16 Campylobacter and Helicobacter Flashcards
The genus campylobacter: Gram -/+? Aerobe? rod? Oxidase?
Campylobacter genus: Gram negative microaerophile slender spiral shaped Oxidase +
Where do you find campylobacter mainly?
GI tract of birds
Non-human animals
T/F Campylobacter is a thermophile?
true (thrives at temps greater than 50 degrees C)
Are campylobacter mobile?
Yes. Motile via polar flagella
What organisms causes the most common form of acute infectious diarrhea in developed countries?
Campylobacter Jejuni
T/F Campylobacter causes more infections than salmonella and shigella combined?
true
Which species of campylobacter causes the most human diseases?
Campylobacter Jejuni
How do you usually acquire C. Jejuni?
1) Undercooked poultry (It grows in their guts)
2) unpasteurized dairy products
T/F C. Jejuni if left untreated usually results in septicemia?
False.
This is opposite. Salmonella usually causes septicemia if left untreated but C. Jejuni almost never does.
What causes Guillain Barre syndrome?
An autoimmune disease that attacks the nervous system. Antigenic mimickry with C. Jejuni. The cross reactivity of o antigens on Campylobacter and myelin proteins.
What is the main host for Campylobacter Coli?
Pigs and livestock (virtually the same infection pattern as C. Jejuni)
what is the main host for Campylobacter upsaliensis?
Dogs and cats (virtually the same infection pattern as C. Jejuni)
What is the reservoir for C fetus and how does this affect pregnant women?
Cattle reservoir.
Causes miscarriage in pregnant women.
T/F campylobacter gastroenteritis is often associated with heavy vomiting?
False. This is the exception.
If you see bloody diarrhea with a campylobacter infection what does this mean?
That there has been local invasion into the jejunum, ileum, and colon.
T/F observation of PMN’s in a simple stain of feces is consistent with campylobacter gastroenteritis?
True. (this tells us its not viral or toxin mediated diarrhea)
T/F Campylobacter gastroenteritis and Salmonella gastroenteritis are indistinguishable on clinical evidence alone?
True
How many bacteria are required to cause disease in a campylobacter infection?
Only 100-1000 organisms
T/F Campylobacter survives within phagocytic cells to cause gastroenteritis?
False. These organism do not survive within phagocytic cells at all.
What within the body rapidly kills Campylobacter?
Complement
Antibodies
How do you confirm a diagnosis of Campylobacter infection?
Confirmed by isolation in the stool
C. Fetalis has a special protein called S protein that works as a _________?
Capsule that prevents C3b binding to the bacteria.
The bacteria that have this are more virulent
What is the most important thing to do for the treatment of someone with campylobacter gastroenteritis?
replace fluids and electrolytes
Which antibiotics are the best choice for treatment of campylobacter infections in immunocompromized and those with the campylobacter fetalis infections?
Erythromycin and Azithromycin
H. Pylori is considered: Gram? Rod? aerobic? fermenter?
Gram -
curved rods or spiral shaped
micoraerophile
non fermenting
How is it thought that H. pylori penetrates the wall of the stomach so efficiently?
They are very strong swimmers with a tuft of 4-7 polar flagella. This allows them to burrow in evading the stomach acid.
T/F H. pylori is catalase +?
True.
Catalase, oxidase, and urease +
H. Pylori gets some of its genetic info from a cag pathogenicity island. What does this encode?
CAG protein that induces inflammation.
cytotoxin associated gene A
What is the only bacteria that can colonize the stomach and cause chronic infections ranging from sub clinical to severe ulcer formation?
H. Pylori
Why is it difficult to grow H. pylori in culture?
It has very few genes and relies on its host.
T/F H. pylori affects half of americans by age 60 and is the most common chronic bacterial infection in humans?
true
What causes B gastritis?
H. pylori causes 100% of B gastritis (inflammation of pyloris)
H. Pylori causes what percent of gastric and duodenal ulcers?
85% of gastric
95% of duodenal
What are some other reasons for ulcer formation within the GI tract?
NSAIDS
Autoimmune disease
H. Pylori increases your risk for which specific types of cancer?
Gastric adenocarcinoma and B cell lymphoma
How does H. pylori not get killed by the stomach acid?
It hydrolyzes the urea to NH4 and CO2 using urease to cause a small neutral zone around itself until it is able to burrow in the gastric wall enough to avoid the low Ph.
How does H. pylori attach to epithelial cells in the stomach?
BAbA protein and other adhesins
How does H. pylori cause ulcers?
1) bacteria release toxins which leads to a lot of inflammation.
2) PMN’s and B and T cells migrate to area and begin killing not only bacteria but also the mucous membrane of the stomach. This may occur because of molecular mimicry between H. pylori and gastric mucosa.
3) without this mucous membrane in place for protection, an ulceration forms.
What is the CLO test?
a rapid urease test checking for H. pylori
T/F H. pylori antigens can be detected in the stool?
true
T/F antibodies against H. pylori can be detected to indicate current or past infections?
true
What is the simple principal behind the urea breath test that checks for H. pylori?
1) Patient ingests C13 or C14 labeled urea
2) If H. pylori is present= urea is hydrolyzed
3) The labeled CO2 is measured on exhalation
What is the best method for detecting H. pylori?
The urea breath test using radiactive carbon
How do you treat H. pylori?
1) PPI
2) Bismuth (It has some antibacterial activity and helps with inflammed gastric mucosa)
3) two or three antibiotics
