Lecture 8

Question 1

Define Cl Tetani

Answer 1

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

Question 2

Portal of entry for Cl tetani

Answer 2

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

Question 3

WHat does Cl tetani cause?

Answer 3

Tetanus- lock jaw

Question 4

Can Cl tetani cause infection in newborns?

Answer 4

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

Question 5

What do vegetative cells of Cl Tetani produce?

Answer 5

exotoxin which spreads through nerve fibers to spinal cord

Question 6

What does exotoxin block release of?

Answer 6

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

Question 7

Is vaccine effective for Cl Tetani?

Answer 7

YES- because only one Ag variety (sero type)

Question 8

How is Tetanus defined?

Answer 8

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

Question 9

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

Answer 9

Risus sardonicus

Question 10

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

Answer 10

Lock Jaw known as trismus

Question 11

What does spasming of back muscles result in?

Answer 11

Arching of back known as Opisthotonus

Question 12

What type of poisoning resembles the condition of Cl Tetanis

Answer 12

strychnine poisoning

Question 13

How do you treat tetanus?

Answer 13

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

Question 14

How do you prevent tetanus?

Answer 14

toxoid vaccine (DTaP) is available

Question 15

What is the natural habitat of Cl Botulinum?

Answer 15

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

Question 16

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

Answer 16

swollen/bloated can tins

Question 17

How do you get the Cl Botulinum toxins?

Answer 17

ingested- absorbed from gut and carried to neuromuscular junction

Question 18

What does Cl Botulinum cause in a person and how?

Answer 18

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

Question 19

Will Cl Botulinum present with a fever?

Answer 19

NO

Question 20

Can an infant get Cl Botulinum?

Answer 20

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

Question 21

Treatment for Cl Botulinum?

Answer 21

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

Question 22

Prevention of Cl Botulinum

Answer 22

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

Question 23

What are some medical uses of Cl Botulinum?

Answer 23

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

Question 24

Describe Cl Perfringens

Answer 24

Gram + rod shaped, anaerobic spore forming bacterium

Question 25

What 2 diseases can Cl Perfringens cause?

Answer 25

Gas gangrene and food poisoning

Question 26

Describe gas gangrene

Answer 26

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

Question 27

Most common mode of contamination of Gas gangrene

Answer 27

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

Question 28

How is the gas gangrene produced?

Answer 28

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

Question 29

Results of Gas gangrene

Answer 29

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

Question 30

Treatment for gas gangrene

Answer 30

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

Question 31

How is Cl perfringens seen in colonies on agar plates?

Answer 31

culture grown in anaerobic conditions and produces double zone of hemolysis

Question 32

Explain food poisoning from Cl perfringens

Answer 32

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

Question 33

Explain mode of food poisoning from Cl perfringens

Answer 33

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

Question 34

Treatment of food poisoning

Answer 34

symptomatic- ends with time

Question 35

What is the most common nosocomial infection?

Answer 35

Cl difficile

Question 36

What does Cl difficile cause?

Answer 36

antibiotic associated pseudo membranous colitis

Question 37

How is Cl difficile transmitted?

Answer 37

by fecal-oral route

Question 38

Explain mode of infection of Cl difficile

Answer 38

antibiotics suppress normal flora allowing organism to over grow

Question 39

Clinical manifestations of Cl difficile

Answer 39

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

Question 40

Treatment of Cl difficile

Answer 40

causative agent should be stopped, metronidazole and fluid replacement

Question 41

Define toxic megacolon

Answer 41

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

Question 42

Describe Corneybacterium Diptheriae

Answer 42

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

Question 43

What is the source for Diptheriae?

Answer 43

humans are the only source

Question 44

How is Diptheriae transmitted?

Answer 44

air born droplets

Question 45

How does Diptheriae cause damage?

Answer 45

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

Question 46

What disease does Corneybact. diphtheria cause?

Answer 46

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

Question 47

3 major complications caused by Diptheria

Answer 47

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

Question 48

Treatment for Diptheria

Answer 48

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

Question 49

Define lysteria monocytogens

Answer 49

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

Question 50

What does lysteria monocytogens cause?

Answer 50

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

Question 51

Can lysteria monocytogens affect babies?

Answer 51

YES- crosses over placenta and produces neonatal sepsis

Question 52

treatment for lysteria monocytogens

Answer 52

ampicillin, gentamycin, trimethoprim and sulfamethoxazole