Mini module - medical microbiology

Question 1

Definition of diarrhoea?

Answer 1

Passage of unusually loose or watery stools, usually at leat three times in a 24hr period.

Question 2

What are the different types of clinical diarrhoea?

Answer 2

Acute watery diarrhoea (osmotic/secretory), acute bloody diarrhoea (dysentery - mucus and blood in faeces), severe malnutrition.

Question 3

What is the leading cause of diarrhoea?

Answer 3

Rotavirus - effective vaccine.

Question 4

Other causes of diarrhoea?

Answer 4

Shigella genus, salmonella entérica, campylobacter jejuni, yersinia genus, Ecoli, vibrio cholerae, clostridium difficile, toxigenic staphyloccus aureus.

Question 5

Characteristics of Ecoli?

Answer 5

10^21 cells in human population, not one pathogen, no vaccine.

Question 6

What is the structure of the digestive system?

Answer 6

Liver, stomach, duodenum, gallbladder, colon, jejunum, ileum, appendix, rectum.

Question 7

Enzyme of alpha-dextrins to glucose?

Answer 7

alpha-dextrinase

Question 8

Enzyme of trypsinogen to trypsin?

Answer 8

Enteropeptidase.

Question 9

What catalyses lactose to glucose and galactose?

Answer 9

Lactase.

Question 10

What is produced when maltase catalyses a reaction with maltose?

Answer 10

Glucose.

Question 11

What is formed when nucleosidases and phosphatases react with nucleotides?

Answer 11

Phosphates, nitrogenous bases, pentoses.

Question 12

What forms when peptidases react with dipeptides?

Answer 12

Forms amino acids and peptides.

Question 13

What is an aminopeptidase?

Answer 13

Enzymes that form amino acids from the amino end of peptides.

Question 14

What are dipeptidases?

Answer 14

Enzyme that forms amino acids from dipeptides.

Question 15

What enzyme catalyses the formation of glucose and fructose from sucrose?

Answer 15

Sucrase.

Question 16

Sources of contamination?

Answer 16

Water and food.

Question 17

Transfer sources?

Answer 17

Water, food, humans.

Question 18

What percentage of people wash their hands before having food?

Answer 18

39%

Question 19

Where are the top 4 contaminators of faecal bacteria in the UK?

Answer 19

Hands (26%), phones (16%), banknotes (14%), credit cards (10%).

Question 20

Name some top ways to prevent contamination?

Answer 20

Safe drinking water, improved sanitation, exclusive breastfeeding (first 6 months), personal and food hygiene, vaccination, health education.

Question 21

By how much does washing hands with soap reduce number of people who get sick with diarrhoea?

Answer 21

23-40%.

Question 22

How much does washing hands with soap reduce diarrheal illness in people with weakened immune systems?

Answer 22

58%.

Question 23

By how much does washing hands with soap reduce respiratory illnesses?

Answer 23

16-21%.

Question 24

By how much does washing hands with soap reduce absenteeism due to gastrointestinal illness?

Answer 24

29-57%.

Question 25

What do oral rehydration salts solution do?

Answer 25

ORS absorbed in small intestine and replaces water and electrolytes lost in faeces.

Question 26

What diarrhoea do ORS help with?

Answer 26

Osmotic diarrhoea.

Question 27

What is used in cases of severe dehydration or shock?

Answer 27

Intravenous fluids.

Question 28

What do zinc supplements do for diarrhoea?

Answer 28

Reduce duration of diarrhoea episode by 25% and reduce stool volume in 30%.

Question 29

What do nutrient rich foods do for diarrhoea?

Answer 29

Reduce malnutrition.

Question 30

What type of diarrhoea do nutrient rich foods help with?

Answer 30

Osmotic diarrhoea.

Question 31

What did Waksman define antibiotics with originally in 1930?

Answer 31

A compound made by a microbe to destroy other microbes.

Question 32

Definition of antimicrobials?

Answer 32

Compounds which kill any type of microbes and could be a mix of active components.

Question 33

Definition of antibiotics?

Answer 33

Chemical compounds with a single mode of action and only active against bacteria.

Question 34

Who discovered Penicillin in 1982?

Answer 34

Alexander Fleming.

Question 35

Characteristics of bacteriostatic agents?

Answer 35

Inhibit important biological processes, weak target binding, cell grows if agent removed, many antibiotics in this category.

Question 36

Characteristics of bactericidal agents?

Answer 36

Kill the cell, strong target binding, cell not lysed, cell count constant, viable cell count.

Question 37

Characteristics of bacteriolytic agents?

Answer 37

Kill and lyse cell, release cytoplasmic contents, rupture membrane, total cell count and viable cell count decrease.

Question 38

What does activity of antibiotics depend on?

Answer 38

Whether the target is present in only certain types of bacteria or in all.

Question 39

Advantages of narrow spectrum activity?

Answer 39

Potential to limit selection for and spread of resistance and to elicit a lesser detrimental effect upon host microbiome.

Question 40

Challenges on narrow spectrum activity?

Answer 40

Require rapid, accurate, sensitive diagnostic assays for the identification of bacterial pathogens.

Question 41

Example of narrow spectrum activity?

Answer 41

Azithromycin (macrolide to treat pneumonia).

Question 42

Advantage of broad spectrum activity?

Answer 42

Can be used quickly before the formal identification of causative bacteria.

Question 43

Challenge of broad spectrum activity?

Answer 43

Selection for and spread of resistance across multiple bacteria species.

Question 44

Example of broad spectrum activity?

Answer 44

Amoxicillin.

Question 45

Give the 6 most common classes of antibiotics.

Answer 45

Beta-lactam, sulfonamides, fluoroquinolones, macrolides, tetracyclines, aminoglycosides.

Question 46

Three sub-sections of beta-lactam antibiotics?

Answer 46

Penicillins, cephalosporins, carbapenems.

Question 47

What do beta-lactam antibiotics do?

Answer 47

Bacterial cell wall synthesis.

Question 48

What do sulfonamides and fluoroquinolones do?

Answer 48

DNA synthesis.

Question 49

What do macrolides, tetracyclines and aminoglycosides do?

Answer 49

Protein synthesis.

Question 50

Summarise Beta-lactam.

Answer 50

Bactericidal, broad spectrum, cell wall synthesis, no side effects, occasional allergies.

Question 51

Summarise sulfonamides.

Answer 51

Big history, bacteriostatic, broad spectrum, target competitive inhibitors, hypersensitivity reactions, hematologic reactions, neurological effects.

Question 52

Summarise fluoroquinolones.

Answer 52

By product of anti-malaria compound, bactericidal, broad spectrum, inhibit bacteria, tendinopathy, hyper/hypoglycaemia.

Question 53

Summarise macrolides.

Answer 53

3 generations, bacteriostatic, broad spectrum, bind to bacterial 50S subunit, cessation of protein synthesis, cardiac arrhythmias, hepatotoxicity.

Question 54

Summarise tetracyclines.

Answer 54

Bacteriostatic, broad spectrum, bind to 30S subunit, teeth discoloration, inhibits bone growth, photosensitive, hepatotoxicity.

Question 55

Summarise aminoglycosides.

Answer 55

Bactericidal, broad spectrum, 30S subunit, nephrotoxic, ototoxic, neuromuscular blockade.

Question 56

What can antibiotics not treat?

Answer 56

Viral infections.

Question 57

What do antibacterial doses depend on?

Answer 57

Age, weight, hepatic function, renal function, severity of infection.

Question 58

What are the two routes of antibacterials?

Answer 58

Oral and intravenous.

Question 59

What can antibiotics help with in agriculture?

Answer 59

Growth promotion, improved feed conversion efficiency, prevention of diseases.

Question 60

What has led to high level of resistance?

Answer 60

Misuse and overuse, not taken as prescribed, poor infection control, lack of tests, poor hygiene and sanitation.

Question 61

Why have some companies abandoned antibiotics?

Answer 61

Lack of incentive, last new class discovered late 1980s, high cost, low revenue, deaths fallen, avoiding over prescription.

Question 62

What are antimicrobial peptides?

Answer 62

Small molecules produced by innate defence system.

Question 63

What do peptide based antibiotics do?

Answer 63

Induce cell disruption through non-specific interactions with membrane surface pathogens.

Question 64

Characteristics of peptide based antibiotics?

Answer 64

Broad spectrum, less chance of resistance, haemolytic activity or nephrotoxicity.

Question 65

Summarise bacteriophages.

Answer 65

Discovered early 20th century, narrow host range, difficult to manufacture.