Bacteriology- Vibrio and non fermenters Flashcards
(42 cards)
Halophillic vibrio need ____ percent salt to grow. examples include ____
7-10 % salt
V. parahemolyticus
V. vulnificus
V. alginolyticus
Non halophillic vibrio examples
V. cholerae
V. mimicus
Which biotype causes more severe cholera?
Classical: More severe diarrhea, higher mortality.
El Tor: Milder disease, but more asymptomatic carriers.
What is the VP test result for each biotype?
Classical: Negative.
El Tor: Positive.
Basically everything classical is negative/ susceptible. El tor is positive/ resistant
Organisms that act by increasing cAMP
Cholera
Anthrax
Pertussis
ETEC (labile)
Transport media of V. cholerae
Cary Blair medium/ VR media
Culture media for V. cholerae
TCBS agar– Bromothymol blue is the indicator
Appearance of V. cholerae in microscopy
Fish in stream appearance
Darting/ shooting star motility is seen in
V. cholerae
Campylobacter
Biochemical tests of V. cholerae
CCOINSS
Cholera red reaction + (nitrosoindole compound formed)
Catalase +
Oxidase +
Indole test +
Nitrate reduction +
Sucrose lysis +
String test +
String test positive is seen in
Vibrio
Klebsiella
Giardia lamblia
Oxidase positive seen in
PVNCH
Pseudomonas
Vibrio cholerae
Neisseria
Campylobacter
Helicobacter
What is the main source of Vibrio parahaemolyticus infection?
Raw or undercooked seafood
What are the clinical manifestations of V. parahemolyticus?
Acute gastroenteritis (watery diarrhea, abdominal cramps, fever).
Wound infections (from seawater exposure).
What is the key virulence factor of V. parahemolyticus?
Kanagawa hemolysin (causes β-hemolysis on high salt (2-4%) blood agar)
If hemolysis +– pathogenic
How is Vibrio vulnificus transmitted?
Raw seafood (oysters) → Sepsis in immunocompromised individuals.
Wound exposure to seawater → Necrotizing fasciitis.
What are the high-risk groups for severe Vibrio vulnificus infection?
Liver disease patients (e.g., cirrhosis, hemochromatosis), diabetics.
What is the hallmark feature of Vibrio vulnificus infection?
Rapidly progressive soft tissue infection with hemorrhagic bullae.
What type of infections does Vibrio alginolyticus cause?
Wound infections (most common).
Ear infections (otitis externa in swimmers and divers).
Conjunctivitis
What is a distinguishing feature of Vibrio alginolyticus?
It is the most halophilic among Vibrio species, requiring high salt concentration for growth (10%)
Non fermenters of sugar
Pseudomonas
Burkholderia mallei
B. pseudomallei
Acinetobacter baumannii
Pigments of pseudomonas
Pyocyanin- blue green (diffusible)
Pyoverdin- green yellow
Pyorubin- red
Pyomelanin- black
What are the major virulence factors of Pseudomonas aeruginosa?
Exotoxin A → Inhibits EF-2 (like diphtheria toxin) → Cell death.
Pyocyanin & Pyoverdine → Generate reactive oxygen species, impair host immunity.
Alginate capsule → Forms biofilms, resistant to immune response & antibiotics.
Elastase & Proteases → Degrade host tissues.
What are the major infections caused by Pseudomonas aeruginosa?
Mnemonic: “PSEUDO”
Pneumonia (Ventilator-associated pneumonia).
Sepsis (esp. in immunocompromised patients).
External otitis (Swimmer’s ear, malignant otitis externa in diabetics).
UTI (esp. in catheterized patients).
Diabetic & burn wound infections.
Other Diseases:
Hot tub folliculitis (from contaminated water).
Ecthyma gangrenosum (black necrotic skin lesions in septicemia).
Corneal ulcers & keratitis (from contaminated contact lenses).
Green nail syndrome
