Microbiology - Edwards Flashcards

1
Q

Difference bn prookaryotic + eukaryotic cell

A

Prokaryotes:
- much smaller
- often single celled
- single circular chromosome
- introns are rare
- 70s ribosomes
- rigid cell walls
- rapid cell cycle

Eukaryotes:
- complex, compartmental
- frequently multicellular
- linear chromsome + histones
- introns/exons
- 80s ribosomes
- flexible cell wall
- cell cycle, mitosis/meiosis

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2
Q

Gram +

A
  • rich, thick, peptidoglycan cell wall
    (hence can stand bigger osmotic pressures)
  • no outer membrane
  • no LPS , bc no outer membrane
  • no periplasmic space
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3
Q

Gram -

A
  • peptidoglycan is reduced
  • has an additional outer membrane
  • often the additional outer membrane is decorated with LPS

** LPS referred to as ENDOTOXIN + linked to SEPSIS/SEPTIC SHOCK
** Antigen + Endotoxin + B cells + Inappropriate immune response

  • has periplasmic space

v thin cytoplasmic cell wall

EXAMPLES:
- neisseria spp (STD/STI + meningitis)
- escherichia coli (GI tract)

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4
Q

Bacterial growth + requirements
Prokaryotic Growth

A
  1. NUTRITION
  2. TEMPERATURE
  3. HYDROGEN ION CONCENTRATION
    human commensals - approx 7 pH
  4. OSMOTIC PROTECTION
    human commensals - approx 0.85% NaCl

BACTERIAL GROWTH CURVE
- lag phase
- exponential growth phase
- stationary phase
- decline phase

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5
Q

TB

A
  • bacterium Mycobacterium tuberculosis
  • primarily affects the lungs but can also spread to other parts of the body, including the brain, kidneys, spine, and lymph nodes
  • spreads through the air when an infected person coughs, sneezes, or talks, releasing droplets containing the bacteria
    • Persistent cough (lasting three weeks or longer), sometimes with blood-tinged sputum.
    • Chest pain.
    • Fever.
    • Night sweats.
    • Weight loss.
    • Fatigue.
    • Loss of appetite.
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6
Q

Protozoa
single/multi?
living? non-living?
euk/prok?

A

single celled
eukaryotes

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7
Q

Fungi
single/multi?
living? non-living?
euk/prok?

A

eukar

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8
Q

Bacteria
single/multi?
living? non-living?
euk/prok?

A

single celled
PROKARYOTES

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9
Q

Viruses
single/multi?
living? non-living?
euk/prok?

A

non-living
obligate parasites

Viruses are neither prokaryotic or eukaryotic. Viruses are not made of cells. Viruses cannot replicate on their own. Most scientists do not consider viruses to be livingm

Obligate parasite = a parasitic organism that is not able to complete its life cycle without exploitation of suitable host

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10
Q

microbiome

A

collection of microorganisms, including bacteria, viruses, fungi, and protozoa, along with their genetic material, that live in a specific environment, such as the human body or a natural habita

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11
Q

microflora / microbiota

A

community of microorganisms, including bacteria, fungi, viruses, and protozoa, that live on or within different parts of an organism, such as the human body, plants, or animals. These microorganisms a

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12
Q

Difference in cell structure bn eukaryotes + prokaryotes

A

Eukaryotes:
- Cell membrane
* Nucleus
* Centriole/Centrosome
* Nucleolus/Ribosomes
* Endoplamsic Reticulum (ER)
* Cytosol
* Mitochondria
* Golgi
* Cytoskeleton
* Secretory Vessicles, Lysosomes

Prokaryotes:
- Plasma Membrane
* Cell Wall (Peptidoglycan)
* Nucleoid (DNA & associated proteins)
* Ribosomes
* Cytoplasm
* Capsule, Flagellar, PiliF

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13
Q

Fermentation VS Anerobic respiration

A

both processes used by cells to generate energy in the absence of oxygen

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14
Q

Fermentation

A

energy is produced by breaking down glucose (or other organic molecules) into smaller compounds without using the electron transport chain or an external electron acceptor.

	○ Involves glycolysis only.
	○ Pyruvate or its derivatives act as the final electron acceptors.
	○ Produces a small amount of ATP (2 ATP per glucose).

END PRODUCTS:
○ Alcohol fermentation: Produces ethanol and CO₂ (e.g., in yeast).
○ Lactic acid fermentation: Produces lactic acid (e.g., in muscle cells under low oxygen).

common in:
- yeast
- bacteria

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15
Q

Anaerobic respiration

A

A process that uses an electron transport chain to generate ATP, with a molecule other than oxygen (e.g., nitrate, sulfate, or carbon dioxide) serving as the final electron acceptor.

	○ Includes glycolysis, the Krebs cycle, and an electron transport chain.
	○ Uses inorganic molecules like nitrate (NO₃⁻) or sulfate (SO₄²⁻) as the terminal electron acceptor instead of oxygen.
	○ Yields more ATP than fermentation but less than aerobic respiration (e.g., 20-30 ATP per glucose).

END PRODUCTS
-> Depends on the final electron acceptor. Examples:
§ Nitrate reduction produces nitrogen gas or ammonia.
§ Sulfate reduction produces hydrogen sulfide.

common in:
- some bacteria
- archaea

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16
Q

Peptidoglycan cell wall
in bacteria
structure

A

peptide side chain:
- D-Ala-D-Ala
- Transpeptidation

repeated sugar chains:
- transglycosylation

Target of PENICILLIN

DD-Transpeptidase, a bacterial enzyme that cross-links the peptidoglycan chains to form rigid cell walls

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17
Q

Flagella + Fimbriae

A

present in both Gram - and + bacteria

injection of toxins + genetic material
adherence, sex, motility

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18
Q

Syphilis

A

an infection caused by bacteria. Most often, it spreads through sexual contact. The disease starts as a sore that’s often painless and typically appears on the genitals, rectum or mouth.

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19
Q

E.Coli

A
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20
Q

Facultative Anaerobs

A

Organisms that can survive and grow in both oxygen-rich (aerobic) and oxygen-poor (anaerobic) environments.

Metabolism:
Prefer aerobic respiration when oxygen is available because it yields more ATP.
Switch to anaerobic respiration or fermentation in the absence of oxygen.

Examples: Escherichia coli, Saccharomyces cerevisiae (yeast), and many species of Staphylococcus.

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21
Q

Obligate Anaerobes

A

Organisms that cannot survive in the presence of oxygen. Oxygen is toxic to them due to the lack of protective enzymes (e.g., catalase, superoxide dismutase).

Metabolism:
Use anaerobic respiration or fermentation to generate energy.

Oxygen exposure can lead to the production of harmful reactive oxygen species (ROS).

Examples: Clostridium botulinum, Bacteroides fragilis, Methanogens.

Environment: Found in oxygen-free environments, such as deep soil, intestines, or anaerobic chambers.

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22
Q

diagnostic approaches to identify prokaryotic pathogens

A

MOLECULAR TESTS:
- antigens (immunological)
- DNA sequencing 16sRNA, qPCR
- protein profiling (mass spec)

METABOLIC TESTS:
- Haemolysis (strepoccocci only) -> destruction of red blood cells
- catalse test/coagulase

GROWTH REQUIREMENTS:
- aerobic/anaerobic
- requirement for blood products (e.g. serum proteins)
- sensitivity to agens (bile / NaCl)

APPEARANCE
- shape
- size
- cell wall (Gram +/-)

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23
Q

Gram stain classification

A

Retention of crystal violet/iodine complex by Gram+ bacteria

distinguishing Gram + and Gram - bacteria according to cell wall structure

stain with crystal violet and rinse:
+ = purple
- = purple

treat with gram’s iodine:
+ = crystal/violet iodine complex
_ = ‘’ ‘’

briefly decolorise with acetone:
+ = purple
- = no colour

counter stain with basic safranin, pink dye, rinse
+= purple
- = pink

** TB , myocobacterium tuberculosis will NOT stain, has lipid rich cell wall
** Treponema will NOT stain

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24
Q

spore + toxin

A
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25
Growth conditions growth media biochemical progiling
26
Antibodies DNA protein ANALYSES
27
Streptococci
genus of gram-positive, spherical bacteria typically form chains or pairs when observed under a microscope facultative anaerobes, classified based on their hemolytic activity (their ability to lyse red blood cells) serological properties (based on the Lancefield grouping system). Diagnosis and Identification: 1. Growth on blood agar to observe hemolysis patterns. 2. Biochemical tests, such as catalase (x catalase-negative,
28
Staphylococci
catalase positive a genus of gram-positive, spherical bacteria tendency to form clusters resembling grape bunches when observed under a microscope. They are facultative anaerobes Staphylococcus aureus: Commonly associated with skin infections, abscesses, pneumonia, sepsis, and food poisoning.
29
SHAPES OF BACTERIA + examples cocci bacilli spiral shaped
SPHERED: * Staphylococcus (forms chains) * Streptococcus (forms clumps) RODS: * Excherichia * Bacillus form chains SPIRAL SHAPED: *Syphillis - flexible spiral: * Treponema - causes Syphilis - transmitted trhough sexual contact * Borella - causes Lyme disease (Spread by ticks)
30
Endometriosis + Fusobacterium
* Endometriosis is derived from the word “endometrium,” which is the tissue that lines the uterus. Patients with endometriosis have endometrial-type tissue outside of the uterus FUSOBACTERIUM: - anaerobic - fusiform-shaped - potential contributor to endometriosis dysbiosis in the gut and reproductive tract microbitoa in women, could promote inflammation chronic inflammation in endometriosis, this exacerbated through: § Releasing toxins. § Activating toll-like receptors (TLRs) on immune cells. § Inducing pro-inflammatory cytokine production.
31
Helicopacter pylori
causing stomach ulcers
32
Syphilis
cause by Treponema bacteria (spiral shaped) - sexualyl transmitted Syphilis in stages 1. Painfless sores 2. Skin rashes, mucous membrane lesions 3. Latent asymptomatic 4. Tertiary: severe organ damage .e.g cardio/neuro issues if left untreated
33
Lyme disease
spread by ticks associated with Borrelia spiral shaped bacterium - Bulls eye rash - Fatigue - Joint pain Neuro problems
34
Influenza type B + Capsule
35
Spores
C.Difficile - metabolically inert - analogous to seeds - resistant to physical and chemical challenge - BINARY FISSION - causing gastroenteritis persistence spread in aerosols no cell wall, no cell membrane, no active respiration, no active protein synthesis, all the ribosomes have been dehydrated
36
C.Difficile
Spore - bacterium using disinfectants persistence to antibiotics causing nasty gastroenteritis
37
obligate anaerobes
killed by O2
38
obligate aerobes
require oxygen in lav
39
facutlative anaerobes
tolerate O2
40
Identifying streptococcus
HAEMOLYSIS alpha - partial - greening of colonies on blood agar ------- not destroying RBCs ** Enterococci **S. pneumoniae beta - complete ----- destroying the RBC ** Streptococci + Langefield Grouping gamma - no hemolysis
41
Serological Tests
Ab/Ag interaction * Detect presence of specific IgM Ab to virus/microbe * Demonstrate in vitro by agglutination (aggregation) reaction * Rapid detection of viruses (24 hours), **** Lateral Flow Tests core response to COVI19 pandemic
42
qPCR
amplification of DNA target or 16sRNA primers amplifying specific piece of DNA or DNA product e.g. virulence factor
43
MALDI-TOF
** not great for streptococci + stahpylococci a mass spectrometry method that works by analyzing the unique protein profiles (or mass spectra) of microorganisms, including bacteria, fungi, and even viruses.
44
Virulence
capacity of a microbe to cause damage to the host
45
Protozoan diseases
Malaria Toxoplasma GI infections Leishmaniasis
46
Fungal infections
Candida spp. Yeast (budding)
47
Gram + prokaryotic pathogens
Streptococcus spp staphylococcus spp enterococcus spp clostridium
48
Gram- prokaryotic pathogens
Neisseria spp - Neisseria meningitidis, causing bacterial meningitis - aerosol, close contact - Neisseria gonorrhoea, sexually transmitted --> antibiotic resistance Escherichia sppG
49
GI tract dominated by gram- bacteria some commensal bacteria in the gut
Enterobacter spp found in small numbers, aprt of metabolism Escherichia spp e.g. Escherichia coli some are pathogenic strains, some are commensals in the gut
50
Coliform
broad group of gram- bacteria rod shaped subgroup under the group enterobacteriaceae ferment lactose aerobic and facultative anaerobes used to test quality of water many of them part of normal bowel flora e.g. Eshcerichia coli - escherichia - salmonella - enterobacter anythign that getrs into sterile site can cause infection - UTIs - peritonitis - biliary tract GENTAMICIN --> 1st line antibiotic for coliform infections - TEMOCILLIN??? FOR GRAM - spectrum --> b-lactamase resistant form of penicillin ENDOTOXIN/LPS release is virulent + patients with sepsis become very unwell very quickly
51
significant gut pathogens
salmonella shigella verotoxin (VTEC) producing E.Coli --> outbreaks of uncooked meat ## Footnote E.Coli = Gram -
52
SEPSIS - what it is, consequences a host response to severe infection mediated by LPS/Endotoxin from Gram - bacteria
Small blood vessels become “leaky” and lose fluid into the tissues * Lower blood volume requires heart to work harderto maintain oxygenation of tissues (↑HR) * Poor tissue oxygen perfusion mean blood supply to less essential organs (skin, kidneys, liver) is shut down to try to maintain blood supply to brain * Blood clotting system is activated causing blood clotting in tiny blood vessels→ uses up all clotting factors→ increased risk of haemorrhage extreme fever with sudden early onset most human pathogens grow best at 37 degrees
53
Gram +
Streptococcus - hemolysis - pneumonia - oral streps Enterococcus Staphylococcus - skin infections + biofilms Clostridia - anaerobic bacilli - C.difficile
54
70% of sore throats will be viral bacterial sore throats 25-30%, most of them Group A streptococci
55
Group A streptococci
most pathogenic streptococci hemolysis - beta sore throat + scarlet fever invasive disease -> necrotising fasciitis puerperal sepsis (infection of pregnant + postnatal women) ## Footnote Fasciitis is an inflammation of the fascia,[1] which is the connective tissue surrounding muscles, blood vessels and nerves.
56
pneumonia
acute inflammation of the lungs sreptococus pneumoniaer???? alveolei and bronchioles of the lung become plugged with a fibrous exudate (fluid that leaks out of blood vessels into nearby tissues. The fluid is made of cells, proteins, and solid materials. Exudate may ooze from cuts or from areas of infection or inflammation. It is also called pus.)
57
streptococcus pneumoniae
Gram + a-hemolytic part of normal upper respiratory tract flora commonest cause of pneumonia - also causes severe meningitis
58
meningitis
Meningitis is inflammation of the lining around your brain and spinal cord. It can be very serious if not treated quickly. Symptoms of meningitis include being sick, a headache, a stiff neck and a dislike of bright lights. You may sometimes get a rash. Meningitis is usually treated with antibiotics in hospital. Treatment should start as soon as possible. Vaccinations can protect you against some types of meningitis. ## Footnote Meninges are three layers of membranes that cover and protect your brain and spinal cord (your central nervous system [CNS]). They're known as: Dura mater: This is the outer layer, closest to your skull. Arachnoid mater: This is the middle layer. Pia mater: This is the inner layer, closest to your brain tissue.
59
meninges
Three layers of membranes known as meninges protect the brain and spinal cord. ---The delicate inner layer is the pia mater. ---The middle layer is the arachnoid, a web-like structure filled with fluid that cushions the brain. ---The tough outer layer is called the dura mater.
60
non-hemolytic cocci
Enterococci AMR VRE - vancomysin resistance enterococci) part of normal bowel flora not pathoegnic, but can cause problems if they get into a normally sterile site common cause for UTIs most strains sensitive to amoxicillin , but not penicillin v.antibiotic resistance strains -- Enterococcus faecium --> VRE -- can cause outbreaks of infections in hospitals
61
Staphylococci
Gram + clumps/clusters - bunch of grapes S.aureus non-motile aerobe + facultative anaerobe catalese + usually coagulase + or - tolerate 15% NaCl oxidase -
62
S.aureus infections
COAGULASE + Methicillin-resistant Staphylococcus aureus (MRSA) - surgical pateinets - elderyly ++ immunocompromised - intravenus lines - dialysis patients - mainly nosocomial - burns patients - ICU skin, soft tissue + wound infection bone and joint infection food poisoning - enterotoxin producing strains multiplies at site of infection causing local infection and inflammation - abscess gets into bloodstream sepsis = life threatening abscess in spleen, liver, kidneys
63
abscess
An abscess is a buildup of a pus that can affect any part of your body. There are many different types of abscesses. They can occur on your skin, in your mouth or around your organs. Skin abscesses may look red and swollen. Bacterial infections usually cause abscesses.
64
Clostridiodes
spores - spread + antimicrobial resistance Gram + anaerobic bacilli part of normal bowel flora - found in faeces + soil EXOTOXINS - C.difficile, antibiotic associated diarrhoea - C. perfringens - gas gangrene, soft tissue infection following contamination of a wound - C. tetani - tetanus, fatal paralytic illness
65
Narrow spectrum antibiotics
Penicillin -> Gram + bacteria
66
Broad spectrum antibiotics
Tetracycline -> for both Gram + and -
67
Bacteriostatic Bacteriocidal
68
antibiotic targets
cell wall ribosomes - protein synthesis dna replciation metabolic pathways cell membrane function
69
pharmacodynamics
whay you do to the target
70
pharmacokinetics
what the body does to it ADME
71
Cell wall targeting antimicrobials
1. PENICILLINS -> b-lactam penicillin amoxicillin tazobactam 2. CEPHALOSPORINS -> b-lactam wider spectrum 3. GLYCOPEPTIDES -> NOT b-lactam vancomycin
72
b-lactams b-lactam ring (e.g. in penicillin)
TARGET: PBP - penicillin binding proteins resembles D-ALA-D-ALA dipeptide + irreversibly binds to PBP prevents the enzyme (transpeptidase) from processing the normal substrate PG synthesis stops (peptidoglycan) cell wall compromisation suicide substrate ***** PENICILLINS (narrow spectrum) - amoxicillin (extended spectrum) - flucloxacillin (methicillin / meticillin) -> resistance to Stap B- lactamases - co-amoxiclav ***** Cephalosporins 1st generation active against Staph + Strep ***** Carbapenems broad spectrum for both + and - resistant to b-lactamase last resort for Gram -
73
Cell wall structure
Crosslinking of peptide side chains Terminal D-Alanine D-alanine -> cleaved by transpeptidase transpeptidase = cell wall synthesising enzyme energy released from D-ALA-D-ALA is then used to form cross-link (peptide bridge)
74
empiric prescribing
Treatment given based on experience, without precise knowledge of the cause or nature of a disorder.
75
penicillin limitations, although empiric
- patients can be hypersensitive, allergic - rapid excretion via kidneys (frequent dosing needed) - resistance
76
penicillin amoxicillin flucloxacillin co-amoxiclav temocillin tazobactam/piperacillin / tazocin
77
b-lactam antibiotics
78
glycopeptide antibiotics
79
antibiotics for Gram+
Flucloxacillin (IV, oral)
80
antibitoics for Gram -
Temocillin (IV only)
81
antibiotics for both Gram+ and -
Amoxicilin (IV, oral) Co-amoxiclav (IV, oral) Tazocin/Tazobactam/Piperacillin (IV only)
82
penicillin class b-lactams
Gram + narrow intestine absoprtion sensitive to stomach acid
83
amoxicillin
IV + oral derivative of penicillin good tissue distribution broader spectrum (both + and -) stable in presence of stomach acid will enter CSF if meninges inflamed most common prescription disturbing gut unnecessarily - target enterococci --> opportunistic infection + VRE
84
co-amoxiclav amoxicillin + clavulanic acid
b lactam + b-lactamase inhibitor clavulanic acid does not have antibiotic properties on its own
85
Flucloxacillin
narrow spectrum STAPHYLOCOCCI + STREPTOCOCCI ONLY IV and oral **CLASSIC ANTIBIOTIC FOR STAPH. AUREUS ** replaced methicillin (MRSA) MRSA resistant to flucloxacillin commonly prescribed for those skin infections
86
Temocillin
b-lactamase resistant form of penicillin IV only for Gram - for COLIFORMS - escherichia - salmonella - enterobacter active againe ESBL (extended spectrum beta lactamse) producers
87
Tazobactam/Piperacillin (Tazocin)
v. broad spectrum antibiotic b-lactamase inhibitor enhances penetration into Gram-bacteria used as empiric prescription HUGE IMPACT ON MICROBIOME OF HOST
88
CPE
CPE (carbapenemase-producing Enterobacterales) are bacteria (bugs) that live in the gut. CPE are a type of superbug. These are bugs that are resistant to many antibiotics.
89
VRE
vancomycin-resistant enterococci. Enterococci are bacteria (germs) that live in the gastrointestinal tract (bowels) of most people without causing illness. This is called colonisation. Vancomycin is an antibiotic used to treat infections caused by enterococci.
90
cephalosporins
bactericidal + inhibit cell wall synthessi safe in pregnancy more resistant to b-lactamases broad spectrum, significantly affecting normal bowel flora, overgrowth of C.difficile -- causing nasty gastroenteritis many hospitals try to avoid using these excreted via kidneys + urine few side effects , reduced allergy
91
b-lactamase inhibitors (IV only)
clavulanic acid tazobactem (IV only)
92
resistant forms insensitive to b-lactamases
carbapenems -- last resort antibiotic now under threat from carbapenemases (CPE)
93
Glycopeptides (NOT b-lactam antibiotics)
VANCOMYCIN (IV) TEICOPLANIN (IV) act on cell wall binds to end of D-ALA-D-ALA + prevent their incrorportaion into the cell wall (binds to the substrate, NOT the enzyme) bactericidal inhibtis peptidoglycan synthesis weaken bacterial cell wall blocks access to substrate by PBP (transpeptidase) excreted via kidneys and urine -- restricted activtiy to Gram + bacteria cell wall ORAL VANCOMYCIN CAN TARGET Gram + as it builds up in intestine NO ACTIVTIY AGAINST GRAM - , excluded by outer membrane
94
treatment for MRSA
Vancomysin
95
Protein synthesis inhibitors
BACTERIOSTATIC - tetracyclines - macrolides BACTERICIDAL - aminoglycosides
96
Aminoglycosides (bactericidal)
protein synthesis inhibitor GENTAMYCIN - not absorbed from the gut -- IV needed - binding to 30s ribosomes, irreversibly - mainly against Gram - - used in serious Gram - infections - excreted in urine - TOXICITY!!!! damage to kidneys + VIII (8th) cranial nerve (dizziness, deafness)
97
Tetracycline (bacteriostatic)
protein synthesis ihibitor Deoxyxycline / minocycline - binds to 30s on ribosomes, preventin tRNA attachment **doxycyline / minocycline more efficient absorption broad spectrum for intracellular bacteria ADVERSE EFFECTS --- destruction of normal intestinal flora --> secondary infections RESTRICTED USED IN CHILDREN, INFANTS, PREGNANCY impairment of structure of bones + teeth
98
macrolides (bacteriostatic)
erythromycin - 50s subunit binding or ribsosomes - excreted via the LIVER, biliary tract and into the gut NOT excreted in urine for intracellyualr bacteria (lipophilic) ERYTHROMYCIN safe in pregnancy **** GO TO DRUG FOR PEOPLE WITH PENICILLIN ALLERGY
99
Antibiotics targeting Nucleic acid
Fluroroquinolones (both Grams) Metronidazole (Anaerobes + Protozoa) Trimethoprim - primary use for UTIs Rifampicin + Rifampin - common use for Mycobacteria, Bacterial meningitis prophylaxis
100
Quinolones Bactericidal
Bind to A subunit of DNA gyyrase (topoisomerase), preventing supercoiling of DNA, indirectly inhibiting DNA synthesis - bones - UTIs, excreted in urine *RESTRICTED FOR USE IN C.difficile GI infection --- BC it is broad spectrum * *** Ciprofloxacin - largely Gram- activtiy good intracellular activity
101
Nitroimadazoles
** metronidaole (oral + IV) - for anaerobes + protozoa - drug activated by reduction process - forms toxic intermediate, inducing DNA breakage - RARE to resistance - ADVERSE REACTIONs limited NOT given in combination with alcohol!!! _ metallic state _ furred tongue
102
inhibitors of folic acid synthesis * key untermediate metabolism
Sulphonamide Trimethroprim - good for UTIs
103
Trimethoprim
some Gram -, some Gram + excreted via urine, concentrates urine common for acute UTIs e.g. E.Coli orally ok combo therapy with sulphamethaxozole BOTH inhibitors of folic acid synthesis - key intermediate metabolism is blocked
104
ERYTHROMYCIN/CLARYTHROMYCIN GENTAMICIN METRONIDAZOLE
105
High risk/ resticted use antibiotics for C. diff The 4C's SOS!!!!!!!!!!!
NO TO - Cephalosporins - Co-amoxiclav - Cirpofloxacin - Clindamycin | The "4 C's" refer to a group of antibiotics that are associated with a h
106
High risk/restricted use antibiotics for sore mouth
antibiotic sore mouth for Candida Albicans
107
Other interactions of Careful prescribing 1. antibiotics generally 2. Gentamicin 3. Ciprofloxacin 4. Metronidazole
1. Nausea, vomiting, diarrhoea + may affect absorption of oral contraceptives + disrupt the gut bacterial flora 2. renal + CN VIII damage (deafness + dizziness) 3. Tendonitis - avoid use in pregnant or breast feeding women 4. interacts with alcohol
108
Primary use of antibiotics for UTIs + other? + other? e.g. E.Coli
- > Trimethoprim (Nitrofurantoin) - > Quinolone (bind to A subunit of DNA gyrase preventing supercoiloing of DNA, inhibit DNA synthesis indirecgly -topoisomerase) - > Trimethoprim (inhibitor of folic acid) Trimethroprim: - Nitrofurantoin - combo with sulfamethoxacole (if poor renal function)
109
Common use antibiotic for Mycobacteria + Bacterial Meningitis prophylaxis
Rifampicing + Rifampin - antibiotic targeting the nucleic acid
110
Intracellular antibiotics
Macrolides Deoxycyline Erythromycin Ciprofloxacin
111
Penicillin allergy
Erythromycin
112
IV serous, Gram-
113
Deoxycycline (Tetracyclin)
intracellular activity good side effects - bone + teeth NOT given in pregnant women, children, infants
114
IV only, Gram-
Tazobactam Temocillin
115
Facultative anaerobes
staphyloc coliform (-) streptococc E.coli
116
Anaerobes
Clostridiodes Fusobacterium + Endometriosis Nucleic acid antibiotics Nitromadazole antibiotics Metronidazole antibiotics
117
Erytrhomycin RECAP
50s intracellualr activtiy good YES for pregnant penicillin allergy LIVER excretion
118
Trimethroprim RECAP
UTIs e.g. E.Coli folic acid inhibitor targetting nucleic acid + and - Gram URINE excretion Nitroflurantin antibiotics
119
Gentamicin RECAP
Gram - Coliform E.Coli toxicity - CN VIII (8th) - deafness, dizziness aminoglycoside
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Biofilms
on a cannula catheter A x is defined as a community of microorganisms attached to an inert or living surface by a self-produced polymeric matrix or an assemblage of microbial cells associated with a surface and enclosed in a matrix of primarily polysaccharide material. - organism behaving as part of multicellular community - making the organism more resistant to antimicroial agents + host defenses - horizontal gene trasnfer, spore formation is more likely (Sacrifice one of your organisms to produce a spore, stress at the back cells) - competition fermentation for anaerboci at the back, thus producing lactose, generatting lactic acid, demineralising the tooth and causing teeth decayt -- -at the front those they don’t hace to do that, they have sugar, they will not ferment anythgin, they will do respiration, long way away from the tooth, not under oxygen stress)
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Clinical resistance + MIC/MBC Minimum inhibitory concentration Minimum bactericidal concentration
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PBP2 *MRSA
changes to ribosome prevent antibiotic bindins
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efflux pumps
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Horizontal gene transfer - spread of resistance - exchange of genetic material commonly occuring in the gut (HGT) genetic variation confering resistance - selective pressure - evolution
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difference between natural + acquired resistance
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beta-lactam antibiotics + resistance 2 different ways of overocming it
1. produce beta lactamase inhibitor (IV only) 2. change the structure, so b-lactamase cannot degrade the b lactam 3. b-lactamases ** PENICILLINASE resistant to amoxicillin Gram+ ***ESBL - extended spectrum b-lactamase resistant to all penicillins *** CPE - Carbapenamase (carbapenamase producing enterobacteriaceae) metalloenzyme based gram -, principally E.Coli + K.pneumoniae resistant to all penicillins, cephalosporins, carbapenems ** CEPHALOSPORINASE ## Footnote β-Lactam antibiotics are bactericidal agents that interrupt bacterial cell-wall formation as a result of covalent binding to essential penicillin-binding proteins (PBPs), enzymes that are involved in the terminal steps of **peptidoglycan cross-linking** in both Gram-negative and Gram-positive bacteria.
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horizontal gene transfer mechanisms 3
transfer proximity ideal in biofilms a) bacterial transformation - natural competence - antibiotic resistance gene released b) bacterial transduction - phage infected donor cell, release of phage to recipient cell attack c) bacterial conjugation - sex pii, trasnfer of plasmid
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persistor cell
- Tolerance - metabolically inert -- v slow growth, dormant-non living - planktonic and biofilm populations
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VRE CPE MRSA ESBL
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antimicrobial drug resistance examples of mechanisms
1. INACTIVATION b-lactamase 2. ALTERED PERMEABILITY altered influx (quinolones) active efflux (tetracycline)
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MRSA is resistant to...
Flucloxacillin Methicillin Penicillin -PBP Staph PBP2* CAHNGES to ribosome preventing antibiotic binding (30s ribosome + 50s ribosome)
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VRE VRSA
VANCOMYCIN RESISTANT ENTEROCOCCUS vancomycin resistant staphylococcus
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E.coli variants + diseases they cause
Shiga toxin producing strains (S/VTEC)
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VTEC
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C.difficile HAI how to control the disease
spore formation toxin production antibiotic resistance gram + anaerobic
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dysbiosis of the gut IBD
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cpe organisms
reside in the gut HGT
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GI tract carbapenamase producing enterobacteriacae
big problem for healthcare
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GI infections
E.Coli + proxy for water quality C. difficile Campylobacter -> food poisoning + poorly controlled hygiene + link with reheated rice, spore forming organism salmonella shigella staph aureus -- even if you ingest the toxin alone --> acute, emetic response fusobacterium nucleatum vibrio cholera
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symptoms for GI tract infections dysbiotic relationship
diarrhoea - dehydration, electrolyte loss - vomiting Gastroenteritis - vomiting - nausea - diarhhoea Dysentery - blood and pus in faeces - inflammatory response upregulated Enterocolitis - inflammation of small and large intestine
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E.coli variants
S(V)TEC / EHEC Shiga toxin-producing Gram- flagella movement villi- injection of toxins pili, fimbriae + flagella important distinct types can produce distinct pathologies HGT has driven variation in virulence factors (key toxins, adhesins) dysentery
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E.coli 0157
enterohemorragic strain (EHEC/STEC) dysentery, severe form of diarrhoea hemorrhagic colitis hemolytic-uremic syndrome -> can lead to kidney failure + death foecal - oral route transmission undercooked food, bbq abdominal cramps little to no fever fatigue nausea shigatoxin (VTEC/EHEC) stx1 + 2 acquired by phage from shigella loss of mucosal integrity + death SHIGATOXIN=VIROTOXIN EHEC = presentation STEC = description of strain
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C.difficile
anitbiotic associated diarrhea pseudomembraneous colitis spores survive mild to severe diarrhea nausea, fever, abdominal pain mild bowel movements severe = vomiting, high fever, rectal bleeding toxin a enterotoxin + toxin B cytotoxin - breakdown of cell junctions RISK FACTORS ALL OF THEM: - co amoxyclav - cephalosporins spores survive in gut also spread and survive in envrionment + RESIST ALCOHOL GELS Handwashing with Soap and Water: This is mandatory because C. difficile spores are not effectively removed by alcohol-based hand sanitizers. treat with narrow spectrum antibiotic e.g. VANCOMYCIN (not absorbed thrugh the GI tract, but it is concentrating in the GI tract) +++ steps to restore the microbiome by faeceal transplant
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IBD dysbiosis
inflammatory bowel disease e.g. Crohn's disease Ulcerative colitis symptoms: - bloating - poor nutrition - stool movements, icnreased bowel movements - diarrhoea - abdominal pain
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Viral diseases of the GI tract
norovirus rotavirus cryptosporidium
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sepsis VS abscess
**Sepsis: **A systemic infection resulting from the body's extreme response to an infection. It occurs when the immune system's response to infection causes widespread inflammation and organ dysfunction. It can originate from infections anywhere in the body (e.g., lungs, urinary tract, skin). *fever, chills, rapid heart rate, rapid breathing, confusion, low blood pressure, and organ failure in severe cases. Symptoms are systemic, affecting the whole body.* **Abscess: **A localized collection of pus within a tissue, often caused by bacterial infection. It is characterized by swelling, redness, pain, and warmth at the site. Typically occurs due to an infection that the body has walled off to prevent the spread. *Pain, tenderness, swelling, redness, warmth at the site of infection, and sometimes fever if the infection is severe. Symptoms are localized to the area of the abscess.* Relationship Between the Two: An abscess can potentially lead to sepsis if the localized infection spreads into the bloodstream. Sepsis is a more severe and life-threatening condition compared to an abscess, which is usually localized and easier to manage if treated early.
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Beta lactams - b lactam
β-Lactam antibiotics are bactericidal agents that interrupt bacterial cell-wall formation as a result of covalent binding to essential penicillin-binding proteins (PBPs), enzymes that are involved in the terminal steps of peptidoglycan cross-linking in both Gram-negative and Gram-positive bacteria.
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b lactamase
The beta-lactamase enzymes inactivate beta-lactam antibiotics by hydrolyzing the peptide bond of the characteristic four-membered beta-lactam ring rendering the antibiotic ineffective. The inactivation of the antibiotic provides resistance to the bacterium.
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B LACTAM EXAMPLES
carbapenem cephalosporins penicillin amoxicillin
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PIC - narrow spectrum / broad spectrum
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PIC - key penicillins
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PIC - narrow spectrum / broad spectrum 2
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PIC - penicillins
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PIC - Gram +
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PIC - Gram -
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PIC - penicillin mindmap
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PIC - folic acid
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PIC - c.diff
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PIC - c.diff
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PIC - MALT