Gram Negative Bacteria A Flashcards
Heliobacter pylori
Gram Negative
Microaerophillic
Lophotrichous flagella
colonizes stomach and duodenum
spiral shape - burrows into mucous lining of the stomach
secretes urease that decreases pH of stomach
When we are born are we H. pylori positive or negative?
negative
70% of persons with gastric ulcers are ___?
Nearly all persons with duodenal ulcer are ___?
- H. Pylori positive
- colonized
How much of the population is infected with H. Pylori?
30%
1% develop duodenal ulcer
1/3 have peptic ulcer disease
Two treatment methods for H. pylori
- Clarithromycin based triple therapy (PPI, amoxil and metronidazole)
- Bismuth quadruple therapy (PPI, bismuth subsalicylate, tetracycline and metronidazole)
Which type of Yersinia causes the plague? Which doesn’t?
Does - Yersinia pestis
doesn’t - Yersinia enterocolitica
Y. enterocolitica characteristics
invasive pathogen that penetrates the gut lining
can enter the lymphatic system and the blood
not a gram staining bacteria
can grow in cold temperatures
motile at room temperature
safety pin appearance
How is Y. enterocolitica transmitted?
ingestion of contaminated foods
What does Y. enterocolitica cause?
Yersiniosis (severe intestinal inflammation)
release of enterotoxin –> severe pain similar to appendicitis
The three types of plagues
bubonic, pneumonic and septicemic
what does the bubonic plague cause?
swelling of the lymph nodes, skin blotches and delirium after a few days, can lead to death
How is Y. pestis transmitted?
through flea (xenopsylla cheopis) bites
What does the toxin of Y. pestis inhibit?
the electron transport chain function
Treatment for Y. pestis
streptomycin and gentamicin
The gold standard for diagnosis of H. pylori
endoscopy with biopsy; H. pylori IgG serology –> positive antibody screen (2nd test)
Yersiniosis
severe intestinal inflammation caused by Y. enterocolitica
Why is Y. enterocolitica easy to identify?
Because it grows in cold temperatures and is motile at room temperature
Treatment for Y. enterocolitica
ahminoglycosides, chloramphenicol or tetracycline
Bordetella pertussis characteristics
gram negative coccobacilli
strictly aerobic
whooping cough
how is B. pertussis transmitted?
via droplets spread by coughing, cannot survive outside of URT
whooping cough is most common in ages ___ when vaccination level is low. When vaccination level is high the age distribution is shifted to
1-5
adults and young infants without vaccination
The incubation period for Bordetella pertussis
1-3 weeks
Pertussis toxins inhibit
G protein coupling
Lymphocytosis
sensitization to histamine; excess number of lymphocytes (WBCs and B cells)
Pertussis toxins cause
lymphocytosis and activation of insulin secreting islet cells (hypoglycemia)
Catarrhal Phase
2-3 weeks after incubation, mild coughing and sneezing, highly infectious not very ill
Paroxysmal phase
cyanosis and vomiting, leukocytosis
Treatment for Bordetella Pertussis
Macrolides (erythromycins, clarithromycins)
Adults - Bactrim (TMP-SMX)
Drug of choice for Bordetella Pertussis
erythromycin
Bordetella pertussis toxins (6)
- pertussis toxin (lymphocytosis, hypoglycemia)
- dermonecrotic toxin (vasoconstriction and ischemic necrosis)
- filamentous hemagglutin ( attachment of bacteria to ciliated epithelial cells)
- tracheal cytotoxin (inhibits cilia movement and regeneration of damaged cells)
- adenylate cyclase toxin (decreased chemotaxis and phagocytosis of bacteria)
- agglutinogens (attachment to host cells)
