Lecture 14 Flashcards
What type of bacteria are Heliobacter pylori?
gram-
What are some characteristics of Heliobacter pylori?
helical-rod shape, motile 6-8 polar flagella
What year and by whom was Heliobacter pylori identified by?
1983 | Australian scientists
What were Heliobacter pylori previously known as and why?
Camplyobacter pylori because it was thought to resemble Camplyobacter species
What percentage of the world population do with Heliobacter pylori?
50%
What is the size of Heliobacter pylori compared to E.coli? (genome and physical size)
thin and long physically but smaller than E. coli | small genome
What is the reservoir for Heliobacter pylori?
human GI microbiota
Why is the stomach not a common environment for bacteria?
due to low pH (pH 2) = very acidic environment = very few survive
What bacteria learned in class causes cancer? (list all)
ONLY H. pylori
Which type of secretion system do Heliobacter pylori use?
type IV secretion system
Why was Heliobacter pylori a hot topic in research during the 90s?
H. pylori are common in the human population (in the GI microbiota) that is able to cause cancer
Are most people infected with Heliobacter pylori symptomatic or asymptomatic? Which condition may they also develop?
asymptomatic and may have chronic gastritis
What percentage of people infected with Heliobacter pylori will develop the disease but not cancer? What is a main tell-tale symptom?
10% – gastric or duodenal ulcer
What percentage of people infected with Heliobacter pylori will develop a cancer?
less than 1%
What are the 3 cancers that a Heliobacter pylori infection can manifest into?
adenocarcinoma, gastric cancer, gastric MALT lymphoma
What is atrophic gastritis?
well-established factor for adenocarcinoma
What do ulcers indicate?
an opening in the epithelium surrounding the stomach
How are ulcers created?
bacteria carries out a mechanism using urease to destroy epithelium cells of stomach lining
What are the common symptoms of gastric ulcers?
epigastric pain, burping, vomit, bleed, anorexia
What is epigastric pain?
pain due to empty stomach
How many new cases/yr in the US of gastric ulcers?
500K to 850K
What is the rate that a disease develops due to an infection from Heliobacter pylori?
slow, can take years
How long does it take for a patient infected with Heliobacter pylori to develop superficial/chronic gastritis?
several weeks to years
Where in the world is Heliobacter pylori most common/prevalent in? (3)
Africa, Asia, South America
What are the 2 modes of transmission of Heliobacter pylori?
oral-oral adn fecal-oral
What are the 5 virulence factors of Heliobacter pylori?
urease, adhesins, exotoxins CagA and VacA, flagella
What is urease and how does Heliobacter pylori use it?
enzyme breaks down urea into NH3 and CO2; does this in the stomach and makes stomach acid more neutral so it can survive
What is the VacA toxin?
transporter protein acting as a vacuolating cytotoxin
What does VacA toxin cause?
immune modulation, vacuolation, damage, apoptosis, permeability
What is the CagA toxin?
Secreted by the type 4 secretion system; linked to initiation of carcinogenesis but not proven
What does the CagA toxin cause?
disrupts cellular junctions and changes cellular polarity
What is mucinase?
enzyme degrades mucous
What are the invasive method(s) to diagnose for Heliobacter pylori infection?
mucosal gastric biopsy (taking tissue sample from stomach)
What are the non-invasive methods to diagnose for Heliobacter pylori?
blood sample, stool, breath sample
How effective and reliable are the diagnostic tests?
very high = 95% effeciency
What are 4 tests to diagnose for Heliobacter pylori?
serological (antigens), PCR, culture, urease test
Can we eradicate Heliobacter pylori from human bodies?
No because the pathogen will come back via transmission AND can cause unnecessary antibiotic resistance = create a superbug
What is the treatment involved for Heliobacter pylori infections?
combination of multiple antibiotics
What kind of bacteria are spirochetes?
different from gram+/– ; has outermembrane and periplasm; fastidious grows at 35ºC = slow growers
What is unique about spirochetes?
periplasmic flagella
What disease does Borrelia cause?
Lyme disease (zoonotic)
What are three species of Borrelia discussed?
B. burgdorferi | B. garinii | B. afzelli
What is periplasmic flagella?
flagella that is loacted in the periplasm
What does the genome of B. burgdorferi consist of?
small linear chormosome (<1 Mbp) and 22 linear/circular plasmids
Wht are spirochete-causing diseases difficult to treat?
complex infections with multiple stages
What is the leading vector-borne bacterial disease of humans in the world?
Lyme disease
When was Lyme disease first described? And where?
1975, Lyme Conneticut
As Lyme disease is a multisystem illness, what organ systems does it affect?
skin, nervous system, heart, joints
What vector does Borrelia reside in for transmission?
deer tick
What are the target mammalian hosts of Borrelia?
white-footed mouse, rates, squirrels, humans, etc.
What is another common bacterial disease that causes multi-stage disease affecting multisystems?
syphillus
Where in the US is Lyme disease most common?
North east USA
Where in the world is Lyme disease most common?
northern parts of the world
What explains for the location of Lyme disease prevalence nationwide and worldwide?
Borellia vector likes northern temperate and cold climates not tropical
How many cases in the US per year does Lyme disease happen?
30K
How many stages does Lyme disease have?
3
How many days does it take to begin seeing the early symptoms (stage 1) of Lyme disease?
3-30 days`
What are common early symptoms of Lyme disease?
swollen lymph nodes, muscle/joint aches, fever, chills, fatigue, EM rash (occasionally)
What is Erythema migrans?
expanding inflammatory skin rash, “bull’s eye” appearance at site of tick bite, rarely itchy/painful
What percent of people with Lyme disease develop an erythema migrans rash?
70-80%
What are the late signs/symptoms of Lyme disease?
heart problems, neurological issues, arthritis, short-term memory loss
How much you remove a tick properly?
Grab by head
What are 2 prevention methods developed/used?
behavioral = right clothing and awareness of nature | vaccine (OspA) but discontinued
What seasons pose the highest risk of infected tick bites happening?
late spring, beginning summer, can still get infected in fall too
What is stage 1 of the pathogenesis of Lyme disease?
localized infection with mild-flue-like symptoms
What is stage 2 of the pathogenesis of Lyme disease?
disseminated infection, transient blood-borne phase, colonization diverse tissues
What is stage 3 of the pathogenesis of Lyme disease?
late stage infection: arthritid, Lyme encephalopathy
What are the 2 virulence factors of Borrelia?
outermembrane proteins (OspA, OspC) (protective antigens) , peptidoglycan as an endotoxin
Where (in which animal) are the virulence factors of Borrelia mostly expressed?
inside the vector (tick), not human host
What are the 4 diagnostic tests used to detect for infection due to Borrelia?
clinical diagnosis, culture from infected sites, PCR-based assay, serological assays (late stages)
What is the treatent against Lyme disease?
Doxy, Amoxy, Cephalo (3rd gen)
