Family Enterobacteriaceae general, E. Coli, Genus Shigella

Question 1

Name the antigens which are common features of all the Enterobacteriaceae family bacteria.

Answer 1

O-Antigen: O Ag side chains

H-Antigen: Flagella

K-Antigen: Capsule

F-Antigen: Fimbriae

P-Antigen: Pilus

Question 2

Why is the family Enterobacteriaceae named this way?

Answer 2

Name is after the most common site where the bacteria are found

Question 3

Family Enterobacteriaceae are commonly found within the normal flora of the intestines in most mammals and birds except for a couple species and one genus of birds. Can you name them?

Answer 3

Not found in rabbits, guinea pigs, and psittacine birds

Question 4

Name the four possible modes of transmission of family Enterobacteriaceae bacteria.

Answer 4

Ingestion (fecal-oral)

Respiratory route

Vectors (fleas, ticks, rats, etc.)

Fomites even

Question 5

Name the general morphology of Family Enterobacteriaceae bacteria including: its gram stain, oxidase results, and shape.

Answer 5

Gram negative bacteria, all are oxidase (-), medium-sized rods (exception is the bubonic plague), and have peritrichous flagella In addition they may contain capsules, many have fimbriae for attachment factors

Question 6

How resistant are Family Enterobacteriaceae bacteria to pasteurization, disinfectants, drying, and cold?

Answer 6

Pasteurization: Most are killed

Disinfectant: Most are readily killed

Drying: Not very resistant

Cold: Most survive

Question 7

Treatment of a bacteria from the Family Enterobacteriaceae should include what prior to decision on antibiotic?

Answer 7

A sensitivity test because a given isolate can be resistant to many different antimicrobials . Extensive drug resistant (XDR); Multi-Drug Resistant (MDR), and Pandrug Resistant isolates of some have become a serious problem

Question 8

In looking at a glucose tube, a lactose tube, a SIM tube and a lysine decarboxylase tube (LIA tube). What biochemically is indicative of Escherichia coli?

Answer 8

Acid and gas from glucose Most ferment lactose Indole positive Decarboxylates lysine

Question 9

List the toxins which are produced by Escherichia coli?

Answer 9

Endotoxins

• Major role in systemic disease

Shiga-toxin (Vasotoxin) important in both human and animal disease

Alpha hemolysin

• Member of the RTX toxin
  
  • Important for human extraintestinal infections Beta hemolysin similar to alpha hemolysin with cleaved C-terminal AA

Question 10

What is the commonly used name describing infections of Escherichia coli?

Answer 10

Colibacillosis

Question 11

In pigs what age group is most likely effected?

Answer 11

Neonates (approximately 1-4 days old)

Question 12

Identify a significant factor why Escherichia coli attach more readily on neonatal intestines

Answer 12

No flora normally found in the small intestine at birth

Question 13

Upon invasion of Escherichia coli. What does the bacteria do?

Answer 13

After invasion it can cause septicemia. As well as, express enterotoxins –> a locall effect ETEC (enterotoxiogenic E. Coli)

Question 14

What are the major toxins involved with the disease colibacillosis?

Answer 14

Labile toxin (LT)

Stable toxin (ST)

Question 15

What is the differences between Labile toxin (LT) and Stable toxin (ST) toxins?

Answer 15

Labile toxin (LT) is heat labile and Stable toxin is heat stable

Question 16

What is the mechanism of action of the Labile toxin (LT) on Escherichia coli

Answer 16

LT is an A-B structure toxin and acts by ADP-ribosylates a Gs alpha protein leading to the activation of adenylate cyclase –> Increase cAMP –> excretion of Cl- and inhibition of Na+ absorption –> excessive fluid loss

Question 17

What pathogen toxin is “Traveler’s diarrhea” linked to?

Answer 17

The labile toxin (LT)

Question 18

What are the two types of stable toxin (ST)? Why do these types not stimulate the immune system?

Answer 18

STa and STb Because they are too small to be immunogenic

Question 19

1. How does the Stable toxin a (STa) act?
2. What age group of pigs are most-likely to be effected?

Answer 19

1. It stimulates guanylate cyclase–> the stimulation of the intracellular production of cyclic GMP. This leads to a downstream effect of pathways leading to loss of water and electrolytes from the intestinal mucosa.
2. Neonatal diarrhea in pigs.

Question 20

1. How does the the Stable toxin b (STb) act?
2. What age group of pigs are most-likely to be effected?

Answer 20

1. STb bind to sulfatide on cell surfaces and is internalized–> cascade of events resulting in the opening of ion channels through which ions and water are lost.
2. Post-weaned pigs

Question 21

What are treatment options for Escherichia coli?

Answer 21

Antibiotic can be useful.

However, one generally tries to prevent with vaccination and management.

Question 22

Has vaccination for Escherichia coli been shown to be effective?

Answer 22

Yes, vaccinations have led to marked decrease in morbidity and mortality.

Question 23

What are the leading causes of Escherichia coli post-weaning diarrhea?

Answer 23

Change in feeding and stress

Question 24

Explain Escherichia coli edema disease

Answer 24

A disease which effects healthy pigs primarily. Disease is caused by elaboration of Vasotoxin. Vasotoxin inhibits protein synthesis of endothelium and–> edema and necrosis

Question 25

What organ is most susceptible in Escherichia coli edema disease in swine?

Answer 25

The brain This often leads to the neurological signs or found dead of pigs

Question 26

1. Cattle colibacillosis is generally caused by what toxin? 2. What clinical signs result in this disease?

Answer 26

1. The STa toxin 2. White scours in calves

Question 27

1. Lamb colibacillosis is generally caused by what toxin? 2. What clinical signs result in this disease?

Answer 27

1. The STa toxin 2. Septicemia, watery-mouth or fettle belly

Question 28

1. How are poultry generally infected by Escherichia coli? 2. What clinical signs result in this disease?

Answer 28

1. Dust containing fecal E. coli infect. 2. Respiratory infection: Airsacculitis, acute septicemia, pericarditis, peritonitis, fibrinopurulent serositis and granulomatous lesions of the intestine

Question 29

What is of primary concern when one is treating rabbits and guinea-pigs with antibiotics?

Answer 29

Knocking out large gram-positive bacteria enabling gram-negative takeover.

Question 30

List three other diseases in animals associated with Escherichia coli

Answer 30

**Pyometra in canines** (ONLY ORGANISM WHICH CAUSES THIS) **Mastitis (dairy cattle, sows)** MOST IMPORTANT OF THE G(-)’s Diarrhea in most any animals Cause umbilical infections (pigs, calves, horses) Urinary tract infections Metritis (esp. in dairy cattle)

Question 31

In human's Escherichia coli is the most common bacteria found in what disease?

Answer 31

Urinary tract infections

Question 32

What is the immunity status for Escherichia coli?

Answer 32

Immune competence develops with age against the diarrheal disease However, other than that immune response is generally poor due to large numbers of somatic (o) antigens.

Question 33

In immunizing a sow or cow for bacteria what type of bacterin has shown to be effective in protecting their offspring?

Answer 33

A fimbrial bacterin

Question 34

Shiga toxin producing Escherichia coli are of HUGE importance to human health. The O157:H7 strain is associated with this toxin. What are the clinical signs can a Escherichia coli bacteria with this toxin cause

Answer 34

Diarrhea Hemorrhagic colitis Hemolytic uremic syndrome (HUS)