Shigella and Salmonella

What are the FOUR spp of Shigella?

S. dysenteriae

S. flexneri

S. boydii

S. sonnei

Shigella is host restricted to what TWO species?

human

higher primates

What disease does Shigella casue?

hemorrhagic dysentery

T/F Shigella is invasive

True

S. dysenteriae is source of ____ -____ encoding phage found in enterohemorrhagic E. coli

shiga toxin

Salmonella was isolated the bacterium ____ ___ ____ from a pig suffering from hog choera

Bacillus cholera-suis

What is the new name of Bacillus cholera-suis?

Salmonella cholerasuis

Salmonella enterica contains how many subspecies?

6

•Salmonella enterica subspecies enterica comprises over ___ serovars

2600

How many phases of antigens are there and what are the antigens?

two

O, H, and Vi-antigens

The top Salmonella serotypes are associated with what?

human foodborne infections

T/F Most of the Salmonella data is from the human side of things

True

AS of 2022, what were the top serotypes of Salmonella? (i am sorry)

•Sal. Enteritidis, Sal. Typhimurium, Sal. Newport, Sal. Javiana, Sal. 1,4,[5],12:i:-

(WTF is that)

What does the O antigen do and what is it associated with?

•Protects from antibiotics and bile salts

Lipopolysaccharide (LPS)

What is the TWO things that H antigen does?

•Motility

Phase Inversion Expression

What is the other name for the H antigen?

Flagella

What does the Phase Inversion Expression promote?

Promoter of gene flips for phase 2 repression and phase 1 expression

What is the other name for Vi Antigen?

Capsule

What does the Vi antigen increase?

What does it reduce?

resistance to complement

phagocytic killing (via protection of reactive oxygen)

What pathway does the Vi antigen interferes with?

pathogen-associated molecular pattern (PAMP) activation of the innate immune system

What are the TWO pathogenesis that Salmonella can go through?

Non-Typhoidal Pathogenesis

Typhoidal Pathogenesis

What is the driver for Non-Typhoidal Salmonella?

inflammation

What does Typhoidal Salmonella do?

Down regulates immune response to avoid immune system

T/F Invasion and intracellular survival enables Salmonella to efficiently invade the host’s intestinal epithelial cells and persist within Salmonella-containing vacuoles

True

What are are believed to be caused by Salmonella biofilm formation on gallstones and/or intercellular survival of the lining of gallbladder?

Persistent shedders

T/F Salmonella has a broad host range, host adapted and host specific

True

Salmonella are _____ that infect and cause disease in a wide range of host species and exhibit what is characterized as non-typhoidal disease

serovars

What are some of the clinical signs you would expect to see in Broad host range?

•diarrhea, nausea, vomiting, intestinal cramping, and fever

T/F Broad host range seortypes cause self-limiting, with acute gastroenteritis, and watery diarrhea

True

What are the FIVE broad host range Salmonella ? Which one causes typhoid disease?

Sal. Typhimurium, Sal. Enteritidis, Sal. Newport, Sal. Infantis, Sal. Kentucky

Sal. Typhimurium

Name the range based on the description below:

•a narrow host range with the ability to disseminate beyond the gastrointestinal tract, colonize systemic sites, persist systemically for long periods, possibly cause persistent asymptomatic infections, and often are vertically transmitted in their preferred hosts

Host Adapted

T/F With host-adapted Salmonella, non-preferred host usually exhibits subclinical infections

True

What are the TWO Host-adapted Salmonella?

Sal. Dublin (cattle), Sal. Cholerasuis (pigs)

Match the Host Range to the description:

Salmonella has a very narrow host range (usually one specific host species) and causes typhoid or typhoid-like disease

Host specific

Match the host to the Salmonella:

Sal. Typhi:

Sal. Gallinarum:

Sal. Abortusovis:

Sal. Typhisuis:

Sal. Abortusequi:

humans and higher primates

horses

pigs

poultry

sheep

Sal. Typhi: humans and higher primates

Sal. Gallinarum: poultry

Sal. Abortusovis: sheep

Sal. Typhisuis: pigs

Sal. Abortusequi: horses

•Fourth highest bacterial pathogen associated with hospital-acquired infections (HAIs; human and veterinary) at what?

15% of reported HAIs.

___ ____ pose risk for nosocomial infections and zoonotic infections

Asymptomatic shedders

What was the prevalence of Salmonella in dogs?

5

•30% of the dogs shed Salmonella after consuming a bone and ___-____ ____

raw-food diet

•Studies shown a prevalence of 20% to 48.7% of ____ ____ have at least one ___ positive for Salmonella

dairy farms

cow

Slide 15 look at it

okay fine (im not)

What are the TWO ways that Sal Dublin is transmitted?

Horizontal Transmission

Vertical Transmission

Give me examples of Horizontal Transmission and Vertical Transmission

Horizontal Transmission

•Feces, animal-to-animal, animal contact

Vertical Transmission

•Intra-uterine transmission

•Most of the time causes abortions

•Milk

What is the THREE primary transmission of Salmonella?

Fecal oral

Ingestion of contaminated water

Fomites

What are the subclinical signs of Salmonella? (3)

decreased weight gain, decreased milk production, sterility

You have a cow that comes in and it has Fever, poor appetite, diarrhea (bloody or mucoid), vomiting, abdominal pain, sepsis, abortion.

What would you classify this as and what do you think caused it?

Gastroenteritidis

Salmonella (duh....)

What are some of the extra-intestinal infections that Salmonella can cause?

Bacteremia, Sepsis, abortion, localized infections (bone/joint infection), infection of mammary tissue (mastitis, abcess, or milk contamination), ovaries

check out slide 20

;)

You have a pig that comes in with cyanosis,

severe gastritis and ulcers are observed in the gastric mucosa, as well as severe colitis with particularly reddened colon mucosa. (YIKES).

What spp of Salmonella do you think the pig has?

Salmonella Choleraesuis

What animals would you look at the mesenteric lymph nodes to see if they're swollen with regards to Salmonella?

Dairy Calves

What other things can happen in dairy calves infected with Salmonella?

-gallbladder is distended and contains bile admixed with abundant fibrin

- spleen is enlarged and there is yellow discoloration of the omentum, serosal surfaces of the forestomachs and adipose tissue (jaundice).

-urinary bladder contains abundant urine with granular to fibrillar yellowish clots

T/F For diagnosis, medical history is important

True

How would you diagnose Salmonella?

Request Salmonella culture

What are the different ways you can do a Salmonella cultures/ ID? (6)

•Direct streak onto selective agar

•Enrichment broths

•Biochemical confirmation

•Serological confirmation

•Antibiotic susceptibility

•Serotyping

How would you serotype Salmonella?

First using the Salmonella O Poly Antiserum to narrow the focus subset of serogroups.

Then taking antisera from each subset of serogroups, each major O antigen will be tested for.

Once a serogroup has been determined such as the O:9 or D serogroup, all additional antigens will be tested for with specific O, H, and Vi antisera

How would you treat Salmonella?

Fluid and electrolyte replacement (Supportive Care)

T/F •\Gastroenteritis is typically self-limiting

True

T/F Antimicrobial use controversial?

True

What are the reasons why Antimicrobials are controversial?

•Many isolates are multidrug-resistant.

•Some strains are not susceptible to antimicrobials labeled for use with septicemia, such as in calves.

•Extra label administration of these drugs and withholding periods for meat in food consumption animals.

•Some animals treated with antimicrobials are more likely to become latent carriers

What are the THREE ways to prevent Salmonella?

Preventing Introduction to a Herd

Limiting Transmission (Biosecurity)

Education