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Flashcards in Lecture 8 Deck (52):
1

Define Cl Tetani

a soil dwelling saprophytic organism- spores wide spread in soil- slender thin rods with tennis racket appearance

2

Portal of entry for Cl tetani

skin-through wound-like nail prick, road accidents where there is contamination of mud, skin popping in drug addicts

3

WHat does Cl tetani cause?

Tetanus- lock jaw

4

Can Cl tetani cause infection in newborns?

can occur through umbilical cord cutting, through circumcision in developing countries-- spores germinate at the wound

5

What do vegetative cells of Cl Tetani produce?

exotoxin which spreads through nerve fibers to spinal cord

6

What does exotoxin block release of?

glycine- inhibitory neurotransmitter- in spinal synapse causing muscle spasms (tetany)

7

Is vaccine effective for Cl Tetani?

YES- because only one Ag variety (sero type)

8

How is Tetanus defined?

characterized by spasm of skeletal muscles starting from face, hardening of facial muscles results in grim face

9

What is the hardening of facial muscles in Cl Tetani known as

Risus sardonicus

10

What is spasm of muscles of mastification from Cl Tetani lead to?

Lock Jaw known as trismus

11

What does spasming of back muscles result in?

Arching of back known as Opisthotonus

12

What type of poisoning resembles the condition of Cl Tetanis

strychnine poisoning

13

How do you treat tetanus?

Tetanus antitoxin serum to neutralize unbound toxins, penicillin and metronidazole may be useful- maintain adequate airway, muscle relaxants like valium

14

How do you prevent tetanus?

toxoid vaccine (DTaP) is available

15

What is the natural habitat of Cl Botulinum?

soil- spores are found in soil, found in contaminated vegetables, alkaline vegetables, spores germinate in anaerobic conditions

16

What is an indication that bacteria may be growing in canned vegetables?

swollen/bloated can tins

17

How do you get the Cl Botulinum toxins?

ingested- absorbed from gut and carried to neuromuscular junction

18

What does Cl Botulinum cause in a person and how?

flaccid paralysis- blocks release of acetylcholine- can cause paralysis of ocular muscles causing vision problems- respiratory failure when pharyngeal muscles are relaxed

19

Will Cl Botulinum present with a fever?

NO

20

Can an infant get Cl Botulinum?

yes- contaminated honey- spores germinate in gut and cause silent death of an infant

21

Treatment for Cl Botulinum?

Trivalent antitoxin available- antitoxin made from horses and given with respiratory support

22

Prevention of Cl Botulinum

The tosin is relatively heat labile so boiling vegetables/food will inactivate toxins

23

What are some medical uses of Cl Botulinum?

to remove wrinkles on forehead or to relieve spastic torticollis (wry neck)

24

Describe Cl Perfringens

Gram + rod shaped, anaerobic spore forming bacterium

25

What 2 diseases can Cl Perfringens cause?

Gas gangrene and food poisoning

26

Describe gas gangrene

vegetable forms are members of normal flora of colon and vagina- spores are found in soil

27

Most common mode of contamination of Gas gangrene

wound contamination with soil/mud (war wounds, automobile accidents, septic abortion

28

How is the gas gangrene produced?

organism grows in traumatized tissues, produced alpha toxin which causes necrosis of muscle and RB cells and enzyme degradation produces gas in tissues

29

Results of Gas gangrene

pain, edema and cellulitis, crepitations, massive hemolysis, jaundice, renal failure, shock and death - high mortality rate

30

Treatment for gas gangrene

Penicillin G- wound should be derided- surgical amputation if necessary

31

How is Cl perfringens seen in colonies on agar plates?

culture grown in anaerobic conditions and produces double zone of hemolysis

32

Explain food poisoning from Cl perfringens

spores contaminated food- heat resistant and grow in large numbers in reheated meat dishes

33

Explain mode of food poisoning from Cl perfringens

After ingestion, sporulation occurs in gut and enterotoxin is liberated causing diarrhea

34

Treatment of food poisoning

symptomatic- ends with time

35

What is the most common nosocomial infection?

Cl difficile

36

What does Cl difficile cause?

antibiotic associated pseudo membranous colitis

37

How is Cl difficile transmitted?

by fecal-oral route

38

Explain mode of infection of Cl difficile

antibiotics suppress normal flora allowing organism to over grow

39

Clinical manifestations of Cl difficile

it causes non bloody diarrhea, yellow white plaques in the colon visible by sigmoidoscopy

40

Treatment of Cl difficile

causative agent should be stopped, metronidazole and fluid replacement

41

Define toxic megacolon

paralysis of one segment of the colon- rare complication which may need surgical resection

42

Describe Corneybacterium Diptheriae

bacteria is club shaped, arranged in V or L forms, beaded appearance with granules- non motile (Chinese letter formation)

43

What is the source for Diptheriae?

humans are the only source

44

How is Diptheriae transmitted?

air born droplets

45

How does Diptheriae cause damage?

the organism produces an exotoxin, which causes damage to eukaryotic cell- any tissue can be affected

46

What disease does Corneybact. diphtheria cause?

Diptheria- local inflammation with fibrinous exudates that form tough, adherent, greyish white psuedomembrane over throat and tonsils, fever, sore throat, bulls neck

47

3 major complications caused by Diptheria

1. extension of membrane in larynx and trachea causing airway obstruction 2. myocarditis with arrhythmias and circulatory collapse 3. nerve paralysis (especially cranial)

48

Treatment for Diptheria

administration of antitoxin to neutralize unbound toxins, penicillin G and erythromycin, tracheostomy may be necessary , DPT vaccine

49

Define lysteria monocytogens

causes sepsis and meningitis in new borns as well as immunosupressed individuals (renal transplant)- present on animals, plants, soil, mainly food born infection

50

What does lysteria monocytogens cause?

abortion/premature delivery in pregnant women/flu/watery diarrhea symptoms

51

Can lysteria monocytogens affect babies?

YES- crosses over placenta and produces neonatal sepsis

52

treatment for lysteria monocytogens

ampicillin, gentamycin, trimethoprim and sulfamethoxazole