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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
Q

Growth conditions
growth media
biochemical progiling

A
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26
Q

Antibodies
DNA
protein

ANALYSES

A
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27
Q

Streptococci

A

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,

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28
Q

Staphylococci

A

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.

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29
Q

SHAPES OF BACTERIA + examples
cocci
bacilli
spiral shaped

A

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)

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30
Q

Endometriosis + Fusobacterium

A
  • 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.

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31
Q

Helicopacter pylori

A

causing stomach ulcers

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32
Q

Syphilis

A

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

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33
Q

Lyme disease

A

spread by ticks
associated with Borrelia spiral shaped bacterium

- Bulls eye rash
- Fatigue
- Joint pain Neuro problems
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34
Q

Influenza type B + Capsule

A
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35
Q

Spores

A

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

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36
Q

C.Difficile

A

Spore - bacterium

using disinfectants
persistence to antibiotics

causing nasty gastroenteritis

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37
Q

obligate anaerobes

A

killed by O2

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38
Q

obligate aerobes

A

require oxygen in lav

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39
Q

facutlative anaerobes

A

tolerate O2

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40
Q

Identifying streptococcus

A

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

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41
Q

Serological Tests

A

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

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42
Q

qPCR

A

amplification of DNA target
or 16sRNA

primers amplifying specific piece of DNA or
DNA product
e.g. virulence factor

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43
Q

MALDI-TOF

A

** 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.

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44
Q

Virulence

A

capacity of a microbe to cause damage to the host

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45
Q

Protozoan diseases

A

Malaria
Toxoplasma
GI infections
Leishmaniasis

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46
Q

Fungal infections

A

Candida spp.
Yeast (budding)

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47
Q

Gram + prokaryotic pathogens

A

Streptococcus spp
staphylococcus spp
enterococcus spp

clostridium

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48
Q

Gram- prokaryotic pathogens

A

Neisseria spp
- Neisseria meningitidis, causing bacterial meningitis - aerosol, close contact
- Neisseria gonorrhoea, sexually transmitted –> antibiotic resistance

Escherichia sppG

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49
Q

GI tract dominated by gram- bacteria

some commensal bacteria in the gut

A

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

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50
Q

Coliform

A

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

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51
Q

significant gut pathogens

A

salmonella
shigella
verotoxin (VTEC) producing E.Coli –> outbreaks of uncooked meat

E.Coli = Gram -

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52
Q

SEPSIS - what it is, consequences

a host response to severe infection mediated by LPS/Endotoxin from Gram - bacteria

A

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

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53
Q

Gram +

A

Streptococcus - hemolysis
- pneumonia
- oral streps
Enterococcus
Staphylococcus
- skin infections + biofilms
Clostridia
- anaerobic bacilli
- C.difficile

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54
Q

70% of sore throats will be viral
bacterial sore throats 25-30%, most of them Group A streptococci

A
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55
Q

Group A streptococci

A

most pathogenic streptococci
hemolysis - beta
sore throat + scarlet fever
invasive disease -> necrotising fasciitis
puerperal sepsis (infection of pregnant + postnatal women)

Fasciitis is an inflammation of the fascia,[1] which is the connective tissue surrounding muscles, blood vessels and nerves.

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56
Q

pneumonia

A

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.)

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57
Q

streptococcus pneumoniae

A

Gram +
a-hemolytic
part of normal upper respiratory tract flora
commonest cause of pneumonia - also causes severe meningitis

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58
Q

meningitis

A

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.

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.

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59
Q

meninges

A

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.

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60
Q

non-hemolytic cocci

A

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

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61
Q

Staphylococci

A

Gram +
clumps/clusters - bunch of grapes

S.aureus

non-motile

aerobe + facultative anaerobe

catalese + usually
coagulase + or -
tolerate 15% NaCl
oxidase -

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62
Q

S.aureus infections

A

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

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63
Q

abscess

A

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.

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64
Q

Clostridiodes

A

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

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65
Q

Narrow spectrum antibiotics

A

Penicillin -> Gram + bacteria

66
Q

Broad spectrum antibiotics

A

Tetracycline -> for both Gram + and -

67
Q

Bacteriostatic
Bacteriocidal

A
68
Q

antibiotic targets

A

cell wall
ribosomes - protein synthesis
dna replciation
metabolic pathways
cell membrane function

69
Q

pharmacodynamics

A

whay you do to the target

70
Q

pharmacokinetics

A

what the body does to it
ADME

71
Q

Cell wall targeting antimicrobials

A
  1. PENICILLINS -> b-lactam
    penicillin
    amoxicillin
    tazobactam
  2. CEPHALOSPORINS -> b-lactam
    wider spectrum
  3. GLYCOPEPTIDES -> NOT b-lactam
    vancomycin
72
Q

b-lactams
b-lactam ring (e.g. in penicillin)

A

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
Q

Cell wall structure

A

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
Q

empiric prescribing

A

Treatment given based on experience, without precise knowledge of the cause or nature of a disorder.

75
Q

penicillin limitations, although empiric

A
  • patients can be hypersensitive, allergic
  • rapid excretion via kidneys (frequent dosing needed)
  • resistance
76
Q

penicillin
amoxicillin
flucloxacillin
co-amoxiclav
temocillin
tazobactam/piperacillin / tazocin

A
77
Q

b-lactam antibiotics

A
78
Q

glycopeptide antibiotics

A
79
Q

antibiotics for Gram+

A

Flucloxacillin (IV, oral)

80
Q

antibitoics for Gram -

A

Temocillin (IV only)

81
Q

antibiotics for both Gram+ and -

A

Amoxicilin (IV, oral)
Co-amoxiclav (IV, oral)
Tazocin/Tazobactam/Piperacillin (IV only)

82
Q

penicillin class
b-lactams

A

Gram +
narrow

intestine absoprtion
sensitive to stomach acid

83
Q

amoxicillin

A

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
Q

co-amoxiclav
amoxicillin + clavulanic acid

A

b lactam + b-lactamase inhibitor

clavulanic acid does not have antibiotic properties on its own

85
Q

Flucloxacillin

A

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
Q

Temocillin

A

b-lactamase resistant form of penicillin
IV only
for Gram -

for COLIFORMS
- escherichia
- salmonella
- enterobacter

active againe ESBL (extended spectrum beta lactamse) producers

87
Q

Tazobactam/Piperacillin (Tazocin)

A

v. broad spectrum antibiotic

b-lactamase inhibitor
enhances penetration into Gram-bacteria

used as empiric prescription
HUGE IMPACT ON MICROBIOME OF HOST

88
Q

CPE

A

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
Q

VRE

A

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
Q

cephalosporins

A

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
Q

b-lactamase inhibitors (IV only)

A

clavulanic acid
tazobactem (IV only)

92
Q

resistant forms insensitive to b-lactamases

A

carbapenems – last resort antibiotic
now under threat from carbapenemases (CPE)

93
Q

Glycopeptides
(NOT b-lactam antibiotics)

A

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
Q

treatment for MRSA

A

Vancomysin

95
Q

Protein synthesis inhibitors

A

BACTERIOSTATIC
- tetracyclines
- macrolides

BACTERICIDAL
- aminoglycosides

96
Q

Aminoglycosides
(bactericidal)

A

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
Q

Tetracycline
(bacteriostatic)

A

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
Q

macrolides
(bacteriostatic)

A

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
Q

Antibiotics targeting Nucleic acid

A

Fluroroquinolones (both Grams)
Metronidazole (Anaerobes + Protozoa)
Trimethoprim
- primary use for UTIs
Rifampicin + Rifampin
- common use for Mycobacteria, Bacterial meningitis prophylaxis

100
Q

Quinolones
Bactericidal

A

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
Q

Nitroimadazoles

A

** 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
Q

inhibitors of folic acid synthesis
* key untermediate metabolism

A

Sulphonamide
Trimethroprim - good for UTIs

103
Q

Trimethoprim

A

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
Q

ERYTHROMYCIN/CLARYTHROMYCIN
GENTAMICIN
METRONIDAZOLE

A
105
Q

High risk/ resticted use antibiotics for
C. diff

The 4C’s

SOS!!!!!!!!!!!

A

NO TO
- Cephalosporins
- Co-amoxiclav
- Cirpofloxacin
- Clindamycin

The “4 C’s” refer to a group of antibiotics that are associated with a h

106
Q

High risk/restricted use antibiotics for sore mouth

A

antibiotic sore mouth for Candida Albicans

107
Q

Other interactions of
Careful prescribing
1. antibiotics generally
2. Gentamicin
3. Ciprofloxacin
4. Metronidazole

A
  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
Q

Primary use of antibiotics for UTIs
+ other?
+ other?

e.g. E.Coli

A
  • > 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
Q

Common use antibiotic for Mycobacteria + Bacterial Meningitis prophylaxis

A

Rifampicing + Rifampin
- antibiotic targeting the nucleic acid

110
Q

Intracellular antibiotics

A

Macrolides

Deoxycyline
Erythromycin
Ciprofloxacin

111
Q

Penicillin allergy

A

Erythromycin

112
Q

IV serous, Gram-

A
113
Q

Deoxycycline (Tetracyclin)

A

intracellular activity good

side effects - bone + teeth
NOT given in pregnant women, children, infants

114
Q

IV only, Gram-

A

Tazobactam
Temocillin

115
Q

Facultative anaerobes

A

staphyloc
coliform (-)
streptococc
E.coli

116
Q

Anaerobes

A

Clostridiodes
Fusobacterium + Endometriosis
Nucleic acid antibiotics
Nitromadazole antibiotics
Metronidazole antibiotics

117
Q

Erytrhomycin RECAP

A

50s
intracellualr activtiy good
YES for pregnant

penicillin allergy
LIVER excretion

118
Q

Trimethroprim RECAP

A

UTIs e.g. E.Coli
folic acid inhibitor
targetting nucleic acid
+ and - Gram
URINE excretion
Nitroflurantin antibiotics

119
Q

Gentamicin RECAP

A

Gram - Coliform
E.Coli
toxicity - CN VIII (8th) - deafness, dizziness
aminoglycoside

120
Q

Biofilms

A

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)

121
Q

Clinical resistance + MIC/MBC
Minimum inhibitory concentration
Minimum bactericidal concentration

A
122
Q

PBP2 *MRSA

A

changes to ribosome prevent antibiotic bindins

123
Q

efflux pumps

A
124
Q

Horizontal gene transfer - spread of resistance - exchange of genetic material commonly occuring in the gut (HGT)

genetic variation confering resistance - selective pressure - evolution

A
125
Q

difference between natural + acquired resistance

A
126
Q

beta-lactam antibiotics + resistance

2 different ways of overocming it

A
  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

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.

127
Q

horizontal gene transfer mechanisms
3

A

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

128
Q

persistor cell

A
  • Tolerance
  • metabolically inert – v slow growth, dormant-non living
  • planktonic and biofilm populations
129
Q

VRE
CPE
MRSA
ESBL

A
130
Q

antimicrobial drug resistance examples of mechanisms

A
  1. INACTIVATION
    b-lactamase
  2. ALTERED PERMEABILITY
    altered influx (quinolones)
    active efflux (tetracycline)
131
Q

MRSA is resistant to…

A

Flucloxacillin
Methicillin
Penicillin -PBP

Staph PBP2*

CAHNGES to ribosome preventing antibiotic binding (30s ribosome + 50s ribosome)

132
Q

VRE
VRSA

A

VANCOMYCIN RESISTANT ENTEROCOCCUS
vancomycin resistant staphylococcus

133
Q

E.coli variants + diseases they cause

A

Shiga toxin producing strains (S/VTEC)

134
Q

VTEC

A
135
Q

C.difficile
HAI

how to control the disease

A

spore formation
toxin production
antibiotic resistance
gram +
anaerobic

136
Q

dysbiosis of the gut
IBD

A
137
Q

cpe organisms

A

reside in the gut
HGT

138
Q

GI tract
carbapenamase producing enterobacteriacae

A

big problem for healthcare

139
Q

GI infections

A

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

140
Q

symptoms for GI tract infections
dysbiotic relationship

A

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

141
Q

E.coli variants

A

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

142
Q

E.coli 0157

A

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

143
Q

C.difficile

A

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

144
Q

IBD
dysbiosis

A

inflammatory bowel disease

e.g. Crohn’s disease
Ulcerative colitis

symptoms:
- bloating
- poor nutrition
- stool movements, icnreased bowel movements
- diarrhoea
- abdominal pain

145
Q

Viral diseases of the GI tract

A

norovirus
rotavirus
cryptosporidium

146
Q

sepsis VS abscess

A

**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.

147
Q

Beta lactams - b lactam

A

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.

148
Q

b lactamase

A

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.

149
Q

B LACTAM EXAMPLES

A

carbapenem
cephalosporins
penicillin
amoxicillin

150
Q

PIC - narrow spectrum / broad spectrum

A
151
Q

PIC - key penicillins

A
152
Q

PIC - narrow spectrum / broad spectrum 2

A
153
Q

PIC - penicillins

A
154
Q

PIC - Gram +

A
155
Q

PIC - Gram -

A
156
Q

PIC - penicillin mindmap

A
157
Q

PIC - folic acid

A
158
Q

PIC - c.diff

A
159
Q

PIC - c.diff

A
160
Q
A
161
Q

PIC - MALT

A

FoM (14 decks)

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