Vibrio, Plesiomonas , HACEK Flashcards
What family do non-enteric gastrointestinal pathogens belong to?
Vibrionaceae
Are members of Vibrionaceae part of the indigenous human microbiota?
No
What type of motility do Vibrio species exhibit?
Rapid darting or shooting motility
Where are Vibrio species commonly found?
Brackish water, marine water, salt water, and recreational facilities like pools
What are the modes of acquisition for Vibrio infections?
Consumption of raw or undercooked seafood, skin trauma due to contact with shellfish, ingestion of contaminated water
List some diseases associated with Vibrio species.
- Cholera
- Wound infection
- Septicemia
- Necrotizing fasciitis
What is the oxidase result for Vibrio species?
Positive
Which Vibrio species are exceptions to being halophilic?
V. cholerae and V. mimicus
What is the antigenic structure of Vibrio species?
O, H, K antigen
Which serogroups are associated with V. cholerae?
- V. cholerae O1
- V. cholerae non-O1
- V. cholerae O139
What is characteristic of the stool in cholera?
Rice water stool
What is the result of the string test for Vibrio species?
Most species are positive
What is the Kanagawa phenomenon associated with?
Vibrio parahaemolyticus
What does Vibrio mimicus commonly cause?
Gastroenteritis and ear infections associated with marine environment
What is the clinical significance of Vibrio vulnificus?
Septicemia and wound infections involving marine environment
What type of infections does Aeromonas hydrophilia commonly cause?
Water-related infections
What is the typical appearance of colonies for Chromobacterium violaceum?
Black or very dark purple colonies
What are the common causes of nosocomial infections?
- Pseudomonas aeruginosa
- Acinetobacter baumannii
- Stenotrophomonas maltophilia
What is the characteristic odor of Pseudomonas aeruginosa?
Sweet or grape-like odor
What is the significance of Burkholderia mallei?
Causes glanders, a transmissible disease from horses to humans
Which test differentiates Vibrio from Aeromonas and Plesiomonas?
String test
What is the optimum temperature for Campylobacter jejuni growth?
42-43°C
What is the main virulence factor of Helicobacter pylori?
Rapid urease production
What condition can be triggered by Campylobacter jejuni infection?
Guillain-Barré Syndrome (GBS)
What does the O-F test measure?
CHO oxidation and fermentation
What color change indicates acid production in the O-F test?
Yellow
What does a positive result in the vibrostic test indicate?
Susceptibility
What is the primary association of Haemophilus species?
Sepsis, neonatal meningitis
Haemophilus species are known to cause serious infections, particularly in vulnerable populations like neonates.
What are the growth factor requirements for Haemophilus species?
X factor (Hemin/Hematin) and V factor (NAD)
These factors are essential for the growth of Haemophilus species, which are obligate parasites.
Which Haemophilus species is the main cause of meningitis in children under 5 years old?
H. influenzae
Particularly serotype B is the most frequently encountered in infections.
True or False: Haemophilus ducreyi is associated with soft chancre.
True
H. ducreyi is known to cause a painful ulceration in the genital area.
What are the preferred incubation conditions for most Haemophilus species?
5% to 10% CO2 at 35°C for 24 to 72 hours
Specific conditions are required for optimal growth of Haemophilus species.
What is the characteristic morphology of H. ducreyi under microscopic examination?
Small, gram (-) coccobacilli to long filaments
They may appear as ‘school of fish’ or ‘railroad tracks’ from genital lesions.
Fill in the blank: The organism responsible for Whooping Cough is ______.
[B. pertussis]
B. pertussis is known for causing whooping cough and is identified through specific culture methods.
What is the culture medium used for Bordetella species?
Bordet-Gengou and Regan Lowe media
These media are enriched and selective for Bordetella growth.
What is the disease associated with Francisella tularensis?
Tularemia
Tularemia is primarily a zoonotic disease transmitted from rodents, especially rabbits.
Identify the primary transmission route of Brucella species to humans.
Ingestion of contaminated animal products
Farmers can also acquire infections through direct animal contact.
What is a common characteristic of the HACEK group of bacteria?
Associated with subacute bacterial endocarditis
These organisms are normal biota of the oral cavity and can lead to serious infections.
Which species is known as the agent of Granuloma inguinale?
Calymmabacterium granulomatis
This organism is encapsulated and pleomorphic, often observed within mononuclear cells.
What is the defining feature of Pasteurella multocida?
Causes wound infections following contact with domestic animals
Commonly associated with cat and dog bites.
What type of motility is exhibited by Capnocytophaga?
Gliding motility
Capnocytophaga species are known for their unique gliding movement.
What is the primary specimen type for Legionella culture?
Bronchial washing, expectorated sputum
Legionella species are often difficult to detect directly through Gram staining.
List the three stages of Whooping Cough.
- Catarrhal: General flulike symptoms
- Paroxysmal: Repetitive coughing episodes
- Convalescent: Recovery phase
Each stage presents distinct clinical features.
True or False: H. aegypticus is associated with purulent conjunctivitis.
True
H. aegypticus is also known to cause Brazilian purpuric fever.
What is the significance of the Neufeld Reaction in laboratory identification?
Tests for X and V factor requirement and hemolytic patterns
It helps differentiate among Haemophilus species based on their growth factor needs.
What is the ideal culture medium for Brucella species?
Castañeda medium (Biphasic medium)
This medium supports the growth of Brucella through its liquid and solid phases.
