MFD 12 Mibrobial Pathogenicity

Question 1

Explain what is meant by pathogenicity

Answer 1

the ability of an organism to cause disease

Question 2

Explain what is meant by pathogenicity factors.

Answer 2

same as virulence factors, Bacterial virulence factors enable a host to replicate and disseminate within a host in part by subverting or eluding host defenses e.g. fimbria

Question 3

What is an epidemological agent?

Answer 3

the bacterium ( the shit it produces maybe e.g. p.gingivalis and gingipains), god damn didn’t see that coming

Question 4

What diseases does Staphylococcus Aureus

cause?

Answer 4

Staphylococcal meningitis, Impetigo

Pneumonia

Question 5

What are the biological characteristics of Staphylococcus aureus
?

Answer 5

In the micrococcaceae family. ( spherical in shape, arranged in grape like structures, gram +)
Produces coagulase and has novobiocin resistance
grows at 15-45 degrees C
Is commensal and pathogenic,

Question 6

What is the virulence factors of s. aureus

Answer 6

Produces coagulase and has novobiocin resistance

Question 7

Who does S.aureus usually infect? and incidence?

3) describe distribution of MRSA infections

Answer 7

1) young children and elderly
2) 10-30 per 100,00 people per year
3) not even

Question 8

What is encompased when describing the epidemiology of an organism?

Answer 8

for example how common it is in the
population, the prevalence of the diseases that it causes or any specific
outbreaks of disease due to the organism.

Question 9

What is Staphylococcal meningitis?

Answer 9

Inflammation of the meninges – the protective membranes around the brain and spinal cord

Question 10

What are the biological characteristics of Staphylococcus aureus
?

Answer 10

In the micrococcaceae family. ( spherical in shape, arranged in grape like structures, gram +)
Produces coagulase and has novobiocin resistance
grows at 15-45 degrees C
Is commensal and pathogenic,

Question 11

Treatments of Staphylococcal meningitis:

Answer 11

1_ Antibiotics such as nafcillin, linezolid and cefazolin.

2_ Meningitis caused by methicillin-resistant strains (MRSA) must be treated with Vancomycin.

Question 12

Symptoms of impetigo:

Answer 12

Red sore, itchy and painful, red sores burst to develop golden crust,

Question 13

Treatments of impetigo:

Answer 13

Usually clears up within 2-3 weeks but topical antibiotics such as mupirocin but oral antibiotics may be used in more serious cases of the disease.

A more serious form can develop called Ecthyma which cause causes fluid and pus-filled sores which turn into deep ulcers.

Question 14

Symptoms of pneumonia:

Answer 14

similar to that of the flu, and include: cough, chest pain, difficulty breathing, fever, loss of appetite

Question 15

Treatments of pneumonia:

Answer 15

Treatments include antibiotics such as zanamivir and amantadine, as well as vaccinations to help with herd immunity

Question 16

What are the virulence factors of S.aureus?

Answer 16

Catalase
Hemolysins
Coagulase
Leukocidin
Also produce proteolytic enzymes, hyaluronidase, fibrinolysin, lipase, ribonuclease, and deoxyribonuclease

Question 17

What is the pathogenesis of toxic shock syndrome?

Answer 17

an exotoxin, produce by S.aureus, called toxic shock syndrome toxin-1 (TSST-1) a superantigen
Toxin recruits large numbers of T cells, culminating in a massive inflammatory response

Question 18

What is the pathogensis of food poisening?

Answer 18

another superantigen, causes a form of food poisoning
Ingestion of toxin-contaminated food, the toxin stimulates T cells localized along the intestine, resulting in a massive T cell response and release of inflammatory mediators
Severe but short-lived diarrhea and vomiting

Question 19

What is the pathogensis of food poisening?

Answer 19

another superantigen, causes a form of food poisoning
Ingestion of toxin-contaminated food, the toxin stimulates T cells localized along the intestine, resulting in a massive T cell response and release of inflammatory mediators
Severe but short-lived diarrhea and vomiting

Question 20

What are the biological characteristics of Neisseria gonorrhoeae
?

Answer 20

gram -.
diplococcus (occurs as pairs of cocci, 2 spheres)
aerobic
catalase positive
modulates immune response, resides within neutrophils
fastiduous ( specific nutrient requirements)

Question 21

How common is Neisseria gonorrhoeae

as an STI?

Answer 21

2nd most common STI,

Question 22

What is the prevalence of the diseases that Neisseria gonorrhoeae causes ?
2) What concerns are there?

Answer 22

78 million new cases of gonorrhea in 2016 worldwide
44,500 new cases in 2017 in the UK alone
2) becoming resistant to antibiotics

Question 23

What disease does neisseria gonorrhoeae cause?

Answer 23

gonorrhoeae

Question 24

What are the symptoms of gonorrhoeae?

Just a rough idea is enough

Answer 24

In women – pain and tenderness in the abdominal area, heavier periods and pain when passing urine, unusual vaginal discharge
In men – pain or a burning sensation when urinating, swelling/ inflammation of foreskin and unusual discharge
Infection in the throat, eyes and rectum which can cause pain and swelling
Gonorrhoea can be passed from a mother to her baby during childbirth. Symptoms in babies include the eyes becoming red and swollen and eyes have a thick, pus-like discharge.
If left untreated, it can cause infertility.
Patients complain of an initial burning sensation in the mouth. Within 1-2days the mouth becomes acutely painful and the sub-mandibular lymph nodes enlarge. Oral functions such as speech and swallowing become very painful.

Question 25

What are the virulence factors of Neisseria gonorrhoeae ?

Answer 25

1) Pilli – Piliated gonoccoci are usually virulent, whereas nonpiliated strains are avirulent.
2) Lipooligosaccharides (LOS)
3) Outer membrane proteins and Opa proteins e.g Porin A:
4) lgA protease

Question 26

Pilli is a virulence factor of neisseria gonorrhoeae, how does it cause disease? (Pathogenic mechanism)

Answer 26

Pilli mediate attachment to mucosal cell surfaces and also are antiphagocytic.

Question 27

Lipooligosaccharides (LOS) is a virulence factor of neisseria gonorrhoeae, how does it cause disease? (Pathogenic mechanism)

Answer 27

like LPS but low molecular weight form, has non-pathogenic role and also is an endotoxic and initiates host immune response

Question 28

Outer membrane proteins and Opa proteins e.g Porin A, is a virulence factor of neisseria gonorrhoeae, how does it cause disease? (Pathogenic mechanism)

Answer 28

Mediates invasion of the epithelial cells.

Question 29

lgA protease is a virulence factor of neisseria gonorrhoeae, how does it cause disease? (Pathogenic mechanism)

Answer 29

It hydrolyzes secretory lgA, which could otherwise block attachment to the mucosa.

Question 30

What are the essential biological characteristics of Legionella pneumophila?

Answer 30

gram -, aerobic, fastidious, have a pilli so are motile, rod or coccoid shape, optimal temperature for in-vitro growth is 36°C
Falcultative intracellular parasite (can reproduce outside and within a cell)

Question 31

Epidemology of legionella pneumophila:

1) outbreaks?
2) environment found in

Answer 31

1) Legionnaires’ disease , 1976, Philadelphia convention of the american legion
2) air-conditioning and water distribution systems

Question 32

What diseases are caused by legionella pneumophilia?

Answer 32

Legionnaire’s disease

Pontaic fever

Question 33

What are the symptoms of Legionnaires’ disease?

Answer 33

cough,shortness of breath, highfever, chest pains (as leads to pneumonia), headaches, nausea, vomiting and diarrhoea. It feels like a severe flu.

Question 34

What is the treatment for Legionnaires’ disease?

Answer 34

antibiotics (venous), oxygen administration and respiratory ventilator. Antibiotic prophylaxis not effective

Question 35

What are the symptoms of Pontaic fever?

Answer 35

cute, nonfatal respiratory that causes a mild upper respiratory infection. It resolves spontaneously and often goes undiagnosed

Question 36

What traditional virulence factors doe L.pneumophila have?

Answer 36

includes lipopolysaccharide (LPS), flagella, pili, a type II secretion system , and outer membrane proteins.

Question 37

What additional virulence factor does L.pneumophila have

2) What does it do?
3) How does this cause damadge to the host cell, and result in disease?

Answer 37

type 4 secretion system,

2) its secretes proteins when within a cell (alveolar macrophage) allowing the bacterium to exsist within a vesicle similiat to the ER,
3) this legionella containing vacoule prevents the host cell signalling for help, allowing further replication to take place

Question 38

What is the essentional biology of Clostridium Difficile?

Answer 38

gram +, spore forming,
saccharolytic and proteolytic metabolism,
thrives in dysbiotic environemtn (where colonic microfloura have been altered)

Question 39

What is the effect of the toxins TcdA and TcdB produced by Clostridium difficile

Answer 39

Disrupts GTPases, causing cell rounding and eventually death.
Both toxins enter the cell by endocytosis, where they are then cleaved, activating them.
Toxin A disrupts colonic mucosal cell adherence to colonic basement membrane and damages villous tips
Toxin B triggers apoptosis
They target GTPases – proteins involved in epithelial barrier function and host immune response
Both toxins stimulate monocytes and macrophages causing release of interleukin 8, resulting in tissue infiltration with neutrophils

Question 40

what are the virulence factor of Clostridium difficile?

Answer 40

1) Produces toxin TcdA and TcdB
2) Has fimbriae/pilus (they are the same thing)
3) has adhesins
4) Colonisation upregulates genes for fermentation

Question 41

What sort of hosts does clostridium difficle infect?

2) Where is there an increased incidence rate?

Answer 41

1) as an opportunistic pathogen, usually infects young children and elderly
2) young children and elderly

Question 42

What does clostridium difficile cause?

Answer 42

infectious diarrhoea

Question 43

Why would you prescribe metronidazole or vancomycin for C.diff infections? Which one would you use?

Answer 43

. Although neither drug has clearly been superior in head-to-head comparisons, some clinicians feel that vancomycin is the “stronger drug.” However, because of vancomycin’s expense and the ever-present worry about drug resistance, current guidelines recommend reserving vancomycin for patients with severe disease.

Question 44

What conditon does Clostridium difficile cause?

2) symptoms?

Answer 44

Clostridium difficile colitis (infection of the colon)

2) symptoms of C. difficile colitis are fever, diarrhea, and abdominal pain