diarrhea with oxidase-positive comma or S-shaped organisms grown at 42 degrees celsius
Campylobacter
226
Diagnosis: Bloody diarrhea with motile, lactose negative gram negative bugs
Salmonella or Shigella
Shigella have a very low ID50 and cause dysentery
227
Diagnosis: Bloody diarrhea with schistocytes and azotemia
Enterohemorrhagic E coli (eg O157:H7)
Caused by shiga-like toxin
228
Diagnosis: Bloody diarrhea with hemolytic uremic syndrome
Enterohemorrhagic E coli (eg O157:H7)
Caused by shiga-like toxin
229
Diagnosis: Bloody diarrhea with pathologic section revealing bacteria invading colonic mucosa
Enteroinvasive E. coli
230
Diagnosis: Bloody diarrhea with symptoms of appendicitis
Yersinia enterocolitica
231
Diagnosis: Bloody diarrhea in a day care center
Yersinia enterocolitica
232
Diagnosis: Bloody diarrhea with pseudomembranous colitis
Clostridium dificile
233
Diagnosis: Bloody diarrhea with protozoans
Entamoeba histolytica
234
Diagnosis: Watery diarrhea in someone who just visited Mexico
Enterotoxigenic E coli (no preformed toxin)
235
Diagnosis: Watery diarrhea with comma-shaped organisms
Vibrio cholerae
236
Diagnosis: Watery diarrhea with appearance of rice water
Vibrio cholerae
237
Diagnosis: Watery diarrhea with gangrenous leg
Clostridium perfringens
238
Diagnosis: Watery diarrhea in an immunocompromised patient
Protozoa (eg Giardia or Cryptosporidium)
239
Diagnosis: Watery diarrhea
Think viruses first.
Rotavirus
Adenovirus
Norwalk virus
240
Difference between mechanisms of cholera and pertussis toxins
Cholera: Permanently activates Gs (turns the "on" on)
Pertussis: Permanently disables Gi (turns the "off" off)
241
What is edema factor?
A toxin in the Bacillus Anthracis exotoxin complex that functions as adenylyl cyclase
