Enterobacteriaceae (without Salmonella) Flashcards
In general, what do Enterobacteriaceae look like on gram stain?
gram-negative, medium-sized rods
How do ALL Enterobacteriaceae react to an oxidase test?
negative
All Enterobacteriaceae ferment what?
glucose
The H antigen is associated with what?
flagella
The K antigen is associated with what?
capsules
The F antigen is associated with what?
fimbria
The O antigen is associated with what?
O-Ag side chains
The P antigen is associated with what?
pili
What disease is associated with the O157:H7 antigen in E. coli?
hemolytic/uremic syndrome
What disease is associated with the O78 antigen in E. coli?
respiratory disease and septicemia in chickens
What disease is associated with the F18 antigen of E. coli?
edema disease in swine
Enterobacteriaceae is part of the ________ ________ of ____ of most mammals and birds.
normal flora; intestines
Generally, how is Enterobacteriacea transmited?
fecal-oral, contamination of wounds, via a respiratory route, or via vectors
Generally, what is Enterobacteriaceae resistant to?
freezing
Generally, what is Enterobacteriaceae killed by?
pasteurization, disinfectants, and drying
Does Escerichia coli produce gas?
yes
Does Escerichia coli ferment lactose?
yes; most of the time
Is Escerichia coli indole positive or negative?
positive
How does Escerichia coli react to lysine?
it decarboxylates it
What do Escerichia coli colonies look like?
medium sized, heaped or raised, with smooth edges - some are hemolytic and can be mucoid
What diseases are hemolytic strains of Escerichia coli associated with?
pyelonephritis in humans and post-weaning diarrhea in pigs
What is alpha hemolysin in Escerichia coli?
an RTX toxin
What disease is alpha hemolysin in Escerichia coli associated with?
human extraintestinal infections
What secretion system does Alpha hemolysin associated with Escerichia coli use?
type 1 secretion - it inserts monomeric subunits into cell membranse and forms a pore
What is beta hemolysin in Escerichia coli?
the same as alpha hemolysin except that some of the C-terminal amino acids have been cleaved
What is the term used for E. coli infections in domestic animals?
colibacillosis
What diseases can the term colibacillosis denote?
enteritis, septicemia, or both
What disease does colibacilliosis cause in swine?
scours (neonatal diarrhea)
How does scours present in swine?
it occurs to piglets usually 1-4 days old and they have perfuse, pale, yellow diarrhea with dehydration that quickly leads to death
Where is E. coli found in piglets that have swine colibacillosis?
in the small intestine
What fimbriae are associated with swine colibacillosis?
F-4 (arguably the most important), F5, F6, and F41
What can the fimbriae do if they attach to the small intestine in swine colibacillosis?
they may invade and cause septicemia and they may express entereotoxins
What does ETEC stand for?
Enterotoxigenic E. coli
What major toxins are associateed with swine colibacillosis?
Labile toxin and two stable toxins (STa and STb)
What is the structure of the labile toxin?
it is an A-B structure toxin where 1 A subunit is surrounded by B subunits
What produces E. coli’s labile toxin (i.e. what species)?
porcine, human,, and some calf ETEC
What is E. coli’s labile toxin neutralized by?
anti-toxic antibody and antibody to cholera toxin
How does E. coli’s liable toxin work?
it ADP-ribosylates a Gs alpha protein leading to activation of adenylate cyclase which increases cAMP, causes the excretion of Cl and inhibitionof Na absorption leading to excessive fluid loss
What is the function of E. coli’s STa toxin?
it stimulates guanylate cyclase which catalyzes the intracellular production of cyclic GMP which leads to loss of water and electrolytes from the intestinal mucosa
STa toxin is the major effector of what?
diarrhea
What is the function of E. coli’s STb toxin?
it binds to sulfatide on cell surfaces and is internalized where it triggers a cascade of events resulting in opening of ion channels through which ions and water are lost
Which stable toxin of E. coli is longer acting?
STb
How is swine colibacillosis treated?
some antibiotics help but it is better to prevent it by stimulating colostral antibody production with immunization of dams and management to ensure colostral intake
How do you immunize for swine colibacillosis?
with killed bacterins or live-oral products administered through water supply to sows
What E. coli strains are associated with post-weaning diarrhea in pigs?
strains that produce STb toxin - these strains are hemolytic
What environmental factors are associated with post-weaning diarrhea in pigs?
change in feeding and stress
What is edema disease in swine caused by?
F18ac- and F18ab-bearing strains of STEC (shiga toxin) E. coli
When do receptors for F18ac and F18ab-bearing strains develop?
not until 15-20 days of age
Where on the body is edema disease from swine colibacillosis usually seen?
the eyelids, facial area, stomach, and other places
Aside from edema, what other symptoms are associated with edema disease?
muscular spasms and tremors
What is the majority of the disease syndrome of edema disease due to?
elaboration of Stx2e
What does shiga toxin do?
it inhibits protein synthesis in the vascular endothelium which leads to edema and necrosis
What disease is associated with cattle colibacillosis?
white scours in calves
What toxins and fimbria are associated with cattle colibacillosis?
Sta toxin and F5
What diseases are associated with lamb colibacillosis?
enteric and septicemic disease similar to calves
What fimbriae are found in isolates of E. coli in lambs?
the F-5 fimbriae
How do E. coli infect poultry?
dust carrying the E. coli and then entering the respiratory tract
What diseases does E. coli cause in poultry?
airsacculitis, acute septicemia, pericarditis, fibrinopurulent serositis, and granulomatous lesions in the wall of the intestine
When pet birds get infected with E. coli, what diseases are caused?
enteritis and septicemia
What ‘other’ diseases are associated with E. coli?
diarrheas in other animals/humans, umbilical infections leading to septicemia and arthritis, urinary tract infections, metritis, pyometra, bacteremia in puppies, and mastitis in cows
What is used to protect against endotoxemia in dairy cattle?
J5 and Endovac immunizing products
What diseases does E. coli cause in humans?
urinary tract infections, neonatal meningitis, pulomary infections, wound infections, and diarrhea
What is STEC?
Shiga toxin producing e. coli
What are the two groups of Shiga toxins?
Stx1 and Stx2
What disease processes are STEC organisms associated with?
diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome
What are the common species of Shigella?
Shigella dysenteriae, flexneri, sonnei, and boydii
What sepcies of Shigella is the most pathogenic?
Shigella dysenteriae
In the United States, what are the most common isolates of Shigella?
Shigella sonnei and flexneri
What species is Shigella pathogenic to?
primates and humans
In lesser developed companies, what disease processes are associated with Shigella?
diarrhea and mortality
How is Shigella transmitted?
fecal-oral
Does Shigella ferment lactose?
no
Is Shigella motile or non-motile?
non-motile
Is Shigella H2S positive or negative?
negative
What disease is associated with Shigella?
bacillary dysentery
What is bacillary dysentery characterized by?
severe abdominal cramps and frequent passage of a low-volume, bloody stool containing mucus
What lesions are associated with Shigella?
acute inflammation and ulceration of the epithelium of the large intestine
What results from perforation of ulcers caused by Shigella?
peritonitis and death
What chemical factors are involved with the pathogenesis of Shigella?
O-antigen, hemolysin, shiga toxins, and enterotoxins
What are the Klebsiella species?
pneumoniae, subspecies ozaenae, and oxytoca
What is the most common Klebsiella species?
Klebsiella pneumoniae
What do colonies of Klebsiella look like?
they are capsulated, large and mucoid
Klebsiella may possess _____ with either _____-sensitive or ______-resistant adhesions.
fibriae; mannose; mannose
Do Klebsiella produce toxins?
yes but they are not common and do not play a major role in production of most diseases
Is Klebsiella motile?
no
Is Klebsiella VP positive or negative?
positive
What type of parasite is Klebsiella?
opportunist
What type of infections is Klebsiella associated with in humans?
nosocomial
What disease processes does Klebsiella cause in humans?
pneumonia and septicemia
What specifically does Klebsiella pneumoniae cause in humans?
meningitis, bacteremia, and wound infections
What does Klebsiella cause in cattle?
mastitis
What other infections can Klebsiella cause in animals?
urinary tract infections and reproductive tract infections
What is Klebsiella always resistant to?
ampicillin
What are the most common Enterobacter species?
cloacae, aerogenes, pantoea (previously Enterobacter) and agglomerans
Is Enterobacter VP positive or negative?
positive
Is Enterobacter ONPG positive or negative?
positive
Is Enterobacter motile?
yes
In what species is Enterobacter an enteric pathogen in?
psittacine birds
What does Enterobacter cause in cattle?
mastitis
Generally, what disease does Enterobacter cause in animals and humans?
urinary tract infections
What is the cause of Sterwart’s wilt of corn?
Pantoea stewartii
Do antibiotics work to treat Enterobacter?
this species can be highly resistant, but 2nd and 3rd generation cephalosporins may be active
What does Erwinia carotovora cause?
rot in carrots and potatoes
What does Erwinia amylovora cause?
fire blight
Pantoea agglomerans produces _____ that inhibit the growth of ______ _____.
antibiotics; Erwinia amylovora
What is the best known Serratia species?
Serratia marcescens
What do Serratia marcescens colonies look like?
distinctive pink color
What does Serratia marcescens cause in dogs?
proliferative osteomyelitis
What does Serratia marcescens cause in cattle?
mastitits
What are the two most common Proteus species?
mirabilis and vulgaris
What diagnostic tests differentiate Proteus mirabilis and from Proteus vulgaris?
Indole (mirabilis is negative, vulgaris is positive) and ODC (mirabilis is postive and vulgaris is negative)
Is the Proteus genus urease positive or negative?
positive
Is the Proteus genus lactose negative or positive?
negative
Is the Proteus genus H2S positive or negative?
positive
What is a characteristic factor of Proteus?
swarming
What is the natural habitat of Proteus?
in the intestinal tract in low numbers
Which species of Proteus is most responsible for infections?
mirabilis
What diseases does Proteus cause?
UTIs, otitis externa in dogs, secondary invaders in wounds, peritonitis, and may be associated with diarrhea in the young
What is the common species of Morganella?
Morganella morganii
What genus did Morganella used to be a part of?
Proteus
Is Morganella urease positive or negative?
positive
What is the natural habitat of Morganella?
in the environment and in feces - it is also commonly found in the mouth of snakes
What disease processes does Morganella cause in humans?
neonatal meningitis, fasciitis, arthritis, skin infections, bacteremia, and CNS infections
How does Morganella morganii cause scromboid poisoning?
it produces histidine decarboxylase which reacts with free histidine in the muscle tissues of some fish which results in high levels of histamine - the high levels of histamine causes this
How many species are in the Providencia genus?
five
What are the most common Providencia species?
stuartii, rettgeri, and alcalifaciens
What is the most common isolate of Providencia in humans?
Providencia stuartii
What disease processes does Providencia cause?
UTIs, wound infections, and septicemia
What animals does Edwardsiella infect?
cold-blooded animals
What temperature is Edwardsiella cultured at?
room temperature
What disease does Edwardsiella ictaluri cause and in what species?
enteric septicemia in cat fish (ESC)
What disease is associated with Hafnia alvei?
extraintestinal disease in humans
Where is Citrobacter found?
in soil, water, sewage, and food
What do organisms in the Citrobacter genus cause?
urinary tract infections, neonatal meningitis, and septicemia in humans
What genus is Citrobacter similar to biochemically?
Salmonella
What is the morphology of Yersinia?
small coccobacills
What is Yersinia pestis the cause of?
the bubonic plague
In what temperature is Yersinia pestis best grown at?
27-29 degrees C
Yersinia pestis exists in endemic areas in rodent populations as _______ ______.
sylvatic plague
How is Yersinia pestis transmitted?
via fleas feeding on infected animals
What specific flea is a good vector for Yersinia pestis transmission?
the oriental rat flea
When transmitted to humans, what does Yersinia pestis infect first and what is this termed?
the lymph nodes - they become very swollen and this is referred to as the bubonic form
Clinically what is the plague characterized by?
rapid rise in temperature, regional buboes, and a characteristic conjunctivitis
What is an extremely fatal form of the plague that is spread via droplet?
the pneumonic form that is essentially 100% fatal
What is another extremely fatal form of the plague that is hard to diagnose because buboes take a while to develop?
the septicemic form of the plague
How is immunity to the plague acquired?
basically you need to be infected with it and survive or it is in your genetics
When do you need to treat for the plague?
very quickly - within 12-15 hours after the fever starts
What antimicrobial is useless against Yersinia pestis?
penicillin
What are the approved treatments for the plague?
Levofloxacin, tetracycline, chloramphenicol, and kanamycin
What disease does Yersinia psuedotuberculosis cause?
epizootics in all animal species
What lesions/disease processes are associated with Yersinia pseudotuberculosis in humans?
mesenteric lymphadenitis, diarrhea, and abdominal pain that mimics appendicitis
What species is Yersinia enterocolitica pathogenic to?
humans, monkeys, chinchillas, and hares
What disease does Yersinia enterocolitica cause?
acute mesenteric lymphadenitis and diarrhea in children
Yersinia enterocolitica is the cause for a lot of false ________ in humans.
appendectomies
What is disease caused by Yersinia pseudotuberculosis and enterocolitica reffered to?
yersinioses
How is yersinioses intitially transmitted?
through food
Where is yersinioses most often seen?
in rural areas
What diseases and lesions does yersinioses mimic when severe enough?
shigellosis, salmonellosis, and typhoid fever
