Microbiology 3

Front 1

How does our normal flora help prevent the entry of pathogens?

Back 1

The normal flora take up space and nutrients so the pathogens have to fight them to be able to reside there.

Front 2

Define antibiotic

Back 2

Drug used to treat bacterial infections

Front 3

List some attributes that an ideal microbial agent should possess.

Back 3

Damages the microorganism not the host (selective toxicity), solubility in body fluids, non-allergenic, stability, long shelf life, reasonable cost, resistance by microorganisms not acquired easily

Front 4

Name the 2 types of antibiotics that are cell wall inhibitors.

Back 4

Penicillin, Cephalosporin

Front 5

Why is chlamydia hard to target?

Back 5

They are intracellular obligate organisms (lives inside cells)

Front 6

What is the role of bacteriostatic agents ?

Back 6

They inhibit the growth of bacteria allowing the hosts immune system to kill it.

Front 7

What does Beta-lactam inhibit?

Back 7

Peptidoglycan cross-linking enzyme (Penicillin Binding Protein)

Front 8

What does Beta - lactam have a similar structure to?

Back 8

D-Alanine

Front 9

Why are penicillin G and V not effective against gram-negative bacteria?

Back 9

Gram negative bacteria have porins on their cell wall which are specific thus inhibiting the entrance of penicillin

Front 10

Define a resistant microorganism

Back 10

Microorganism that is not inhibited or killed by antibacterial agent at concentrations of the drug achievable in the body after normal dosage

Front 11

Name 3 mechanisms of antibiotic resistance

Back 11

Altered porin channels to decrease permeability, Active effiux, Target modification, Enzymatic inactivation or modification, Bypass pathways, over production of target.

Front 12

Which enzyme is responsible for breaking beta-lactam.

Back 12

Beta-lactamase (also called penicillinase)

Front 13

Which antibiotic is Beta-lactamase resistant?

Back 13

Methicillin

Front 14

What is the amoxicillin and clavulanic acid combination called?

Back 14

Augmentin

Front 15

What are the three anti-fungal agents?

Back 15

Flucytosine, Azole, Polyene

(FAP)

Front 16

Name the 4 antibiotics that inhibit protein synthesis

Back 16

Macrolides, chloramphenical, Tetracycline, Aminoglycoside

Front 17

Why is there a limited use of the anitbiotic Chloramphenicol ?

Back 17

It has major side effects - bone marrow suppression, nausea, severe allergies and vomiting

Front 18

What does PABA stand for ?

Back 18

Para-aminobenzoic acid

Front 19

Sulphonamides and Trimethoprim inhibit folic acid synthesis. Why is this process highly selective?

Back 19

Bacteria synthesise their folic acid rather than obtain it from diet like mammals do.

Front 20

What is minimal inhibitory concentration (MIC)?

Back 20

lowest concentration of an antibiotic able to inhibit the growth of an organism.

Front 21

What is the function of smooth endoplasmic reticulum?

Back 21

Synthesise lipids

Front 22

What are the 5 types of histones found in the nucleosome?

Back 22

H1,H2a,H2b,H3,H4

Front 23

Describe hydrogenosomes

Back 23

>They are small energy conservation organelles in some anaerobic microorganisms.

>They have a double membrane with no cristae

>Their ATP is generated through fermentation

>They produce CO2, H2 and acetate

Front 24

What occurs in chloroplast?

Back 24

Photosynthesis

Front 25

What are thylakoids?

Back 25

They are in the stroma of choloroplast and are the site of light reactions.

Front 26

List two reasons why mitochondrion are supposedly of bacterial origin.

Back 26

>The genome of obligate intracellular pathogens closely resememble mitochondrial genome

> The organelle membrane has porins

>They reproduce by binary fission like bacteria

Front 27

What type of microorganism are fungi? (carbon, electron and energy source)

Back 27

Chemoorganoheterotrophs

Front 28

What are the 6 major groups of fungi?

Back 28

Chytridiomycota, Zygomycota, Ascomycota, Glomeromycota, Basidiomycota, microsporidium

Front 29

What are the two types (in terms of structure) of fungi and what are they called?

Back 29

> Single celled - yeast

> filamentous - thallus

Front 30

Give a description of septate hyphae

Back 30

Segmented with centrally located nuclei in each

Front 31

Give a description of Coenocytic hyphae

Back 31

They have a continuous cytoplasm (no segments) and are multinucleated.

Front 32

What are the two types of hyphae?

Back 32

Septate and coencytic

Front 33

What type of hyphae does the fungi group zygomycota form?

Back 33

Coenocytic hyphae

Front 34

There are > 70 000 species of fungi. How many of these cause disease in humans and animals?

Back 34

300

Front 35

List the three types of mycoses

Back 35

Superficial, cutaneous, systemic (deep)

Front 36

Where are superficial mycoses infections found?

Back 36

Outer most layer of skin (stratum corneum) and hair shaft

Front 37

Name a type of superficial mycoses

Back 37

Pityriasis versicolour (tinea versicolour)

Front 38

What is the causative agent of pityriasis versicolour?

Back 38

Malassezia furfur (yeast)

Front 39

Where are cutaneous mycoses infections found?

Back 39

keratinised layer of epidermis, nails and hair

Front 40

What type of spore is involved in dermatophytosis? What type of cell does it invade? What do they use as nutrients?

Back 40

Arthrospores, keratinocytes, keratin (using keratinase)

Front 41

What is the infection of the keratinised layer of nail called?

Back 41

Onychomycosis

Front 42

What are the 5 methods of diagnosing dermatophyte infections?

Back 42

1. Clinical assessment, 2. Specimen collection, 3. Culture (SAB agar) 4. Wood's light 5. Microscopy

Front 43

Name 2 types of cutaneous mycoses

Back 43

Ringworms , Vaginal thrush, Athlete foot

Front 44

What is the main symptom of tinea corposis

Back 44

Itching

Front 45

What are the sources of infection of tinea corposis?

Back 45

Animals, Humans and soil

Front 46

What are the symptoms of tinea pedis?

Back 46

Erythema (redness) of toes, webbed-toe maceration

Front 47

What is the causative agent of thrush?

Back 47

Candida albican

Front 48

What type of bacteria are responsible for maintaining the pH of the vagina? What is the normal pH range of the vagina?

Back 48

Lactobacilli, 3.5 -4.5

Front 49

How do oral contraceptives lead to the overgrowth of Candida albican

Back 49

Increases glycogen levels

Front 50

How is oral candidiasis acquired in newborn babies

Back 50

During birth or through the nipple

Front 51

What do systemic mycoses infect?

Back 51

Internal organs

Front 52

What type of mycoses are Cryptococci associated with?

Back 52

Systemic

Front 53

Which type of cryptococci primarily infect the lungs?

Back 53

Cryptococcal neoformans

Front 54

What is the Rapid latex agglutination test used to detect ?

Back 54

Capsular polysaccharide antigens of Cryptococcal neoformans

Front 55

what percentage of people with AIDs are infected with cryptococcal meningitis?

Back 55

7 - 10%

Front 56

Why are fungal infections hard to treat?

Back 56

They are eukaryotic so they are hard to target.

Front 57

How does the antifungal agent Flucytosine work?

Back 57

It interrupts DNA and RNA synthesis

Front 58

Which part of the fungal cell do Azoles work on?

Back 58

Cell membrane and mitochondria

Front 59

Name the types of polyenes

Back 59

Amphotericin B and Nystatin

Front 60

How do sulphonamides inhibit folic acid synthesis?

Back 60

They bind to dihydropterate synthase

Front 61

How do trimethoprim inhibit folic acid synthesis?

Back 61

They bind to Dihydrofolate reductase

Front 62

Explain the resistance against macrolides

Back 62

Alteration of binding site by methylation of 2 adenine nucleotides by methylase

Front 63

Which enzyme is responsible for chloramphenicol resistance?

Back 63

Chloramphenicol acetyl transferase

Front 64

What type of protein inhibitor is gentamicin?

Back 64

Aminoglycoside