14: Curved Bacteria Flashcards
Helicobacter pylori
-gram +/-
-shape
-colonization
-clinical manifestations
(H. Pylori)
Gram-negative spiral-shaped bacterium that primarily colonizes the stomach lining (stomach mucosa) and is associated with various gastrointestinal conditions, including chronic gastritis, peptic ulcers, and even gastric cancer.
It is highly adapted to survive the harsh, acidic environment of the stomach
Helicobacter pylori pathogenesis
colonizes the stomach lining (stomach mucosa)
H. pylori can survive in the acidic environment of the stomach due to its ability to produce urease, an enzyme that breaks down urea into ammonia and carbon dioxide.
Ammonia neutralizes stomach acid, creating a more favorable microenvironment around the bacterium.
The bacterium uses its flagella to penetrate the mucus layer that coats the stomach lining, allowing it to reach and colonize the epithelial cells beneath.
Campylobacter
-gram +/-
-shape
-flagella
-transmission
Campylobacter is a genus of Gram-negative, spiral-shaped bacteria
Polar flagella
Typically acquired through consumption of contaminated food or water, especially undercooked poultry.
What bacteria is the leading cause of bacterial-related diarrhea in the U.S.?
Campylobacter are among the most common causes of bacterial gastroenteritis worldwide.
The most common species responsible for human infections are Campylobacter jejuni
Campylobacter pathogenesis
Once ingested, Campylobacter passes through the stomach and colonizes the ileum of small intestine and may infect jejunum and colon. The bacteria use their flagella to move through the intestinal mucus (attachment) and invasion into the epithelial cells lining the intestines.
Invasion of intestinal cells triggers an inflammatory response. Infection induces the release of cytokines and the recruitment of immune cells, which leads to inflammation and further epithelial damage.
The bacteria also produce toxins that contribute to the development of diarrhea and tissue damage:
Cytolethal distending toxin (CDT):This toxin disrupts the cell cycle, leading to cell death and damage to the intestinal lining.
Campylobacter clinical manifestations and complications
Also state incubation period
After a mean incubation period of 3 days. The symptoms generally begin 2 days after exposure
-Diarrhea: Ranges from watery to bloody diarrhea, often the most common symptom.
-Abdominal cramps: Severe, crampy abdominal pain is a hallmark symptom (can mimic appendicitis)
Complications
-Guillain-Barré syndrome (GBS): One of the more serious complications associated with Campylobacter infection. It is an autoimmune disorder where the body’s immune system attacks peripheral nerves, leading to muscle weakness and, in severe cases, paralysis. C. jejuni is a known trigger for GBS in some individuals.
-bacteremia
-Hemolytic Uremic Syndrome
-reactive arthritis
Campylobacter Diagnosis
Stool culture on CAMPY-agar
(Looks red)
Microaerophilic environment (10% oxygen and 10% carbon dioxide) at 42°C
Campylobacter species require low levels of oxygen for growth. They thrive in a microaerophilic environment, typically with 5% oxygen, 10% carbon dioxide.
The optimal temperature for Campylobacter is 42°C, which mimics the body temperature of birds (the primary reservoir of Campylobacter). This temperature is selective as it inhibits the growth of most other bacteria.
CAMPY-agar, also known as Campylobacter agar or is a specialized growth medium used for the selective isolation of Campylobacter species, particularly Campylobacter jejuni from stool samples.
The selective nature of CAMPY-agar is due to the inclusion of antibiotics, which suppress the growth of competing intestinal bacteria
CAMPY-agar
CAMPY-agar, also known as Campylobacter agar or is a specialized growth medium used for the selective isolation of Campylobacter species, particularly Campylobacter jejuni from stool samples.
-The selective nature of CAMPY-agar is due to the inclusion of antibiotics, which suppress the growth of competing intestinal bacteria
-Microaerophilic environment (10% oxygen and 10% carbon dioxide) at 42°C
Campylobacter species require low levels of oxygen for growth. They thrive in a microaerophilic environment, typically with 5% oxygen, 10% carbon dioxide.
The optimal temperature for Campylobacter is 42°C, which mimics the body temperature of birds (the primary reservoir of Campylobacter). This temperature is selective as it inhibits the growth of most other bacteria.
Campylobacter treatment
Most Campylobacter infections are self-limiting and resolve without the need for antibiotics. The primary treatment involves rehydration and electrolyte replacement, especially in cases of severe diarrhea.
Antibiotics for those who are immunocompromised or those with persistent diarrhea >1 week
Erythromycin or ciprofloxacin
Oral Campylobacter Species
Several Campylobacter species have been identified as part of the oral microbiome or are associated with oral infections. These oral Campylobacter species are typically present in the mouth, especially in individuals with poor oral hygiene or periodontal disease.
C.rectus - Pathogenic bacteria (b/c cytotoxic production), isolated from periodontal diseases, Stimulates human gingival fibroblasts to produce proinflammatory cytokines contributing to the destruction of periodontal tissue.
C.concisus -healthy subgingival sites, shallow periodontal pockets
C.gracilis
Which gram (-) bacteria is frequently associated with periodontal disease and is considered a pathogenic bacterium in the context of oral health.
Campylobacter Rectus
Isolated from periodontal disease!!!
PATHOGENIC BACTERIA = Produces cytotoxin!!
Stimulates human gingival fibroblasts to produce a strong inflammatory response, contributing to the destruction of periodontal tissue.
Which gram (-) bacteria is part of the normal oral flora in many healthy individuals but has been found at higher levels in people with periodontal disease and other oral infections.
Campylobacter Concisus
Isolated in higher proportions from shallow periodontal pockets and healthy subgingival sites
Vibrio
-gram +/-
-shape
-flagella?
-commonly found in
Gram (-)
Curved rod
Polar flagella (similar to campylobacter)
Commonly found in marine and brackish water Many species are halophilic (salt-loving) and are associated with water and seafood.
What are the most clinically significant species of Vibrio
Vibrio vulnificus: causes severe wound infections and septicemia
Vibrio parahaemolyticus: causes gastroenteritis
Vibrio cholerae: causes cholera
Which bacteria is the leading cause of shellfish-ass deaths in the U.S.?
VIBRIO
V.vulnificus: exposure to contaminated seawater or consumption of contaminated seafood (especially raw oysters).
