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Flashcards in BacT lecture 5 Deck (70):
1

What is a Opportunistic pathogens?

Pathogens are organisms that do not cause disease in a healthy host, with a healthy immune system.

2

What pathogens are equipped with virulence genes for adherence, invasion, evasion form the immune system and toxins?

True pathogens

3

Nosocomial Infections

Hospital acquired infections

4

Which type if infection almost always causes nosocomial infections?

Opportunistic pathogens

5

Clinical classifications in diagnostic microbiology of bacterial pathogens?

Gram-neg vs Gram-pos
Cocci vs Rods
Fermenter vs Nonfermenter

6

Based on their oxygen requirements of bacterial pathogens?

Aerobic
Facultative anaerobic
Anaerobic
Microaerophillic

7

Dichotomous keys are like?

Phylogenetic trees used to ID bacteria in diagnostic labs

8

The majority of bacteria are?

Extracellular pathogens

9

Extra cellular pathogens

Multiply, feed, and replicate in the fluid outside the cell

10

Obligate Intracellular pathogens are

Pathogens that only survive and replicate inside the cell. Lack the metabolic pathways to live outside the cell

11

T:F Obligate intracellular pathogens can be cultivated in medium?

False
Obligate intracellular pathogens can only be grown in cells or animals

12

Facultative intracellular pathogens are

Pathogens that can survive inside the cell to protect from the immune system, but also can survive outside the cell.

13

Example of Obligate intracellular pathogen?

Rickettsia, Chlamadia

14

Example of Facultative intracellular pathogen?

Mycobacterium

15

In terms of veterinary practice what are the two important Gram positive cocci?

Staphylococcus
Streptococcus

16

Staphylococcus is a?

Facultatively anaerobic, that is an opportunistic pathogen. Often skin infections, mucus membrane infections, Pyogentic bacteria (puss producing), post surgical infection.

17

The four veterinary significant Staphylococcus

S. aureus
S. intermedius (Dogs)
S. hyicus (Greasy pig disease)
S. Schleiferi subsp. coagulans

18

What is significant about Staphylococcus aureus?

Opportunistic nosocomial and community infection. Increased notoriety due to methicillin-resistant Staphylococcus aureus (MRSA) infection.

19

Staphylococcus cause?

Hot spots in dogs -traumatic dermatitis
Greasy pig disease
Peracute gangrenous mastitis in cows, goat, sow, ewe

20

Pathogenicity in Staphylococcus?

Botryomycosis- also known as bacterial pseudomycosis are a rare chronic granulomatous bacterial infection that affects the skin, and sometimes viscera; infrequent chronic pyogranulomatous inflammation, leasions, udder

21

Coagulase is?

An enzyme that virulent strains produce that coagulate blood plasma

22

Staphylococcus exotoxins and virulence factors that are produced?

Enterotoxin A-E
Exfoliatin
Epidermolytic toxin
Haemolysins
Leukocidins
Protein A

23

What is Enterotoxin A-E

Food poisoning superantigens. Heat resistant. Most common cause of food poisoning.

24

Exfoliatin

Skin- toxin specific for the epidermidis, produced by S. aureus and S. hyicus.

25

Epidermolytic toxins effect the?

skin

26

Haemolysins

Destroy blood cells- erythrocytes from various species differ in susceptibility to the 4 different toxins.

27

Leukocidins

Kills immune system cells. Leucocites- granulocytes and macrophages

28

Protein A

Present as a surface component (cell wall) on most strains of virulent S. aureus. Is antiphagocytic and has the ability to bind to Fc fragment of IgG

29

What type of antibiotic is S. aureus resistant to?

Beta-lactam antibiotics (penicillins and cephalosporins)

30

How are S. aureus resistant to Beta-Lactam antibiotics?

They produce a phage-coded penicillinase. Some strains have a modified penicillin binding protein PBP2A conded by a Mec A gene

31

Healthy person carrying MRSA and not becoming ill, but passing it on to others that become ill is known as

MRSA-Community acquired

32

Streptococcus is

A large group that occurs widely in nature and also as normal flora of man and animal. Facultatively anaerobic.

33

List some Streptococcus

S. pyogenes - mostly human
S. agalactiae - mastitis
S. dysgalactiae - mastitis
S. equi subsp. equi - strangels in horses
S. equi subsp. zooepidemicus

34

The two Streptococcus that are pyogenic bacteria are?

S. pneumonia
S. equi subsp. equi

35

Streptococcus pyogenic bacteria have?

Capsule - non antigenic but interferes with phagocytosis

36

Streptococcus have homolysins. What are homolysins?

Production of a wide variety of toxins capable of destroying erythrocytes, resulting in a clear area surrounding colonies.

37

What is Lancefield groups?

Serological classification of Streptococcus based CHO cell wall antigens.

38

The most important groupable streptococci are?

A,B and D

39

Groupable Streptococcus, infectious disease group A include?

S. pyogenes - scarlet fever in humans
S. pneumoniae
S. mutans

40

Gram-positive rods can be classified into what two groups?

Endospore- forming and non endospore- forming

41

Give examples of Gram-pos rods that are endospore forming.

Bacillus
Clostridium

42

What was the first bacterium shown to cause disease?

Bacillus anthracis

43

Bacillus anthracis is commonly known as?

Anthrax - serious, often fatal zoonotic disease of wild and domestic mammals

44

Bacillus is a?

Obligate aerobe that is a edospore producing gram-pos rod

45

Bacillus anthracis's virulence factors include?

Endospores
Capsule
Exotocins

46

Despite Bacillus anthracis's exotocins being 3 heat labile protein components it is still a?

A-B toxin

47

Horizontal gene transfer of the virulent strains in plasmids of Bacillus anthracis was done by?

Conjunction

48

Virulent strains of Bacillus anthracis harbor two plasmids, what are they

PXO1 -codes for the toxin (EF, PA, LF)
PXO2 -condes for the Capsule- (Poly D glutamic acid capsule)

49

Bacillus anthracis causes?

Spleenomegaly

50

T:F You should never open a animal that is thought to have Bacillus anthracis infection?

True
The spores can spread to you or other animals.

51

Which parts of the protein belong to parts of the A-B toxin?

Lethal factor and edema factor enzymes are Part A
Protective antigen binding is Part B

52

What are the ways humans can become infected with Bacillus anthracis?

Cutaneous - direct contact with disease animals
Inhalation - Woolsorter's disease
Ingestion - meat from diseased animals

53

Clostridium is a?

Obligate anaerobe

54

What are the four groups that Clostridium can be divided into according to what disease they produce.

Histotoxic Clostridia
Hepatotoxic Clostridia
Enterotoxigenic Clostridia
Neurotoxic Clostridia

55

Clostridium that cause tissue infections (mostly muscle) following wounds, other trauma eg Malignant edema

Histotoxic Clostridia

56

Hepatotoxic Clostridia

Clostridium that produces toxins in the liver (cause bacillary hemogleobinuria and black disease)

57

Clostridium that produces mainly enterotoxemia and food poisoning.

Enterotoxigenic Clostridia

58

Neurotoxic Clostridia

Clostridium that causes disease by production of potent exotosins (neurotoxins) of tetanus and botulism (not food botulism)

59

What are the Histotoxic and invasice clostridium species?

C. chauvoei (black leg)
C. septicum (malignant edema and braxy)
C. novyi (Types A, B, C- gas gangrene, black disease, ost)
C. perfringens (gas gangrene)

60

C. perfringens (gas gangrene)

Gangrenous and emphysematous myositis. Caused wound colonization after soil, and to a lesser extent intestinal tract, contamination. Primarily seen in times of war as a result of non-sterile field hospitals and projectile wounds. The term gas gangrene refers to swelling of tissues due to release of gas, as fermentation products of clostridia

61

What are the Neurotoxic Clostridium species?

C. tetani - TeNT - tetanus (exotoxin tentanopasmin, AB toxin)
C. botulinum - BoNT

62

What are some of the disease caused by Neurotoxic Clostridium botulinum?

Food- borne botulism (not infection but an intoxication)
Infant botulism (non pasteurized honey)
Wound botulism (wound infection)
Botox related botulism

63

Clostridium botulinum in animals food related.

Flaccid paralysis. Not an infection but a intoxication. Animals ingesting large amounts of toxins. Eg. dead fish or grass with lots of toxins.

64

Clostridium botulinum characteristics?

Multiply in dead carcass and produce toxin.
Eating spoiled foods in which the toxin has been produced under anaerobic conditions.
Different types of toxin (A-G) preference in what they attack.
Neurotoxin: heat-labile protein - destroyed when food is cooked properly

65

Clostridium tetani

Spastic paralysis originates from trauma, surgical wound, puncture. Tetanus (Locked jaw or wooden horse). Commonly found in the soil, dust and animal feces. Anaerobic conditions

66

What are the same about Neurotoxins - BoNT & TeNT?

Same mode of action: bind to neuromuscular junctions. Cleaves synaptobrevin and prevent release of neurotransmitter acetylcholine.

67

What are the different about Neurotoxins - BoNT & TeNT?

Different site of action: BoNT-peripheral neurons- flaccid paralysis. TeNT - central nervous system- spastic paralysis.

68

What are the two Enterotoxigenic Clostridium

C. perfringens
C. difficile

69

What is the only gram negative Clostridium?

Atypical Clostridium pilliforme

70

What is Clostridium pilliforme

It is a an atypical obligate intracellular pathogen that causes Tyzzer disease and colitis in rodents, rabbits and horses.