Gram Negative Rods 2 Flashcards
State the antigenic structure of salmonella ?
O antigen somatic o
H antigen flagellar
Vi antigen virulance capsular like
Serotype of salmonella paratyphi ?
Group A,B,C based on o antigen
Serotype of salmonella typhi ?
Group D
State the test of indole and ureas for salmonella ?
Negative
Triple sugar iron test TSI slant for salmonella typhi ?
Partial fermentation with H2s production
Intra cellular persistence in macrophage ?
Salmonella typhi by the presence of Vi antigen capsule
Feco-oral route after ingestion of contaminated food or drinks e.g. raw vegetables, fruits, raw shell fish and milk products. The primary site of infection is the small intestine
Enteric fever typhoid
Clinical manifestations of typhoid enteric fever start with ?
fever, headache, malaise,
tender abdomen, constipation.
Secondry bacterimia
Incubation period of salmonella typhi ?
1-2 weeks
tube agglutination test designed to
detect anti-salmonella antibodies titre in the
patient’s serum.
Widal test
Serologic diagnosis of enteric fever typhiod can be done with
Elisa , widal and immunoblot assay
intestinal Infection(enteritis) with no blood invasion caused
by
Salmonella typhimurium and Salmonella enteritidis.
Blood culture and serological tests is of no value (no blood invasion). In which case ?
Salmonella food poisoning
Gram negative bacilli, non-motile, non-capsulated. Causing bacillary
dysentery(bloody diarrhea).
Shigella
It is heat labile.
The toxin has enterotoxic, cytotoxic and neurotoxic effects:
o causes watery diarrhea.
o causes necrosis and ulceration of mucosa with formation of a
pseudomembrane.
o It is similar to EHEC E. coli verotoxin .
Shiga toxin (Shigella dysenteriae type I)
acid resistance which allows it to survive passage through the stomach to reach the intestine.
Bacillary dysentery shiglosis
The organisms grow on simple and enriched media, and may
produce concentric wavy “swarming” growth, due to their
high motility.
Proteus
Urease hydrolyzes the urea in urine to form ammonia, which raises the pH,
producing an alkaline urine.
Cause urinary tract infection
Proteus
Your patient is a 6-year-old boy with bloody diarrhea for the past 2 days accompanied by fever to 40°C and vomiting. He has a pet corn snake. Blood culture and stool culture from the boy and stool culture from the snake (taken very carefully!) revealed the same organism. The cultures grew a gram-negative rod that formed colorless colonies on EMB agar. Which one of the following bacteria is the most likely cause of this infection?
(A) Helicobacter pylori
(B) Proteus mirabilis
(C) Salmonella enterica
(D) Shigella dysenteriae
(E) Vibrio cholerae
Salmonella enterica
Your patient is a 25-year-old woman with pain on urination and cloudy urine but no fever or flank pain. She has not been hospi-talized. You think she probably has cystitis, an infection of the urinary bladder. A Gram stain of the urine reveals gram-negative rods. Culture of the urine on EMB agar shows colorless colonies, and a urease test was positive. Swarming motility was noted on the blood agar plate. Which one of the following bacteria is the most likely cause of this infection?
(A) Escherichia coli
(B) Helicobacter pylori
(C) Proteus mirabilis
(D) Pseudomonas aeruginosa
Proteus mirabilis
Medical physicians, working in a refugee camp in central Africa, are concerned with the number of young children presenting with high fever, bloody diarrhea, and dehydration. The crowded living conditions of the camp suggest person-to-person contact. laboratory studies are available. The suspected organism is nonmotile, Gram-negative bacilli
What is the causative organism
Shigellae
Medical physicians, working in a refugee camp in central Africa, are concerned with the number of young children presenting with high fever, bloody diarrhea, and dehydration. The crowded living conditions of the camp suggest person-to-person contact. laboratory studies are available. The suspected organism is nonmotile, Gram-negative bacilli
1- Describe the appearance of the microbial colonies on macConkeys medium.
Shigellea , pale yellow on maconcky agar
78-year-old hospitalized male with an indwelling catheter develops a new onset of fever. The urine sample has an alkaline pH. The bacterium isolated from the urine is a urease-producing, highly motile, Gram- negative bacillus. Giving the following appearance on MaCconkeys medium
1-Write the name of the organism
Proteus
78-year-old hospitalized male with an indwelling catheter develops a new onset of fever. The urine sample has an alkaline pH. The bacterium isolated from the urine is a urease-producing, highly motile, Gram- negative bacillus. Giving the following appearance on MaCconkeys medium
2-Is this organism lactose fermenter or non lactose fermenter
Non lactose
