Family Enterobacteriaceae general, E. Coli, Genus Shigella Flashcards
Name the antigens which are common features of all the Enterobacteriaceae family bacteria.
O-Antigen: O Ag side chains
H-Antigen: Flagella
K-Antigen: Capsule
F-Antigen: Fimbriae
P-Antigen: Pilus
Why is the family Enterobacteriaceae named this way?
Name is after the most common site where the bacteria are found
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?
Not found in rabbits, guinea pigs, and psittacine birds
Name the four possible modes of transmission of family Enterobacteriaceae bacteria.
Ingestion (fecal-oral)
Respiratory route
Vectors (fleas, ticks, rats, etc.)
Fomites even
Name the general morphology of Family Enterobacteriaceae bacteria including: its gram stain, oxidase results, and shape.
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
How resistant are Family Enterobacteriaceae bacteria to pasteurization, disinfectants, drying, and cold?
Pasteurization: Most are killed
Disinfectant: Most are readily killed
Drying: Not very resistant
Cold: Most survive
Treatment of a bacteria from the Family Enterobacteriaceae should include what prior to decision on antibiotic?
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
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?
Acid and gas from glucose Most ferment lactose Indole positive Decarboxylates lysine
List the toxins which are produced by Escherichia coli?
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
What is the commonly used name describing infections of Escherichia coli?
Colibacillosis
In pigs what age group is most likely effected?
Neonates (approximately 1-4 days old)
Identify a significant factor why Escherichia coli attach more readily on neonatal intestines
No flora normally found in the small intestine at birth
Upon invasion of Escherichia coli. What does the bacteria do?
After invasion it can cause septicemia. As well as, express enterotoxins –> a locall effect ETEC (enterotoxiogenic E. Coli)
What are the major toxins involved with the disease colibacillosis?
Labile toxin (LT)
Stable toxin (ST)
What is the differences between Labile toxin (LT) and Stable toxin (ST) toxins?
Labile toxin (LT) is heat labile and Stable toxin is heat stable
What is the mechanism of action of the Labile toxin (LT) on Escherichia coli
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
What pathogen toxin is “Traveler’s diarrhea” linked to?
The labile toxin (LT)
What are the two types of stable toxin (ST)? Why do these types not stimulate the immune system?
STa and STb Because they are too small to be immunogenic
- How does the Stable toxin a (STa) act?
- What age group of pigs are most-likely to be effected?
- 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.
- Neonatal diarrhea in pigs.
- How does the the Stable toxin b (STb) act?
- What age group of pigs are most-likely to be effected?
- 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.
- Post-weaned pigs
What are treatment options for Escherichia coli?
Antibiotic can be useful.
However, one generally tries to prevent with vaccination and management.
Has vaccination for Escherichia coli been shown to be effective?
Yes, vaccinations have led to marked decrease in morbidity and mortality.
What are the leading causes of Escherichia coli post-weaning diarrhea?
Change in feeding and stress
Explain Escherichia coli edema disease
A disease which effects healthy pigs primarily. Disease is caused by elaboration of Vasotoxin. Vasotoxin inhibits protein synthesis of endothelium and–> edema and necrosis
What organ is most susceptible in Escherichia coli edema disease in swine?
The brain This often leads to the neurological signs or found dead of pigs
- Cattle colibacillosis is generally caused by what toxin?
- What clinical signs result in this disease?
- The STa toxin
- White scours in calves
- Lamb colibacillosis is generally caused by what toxin?
- What clinical signs result in this disease?
- The STa toxin
- Septicemia, watery-mouth or fettle belly
- How are poultry generally infected by Escherichia coli?
- What clinical signs result in this disease?
- Dust containing fecal E. coli infect.
- Respiratory infection: Airsacculitis, acute septicemia, pericarditis, peritonitis, fibrinopurulent serositis and granulomatous lesions of the intestine
What is of primary concern when one is treating rabbits and guinea-pigs with antibiotics?
Knocking out large gram-positive bacteria enabling gram-negative takeover.
List three other diseases in animals associated with Escherichia coli
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)
In human’s Escherichia coli is the most common bacteria found in what disease?
Urinary tract infections
What is the immunity status for Escherichia coli?
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.
In immunizing a sow or cow for bacteria what type of bacterin has shown to be effective in protecting their offspring?
A fimbrial bacterin
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
Diarrhea
Hemorrhagic colitis
Hemolytic uremic syndrome (HUS)
