Midterm #2 Material Flashcards
1
Q
Define prophylaxis
A
Use of a drug to prevent potential for infection of a person at risk
2
Q
Define chemotherapeutic drug
A
Any chemical used in the treatment, relief, or prophylaxis of a disease
3
Q
Define Antimicrobial
A
All inclusive terms for an antimicrobial drug
- regardless of its origin
4
Q
Define Antibiotics
A
Substance that can inhibit or destroy other microorganisms
5
Q
What is the difference between antimicrobial and antibiotics?
A
a
6
Q
What are narrow spectrum antimicrobials?
A
Antimicrobials effective against a limited array of microbial types
7
Q
What are broad spectrum antimicrobials?
A
Antimicrobials effective against a wide variety of microbial types
8
Q
What is monotherapy?
A
Treatment using a single drug
9
Q
What is combined therapy?
A
Treatment using more than one drug
drugs could be contained in the same pill
10
Q
Define bacteriostatic agents
A
Agents that inhibit or prevent the growth of bacteria
11
Q
Define disinfection
A
Physical or chemical process that destroys vegetative pathogens
- but NOT bacterial endospores
12
Q
Define antiseptic
A
Chemical applied to living tissues to render them free of pathogens
13
Q
Define sanitization
A
Forceful cleaning that removes contaminants and makes objects hygienic and safe for use
14
Q
How do autoclaves sterilize objects?
A
Utilize steam under pressure to sterilize heat-resistant materials
15
Q
How does pasteurization disinfect?
A
Subjects liquids to temperatures below 100 degrees C and is used to lower the microbial load in liquids
16
Q
What does it mean to say that an antimicrobial has a selective toxicity?
A
Means that it is effective against the microbes without harming the host
17
Q
What does it mean to say that an antimicrobial has selective toxicity?
A
Means that it is effective against the microbes without harming the host
18
Q
True or False:
It is more beneficial to have an antimicrobial drug that is microbistatic instead of microbicidal
A
False!
- it is better to have microbicidal
- “static” means that you prevent the growth, not kill the organism
19
Q
What does actinomycin interfere with?
A
Interferes with the synthesis of nucleic acid AND proteins
- in bacterial AND human cells
- NOT selectively toxic
20
Q
Why do we hold off on giving honey to kids under 1 year old?
A
Interferes with normal development
21
Q
True or False:
Selective toxicity is a characteristic of antimicrobials
A
True
22
Q
How do antibiotics work against microbials (2)?
A
- By inhibiting one or more steps in the synthesis of essential cellular components
- Increasing permeability of microbial cell membrane
23
Q
What are 5 examples of major actions that antibiotics can work on against microbials?
A
- Cell wall inhibitors
- Cell membrane
- DNA/RNA
- Protein synthesis inhibitors acting on ribosomes
- Metabolic pathways and products
24
Q
True or False:
Drugs can target the ribosomes of the bacterial proteins
A
True
25
What do cell wall inhibitors prevent?
Cross-linkage between the two key polymer carbohydrates in the peptidoglycan
26
What gives bacteria their cell shape and integrity?
Peptidoglycan
27
What examples of beta-lactam antibiotics (2)?
1. Penicillin (ex: Ampicillin and Amoxicillin)
| 2. Cephalosporins (methicillins, vancomycins, and isoniazid)
28
What is a characteristic of beta-lactam antibiotics?
Class of broad spectrum antibiotics
| - contains a beta-lactam ring in their molecular structure
29
What drug is the last resort for treating gram-positive bacterial infections not responsive to other drugs?
Vancomycin
30
What is the first line drug for TB?
Isoniazid (INH)
31
How do antibiotics disrupt the cell membrane/permeability and/or function?
The drugs bind to the microbial cell membrane leading to alteration in membrane permeability and cell death
32
What is amphotericin B used for?
Life threatening fungal infections
33
What the group of polymyxin antibiotics used for?
Primarily for gram-negative bacterial infections
34
What is the common drug in over the counter antibiotics that disrupt the cell membrane in gram-negative bacteria?
Polymyxin B
35
What is an example of a last resort drug that is used to disrupt the cell membrane of gram-negative bacteria?
Polymyxin E
36
True or False:
| Polymyxin B is more potent than Polymyxin E
False!
| - E is more potent than B
37
What do antibiotics do to inhibit nucleic acid synthesis?
Block synthesis of microbial DNA or RNA
38
What does Fluoroquinolone (Ciprofloxacin) do?
Inhibits two enzymes required for DNA replication
- inhibits nucleic acid synthesis
(1 of the major actions of antibiotics)
- UTIs and healthcare associated pneumonia
39
What does rifampin (rifampicin) do?
Inhibits RNA polymerase (enzyme required to produce all types of RNA in bacteria)
- used as part of COMBINED therapy to prevent/treat TB and meningitis
40
What are the two examples of drugs (antibiotics) that inhibit nucleic acid synthesis?
1. Fluoroquinolone (Ciprofloxacin)
| 2. Rifampin (Rifampicin)
41
How do antibiotics block protein synthesis on microbial agents?
Target ribosomes at various stages of protein synthesis
42
Aminoglycosides effectively block the protein synthesis of what kinds of bacteria?
Most gram-negative aerobic and facultative anaerobic rod-shaped bacteria
43
What is erythromycin used for specifically in blocking protein synthesis?
For skin and upper respiratory infections
44
Linezolid effectively blocks the protein synthesis of what kinds of bacteria?
Most gram-positive bacteria
| - including MRSA and VRE
45
How do antibiotics inhibit metabolic pathways?
They work by competitive inhibition
46
Sulfamethoxazole-trimethoprim (SMZ-TMP) is used to treat? And to inhibit the metabolic pathway of what?
Used to treat pneumonia
| - caused by the protozoan PNEUMOCYSTIS in HIV/AIDS patients
47
What is the role of sulfonamide and trimethoprim in the inhibition of metabolic pathways?
Interferes with the metabolic pathways for production of essential nutrients (such as folic acid)
48
What is the important role that folic acid plays in protein synthesis?
It's a coenzyme for the DNA and RNA synthesis
49
True or False:
| Trimethoprim is bacteriostatic when used alone but bactericidal when used WITH sulfonamide
TRUE!
50
What are the major mechanisms of antivirals?
1. Protecting host cells from being infected (interferons)
2. Enhancing the host defense against viruses (transfer of antibodies from immune person to the susceptible person)
3. Interfering with specific steps of the viral replication cycle
51
True or False:
| Even though interferons help protect the host cell from being infected, they do have some toxic effects
True
52
What three drugs inhibit the release or virus entry?
1. Fuzeon
2. Amantidine
3. Tamiflu
53
What are three drugs that inhibit the synthesis of nucleic acid of viruses?
1. Acyclovir (Herpes)
2. Nucleotide analog reverse transcriptase (RT) inhibitors (HIV)
3. NON-nucleoside reverse transcriptase inhibitors
54
Describe a retrovirus
2 strands of RNA
| - use reverse transcription to form DNA (uses the enzyme reverse transcriptASE)
55
What is an example of a drug that inhibits the assembly of viruses?
Protease inhibitors (HIV)
56
What does combined therapy do for persons infected with HIV (3)?
1. Reduces viral load
2. Restores immune function
3. Reduces the emergence of drug-resistant HIV
- does NOT cure!
57
What are antibiotics?
Natural substances produced by one microbe (bacteria, fungi, protozoa) that inhibits the growth or kills other microorganisms
58
True or False:
| Antibiotics work well on viruses
FALSE
| - antibiotics do NOT work on viruses
59
What are antimicrobials?
Chemotherapeutic agents against viruses (antivirals) and other types of microbes (antibiotics)
60
True or False:
| Antibiotics can be useful against a narrow or broad group of microbes
True
61
What does the suffix "-static" mean?
Inhibit growth
62
What does the suffix "-cidal" mean?
Kill
63
What is the action of penicillin?
Inhibits the synthesis of peptidoglycan (found only in bacteria but not human cells)
- has desirable selective toxicity
64
What is the action of actinomycin?
Does NOT have selective toxicity
| - inhibits the synthesis of nucleic acids/protein synthesis on BOTH bacteria and human
65
If you are exposed to HIV (needle stick injury) what is the post-exposure prophylaxis?
Tenofovir (300 mg QD)
+ Lamivudine (150 mg BID)
+ Kaletra (2 tabs (BID)
66
What is asepsis or septic technique?
Practice of preventing or minimizing the risk of introducing microbes into key sterile equipment parts
67
What is an aseptic field?
An area created to control the environment around the procedure to protect the key parts
68
What is the ANTT approach (6 steps)?
1. Risk assessment
2. Mange the environment
3. Decontaminate and protect
4. Use aseptic fields
5. Use non-touch technique
6. Prevent cross infection
69
Define sterile
State of being free (or absence) of all viable microorganisms
- including bacterial spores
70
Define sterility testing
IN VITRO test to check for any contamination to ensure any injectable drugs must be sterile
71
Define sterilization
Destruction of ALL VIABLE life form
- including bacteria spores
- by physical or chemical means
72
Define disinfection
Destruction of microorganisms (esp. pathogens) by physical or chemical means
- NOT effective against bacterial spores
73
Define antisepsis
Similar to disinfection but applied to LIVING TISSUES
| - reduce/remove resident skin microbiota before surgery and injection
74
Define decontamination
Applies to BOTH living and non-living objects
75
What are the three major modes of action to control microbiota?
1. Protein denaturation
2. Permanent damage to microbial nucleic acids
- including their genome
3. Destruction of structural integrity of microbes
- damaging bacterial cell wall and/or cell membrane
76
What are critical items?
Items that enter sterile tissue or vascular space
77
What is applied to semi-critical items (does not penetrate the bloodstream)?
Disinfection
78
What can be used to disinfect an entire building?
Chlorine dioxide
79
What does a TYPICAL ANTT approach to prevent cross infection include?
1. Environmental risk assessment
2. Decontamination and protection
3. Aseptic field selection and management
4. Non-touch technique
80
What are the factors influencing the efficacy of disinfecting and sterilizing agents (death rate) (6)?
1. Number of microbes present
2. Nature of microbes present (ex: spores)
3. Temp and pH
4. Concentration (dosage or intensity) of agent used
5. Modes of action of the agent (microbistatic or microbicidal)
6. Presence of contaminants (blood/mucus)
81
What are two methods of sterilization using heat?
1. Dry heat
| 2. Moist heat
82
How hot and how long do you have use dry heat for to have sterilization?
160 degrees
| 2 hours
83
How hot and for how long do you have to use moist heat for to have sterilization?
121 degrees
15 min
- 15 psi/pound per squared inch in an autoclave
84
True or False:
| If you increase the heat during sterilization, you can reduce the time it takes
True
85
What is the method called if you use high energy (short wavelength) radiation to sterilize?
Ionizing radiation
86
What are the benefits of using ionizing radiation (3)?
- strong penetrating power
- causes permanent damage to nucleic acid
- can be used on heat-sensitive items
87
What is the most commonly used sterilization method in healthcare settings?
Ethylene Dioxide (gas)
88
What does ethylene dioxide do and what is it used for?
Blocks DNA replication and enzymatic functions
| - used for sterilizing heat-sensitive, delicate instruments
89
What are the characteristics of using ultraviolet light to disinfect?
- Non-ionizing radiation
| - Exposure to UV leads to the formation of thymine dimers
90
True or False:
| Ultraviolet light has less energy and less penetrating power than ionizing radiation
True
91
What does ultraviolet light do?
Blocks normal DNA replication
92
True or False:
| Bacteria cannot repair the DNA damage cause by UV light
FALSE!
| - SOME microbes CAN repair the DNA damage caused by UV light
93
What is used for air and water disinfection?
UV light
94
What is the agent that is used for antisepsis and disinfection?
Iodine
95
What are the benefits of using iodine?
- strong oxidizing agent
- good penetrating power
- rapid action
96
What is the preferred method of cleaning your hands when they are visibly soiled?
Soap and water
97
What does soap contain that reduces the surface tension between a liquid and a solid?
Surfactant molecules
98
What antimicrobial agent might be contained in soap?
Chlorhexidine
99
What are the benefits of using an alcohol based hand rub?
- takes less time than hand washing
- more effective than hand washing when hands are NOT visibly soiled
- less drying
100
True or False:
| It is preferred to use soap and water when dealing with C. diff
True
101
True or False:
| Studies have not shown a decrease of MRSA and VRE associated with the use of alcohol-based hand rub
FALSE
| - studies did show a decrease of MRSA and VRE associated with the use of ABHR
102
Rank the following 8 agents in terms of their resistance ( 1 = most resistant; 8 = least resistant):
Bacterial spores, enveloped viruses, fungi, gram + bacteria, gram - bacteria, non-enveloped viruses, prions, protozoa cysts
1. Prions
2. Endospores of bacteria
3. Protozoa cysts
4. Gram - bacteria
5. Fungi
6. Non-enveloped viruses
7. Gram + bacteria
8. Enveloped viruses
103
What does the binomial nomenclauture of bacteria consist of?
1. Genus
| 2. Species
104
What 4 things can bacteria be classified and grouped into?
1. Family
2. Genus
3. Species
4. Subspecies
105
True or False:
| There could be a single or many species within a genus
True
106
If bacteria are members of the same species, what are the three ways that they can be classified in terms of strains?
1. Biotypes
2. Phage types
3. Serotypes
107
What is an example of a biotype of bacteria?
Resistant to antibiotics
| - such as MRSA
108
How are different strains of serotypes differentiated by?
Based on the use of antibodies or serum
109
How can different strains of bacteria of the same species differ
1. Communicability
2. Reservoirs and modes/routes of transmission
3. Vaccine (preventability)
4. Diagnostics
5. Susceptibility to antimicrobials
6. Virulence
7. S/S of diseases
110
What are the names of the different groups of meningococcal?
```
A
B
C
Y
W-135
```
111
What happens if you are vaccinated with meningococcal polysaccharide vaccine, Groups A, C, Y and W-135?
You are protected against all of them
| - EXCEPT group B!
112
What are the S/S associated with different escherichia coli serotypes?
- urinary frequency
- dysuria
- hematuria
- pyuria
113
Why is the microscope an essential tool?
To examine and study microbes and cellular structures
114
What are the two major types of microscopes?
1. Light
| 2. Electron
115
A microscope will have a better resolving power, if ________
It has a smaller value of resolution
| - shortest distance between 2 points on a specimen
116
What kind of microscope has a high magnification (light or electron)?
```
Electron = 1,000,000 x or more
Light = only 2,000 x
```
117
What is the maximum resolution of a light microscope?
200 nm
118
What is the maximum resolution of an electron microscope?
0.5 nm
119
What kind of microscope is required to study viruses or cellular details?
Electron microscope
120
True or False:
| An electron microscope has greater magnification and better resolution than a light microscope
True!
121
What kind of microscope is commonly used with staining methods, to identify disease-causing microbes?
Light microscope
- gram-stain
- but NOT viruses or prions
122
Why do gram stains not work well with some bacteria?
B/c they have ATYPICAL cell walls
123
If a bacteria has an ATYPICAL cell wall, what kind of stain can be used to identify them?
Acid-fast stain
124
What are two examples of bacteria that need an acid-fast stain to identify them?
1. Nocardia
| 2. Mycobacterium (TB and leprosy)
125
What is nocardia?
Opportunistic infection of the lungs, heart and brain
126
What is obtained as part of the conventional approach in identifying disease-causing bacteria?
Bacterial morphology - shape
127
True or False:
| Bacterial cell shapes and their arrangement cannot be revealed under microscope examination
False
| - obviously it can be
128
What are the three most common shapes of bacterial cells?
1. Coccus/cocci
2. Bacillus/bacilli
3. Spiral (vibrio and spriochete)
129
Describe the coccus/cocci shape
Berry-shaped
130
Give three examples of bacteria that have the coccus/cocci shape
1. Staphylococcus
2. Stroptococcus
3. Enterococcus
4. Neisseria
131
Describe the bacillus/bacilli shape
Rod-shape
132
Give 4 examples of bacillus/bacilli shaped bacteria
1. Bacillus
2. Lactobacillus
3. E. coli
4. Clostridium
133
Describe the Vibrio (spiral) shape
Comma-shaped or short-curved rod
134
Give 2 examples of vibrio shaped bacteria
1. Vibrio
| 2. Campylobacter
135
Describe the spirochete (spiral) shape
Corkscrew-shaped
136
What are 2 examples of spirochete (spiral) bacteria?
1. Borrelia (Lyme disease)
| 2. Treponema (syphillis)
137
What environment conditions need to be optimal for bacterial growth (5)?
1. Oxygen
2. pH
3. Water
4. Nutrients
5. Temperature
138
What are the 4 ways that bacterial growth can be limited or controlled?
1. Use of chemicals and/or physical methods of control
2. Antibiotics
3. Immune responses by host (enhanced by vaccination)
4. Microenvironment of bacteria
139
True or False:
| Bacteria growth is infinite and constant
False
| - it's not ...
140
What are the 4 phases of bacteria growth?
1. Lag phase
2. Exponential (log) phase
3. Stationary phase
4. Death phase
141
What happens in the lag phase of bacteria growth?
Bacteria are adjusting to the environment (pH, temp, acidity, etc)
- there is not a lot of growth
- just some growth
142
What happens in the exponential growth phase of bacteria growth?
Numbers rise steeply
- bacteria are actively multiplying
- generation time or doubling time
143
What happens during the stationary phase of bacteria growth?
Rate of growth equals the rate of dealth
| - bacteria are competing for limited resources
144
What happens during the death phase of bacteria growth?
More bacteria are dying than the reproduction rate
145
At what phase of growth are bacteria most susceptible to antibiotics?
Exponential (log) phase
146
Give a reason why the growth rate equals the death rate during the stationary phase
Due to micro-environmental factors
| - lack of nutrients, pH changes, toxic metabolites, etc
147
How does asexual reproduction occur?
| What does it produce?
Binary fission
| - a parent cells give rise to two identical daughter cells
148
What is important to keep in mind with asexual reproduction and resistance?
Daughter cells inherit EVERYTHING from parent cell
| - this includes RESISTANCE to antibiotics!
149
What is the doubling time or generation time?
Time it takes for a bacterial population to double its number
150
What is the generation time of E. coli?
15 - 20 min in the lab
| - 12 - 24 hours in the intestine
151
What is the generation time for mycobacterium tuberculosis?
12 - 20 hours in the LAB
152
What is the formula for bacteria reproduction?
Nt = No x 2^n
```
Nt = number of bacteria at time, t
No = number of bacteria at time o (starting number)
n = number of generations in time, t
```
153
If bacteria are fast-growing, they have a _____ generation time
short
154
If bacteria are slow-growing, they have a ____ generation time
long
155
Why are fast-growing bacteria more susceptible to antibiotics?
B/c antibiotics act in the exponential growth phase
| - more likely that you are going to catch more bacteria during this phase
156
Why is it a problem if a patient's wound is contaminated with a fast-growing bacteria?
A small number could result in a large bacterial population
157
For fast-growing bacteria, what is needed to stop the infection in patients?
Prompt diagnosis and timely interventions
158
True or False:
| Slow-growing bacteria are less susceptible to antibiotics
True
| - antibiotics affect bacteria during their growth
159
If a patient is infected with a slow-growing bacteria, how long will the antimicrobial therapy usually take?
Longer duration of therapy
| - when compared to a fast-growing bacteria
160
Why might a patient stop their antimicrobial treatment if they are infected with a slow-growing bacteria?
It requires a LONG treatment plan, and the patient may no longer feel sick
- might lead to re-infection
161
Using the formula:
Nt = No x 2^n
Calculate the number of bacteria in a patient's wound at the end of 5 hours after it was contaminated by a HCW with 1,000 bacteria with a generation time of 30 minutes, assuming the growth conditions for the bacteria are optimal
```
No = 1,000
T = 5 hours
G = 30 minutes
Number of generations = 10
(5 x 60 minutes)/30 mins
```
```
Nt = 1,000 x (2^10)
Nt = 1,024,000
```
162
Define antibiotic resistance
Lost the ability to effectively control bacterial growth or kill bacteria
163
True or False:
| Antibiotic resistant bacteria continue to grow and multiply in the presence of therapeutic dose of the drug
True
| - because they have developed resistance, so the drug is not stopping their growth
164
What are the 4 major mechanisms of antibiotic resistance?
| How do they do it?
1. Alteration of target site
2. Efflux pumps
3. Enzymatic degradation or modification
4. Altered permeability
165
How do efflux pumps work to increase antibiotic resistance?
Bacteria cells have active pumps that pump the drug out of their cells
- if the drug is not in their cell, it cannot be effective
166
How does enzymatic degradation or modification work to increase antibiotic resistance?
Bacteria cells would create enzymes that degrade or breakdown the drug
167
What can some bacteria produce that degrade drugs such as penicillin and cephalosporins?
B-lactamases
168
Describe the action of B-lactamases
Destroys the B-lactam ring structure (active site of the drug) which binds to penicillin-binding proteins
169
What happens if an antibiotic resistant bacteria has altered permeability?
Permeability to antibiotics is altered
| - makes the cell impermeable or very hard to permeate
170
What are the 3 ways that the bacterial cell can alter their permeability?
1. Lose porins (no porins, drug can't get in)
2. Reduce porin channel size (hole is too smale, drug can't get in)
3. Decreased expression of porin (there would be fewer porins at the cell membrane)
171
What is the function of porin protein channels in the outer membrane of gram-negative bacteria?
Bacteria can alter these protein channels to block the entry of antibiotics into their cell
172
What two examples of bacteria have become resistant by altering their penicillin-binding proteins?
1. MRSA
| 2. Streptococcus pneumoniae
173
What is the function of an efflux (drug) pump?
Cell membrane proteins that can actively tranport drugs out of the bacteria
174
What are 4 examples of bacteria that have created efllux pumps?
1. Staphylococcus
2. Streptocuccus
3. Psudomonas
4. E. coli
175
True or False:
| Efflux pumps only work on one type of drug at a time
False
| - there is one type of efflux pump that can expel a broad varieties of antibiotics (multi-drug resistance)
176
How do bacteria create antibiotic resistance with alternative metabolic pathways?
Bypass the action of the antibiotic
| - if the drug has blocked the USUAL metabolic pathway, the microbe create an alternative metabolic pathway
177
What are the two ways that microbes can acquire antibiotic resistance through the acquired or genetic way?
1. Mutation
| 2. Genetic exchange
178
What are the 3 ways that genetic exchange can occur (to develop antibiotic resistance)?
1. Conjugation
2. Transformation
3. Transduction
179
How can a bacterial microbe acquire antibiotic resistance intrinsically (or naturally)?
By lacking target sites or metabolic processes
180
What happens if an antibiotic only kills some of the bacteria?
Creates stronger and more resistant bacteria
| - only the weaker bacteria are killed
181
What is conjugation?
Transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells.
182
What is transformation?
Transfer of drug-resistant genes from a lysed donor bacterium to a genetically closely related recipient
183
What is transduction?
Transfer of donor DNA through a (transducing) phage into the recipient bacterium
- foreign DNA is inserted through a virus
184
What is horizontal transfer?
Genetic mechanisms to acquire and spread drug-resistance
185
What is vertical transfer?
Passage of antibiotic-resistance genes during replication
| - from one generation to the next
186
What are some intrinsic factors that contribute to the emergence and spread of AROs (antibiotic resistant organisms)?
- Natural selection
- Biofilm formation
- Horizontal transfer
- Vertical transfer
187
What are some extrinsic factors that contribute to the emergence and spread of AROs?
- Overuse and misuse of antibiotics (non-compliance)
- using antibiotics for viral infections
- using antibiotics in animal feeds
188
Why is it risky to put patients on antibiotics for a long period of time?
Higher chance that you kill off healthy bacteria too (good bacteria)
189
What does that use of broad spectrum antibiotics put clients at risk for?
Lowers patient's natural defenses against certain infections
190
What is the clinical significance of rising antibiotic-resistance on patients?
- ineffective therapy and unfavorable disease outcomes
- increase morbidity
- longer stays in hospitals
- increase mortality
191
What is the clinical significance of rising AROs on hospital practice?
- additional workload for HCWs
- infection control precautions
- lab technologists = testing for AROs
- extra demands on resources (isolation rooms, dedicated equipment, expensive drugs)
192
What are CREs?
Carbapenem-Resistant Enterobacteriaceae
193
What are enterobacteriaceae (EB)?
Large family of gram-negative facultative anaerobicbacilli
| ex. E. coli
194
What are carbapenems?
Beta-lactam drugs used to treat multi-drug resistant (extended spectrum beta lactamases/ESBLs) infections
195
What do enterobacteriaceae commonly cause?
HAIs such as UTIs
196
What is the mechanism of antibiotic resistance for CREs?
Produce enzymes carbapenemases to inactivate the drugs
197
What are the two treatment options for CREs?
1. Colistin
| 2. Combination therapy including aminoglycosides
198
What is the most common mechanism of transmission for CREs?
Contact
| - both direct and indirect
199
What 4 areas need targeting for prevention and control of antibiotic resistant organisms?
1. Reduce antibiotic selection pressures
2. Prevent spread of AROs introduced from outside health care facility (HCF)
3. Decrease spread of AROs in HCF
4. Decrease genetic mutation and/or antibiotic resistance gene transfers by reducing bacterial burdens
200
What are the two ways to decrease genetic mutations or gene transfers by reducing the bacterial burden?
1. Use appropriate antibiotic prophylatic and decontamination
2. Decrease microorganism concentrations (ex. drain abscesses)
201
What are 4 basic steps that can be taken to prevent antimicrobial resistance?
1. Prevent transmission
2. Use antimicrobials wisely
3. Diagnose and treat effectively
4. Prevent infections
202
What is the purpose of the Flagella in bacteria?
Provides motility
203
What is the basal body of the flagella similar to?
Type 3 secretions systems (T3SS) in some gram-negative bacteria
204
What is a T3SS (Type 3 secretions systems)?
"Molecular syringe"
| - to allow bacteria to infect cells and inject certain toxins
205
What is the function of fimbriae?
Adherence/adhesion
| - helps to provide attachment to susceptible host cells and each other
206
What contributes to colonization and biofilm formation?
Fimbriae
207
What are the 3 functions of pili?
1. Attachment to host cells
2. Motility
3. Conjugation ("sex pili" - allow transfer of bacterial DNA from a host to a donor bacterium)
208
What are the two types of glycocalyx?
| What is it?
Adhesive polysaccharide substance found in some bacteria
1. Capsules
2. Slime layer
209
Which of the two types of glycocalyx provides a more even (uniform distribution) of carbohydrates around the bacterial cell?
Capsule
| - not slime layer
210
What is the function of the glycocalyx?
- Retains moisture
| - Helps to survive the host's defenses (resists capture by phagocytes)
211
What are biofilms?
Layers of microbes largely made up of bacteria (with glycocalyx) formed on living and non-living surfaces
212
What three things can biofilms do?
1. Attach to host cells/non-living surfaces
2. Makes cleaning, disinfection and sterilization difficult
3. Acts a protective barriers - difficult for chemical biocides to penetrate
213
In what bacteria are cell walls found?
In all bacteria except: mycoplasma (STIs, pneumonia, skin infections and cancers)
214
What is the function of the cell wall?
Surround the bacterial cell membrane
| - give shape and structure
215
Cell walls are made up of multiples layers of which two types of carbohydrates?
1. N-acetyl muramic (M/NAM) acid
2. N-acetyl glucosamine (G/NAG)
- joined together by 4 amino acids
216
True or False:
| Gram-negative bacteria have a cell wall
True
217
What do cell walls contain?
- porins
| - lipopolysaccharides (LPS) - contains Lipid A
218
What happens when a bacterial cell wall is damaged?
1. Large amounts of Lipid A and tumor necrosis factor are released into the body
2. Stimulates over-production of cytokines
3. Results in fever and systemic inflammation
4. Ends in ENDOTOXIC SHOCK SYNDROME
219
True or False:
| O-antigen is part of the LPS. Antibodies can be raised in animals against them and then use them in serotyping in labs
True
| - I didn't know a good question to write for this one ...
220
What kind of bacteria have atypical cell walls?
Mycobacterium and Nocardia
221
What are the characteristics of atypcial cell walls?
- high concentrations of unique types of lipids
| - resistance to chemical biocides, dehydration, and host defenses
222
What does the cell membrane consist of?
Phospholipid bi-layer
223
What is the function of the cell membrane?
Highly selective barrier
- allows for passage of nutrients and metabolic wastes
- it is an important site for certain metabolic activities
224
In Mycoplasma, what does the cell membrane contain a lot of and what does it do?
Large quantities of sterols - rigid lipids that gives the bacteria cell shape and integrity
225
What do chromosomes contain?
All essential genetic information
226
How many chromosomes do bacteria have?
1
| - yup, just one
227
What is inside the nucleoid or nuclear region of the bacterial cell?
Highest concentration of bacterial chromosomal DNA is localized
228
What are plasmids?
Short, circular, double-stranded DNA molecules found in some bacteria
- not part of the chromosome
- it is extra chromosomal DNA
229
If a bacteria has plasmids, what % of total DNA is contained in those plasmids?
3-5%
230
What do plamsids code for (2)?
- antibiotic resistance
| - toxin production
231
How can plasmids be passed on from bacteria to bacteria?
Through conjugation
232
How do we use plasmids to our benefit?
Used in recombinant DNA technology
- producing drugs
- producing vaccines
233
What is the dormant state of a bacteria?
Endospore
234
What do endospores help bacteria to do?
Survive unfavourable conditions by sporulation
235
What are examples of conditions that an endospore could survive in?
- extreme high temp
- too acidic or alkaline
- lack of water/nutrients
- inappropriate gaseous environment (oxygen or no oxygen)
236
What are the 3 survival mechanisms of endospores?
1. Thick spore coat
2. Large amount of dipicolinic acid-calcium complexes
3. Metabolically inactive
237
What is the benefit of the thick spore coat to the endospore?
Physical barrier
| - difficult for chemical compounds to penetrate
238
What is the benefit of the large amount of dipicolinic acid-calcium complexes to the endospore?
Stablizies proteins to prevent their denaturation at high temp
239
What is the benefit of the being metabolically inactive to the endospore?
Does not require foods or much energy
240
What are 3 examples of sporeforming bacteria: Clostridium?
1. C. difficile
2. C. tetani
3. C. botulinum
241
What does botulism do to the body?
Flaccid paralysis
| - numbness
242
What does tetanus do to the body?
Spastic paralysis
| - muscles fail to relax
243
What are 2 examples of sporeforming bacteria: Bacillus?
1. B. anthracis (anthrax)
| 2. C. cereus (food poisoning)
244
Define infection
Entry and development/multiplication of an infectous agent in the body of a living object
245
What are the two types of infections?
1. Asymptomatic
| 2. Symptomatic
246
What is IN VITRO intoxication?
Exposure to bacterial toxins outside the body
| - ex: ingestion of toxins in food
247
What is IN VIVO intoxication?
Bacteria produce toxins INSIDE the body
248
What is the rationale behind vaccinations (2)?
1. Stimulates the immune system to create long-lasting protective immunity
2. Creates high-level of herd immunity to prevent transmission of the infection in a community
249
Why is it important to obtain herd immunity?
Protects those people who cannot receive vaccinations (they are immune suppressed)
250
Why do some people choose not to receive vaccinations?
- personal/religious/cultural beliefs
- concerns about vaccine safety
- complacency ("disease is rare - therefore, it's not needed")
- mistrust of government, health agencies
251
Define herd immunity
The protection a mostly vaccinated population givers to unvaccinated groups
- protection weakens as the vaccination rate falls
252
What is pertussis also known as? What is the causative agent?
Whooping cough
| - Bordetella pertussis
253
What is the mode of transmission for pertussis?
Direct Contact (droplet)
254
True or False:
| Pertussis is a gram-positive aerobic bacilli
False
| It is a GRAM-NEGATIVE aerobic bacilli
255
How is the pertussis vaccine different than a regular vaccine?
Acellular pertussis vaccine - does not contain a whole cell but only components of the bacteria
256
What are the risk factors for pertussis?
- living in same house
- unvaccinated person
- children not fully vaccinated ( < 6 months)
- Immunity can wear off in adults
- immunocompromised
257
What are the 3 stages of pertussis?
1. Catarrhal stage (1-2 weeks)
2. Paroxysmal stage (1-6 weeks)
3. Convalescent stage (2-3 weeks)
258
What are the clinical features and complications of pertussis?
- apnea
- pneumonia
- convulsions
- encephalopathy
- death
259
What is the causative agent of diphtheria?
Corynebacterium diphtheriae
260
True or False:
| Diphtheria is a gram-positive aerobic bacilli
True
261
True or False:
| Diphtheria bacteria can enter through any mucus membrane
True
262
What are the S/S of Diphtheria?
- white, greyish-white or bluish-white pseudo-membrane on the infected site
- maliase
- low grade fever
- cough
- sore throat
- BULL neck appearance
263
What will happen if you don't treat Diphtheria?
Death within 6 - 10 days
264
What is the major virulence factor of Diphtheria?
Diphtheria toxin inhibits protein synthesis causing host cell death
265
Where is the Diphtheria toxin absorbed?
Bloodstream
266
What is the pseudo-membrane of Diphtheria made up of?
- Coagulated fibrin
- WBCs
- Dead cells
- Bacteria
267
What are the complications of Diphtheria?
- airway obstruction
- damage to the heart (myocarditis)
- nerve damage
- paralysis
- lung infection
- death
268
What are the risk factors of Diphtheria?
- lack of vaccination
- waning immunity
- overcrowded/unsanitary living conditions
- immunocompromised
269
What kind of vaccine is the Diphtheria vaccine?
Toxoid (modified toxin) vaccine
270
What happens if a person is admitted to the hospital with Diphtheria?
Person does not have time to make antitoxins
| - therefore they are directly given antitoxins
271
What is the causative agent of tetanus?
Clostridium tetani
272
True or False:
| Tetanus is a GRAM-NEGATIVE obligate anaerobic sporeforming bacilli
False
| - it is a gram POSITIVE obligate anaerobic sporeforming bacilli
273
What is the reservoir of tetanus?
Soil, contaminated fomites, and intestinal tracts of humans and animals
274
What is the mode of transmission for tetanus?
Through broken skin (puncture, injection or bite wounds)
275
What is the IP of tetanus?
It depends on the site of injury
| - closer to the brain, faster the IP
276
What is the pathogensis of tetanus?
1. Infection of the wound by spores
2. Germination of spores into bacilli
3. Bacilli produce toxins
4. Toxins affect CNS
277
What are the clinical features of tetanus?
- mild spasms
- lock jaw
- problems with swallowing
- back spasms
- pulmonary embolism
- pneumonia
- death
278
What are the risk factors for generalized tetanus?
- unvaccinated
- injected street drugs
- occupational exposure
279
What kind of vaccine is the tetanus vaccine?
Toxoid vaccine
280
What does the DTaP protect against?
Diphtheria
Tetanus
Pertussis
281
What is the medical management for a tetanus?
1. Clean the wound
2. Keep wound aerated
3. Remove any foreign objects
4. Remove necrotic tissue
282
What is the causative agent of Pneumococcal disease?
Streptococcus penumoniae
283
What kind of bacteria are streptococcus pneumoniae?
Gram-positive cocci, most are facultative anaerobes and encapsulated
284
What happens in invasive pneumococcal disease (meningitis)?
When bacteria invade parts of the body that are normally sterile
285
When does the POC stop in meningitis?
Within 24 hours of antibiotic therapy
286
What are the S/S of meningitis?
- fever
- severe headache
- poor eating
- vomiting
- drowsiness
- STIFF NECK
287
What are the complications of meningitis?
- Hearing loss
- Developmental delay
- Death
288
What are the two major types of pneumococcal vaccines?
1. Pneumococcal conjugate vaccine (PCV)
| 2. Pneumococcal polysaccharide vaccine (PPV)
289
How id PCV different than PPV?
```
PCV = old vaccine, protects against 13 strains
PPV = new vaccine, protects against 23 strains
```
290
What is another form of pneumococcal are the elderly and immuno-compromised people at a higher risk of contracting?
Pneumococcal Pneumonia
291
What kind of bacteria are hemophilus influenzae b (Hib)
Gram negative coccobacilli, aerobic, encapsulated serotypes
292
What are the S/S of Invasive Hib (Meningitis)?
- Fever
- Headache
- N/V
- Confusion
- STIFF NECK
- increased sensitivity to light
293
What is the IPV vaccine for?
Polio
294
What does the Hib vaccine contain?
Capsular polysaccharide
| - not whole cell vaccine
295
What is IMD?
Invasive meningococcal disease
296
How many serotypes of IMD are there? What are they?
```
A
B
C
X
Y
W-135
```
297
In what disease do the invasion of the bacteria cause reddish or purple skin rash?
Meningococcal septicemia/bacteremia
