Things I Don't Know

Front 1

What are the features of a gram +ve cell wall?

Back 1

- Proteins

- Teichoic Acid

- Lipoteichoic Acid

- Peptidoglycan

Front 2

How can gram stain differentiate between +ve and -ve?

Back 2

+ve shows as purple-blue

-ve shows as red

Front 3

What are the features of a gram -ve cell wall?

Back 3

- O Polysaccharide / Lipopolysaccharide (Endotoxin)

- Porins

- Proteins

- Lipid A (innermost part of LPS)

Front 4

Survive on drying?

Back 4

+ve Yes

-ve No

Front 5

Produce spores?

Back 5

+ve Yes

-ve No

Front 6

What do all gram -ve have in their cell wall?

Back 6

Lipopolysaccharide (endotoxin)

Front 7

Name three gram +ve rods?

Back 7

- Clostridium

- Bacillus

- Diptheria / Listeria

Front 8

Name some gram -ve rods?

Back 8

- Enterobacteriacaea

- Pseudomonas

- Legionella

- Haemophilus Influenzae

- Bacteroides

Front 9

Pathogenic mechanisms of E.Coli?

Back 9

- LPS binds to LPS binding protein which binds to cell surface molecules eg. TLR4

- Stimulates pro-inflammatory cytokines (TNFα / IL-1 / IL-6)

- Small capsule is antiphagocytic

- Iron binding proteins scavenge iron

Front 10

Two types of E.Coli?

Back 10

- ETEC - Enterotoxigenic (Traveller's Diarrhoea)

- EHEC - Enterohaemorrhagic (colitis / Blood diarrhoea)

Front 11

What infections can E.Coli cause?

Back 11

- 80% of community acquired UTI

- Pyelonephritis (from urinary tract -> kidney)

- Intraabdominal infections

- Septic shock / bloodstream

- Pneumonia

Front 12

Drugs for E.Coli treatment?

Back 12

- Amoxicillin if sensitivity confirmed (<50%)

- UTI / Communty acquired severe sepsis - Trimethoprim / Nitrofurantoin

- Hospital acquired severe sepsis - Tazobactam / Pipericillin

- Aminoglycosides (sometimes for severe sepsis)

Front 13

What type of bacteria is salmonella?

Back 13

- Non-lactose fermenting gram -ve rod

- Enteric fever types (typhoid)

Front 14

Pathogenic factors of Pseudomonas Aeruginosa?

Back 14

- Heat tolerant

- Endotoxin

- Exotoxin A / Elastase / Leucocidin

- Iron binding proteins

- (Produces pyocyanin - green pigment)

Front 15

Who is extremely susceptible to Pseudomonas infection?

Back 15

- Those with mucus accumulation ie CF

Front 16

What infections can Pseudomonas Aeruginosa cause?

Back 16

- Neutropenia

- UTI (instrumentation)

- Pneumonia

- Skin & soft tissue

- Eye keratinitis

- Endopthalmitis

Front 17

Where does Pseudomonas Aeruginosa typically transmit from?

Back 17

- Unclean water

- Contaminated equipment

- Poor quality drinking water

Front 18

Which drugs should be used to treat Pseudomonas?

Back 18

- Fluoroquinolone (Aproflaxin) only oral agent

- Pipericillin / Tazobactam for hospital acquired severe sepsis

- Gentamicin if severe

Front 19

What are the pathogenic factors of Haemophilus influenzae?

Back 19

- Large polysaccharide capsule (types a-f) but b is most invasive therefore vaccine as a child

- IgAse inactivated IgA on mucosal surfaces

- Adhesins in cell wall promote colonisation

Front 20

Where does HI mostly colonise?

Back 20

- Mucosal surfaces

- Mostly the Upper RT

Front 21

What infections does Haemophilus cause?

Back 21

- Invasive - Meningitis / Pneumonia / Cellulitis / Epiglottitis (pain swallowing food)

Non-invasive - Blood cultures -ve / Otitis media / Conjunctivitis

Front 22

Which drugs are used to treat Haemophilus?

Back 22

- Amoxicillin - 15% resistant

- Co-Amoxiclav if resistant

- Rifampicin given as chemoprophylaxis when other children <5y/o in the family

Front 23

How do you get E.Coli

Back 23

Eating / drinking food / contact with human / animal faeces contamination

Front 24

How does haemophilus spread?

Back 24

- Usually harmless in the nose and throat

- Can spread to blood --> infection

Front 25

What are bacteroides and what drug are some sensitive to?

Back 25

- Most common bacteria in body (faeces)

- Anaerobes are sensitive to Metranidazole

Front 26

How do Neisseria species replicate?

Back 26

- Unable to survive outside of the body

- Survive and replicate inside neutrophils

Front 27

Where can Legionella Pneumophila be found?

Back 27

- Gram -ve rod in freshwater aquatic environments

- Infection by aerosol contaminated water

Front 28

What can Legionella cause and how can it be detected?

Back 28

- Severe community acquired Pneumonia

- Legionella urinary antigen is +ve for 7-10 days post symptoms

Front 29

How does Helicobacter Pylori affect the host? What conditions does it cause?

Back 29

- Colonises stomach & lives under mucus

- Produces urease to increase local pH

- CagA associated with virulence

- Gastritis / Duodenal Ulceration / Gastric Lymphoma

Front 30

How is Helicobacter detected? How is it treated?

Back 30

- Antigen detection in the stool

- PPI + Dual / triple antibiotics required for erad.

Front 31

What are the Staph Aureus virulence factors (not inc. exotoxins)?

Back 31

Surface

Protein A which binds the Fc portion of IgG and is therefore anti-phagocytic

Secreted

Coagulase which deposits fibrin around bacteria in tissues

Front 32

Which exotoxins do Staph Aureus produce?

Back 32

- Haemolysins

- Enterotoxins (short lived, profuse vomiting)

- Exfoliatin

- PVL (vs neutrophils)

- TSST (IL-1 / 2 / TNF)

Front 33

What drugs are used to treat Staph Aureus?

Back 33

- 90% of strains are resistant

- Flucloxacillin & Co-Amoxiclav effective

- Macrolides (Erythromycin & Clarithromycin) in penicillin allergy

Front 34

What is special about MRSA resistance?

Back 34

- Has mecA gene - altered penicillin binding sequence

- Low affinity for all B-Lactams

- Frequently has macrolide resistance

Front 35

What is Strep Pyogenes' main virulence factor?

Back 35

M Protein in its cell wall is anti-phagocytic

Front 36

What can Strep Pyogenes cause?

Back 36

- Suppurative infections

- ENT - Pharyngitis / Tonsilitis / Sinusitis

- Puerpal Fever (& scarlet fever)

- Skin - Impetigo / Cellulitis / Necrotising fasciitis

- Streptococcal toxic shock (SpE superantigen)

- Acute Rheumatic fever

- Acute Glomerulonephritis

Front 37

What is the difference between Staph Aureus & Strep Pyogenes toxic shock?

Back 37

Unlike Staph Aureus toxic shock, blood cultures are usually positive

Front 38

What are the mnemonics to remember SA Vs SPy manifestation?

Back 38

SA produces HEEPT

SPy causes SEPSS AA

Front 39

What are the mnemonics to remember SA Vs SPy manifestation?

Back 39

SA produces HEEPT

SPy causes SEPSS AA

Front 40

How does SPy cause Acute Rheumatic Fever?

Back 40

- 2-3 weeks post acute streptococcal pharyngitis / scarlet fever in 5-15 year olds

- Fever / rash / polyarthritis / pancarditis

Front 41

Which parts of the body are most affected in Acute Rheumatoid Fever?

Back 41

- Heart Valves

- Basal Ganglia

- Joints

Front 42

How does SP cause Acute Glomerulonephritis?

Back 42

- 3 weeks after SP in 2-6 y/o

- Fluid overload - Oedema / Hypertension / Oliguria

Front 43

Which drugs are used to treat SPy?

Back 43

- Group A strep are 100% sensitive to penicillin

- Erythro / Clarithro / Vanco

Front 44

Distinctive features of Strep Pneumoniae?

Back 44

- Pneumolysin (alpha haemolysis on blood agar)

- Cell wall contains C-Polysaccharide & Pneumococcal teichoic acid

Front 45

What is the effect of C-Polysaccharid?

Back 45

- Induces C-reactive protein production in the host

- Non-specific marker of INFLAMMATION

Front 46

What can SPn cause?

Back 46

- Upper respiratory (sinusitis)

- Lower respiratory (pneumonia)

- CNS (meningitis)

Front 47

Who's most at risk of SPn infection?

Back 47

- Hyposplenic / Splenectomised
- Bacterial Peritonitis

Front 48

What is the current preventation / treatment for SPn?

Back 48

- 2 Vaccines

- 7 valent conjugate as part of childhood imm.

- 23 valent polysaccharid for adults at risk of invasive

Front 49

What famous disease can Bacillus cause?

Back 49

Bacillus --> Enterotoxins & Anthracis --> Anthrax

Front 50

Name a coagulase +ve and a -ve?

Back 50

+ve - Staph Aureus

-ve - Staph Epidermis

Front 51

Distinctive properties of the Clostridium species?

Back 51

- Ubiquitous

- Produce exotoxins with diverse effects

Front 52

What is the mechanism by which C Dif works?

Back 52

- Spores ingested germinate and infect colon

- Enterotoxins produced --> inflammatory diarrhoea / collitis

Front 53

How does C Tet work?

Back 53

- Gains entry through wound

- Tetanospasmin prevents inhibitory neurotransmitter release

- Lockjaw

Front 54

How does C Bot work?

Back 54

- Ingested from contaminated food

- Imported to CNS and inhibits ACh release at NMJ --> Paralysis

Front 55

What are the Mycobacterium Tuberculosis pathogenic factors?

Back 55

- Replicates inside macrophages

- Mycolic acid stimulate host sensitivity

Front 56

What is the hose response to MT?

Back 56

- Antibodies formed but ineffective

- Mycobacterial antigens presented on surface

- Lymphokine contribute to tissue damage and attract activated macrophages

Front 57

How is MR transmitted?

Back 57

- Exposure to droplet nuclei

- Cumulative <8h required

- Extrapulmonary --> any system

- 85% involve lower RT

- BCG ONLY PARTIALLY PROTECTIVE

Front 58

What antibiotics are used to treat TB?

Back 58

2 Months

Rifampicin / Isoniazad / Pyrazinamide / Ethambutol

4 Months

Rifampicin / Isoniazad

Front 59

What can Treponema Pallidium cause?

Back 59

- Syphillis

- Lyme Disease

Front 60

What are the problems with Treponema identification? How is it transmitted?

Back 60

- Cannot be gram stained so viewed by dark ground microscopy

- Congenital / Sexual transmission

Front 61

Phases of Syphillis?

Back 61

1' - Genitals / mouth chancre

2' - 2-8w post primary systemic illness due to dissemination

Latent - 2/3 do not progress & may last years

3' - Late - CV / neurosyphilis / gummatous

Front 62

How is Syphilis treated?

Back 62

Penicillin

Front 63

What are the hallmark symptoms of congenital syphilis?

Back 63

Hutchinson's Triad

- Hutchinson's Teeth - Barrel Shaped / Notched incisors

- Deafness

- Interstitial Keratitis

Front 64

What are the distinctive feature of Mycoplasma Pneumoniae?

Back 64

- Contain sterols not peptidoglycan

- No gram stained but can be slow cultured

Front 65

How can Mycoplasma Pneumoniae be detected?

Back 65

Ig<

Front 66

Distinctive features of Chlamydia species?

Back 66

- Intracellular and reuire host cell ATP to replicate

- Not visible on gram stain

Front 67

What diseases can Chlamydia Trachomatis cause?

Back 67

- STI --> Urethritis

- Eye infection --> Blindness

Front 68

What diseases are cause by Chlamydia Psittaci / Pneumoniae?

Back 68

Pneumonia (both)

PCR for diagnosis