ENTEROBACTERIACIAE - SALMONELLA INFECTION to Flashcards
One of the most common forms of food poisoning.
Gastroenteritis
Gastroenteritis is commonly caused by
S. enterica subsp. Enterica that comes from animals
The Salmonella serotype Typhimurium outbreak in the U.S. in 2009 came from __
contaminated peanut butter crackers.
Gastroenteritis sources of infection
Poultry products, milk, and handling of pets.
Gastroenteritis mode of dessimenation
Contaminated kitchen utensils
symptoms of gastroenteritis
Nausea, vomiting, fever and chills, watery diarrhea, and abdominal pain.
Febrile disease that develops from eating contaminated food prepared by infected individuals or carriers and direct transmission through fomites is also possible
Enteric fever ( Typhoid fever)
Enteric fever ( Typhoid fever) source of infection
Human carriers, contaminated food, and water
Enteric fever causes of outbreaks
Improper sewage disposal, poor sanitation, and lack of clean water source.
enteric fever symptoms
Malaise, anorexia, myalgia, and severe frontal headache
enteric fever complications
Necrosis in the gallbladder ( necrotizing cholecystitis) and Peyer’s patches
the hallmark of enteric fever infection
Appearance of “rose spots” during the second week of fever
The site of long term carriage for enteric fever
gallbladder
Occurs with or without extraintestinal infection that is caused by non-typhoidal Salmonella species.
Characterized by prolonged fever and intermittent bacteremia.
Bacteremia
Bacteremia causative agents
Salmonella serotype Typhimurium, Salmonella serotype Paratyphi, and Salmonella serotype Choleraesius.
The carriers of Salmonella excrete the organisms along with their feces and thus cause ___
“ accidental” contamination of food and water.
salmonella carriers can be treated by ___ if the gallbladder infection is not evident.
antimicrobial therapy
Isolation of Salmonella from culture plates is significant and specific for
diagnosis of thypoid fever
Specimens for Salmonella Identification
Blood – first week of infection
Stool – second to third week of infection
Urine – third week of infection
serological test for typhoid fever and detects for antibodies against the specific O and H antigens of S. typhi
Widal’s test-
Closely related to Escherichia.
Not member of the indigenous GI microbiota
Non-motile, intracellular pathogens that multiply within the cells of the intestinal epithelium
Shigella
disease of shigella and most species can cause bacillary dysentery
shigellosis
shigella reservoir
humans
shigella Modes of transmission
Flies, fingers, food, and feces ( four F’s) and water from infected persons (fecal-oral route)
shigella species
S.dysenteriae, S. flexneri, S. boydii and S. sonnei
shigella most virulent specie
S. dysenteriae
one of the causes of gay bowel syndrome
S. flexneri
shigella serogroups
A (S.dysenteriae), B (S.flexneri), C ( S. boydii), and D ( S. sonnei)
shigella antigenic structure
Somatic O
shigella culture
MAC – clear, fragile, and colorless (NLF)
SSA – colorless, without black centers
shigella IMViC reaction
v + - -
shigella TSIA reaction
K/A, (-) gas, (-) H2S
Shigella vs. E.coli
Shigella - NLF, Indole(-), non-motile
E. coli - LF, Indole(+), motile
Biochemical Characteristics of Shigella species:
- All species do not produce gas from glucose except for S. flexneri
- All species are mannitol fermenters except for S. dysenteriae.
- All species do not decarboxylate lysine
- All species do not decarboxylase ornithine, except for S. sonnei
- S. sonnei is a late lactose fermenter and has a positive reaction with the ONPG (O-nitrophenyl-beta-D-galactopyranoside)
All shigella species do not produce gas from glucose except for
S. flexneri
All shigella species are mannitol fermenters except for
S. dysenteriae
All shigella species do not decarboxylate lysine
YES THEY DO NOT HAHAHAH
All shigella species do not decarboxylase ornithine, except for
S. sonnei
shigella specie that is a late lactose fermenter and has a positive reaction with the ONPG (O-nitrophenyl-beta-D-galactopyranoside)
S. sonnei
Shigella dysenteriae is also known as
Shiga bacillus
Most virulent of the species and causes bacillary dysentery
Shigella dysenteriae (Shiga bacillus)
Shigella dysenteriae virulent factor
Shiga toxin
Shigella dysenteriae is urease
negative
Shigella dysenteriae IMViC reaction
v + - -
Shigella dysenteriae TSIA reaction
K/A, (-) gas, (-) H2S
Infection is self-limiting, and usually characterized by fever and watery diarrhea ( stool without blood)
Has one serotype as opposed to the other species which have several serotypes.
Shigella sonnei (Sonne Duval bacillus)
causes Gay bowel syndrome
Shigella flexneri (Strong’s bacillus)
known also as Boyd’s bacillus
Shigella boydii
Shigella species are sensitive to ____
and aside from stool specimens, _____ can also be used for isolation.
pH changes ; rectal swabs
- Infection that is commonly caused by S. dysenteriae type 1
- Acute inflammatory colitis and bloody diarrhea ( blood, mucus, and WBC’s in the stool).
Highly communicable because of low infective dose that is required to produce the disease ( < 200 bacilli)
Bacillary Dysentery
In young children, rectal prolapse occurs due to the ___
excessive straining.
bacillary desentery source of infection
human carriers
bacillary desentery mode of transmission
Person to person contact, fecal-oral route, 4F’s, and contaminated water from infected persons
bacillary desentery symptoms
Fever, chills, abdominal cramps, painful bowel movement.
bacillary dysentery complications
Ileus (obstruction of intestine), seizure and haemolytic-uremic syndrome.
Also known as ‘Plague bacillus”
Class A bioterrorism agent
Not part of GIT microbiota and non-motile enterobacterium
Only enterobacterium that is transmitted to human through the bite of an infected flea.
Causative agent of Plague (black death)
Reservoir are the rats.
non-motile.
Yersinia pestis
Yersinia pestis can be isolated in _____ and grows best at ____ deg. cent
culture media ; 25 to 30 degree centigrade
yersinia pestis vector
Xenopsylla cheopis (Oriental rat flea)
Yersinia pestis virulence factors
Endotoxin, coagulase, and fibrinolysin.
yersinia pestis microscopy
Short, plumprod with a bipolar body or a “ closed safety pin appearance”
yersinia pestis culture
MAC
BAP
BROTH
in this culture, yersinia pestis appears clear and colorless (NLF)
MAC
in this culture, yersinia pestis is pinpoint at 24 hours and “Fried Egg” or “Hammered copper” apperance in older cultures
BAP
in this culture, yersinia pestis has “stalactite-shaped” pattern
Broth
yesinia pestis IMViC reaction
– + - -
yersinia pestis TSIA reaction
K/A, (-) gas, (-) H2S
Disease of the rodents that is caused by Yersinia pestis and is transmitted to humans through the flea bites.
Humans may acquire by ingestion of contaminated animal tissues and inhalation of contaminated airborne droplets.
Once inside the human body, tha bacteria multiply in the blood and lymph.
plague
3 forms of plague
Bubonic
Pulmonary/Pneumonic
Septicemic
results from the bite of an infected flea. Associated with high fever and painful inflammatory swelling of the axilla and groin; bacteria infiltrate the lymph nodes.
Bubonic plague
Acquired by close contact with infected individuals. Occurs secondarily to bubonic plague.
Pulmonary/pneumonic plague
This form of plague is a result of plague bacteria entering the bloodstream.Tissue bleeding and death may cause the dying tissues to appear black.
Septicemic plague
Most commonly isolated species of Yersinia
Causative agent of enterocolitis or waterborne gastroenteritis.
Isolated from contaminated packed RBC units, thus considered as a blood transfusion hazard.
Has the ability to survive in cold temperatures.
Yersinia enterocolitica
Yersinia enterocolitica is motile in SIM at
22 deg.cent.but not at 35 deg.cent.
Yersinia enterocolitica modes of acquisition
Ingestion of undercooked food and dairy products and handling of pets.
Yersinia enterocolitica reservoir
swines, dogs, cats, rabbits and cows.
Yersinia enterocolitica related infections
Appendicitis like syndrome, arthritis, and erythema nodosum.
Yersinia enterocolitica selective medium
Cefsulodin-irgasan-novobiocin agar
Yersinia enterocolitica microscopy
Coccobacilli with bipolar bodies.
Yersinia enterocolitica culture
MAC - clear and colorless
CIN
Yersinia enterocolitica in CIN culture
exhibits a “bulls-eye” appearance or dark red or burgundy centers with transparent borders at 48 hours of incubation.
Yersinia enterocolitica IMViC reaction
v + - -
Yersinia enterocolitica TSIA reaction
K/A, (-) gas, (-) H2S
Pathogens of the rodents, particularly guinea pigs.
Yersinia pseudotuberculosis
Yersinia pseudotuberculosis is motile in SIM at ___ deg,cent but not at ___ deg
18 - 25 deg.cent but not at 35 deg
Yersinia pseudotuberculosis mode of acquisition
Direct contact with infected animals or their feces, and ingestion of contaminated food and water.
Yersinia pseudotuberculosis reservoir
farm and domestic animals, usually birds
Yersinia pseudotuberculosis culture
MAC - clear and colorless
Yersinia pseudotuberculosis biochemical test
Urease (+) and rhamnose fermentation
Yersinia pseudotuberculosis TSIA reaction
K/A, (-) gas, (-) H2S
- Only species in the genus Plesiomonas
- Not part of human microbiota
-Causes secretory diarrhea
Plesiomonas shigelloides
Cross-agglutinates with Shigella, hence called _____
shigelloides
Only oxidase-positive member of the enterobacteriaceae.
Motility is attributed to its polar flagella
Associated with HIV-positive individuals with inflammatory bowel disease.
Plesiomonas shigelloides
Plesiomonas shigelloides mode of acquisition
Ingestion of undercooked seafoods, and contaminated water.
Plesiomonas shigelloides Vibriostatic test O/129
Sensitive
Plesiomonas shigelloides culture
MAC
BAP
Inositol-brilliant green-bile salt agar
HEA
TCBS
Media with NaCl
Plesiomonas shigelloides on mac appears
clear and colorless and some strains will not grow on MAC
Plesiomonas shigelloides on BAP appears
shiny, opaque and non-hemolytic
Plesiomonas shigelloides on inositol-brilliant green-bile salt agar exhbits
exhibit white or green to pink color for other enterics.
Plesiomonas shigelloides on HEA exhibit
growth
Plesiomonas shigelloides on TCBS culture
do not exhibit growth
Plesiomonas shigelloides on media with NaCl
do not exhibit growth
Plesiomonas shigelloides is positive on the ff.
oxidase
decarboxylase
inositol fermentation
Plesiomonas shigelloides TSIA reaction
K/A, (-) gas, (-) H2S
Plesiomonas shigelloides antigenic structure
O and H antigens
Species have been isolated from cold-blooded and warm blooded animals.
Edwardsiella
Edwardsiella specie that is human pathogen
E. tarda
Edwardsiella culture
MAC - clear and colorless
Edwardsiella is urease
negative
Edwardsiella is LDC test
positive
Edwardsiella IMViC reaction
+ + - -
Edwardsiella TSIA reaction
K/A, (+) gas, (+) H2S