Salmonella

Question 1

What are the two possible modes of transmission of Salmonella?

Answer 1

Fecal-oral

Respiratory route

Question 2

What are the three possible manifestations of a Salmonella infection?

Answer 2

Enteritis resulting in diarrhea

Septicemia

Nothing!

Question 3

Name the host-adapted strain of Salmonella which is ONLY seen in humans

Answer 3

Salmonella typhi

Question 4

How do is typhoid (disease of Salmonella typhi) transmitted?

Answer 4

Fecal-oral

Mostly a water-borne infection in the developing world

Question 5

In older human women what disease is generally associated with infection of Salmonella typhi?

Answer 5

Biliary diseases (cholecystitis and cholelithiasis)

Disease is characterized by septicemia and enteritis whereby the biliary tract is persistently seeded

Question 6

What is the Salmonella which is generally associated with swine?

This Salmonella contains a host-restricted and host-adapted strain which is which?

Answer 6

Salmonella choleraesuis kunzendorf variety

Host-restricted: Salmonella choleraesuis kunzendorf variety

Host-adapted: Salmonella choleraesuis non-kunzendorf variety

Question 7

What diseases are generally seen with Salmonella choleraesuis kunzendorf variety?

Answer 7

Respiratory disease

Button ulcers of the intestines (see photo)

Question 8

What is the host-adapted strain of Salmonella found in cattle?

Answer 8

Salmonella dublin

Question 9

What clinical signs are associated with Salmonella dublin?

Answer 9

Septicemia and enteritis (pseudomembranosis colitis) (leading to hemorrhagic enterocolitis)

Question 10

What are the HOST-ADAPTED strains of Salmonella found in poultry?

Answer 10

• Salmonella gallinarum*
• Salmonella anatum*
• Salmonella arizonae*

Question 11

What is the HOST-RESTRICTED strain of Salmonella found in chickens?

Answer 11

Salmonella pullorum

Question 12

What clinical sign can be seen with an avian infected with Salmonella pullorum?

Answer 12

Bacillary white diarrhea

Question 13

What clinical sign can be seen with an avian infected with Salmonella gallinarum?

Answer 13

Fowl typhoid

Question 14

What clinical sign can be seen with an avian infected with Salmonella anatum?

Answer 14

Keel disease in ducklings

Question 15

What clinical sign can be seen with an avian infected with Salmonella arizonae?

Answer 15

Septicemia

Question 16

Salmonella can be found in the normal flora of what species

Answer 16

Reptiles (esp. turtles)

This is the reason pet stores cannot cell turtles under certain sizes for fear of children placing them in their mouths

Question 17

Host specificity of Salmonella occurs because of two reasons what are they?

Answer 17

Adherence of Salmonella to host epithelial cells

Ability of Salmonella to survive inside macrophages

Question 18

What Salmonella is the most common cause of salmonellosis in mammalian hosts

Answer 18

Salmonella typhimurium

Question 19

_________ is with in the normal gut flora of poultry so is allowed in small numbers in USDA inspection of poultry. But is not allowed during inspection of other meats (beef, pork)

Answer 19

Salmonella typhimurium

Question 20

What is a Strain DT104 Salmonella?

Answer 20

A multiple antibiotic resistant gene which has been inserted into Salmonella

Which was acquired by a phage through one INTEGRON

Question 21

Why is Salmonella Strain DT104 more virulent in cattle?

Answer 21

Because of the integron associated multiple antibiotic resistance as well as, the protozoa within the rumen which help select for more the more virulent Salmonella leading to reduced competition for binding sites.

Question 22

What serovars has strain DT104 been found in?

Answer 22

• Salmonella typhimurium*
• Salmonella choleraesuis*

Question 23

1. What is the broad range Salmonella which is the second most common serotype isolated from human cases?
2. How is it contracted?

Answer 23

1. Salmonella enteritidis It is within the normal flora of chickens and resides inside the ova.
2. It is contracted by the consumption of raw or undercooked eggs

Question 24

What are the three mechanisms of Salmonella virulence?

Answer 24

Intestinal colonization

Invasion of intestinal cells

Diarrhea

Question 25

What cell type do Salmonella prefer to adhere to and why?

Answer 25

M cells They prefer M cells because they contain shorter and less dense glycocalyx and do enterocytes. Think of the parachuting into the forest analogy

Question 26

Briefly explain Salmonella's mechanism invasion of intestinal cells

Answer 26

Salmonella attach to the outside of M cells --\> they then release bacterial proteins --\> these proteins rearrange actin w/in the plasma membrane --\> invasion of the plasma membrane by Salmonella

Question 27

True or False ## Footnote Salmonella are not able to invade plant cells because of the lignin within in the cell wall prevents bacterial rearrangement and subsequent entry

Answer 27

False! ## Footnote Salmonella can also invade plant cells and form a “ruffle” after the rearrangement of actin. They then will reside within a plant cell and await ingestion by a mammal or bird

Question 28

Briefly explain how Salmonella causes diarrhea

Answer 28

Salmonella attach to the outside of M cells --\> they then release bacterial proteins --\> these proteins cause inflammatory process to occur within the cell and results in fluid and electrolyte loss

Question 29

How do normal flora help in the prevention of salmonellosis?

Answer 29

Normal flora compete for receptor binding sites Normal flora also produce compounds which inhibit/kill Salmonella

Question 30

List the ways one can diagnose Salmonella

Answer 30

Fecal culture for enteritis Spleen culture for septicemia Immunodiagnostics (serogrouping and serotyping)

Question 31

Diagnosing a Salmonella serovar using immunodiagnostics serogrouping is based upon what part of the Salmonella?

Answer 31

The O-antigens on the surface

Question 32

Diagnosing a Salmonella serovar using immunodiagnostics serotyping is based upon what part of the Salmonella?

Answer 32

The H antigen flagellar

Question 33

Define a monophasic and diphasic H antigen

Answer 33

Monophasic H antigen can either have phase 1 OR phase 2 flagellins Diphasic H antigen can make BOTH phase 1 and phase 2 flagellins

Question 34

Immunity to *Salmonella* is mostly ______ and is generally \_\_\_\_\_\_

Answer 34

Immunity to *Salmonella* is mostly **CMI** and is generally **LIFELONG**

Question 35

What does SRP stand for and how do these vaccines act?

Answer 35

Siderophore receptor protein (SRP) vaccine. Act by causing antibodies to be made against SRP. Resulting in an anamnestic response during infection which **STOPS THE IRON INTAKE into *Salmonella*.** Leading to the death of the Salmonella.

Question 36

Why are killed bacterins not as effective against Salmonella?

Answer 36

They generally do not elicit a CMI response and the epitopes are usually the O antigens. The O antigens are serogroup-specific leading these killed bacterins bacterins to be monovalent. Salmonella can also readily shed its O antigens if needed removing the Ab against them.

Question 37

List two other preventative methods besides vaccination which may be effective against salmonellosis

Answer 37

LPS toxoid Defaunation (elimination of rumen parasites) Extra note: Sanitation and improved management practices are also very effective as preventative measures

Question 38

Name when antibiotic treatment against *Salmonella* is warranted. What treatment would one use in each case?

Answer 38

Cases of enteritis and systemic infection. **Enteritis-** know which antibiotic is susceptible and treat with that antibiotic **Systemic infection-** treat with Ceftiofur intravenously

Question 39

In what instances are virulence genes for Salmonella hyperactivated?

Answer 39

At microgravity