Module 16 Flashcards
1
Q
Bacteria
A
Single celled organisms shaped as rods, spheres, spirals
2
Q
Bacteria + the body
A
- most rendered harmless by immune system
- some are beneficial
- some are pathogenic + cause disease
3
Q
Bacterial Pathogenicity - virulence factors
A
- Fimbriae and pilli
- flagella
- secretion of toxins and enzymes
- invasion
4
Q
Fimbriae and Pilli - what
A
Hair-like structures that project from the surface of bacteria cells
5
Q
Fimbriae and Pilli - function
A
allow bacteria to attach to certain sites in our body so they are not washed away
6
Q
Fimbriae and Pilli - example of bacterium
A
E. Coli (use fimbriae that attach to urogenital tract –> bladder infection)
7
Q
Flagella - what, function
A
- projection of bacteria
- allows bacteria to “swim” through aqueous environment –> get to sites where they may survive
8
Q
Toxin symptoms (bacteria) (7)
A
- nausea, vomiting, diarrhea, cramps, pain, fever, paralysis
9
Q
Toxin function (bacteria)
A
- (some cases) bacterial toxins produced outside of our body can mediate toxic reactions if the gain entry to our body
- ex poisoning
10
Q
Enzymes (bacteria)
A
- can degrade tissue or breakdown antibodies (our defense against infection)
11
Q
Invasion (what, Example x2)
A
some bacteria can invade our cells
- EX salmonella invade cells of intestine –>diarrhea
- EX2 tuburculosis causing bacteria enter body in the lungs and can “hide” inside cells making it impossible for immune system to act on the
12
Q
Gram staining of Bacteria
A
- classify bacteria as gram positive or gram negative
- gram stain –> tells us about cell wall structure of bacteria (amount of peptidoglycan) which impacts antibiotic use
13
Q
Characteristics of Gram positive stain (6)
A
- thick peptidoglycan wall (Cell wall)
- stains purple
- Techoic acids (rigid cell wall)
- no LPS
- no outer membrane
- Do not have porins
14
Q
Characteristics of Gram negative bacteria (6)
A
- thin peptidoglycan layer (cell wall)
- no techoic acids
- LPS (lipopolysaccharides) are component of outer membrane
- outer membrane (protect bacteria from bile salt + detergents)
- stain pink during staining
- porins (allow sugar, ions, amino acids to enter)
15
Q
Signs of Infection
A
- fever, malaise, local redness, swelling
- increased respiratory rate, tachycardia
- other specific symptoms (ex UTI = frequency of urination)
16
Q
Selective toxicity (bacteria)
A
Therapy that destroys bacteria without harming the host
- target differences between cellular chemistry of bacteria and humans
17
Q
Antibiotic therapy produces selective toxicity by (3)
A
- disrupting bacterial cell wall (human cells do not have cell wall)
- targeting enzymes unique to bacteria
- disrupting bacterial protein synthesis (bacterial and human ribosomes are different)
18
Q
4 questions for selection of an antibiotic
A
1) has the infectious bacteria been identified
2) bacterial sensitivity to the antibiotic?
3) can antibiotic access site of infection?
4) is the patient able to battle the infection?
19
Q
Identification of the Bacteria (2)
A
- ideally done before selection of treatment
- gram stain (rapid, provides info on structural features of bacteria)
- culturing = best basis for selection of the therapy
20
Q
Identification of Bacteria - barriers (2)
A
- cant take culture from child ear infection
- lower respiratory infections may have several species of bacteria)
21
Q
Bacterial Sensitivity to Antibiotic - 2 categories
A
- bacteriostatic
- bactericidal
22
Q
Bacteriostatic
A
- stops growth and replication of bacteria (stops spread of infection)
- body’s immune system can then attack and remove bacteria
23
Q
Bactericidal
A
drugs kill the bacteria
24
Q
MIC
A
MIC = minimum inhibitory concentration
25
MBC
minimum bactericidal concentration
26
Penetration to the site of action - which infections require careful selection of antibiotics?
- meningitis
- urinary tract infections
- osteomyelitis
- abscesses
- otitis Media
27
Meningitis (what)
- infection of the meninges (membranes covering brain and spinal cord)
- bacterial meningitis (rare, more life threataning)
28
Meningitis - treatment
- antibiotic that penetrates the meninges
29
Urinary Tract Infections (UTIs) = what?
- when bacteria enteres any part of urinary system
| - most often = infection of bladder (cathaterization)
30
UTI treatment
antibiotic that enters urinary system
31
Osteomyelitis (what)
- infection of the bone
32
Osteomyelitis - treatment
- very few antibiotics enter bone = limited treatment
| - usually treat with antibiotics for 4-6 weeks
33
Abscesses (what)
- pus or other infected material collect under skin
34
Abscesses - treatment
- difficult to treat with antibiotics (poorly perfused with blood)
35
Otitis Media (what)
- infection of the middle ear (ear infection)
| - much more common in children
36
Otis Media - treatment
- many antibiotics do not penetrate inner ear = not effective to treat otitis media
37
Ability of the patient to battle infection - selection of antibiotic
- immunological state
- bactericidal antibiotics KILL bacteria --> can be used in
immunocompromised patients
- bacteriostatic antibiotics require actions of immune function = less
used in immunocomprimised patients
38
Complications of antibiotic therapy (6)
- resistance
- allergy
- serum sickness
- superinfection
- destruction of normal bacterial flora
- bone marrow toxicity
39
Antibiotic resistance
- a bacteria that did respond to an antibiotic and has lost sensitivity over time
40
Antibiotic resistance (3 major mechanisms)
- Reduction of the drug at the site of target
- increased drug inactivation
- alteration of the bacterial target
41
Antibiotic resistance - reduction of the drug at the site of the target
- bacteria decreases uptake of antibiotics
- bacteria increases expression of efflux pumps (extrude antibiotics)
- COMBo - drug that is less able to access its bacterial target
42
Antibiotic resistance - increased drug inaction (+ example)
- bacteria that evolved to produce increased enzymes that inactivate antibiotics
- EX enzyme beta lactamase will degrade antibiotics with beta lactam ring (penicillin, cephalosporins)
43
Alteration of bacterial target (Antibiotic resistance)
- bacteria may evolve mutations in the target htat make antibiotic ineffective
- EX a mutation in bacterial ribosomes renders some antibiotics ineffective
44
Preventing resistance (4)
1) prevent infection (vaccinate, get catheters out if possible)
2) diagnose and treat effectively (patients with cold / a virus want antibiotics despite that it will not be effective)
3) use antibiotics wisely (only when necessary)
4) prevent transmission (isolate pathogen and prevent its spread, wash hands)
45
Allergy - most common antibiotic
penicillin
46
Signs of allergy (antibiotics) (5)
- urticaria (hives)
- anxiety
- swelling of hands, feet, throat
- difficulty breathing
- hypotension
47
time of onset (fatal allergy to antibiotic)
20 minutes of dosing
48
What to do if patient is experiencing an allergic reaction?
- stop antibiotic
- monitor vitals
- diphenhydramine (antihistamine)
- epipen (epinephrine, vasoconstrictor)
49
Serum sickness (time of onset)
- similar to allergy but deveops 7-21 days after antibiotic exposure
50
What is serum sickness
- body's immune system improperly identifies drug or drug protein complex as harmful
- body then produces immune reaction (inflammation)
51
Serum sickness symptoms (7)
- fever
- hives
- rash
- joint pain
- itching
- angioedema
- enlarged lymph nodes
52
Serum Sickness - treatment (4)
- antihistamine (for itching)
- analgesics (for pain)
- corticosteroids (for inflammation)
- stop antibiotic???
53
Superinfection
- type of resistance
- when a new type of infection develops during the course of antibiotic therapy
- broad spectrum antibiotics kill both pathogenic bacteria and normal flora
- -> allowing new bacteria to flourish
- superinfection caused by drug-resistant bacteria
54
Superinfection - treatment
hard to treat (drug resistant bacteria has grown)
55
Destruction of normal bacterial flora - 3 effects
1) impair intestinal bacterial synthesis of vitamin K. (danger = anticoagulant Warfarin requires vitamin K --> increased risk of bleeding)
2) impair Intestinal bacteria metabolize + first pass effect (danger = increased blood drug levels = toxicity
3) Enterohepatic recycling of drugs (danger = drug therapy, contraceptive failure with birth control pills)
56
Bone marrow toxicity (what, signs, symptoms)
- rare but serious complication
- SIGNS = aplastic anemia, thrombocytopenia, agranulocytosis, leukopenia
- symptoms = sore throat, bruising, fatigue
57
Autolysins
- bacterial enzymes that degrade peptigdoglycan cell wall
58
Transpeptidases
- enzymes that function to form cross bridges between peptidoglycan strands therefore making cell wall strong
59
Penicillin Binding Proteins (PBPs)
- transpeptidases
| - autolysis
60
Penicillins - mechanism of action
- inhibid transpeptidases (disrupt synthesis of cell wall)
- activate autolysins (promote cell wall destruction)
- net result = cells take up excess water and die (lyse)
61
Penicillin - target bacteria
more effective against gram positive bacteria (since they do not have outer membrane)
62
Penecillin - class of antibiotic
- bactericidal
| - only effective against bacteria that are actively growing and dividing
63
Penicillin resistance (3 types)
- inability to reach target
- inactivation
- mutation in PBPs (low affinity for penicillins IE MRSA)
- PREDOMINANT = beta lactamase inhibiting
- treat with beta lactamase inhibitors
64
Classes of penicillins
- narrow spectrum penicillins
- narrow spectrum penicillinase resistant penicillins
- broad spectrum penicillins
- extended spectrum penicilins
65
Narrow Spectrum Penicillins - target bacteria
- gram positive bacteria
66
Narrow Spectrum Penicillins - route of administration
- IV or IM (destroyed by gastric acid)
67
Narrow Spectrum Penicillins - target types infections
- pneumonia and meningitis
68
Narrow Spectrum Penicillins - adverse effects
allerguy
69
Narrow Spectrum Penicillinase Resistant Penicillins - what
- altered side chain that makes them not susceptible to inactivation by beta lactamase enzymes
70
Narrow Spectrum Penicillinase Resistant Penicillins - target bacteria
- effective in treating penicillinase producing staphylococci
71
Narrow Spectrum Penicillinase Resistant Penicillins - not effective (bacteria, and condition)
- bacteria - non-penicillinase producing bacteria
| - not effective in treating absecess or penetrating into bone
72
Narrow Spectrum Penicillinase Resistant Penicillins - resistance?
some are (ex MRSA)
73
Broad Spectrum Penicillins - target bacteria
- gram positive and gram negative bacteria (bc it can penetrate outer wall)
74
Broad Spectrum Penicillins - resitance
easily inactivated by beta lactamases
75
Extended Spectrum Penicillins - target bacteria (2)
- gram positive and gram negative bacteria +
| - Pseudomonas aeruginosa (is resistant to all other penicillins)
76
Extended Spectrum Penicillins - resistance
degradation by beta lactamase enzymes
77
Cephalosporins - mechanism of action
- same mechanism of action as penicillin
| - inhibit transpeptidases, activate autolysins
78
Cephalosporins - classification
bactericidal, 4 generations
1st generation
2nd generation
3rd generation
4th generation
79
Cephalosporins - difference between generations (3)
moving from 1 to 4, drugs will
- increase in activity against gram negative bacteria
- increase in resistance to destruction by beta lactamases
- increase in ability to penetrate cerebrospinal fluid
80
Cephalosporins - adverse effect
- allergy
| - cross sensitivity with allergy to penicillin is rare
81
Vancomycin - when used
- potentially toxic drug
| - only treats serious infection (ex caused by MRSA)
82
Vancomycin - target infections
MRSA infecting osteomyelitis, meningitis, pneumonia, septicemia
83
Vancomysin - mechanism of action
- inhibits cell wall synthesis by binding to precursors of cell wall synthesis to block the transglycosylation step in cross bridge synthesis
84
Vancomysin - adverse events
- ototoxicity
| - Red person syndrome = flushing, rash, itching, hypotension
85
Tetracylines - mechanism of action
- bind to 30S ribosomal subuint of bacteria and prevent amino acid addition to peptide chain
86
tetracyclines - class
- Bacteriostatic
87
tetracyclines - target infections
- typhys fever, clamydia, cholera
88
tetracyclines - adverse effects
- GI upset
- photosensitivity (avoid UV and wear sun block)
- susceptibility to superinfection
89
Macrolide Antibiotics - mechanism of action
- block 50S ribosomal subunit of bacteria --> block addition of amino acids to peptide chain
90
Macrolide Antibiotics - classification
- bacteriostatic
91
Macrolide Antibiotics - adverse effects (2)
- GI upset'
| - QT interval prolongation
92
Tetracyclines - target bacteria
Broad spectrum (gram + and -)
93
Macrolide Antibiotics - target bacteria
- broad spectrum (gram + and - )
94
Oxazolidinones - classification
bacteriostatic
95
Oxazolidinones - target bacteria
- narrow spectrum
| - gram positive bacteria
96
Oxazolidinones - mechanism of action
- bind to specific region of 50S ribosomal subunit to inhibit protein synthesis
97
Oxazolidinones - target bacteria species
treat MRSA and vancomycin resistant enterococci (VRE)
98
Oxazolidinones - adverse events
- reversible myelosupression
99
Aminoglycosides - class
- bacteriocidal
100
Aminoglycosides - target bacteria
narrow spectrum (gram negative)
101
Aminoglycosides - mechanism of action
- protein synthesis inhibitors
| - bind to 30S ribosomal subunit to prevent protein synthesis
102
Aminoglycosides - mechanism of action
- rapidly lethal to bacteria
| - mechanism unknown
103
Aminoglycosides - adverse effects (2)
- irreversible ototoxicity
| - reversible nephrotoxicity
104
Sulfonamides and trimethoprim - mechanism of action
- bacteria depend on synthesis of folic acid to incorporate into DNA
- Sulfoamides and trimethoprim act on different stages to block synthesis of folic acid
105
Sulfonamides and trimethoprim - class
- bactericidal
106
Sulfonamides and trimethoprim - target infection
- UTIS
107
Sulfonamides and trimethoprim - adverse effect
- hypersensitivity reactions (fever, photosensitivity)
| - small risk of severe hypersensitivity reaction called Stephens-JOHNSON SYNDROME
108
Fluroquinoones - mechanism of action
- inhibit DNA replication
| - inhibit 2 enzymes, DNA gyrase and topoisomerase IV
109
Fluroquinoones - class
- bacgtericidal
110
Fluroquinoones - target bacteria
broad spectrum (gram + and -
111
Fluroquinoones - target infection
- UTI, osteomyelitis, soft tissue infections
112
Fluroquinoones - adverse effects
GI symptoms (nausea, vomitting, diarrhea)
113
Isoniazid - target infection
tuburculosis
114
Isoniazid - mechanism of action
inhibiting synthesis of mycolic acid, component unique to cell wall of tuburculosis causing bacteria
115
Isoniazid - adverse effects (2)
peripheral neuropathy and hepatotoxicity
