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).
Vibrio Vullnificus virulence factors (6)
Pathogenesis:
-Hemolysins
-Metalloproteases break down basement membrane to invade blood stream
-Mucinase
-DNAse
-capsule (K antigen)
-gram (-) = LPS = endotoxin
Which Vibirio specie is the most reported in the U.S?
V.Parahemolyticus
The most reported Vibrio species in the U.S. Major cause of seafood-borne illness in Asia (most common in Japan) Cases in the Pacific, gulf coast and Northeast Transmitted by consumption of undercooked or raw shellfish
Especially oysters
Which bacteria is the major cause of seafood-burned illness in Asia?
V.Parahemolyticus
The most reported Vibrio species in the U.S. Major cause of seafood-borne illness in Asia (most common in Japan) Cases in the Pacific, gulf coast and Northeast Transmitted by consumption of undercooked or raw shellfish
Especially oysters
Vibrio Parahemolyticus Virulence factor
-B-hemolysins
=forming pores in RBCs and intestinal cells (induces chloride ion secrete ion = watery diarrhea)
-other factors
=inhibits phagocytosis
=Disrupts interaction between cell membrane and actin cytoskeleton
Which bacteria is isolated from oral cavity, especially in the gingival sulcus?
WOLINELLA
Wolinella succinogenes is the main species
Gram (-)
Curved rod (like vibrio)
Polar flagella (like vibrio & Campylobacter)
Which bacteria is a possible periodontal pathogen: isolated from periodontal disease and can induce alveolar bone loss in experimental animals
WOLINELLA
Gram (-)
Curved rod (like vibrio)
Polar flagella (like vibrio & Campylobacter)
Isolated from the oral cavity, especially the gingival sulcus
Wolinella succinogenes is the main species
Selenomonas
-gram -/+
-shape
-flagella?
-found in?
-gram -
-curved rod
-tufts of flagella
-found in gingival crevice
Which bacteria is a late colonizer of the plaque biofilms?
Selenomonas Flueggei
Which bacteria is associated with chronic periodontitis and
Necrotizing ulcerative gingivitis and periodontitis?
Selenomonas
-tufts of flagella
-gram (-) curved rod
-anaerobe
Spirochetes
-gram -/+
-shape
-flagella
-neither- cell wall similar to gram (-): stains poorly w/ gram stain
-motile by endoflagellum/axial filament
NO TOXIN PRODUCTION
They belong to the phylum Spirochaetes and are known for their ability to move in a corkscrew-like fashion due to the presence of endoflagella (also called axial filaments) located between the outer membrane and the cell wall
Genera of spirochetes
-Borrelia
-Leptospira
-Treponema
Which bacteria contains a motility factor that allows migration w/n gingival crevicular fluid and penetration in the gingival connective tissue?
Oral Treponemas
Oral Treponema species are a group of spirochetes that are commonly found in the human oral cavity and play a significant role in periodontal disease. Characterized by their spiral-shaped morphology, motility via endoflagella, and their ability to survive in anaerobic or microaerophilic environments.
Treponema denticola
T. denticola is a key member of the “red complex” of bacteria, which is strongly associated with chronic periodontitis.
More proteolytic and degrades collagen and dentin
Oral Treponemas are considered late/early colonizers of the oral cavity?
Late colonizers
Interact with Fusobacterium nucleatum (the big, long one in the middle), Porphyromonas and other bacteria Part of the fusospirochetal complex.
Which bacteria is extremely difficult to culture on an agar plate and therefore not possible to identify this bacteria with classic culture. Microscopy is often used to visualize this bacterium
Treponemas
Gram-stained smear of deep gingival plaque from diseases lesions
Bacteria that has antibiotic sensitivity to Pencillin and Metronidazole
Treponemas
