Robbins 9th ed - Chapter 8 - Infectious Disease - Bacteria (1)

Question 1

Name the infectious agent causing anthrax. Describe the key distinguishing features of it.

Answer 1

Bacillus anthracis is a large, spore-forming, gram positive, rod-shaped bacterium.

Question 2

How is anthrax spread?

Answer 2

Spores in contaminated livestock are spread amongst humans by contact with contaminated meat. This can be by handling, inhaling, or eating the spores.

Question 3

Name three types of patients that are more common victims of Pseudomonas infection.

Answer 3

Cystic Fibrosis - respiratory Pseudomonas
Burns - burns infected with Pseudomonas –> sepsis
Neutropaenia

Question 4

What is the key difference in the clinical signs of a patient with Clostridium tetani and a patient with Clostridium botulinum infection?

Answer 4

Clostridium tetani - spastic paralysis

Clostridium botulinum - flaccid paralysis

Question 5

What is trismus?

Answer 5

Lockjaw (spasm of the jaw muscles).

Question 6

Describe the key distinguishing features of all Clostridium species.

Answer 6

Gram positive, anaerobic, spore-forming bacilli.

Question 7

What is the name of the GIT infection caused by Clostridium difficile?

Answer 7

Pseudomembranous colitis.

Question 8

Name the two clinically significant Neisseria species.

Answer 8

N. meningitidis

N. gonnorhoea

Question 9

Describe the key distinguishing features of Neisseria species.

Answer 9

Gram negative diplococci.

Question 10

What is the infectious agent causing Scarlet fever? What is Scarlet fever?

Answer 10

Group A Streptococci (Strep pyogenes). Scarlet fever is an erythematous rash associated with Strep pharyngitis, most commonly in the age range 3-15 years.

Question 11

Name two diseases that can be caused either by Staph aureus or by Strep pyogenes.

Answer 11

Impetigo (“school sores”).

Toxic Shock Syndrome.

Question 12

What is clumping factor?

Answer 12

This is a surface feature of Staphylococcal species that allows them to bind fibrinogen and thereby bind to host endothelial cells.

Question 13

Which gram positive bacteria form clusters like grapes?

Answer 13

Staphylococci (“staphyl” = Greek word for grape). Streptococci form chains.

Question 14

What does Campylobacter Jejuni infection cause? How is it transmitted?

Answer 14

Campylobacter jejuni is the most common bacterial enteric pathogen in developed countries. It causes traveller’s diarrhoea. It is transmitted by contaminated water, chicken and milk.

Question 15

Name the virulence factors of campylobacter jejuni.

Answer 15

Motility (with a flagellum), Adherence, Toxin production, Invasion.

Question 16

Name two extra-intestinal manifestations of campylobacter jejuni infection.

Answer 16

Guillain Barre Syndrome.

Arthritis.

Question 17

Give three defining features of Shigella.

Answer 17

Non-encapsulated, Non-motile, Facultative Anaerobes.

Question 18

Describe the pathogenesis of salmonellosis.

Answer 18

Salmonella are gram-negative, flagellated bacilli. Salmonella enteritidis and Salmonella typhimurium invade the intestinal epithelium, and cause gut wall inflammation.

Question 19

Which of the four different malarial species causes the most severe form of malaria?

Answer 19

Plasmodium falciparum.

Question 20

Name two cell types in the human body that are infected by malarial parasites.

Answer 20

Hepatocytes and RBCs.

Question 21

What is the molecular effect of the toxin of Clostridium tetani?

Answer 21

It blocks the release of GABA from neurons.

Question 22

What is the molecular effect of the toxin of Clostridium botulinum?

Answer 22

It blocks the release of ACh at the neuromuscular junction.

Question 23

Name the different types of E.Coli

Answer 23

Enteroinvasive E.Coli
Enterohaemorrhagic E.Coli
Enterotoxic E.Coli
Enteroaggregative E.Coli