Bacteriology- Vibrio and non fermenters

Question 1

Halophillic vibrio need ____ percent salt to grow. examples include ____

Answer 1

7-10 % salt
V. parahemolyticus
V. vulnificus
V. alginolyticus

Question 2

Non halophillic vibrio examples

Answer 2

V. cholerae
V. mimicus

Question 3

Which biotype causes more severe cholera?

Answer 3

Classical: More severe diarrhea, higher mortality.
El Tor: Milder disease, but more asymptomatic carriers.

Question 4

What is the VP test result for each biotype?

Answer 4

Classical: Negative.
El Tor: Positive.

Basically everything classical is negative/ susceptible. El tor is positive/ resistant

Question 5

Organisms that act by increasing cAMP

Answer 5

Cholera
Anthrax
Pertussis
ETEC (labile)

Question 6

Transport media of V. cholerae

Answer 6

Cary Blair medium/ VR media

Question 7

Culture media for V. cholerae

Answer 7

TCBS agar– Bromothymol blue is the indicator

Question 8

Appearance of V. cholerae in microscopy

Answer 8

Fish in stream appearance

Question 9

Darting/ shooting star motility is seen in

Answer 9

V. cholerae
Campylobacter

Question 10

Biochemical tests of V. cholerae

Answer 10

CCOINSS
Cholera red reaction + (nitrosoindole compound formed)
Catalase +
Oxidase +
Indole test +
Nitrate reduction +
Sucrose lysis +
String test +

Question 11

String test positive is seen in

Answer 11

Vibrio
Klebsiella
Giardia lamblia

Question 12

Oxidase positive seen in

Answer 12

PVNCH
Pseudomonas
Vibrio cholerae
Neisseria
Campylobacter
Helicobacter

Question 13

What is the main source of Vibrio parahaemolyticus infection?

Answer 13

Raw or undercooked seafood

Question 14

What are the clinical manifestations of V. parahemolyticus?

Answer 14

Acute gastroenteritis (watery diarrhea, abdominal cramps, fever).
Wound infections (from seawater exposure).

Question 15

What is the key virulence factor of V. parahemolyticus?

Answer 15

Kanagawa hemolysin (causes β-hemolysis on high salt (2-4%) blood agar)
If hemolysis +– pathogenic

Question 16

How is Vibrio vulnificus transmitted?

Answer 16

Raw seafood (oysters) → Sepsis in immunocompromised individuals.
Wound exposure to seawater → Necrotizing fasciitis.

Question 17

What are the high-risk groups for severe Vibrio vulnificus infection?

Answer 17

Liver disease patients (e.g., cirrhosis, hemochromatosis), diabetics.

Question 18

What is the hallmark feature of Vibrio vulnificus infection?

Answer 18

Rapidly progressive soft tissue infection with hemorrhagic bullae.

Question 19

What type of infections does Vibrio alginolyticus cause?

Answer 19

Wound infections (most common).
Ear infections (otitis externa in swimmers and divers).
Conjunctivitis

Question 20

What is a distinguishing feature of Vibrio alginolyticus?

Answer 20

It is the most halophilic among Vibrio species, requiring high salt concentration for growth (10%)

Question 21

Non fermenters of sugar

Answer 21

Pseudomonas
Burkholderia mallei
B. pseudomallei
Acinetobacter baumannii

Question 22

Pigments of pseudomonas

Answer 22

Pyocyanin- blue green (diffusible)
Pyoverdin- green yellow
Pyorubin- red
Pyomelanin- black

Question 23

What are the major virulence factors of Pseudomonas aeruginosa?

Answer 23

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.

Question 24

What are the major infections caused by Pseudomonas aeruginosa?

Answer 24

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

Question 25

Enhancement media for Pseudomonas

Answer 25

King’s A and B media for Pyocyanine and Pyoverdine respectively

Question 26

Selective media for pseudomonas

Answer 26

Cetrimide agar (enhances pyocyanin production)

Question 27

On nutrient agar, Pseudomonas shows

Answer 27

Blue green pigment

Question 28

Characteristic appearance of pseudomonas colonies

Answer 28

Iridescence

Question 29

WHO priority organisms causing Nosocomial infections having MDR

Answer 29

Mnemonic: ESKAPE
Enterococcus faecium
S. aureus
K. pneumoniae
Acinetobacter baumanni
Pseudomonas aeruginosa
Enterobacter species

Question 30

Burkholderia cepacia is associated with ____ disease

Answer 30

Cystic fibrosis
C/c granulomatous disease

Question 31

Burkholderia mallei
1. Seen in
2. Strauss reaction
3. Clinical features

Answer 31

1. Animals (glander’s disease)
2. Inoculation into guinea pig– testicular swelling
3. Skin ulcers, pneumonia, scrotal swelling

Question 32

Burkholderia pseudomallei
1. Causes disease named which is also called
2. The organism is aka
3. Culture media used
4. Microscopic appearance
5. Treatment

Answer 32

1. Melioidosis; Vietnamese time bomb (bec it can reactivate anytime)
2. Whitmore bacillus
3. ASA/ Ashdown agar
4. Safety pin appearance
5. Carbapenem, Imipenem

It is asso with bioterrorism

Question 33

Swarming motility seen in

Answer 33

B cereus
Proteus
C. septicum

Question 34

Tumbling motility seen in

Answer 34

Listeria

Question 35

Spinning motility

Answer 35

Fusobacterium gyrans

Question 36

Cork screw motility seen in

Answer 36

Treponema

Question 37

Falling leaf motility

Answer 37

Giardia

Question 38

Twitching motility

Answer 38

Eikenella corrodens

Question 39

Differential motility seen in

Answer 39

Yersinia enterocolitica
Listeria

Question 40

Jerky motility

Answer 40

Trichomonas

Question 41

Gliding motility

Answer 41

Mycoplasma, Entamoeba

Question 42

Lashing motility

Answer 42

Saprophytic spirochetes