Infection, microbes etc

Question 1

What is infection?

Answer 1

The multiplication/colonisation of a pathogenic microbe on/in a susceptible host with associated dysfunction/damage.

Question 2

What causes infection?

Answer 2

Pathogenic microbes

Question 3

What three stipulations are used to determine whether a pathogen causes a disease?

Answer 3

• The agent must be shown to be present in every case of the disease by isolation in pure culture- The agent must not be found in cases of other disease- Once isolated, the agent must be capable of reproducing the disease in experimental animals, and must be recovered from the experimental disease produced.

Question 4

Why do particular individuals get particular infections?

Answer 4

• Weakened immune systems- Poor nutrition- Poor living circumstances- No access to health care (vaccinations)- Genetic predisposition- Lifestyle (e.g. STDs)

Question 5

What influences the outcome of infection?

Answer 5

The host’s immune system, the affected body systems and the drugs used.

Question 6

What are the key properties of a Eukaryote?

Answer 6

No cell wallNo envelopeNo capsidMembrane bound organellesNucleusDNA and RNANo pili or flagellaNo reverse transcriptase

Question 7

What are the key properties of a Bacterium?

Answer 7

Peptidoglycan or lipopolysaccharide cell wallNo capsidNo membrane bound organellesNo nucleus – Circular DNADNA and RNAPili, flagellaNo reverse transcriptase

Question 8

What are the key features of a virus?

Answer 8

Can be envelopedNo organelles – obligate intracellular parasitesCan have capsidsDNA or RNANo pili or flagellaCan have reverse transcriptase

Question 9

What does gram staining allow us to do?

Answer 9

detect and begin to classify most bacteria

Question 10

What are the two classifications of bacteria within gram staining?

Answer 10

. Bacteria can be classified as Gram positive or negative depending on its cell wall.

Question 11

What colour are gram negative bacteria in a Gram stain and vice versa?

Answer 11

Gram negative bacteria are stained red whereas Gram positive bacteria are blue after staining.

Question 12

Describe the process of gram staining

Answer 12

• Positively charged crystal violet binds to negatively charged cell components- Iodine forms a large molecular complex with crystal violet- Acetone or methanol extract the complexes through the Gram-negative cell wall but not through the Gram-positive- A red dye is used to stain the now unstained Gram-negative cells

Question 13

What do acid fast stains allow us to do?

Answer 13

detect the bacterial causes of tuberculosis and leprosy (mycobacteria) – bacteria that cannot be identified by gram staining.

Question 14

What is a pathogen?

Answer 14

a bacterium, virus, or other microorganism that can cause disease

Question 15

What is a non pathogen and what roles do they peform?

Answer 15

a bacterium that doesn’t cause disease. Many non-pathogens perform essential ecological roles.

Question 16

What is the significance of genome compositon in the classification and detection of viruses?

Answer 16

RNA viruses are more likely to mutate, as RNA is less stable. DNA more stable.

Question 17

What is the significance of a viral envelope, and whether it is present for the classification and detection of viruses?

Answer 17

If a virus has an envelope it’s more easily sterilised as if holes are punched in the envelope the virus cannot survive

Question 18

What is the significance of replication strategy for classification and detection of viruses?

Answer 18

RNA viruses can use reverse transcriptase (HIV), DNA viruses can use cell machinery (HPV), or a virus can carry its own replication enzymes.

Question 19

Classify Hepatitis B virus and give disease association

Answer 19

DNA EnvelopedInflamed liver

Question 20

Classify Herpes virus and give disease association

Answer 20

DNA Enveloped Oral/genital

Question 21

Classify smallpox virus and give disease association

Answer 21

DNA envelopedSmallpox

Question 22

Classify and give disease association of HPV

Answer 22

DNA non-envelopedWarts, Cervical Cancer

Question 23

Classify and give disease association of HIV

Answer 23

RNA envelopedAIDS

Question 24

Classify and give disease association of Rubella

Answer 24

RNA envelopedRash, congenital rubella syndrome

Question 25

Classify and give disease association of Rota virus

Answer 25

RNA envelopedDiarrhoea

Question 26

Classify and give disease association of Coronavirus

Answer 26

RNA envelopedSARS

Question 27

Classify and give disease association of Polio

Answer 27

Inflammation of the spinal cordRNA non-enveloped

Question 28

Classify and give disease association of Hepatitis A

Answer 28

RNA non-enveloped Liver disease

Question 29

Give gram reaction and disease association of Staphylococcus aureus

Answer 29

+’veAbscesses, toxic shock syndrome and food poisoning. If organisms enter the bloodstream they may cause endocarditis and osteomyelitis.

Question 30

Gram reaction and disease for Streptococcus pyogenes

Answer 30

+’veNecrotising fasciitis (flesh easting bacteria)

Question 31

Gram reaction and disease for Group B Streptococci

Answer 31

+’veNeonatal sepsis and meningitis

Question 32

Gram reaction and disease for Streptococcus pneumoniae

Answer 32

+’vePneumonia (also meningitis, sepsis, endocarditis)

Question 33

Gram reaction and disease for Clostridium perfingens

Answer 33

+’veGas gangrene

Question 34

Gram reaction and disease for Clostridium difficile

Answer 34

+’veAntibiotic associated diarrhoea (can lead to pseudomembranous colitis)

Question 35

Gram reaction and disease for Neisseria meningitidis

Answer 35

-‘veSepticaemia and meningitis

Question 36

Gram reaction and disease for Neisseria gonorrhoea

Answer 36

-‘veGonorrhoea, which can lead to pelvic inflammatory disease and epididymitis

Question 37

Gram reaction and disease for Escherichia coli

Answer 37

-‘veWatery diarrhoea, acute renal failure (haemolytic-uremic syndrome)

Question 38

Gram reaction and disease for Salmonella spp.

Answer 38

-‘veGastroenteritis, typhoid fever

Question 39

Gram reaction and disease for Shigella

Answer 39

-‘veDysentery, bloody diarrhoea (is closely related to E.coli)

Question 40

Gram reaction and disease for Pseudomonas aeruginosa

Answer 40

-‘veGeneralised inflammation, sepsis

Question 41

Gram reaction and disease for Legionella spp.

Answer 41

-‘vePontiac fever, Legionnaire’s disease (legionellosis)- acute influenza or pneumonia

Question 42

Gram reaction and disease for Helicobacter pylori

Answer 42

-‘veCausal role in peptic ulcers, especially duodenal

Question 43

Gram reaction and disease for Bacteroides spp.

Answer 43

-‘veAbcesses, lesions

Question 44

Gram reaction and disease for Chlamydia spp.

Answer 44

-‘veChlamydia

Question 45

Mycobacterium tuberculosis

Answer 45

Acid FastTuberculosis

Question 46

Mycobacterium leprae

Answer 46

Acid FastLeprosy

Question 47

What are the two methods of identifying bacteria?

Answer 47

Gram Stain and Acid Fast

Question 48

DNA enveloped viruses?

Answer 48

Hepatitis BHerpesSmallpox

Question 49

DNA non-enveloped viruses?

Answer 49

HPV

Question 50

RNA enveloped viruses?

Answer 50

HIVRubellaRotavirusCoronavirus

Question 51

RNA non-enveloped viruses?

Answer 51

PolioHepatitis A

Question 52

Which antibiotics target the cell wall?

Answer 52

PenicillinAmoxicillinFlucloxacillinCephalexinVancomycin

Question 53

Which antibiotics target protein synthesis?

Answer 53

GentamicinErythromycinTetracycline

Question 54

Which antibiotics target antifolates?

Answer 54

TrimethoprimMetronidazole

Question 55

Which antibiotic targets RNA polymerase?

Answer 55

Rifampicin

Question 56

Which antibiotic targets DNA?

Answer 56

Ciprofloxacin

Question 57

Antibiotics in Beta-Lactams group?

Answer 57

PenicillinAmoxicillinFlucloxacillinCephalexin

Question 58

Antibiotics in glycopeptide group?

Answer 58

Vancomycin

Question 59

Antibiotic in Macrolide group?

Answer 59

Erythromycin

Question 60

Antibiotic in polypeptide group?

Answer 60

Tetracycline

Question 61

Antibiotic in chemotheraputic group?

Answer 61

Ciprofloxacin

Question 62

What habitats can microbes occupy?

Answer 62

SoilAirBodily fluidsAnimalsPlantsHumans

Question 63

Define Reservoir

Answer 63

Any person, plant, animal, soil or substance in which an infectious agent lives

Question 64

Define source

Answer 64

Readily available form of an infective agent

Question 65

Define mode of transmission

Answer 65

Ingestion, inhalation, physical contact, inoculation, sexual transmission

Question 66

Define carriage

Answer 66

Passage taken by microorganism

Question 67

Define normal flora

Answer 67

Non-pathogenic bacteria found in our bodies E.g. In the gut

Question 68

Define commensal

Answer 68

Symbiotic relationship where one species (microbe) benefits from the relationship and the host is unaffected -- when microbe is replicating or waiting for immune system to be compromised

Question 69

Where is lipopolysaccharide found?

Answer 69

In the outermembrane-- would give a gram negative stain result